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Thoughts on moisture problem inside insulators/and distributor caps :VIDEO
- Thread starter lowman
- Start date
Just clearcoat the insulator and dist.cap
Thats what i did 3 years ago and i have not had any problems with misfire after that.
Sent from my iPhone using Tapatalk
Thats what i did 3 years ago and i have not had any problems with misfire after that.
Sent from my iPhone using Tapatalk
What product did yo use to clearcoat? Something like this?
https://www.amazon.com/3M-Scotch-Insulating-Spray-12-Ounce/dp/B001CGX8ZK
Thanks for the video. I understand your porous-insulator-absorbing-oil-vapor-theory (PIAOVT) now.
May I ask two questions?
+ How cold does the garage in which you park get?
+ What weight motor oil do you use?
I have not experienced this problem, but, to be fair, I've only put 3,200 miles on my car as opposed to the 20,000 kilometers that you've accrued on yours. As well, in anticipation of avoiding this problem, I changed the caps/rotors/insulators to new aftermarket Bosch parts exactly 3,200 miles ago when I first took delivery of the car.
I wonder if motor oil weight as any affect on PIAOVT.
For what it is worth, my garage never gets colder than 55F and never gets hotter than 90F. Furthermore, I use 15W-50 weight motor oil year round.
May I ask two questions?
+ How cold does the garage in which you park get?
+ What weight motor oil do you use?
I have not experienced this problem, but, to be fair, I've only put 3,200 miles on my car as opposed to the 20,000 kilometers that you've accrued on yours. As well, in anticipation of avoiding this problem, I changed the caps/rotors/insulators to new aftermarket Bosch parts exactly 3,200 miles ago when I first took delivery of the car.
I wonder if motor oil weight as any affect on PIAOVT.
For what it is worth, my garage never gets colder than 55F and never gets hotter than 90F. Furthermore, I use 15W-50 weight motor oil year round.
thank you for tip.Im not going to do this(At least not for now)..as the original ones do not have any cleacoat on them...only the Bosch ones does.The insulators where now perfectly cleaned,and dried up.And i did heat them up for almost 24hours..to see if some moisture was collected inside the insulator..and there was NONE to be found.
So everything is just cleaned up proper,and the testing continues.Going to remove them in a couple of months ,to inspect and see how things are going
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hey mister
The room where the car is stored..gets down to around 35-39 degrees fahrenheit,and the workshop is around 59-68 degrees fahrenheit,, so there is quite a temperature difference..especially when it happens so "fast"(Going from cold to hot in a very short period of time) ..if you can put it that way..
The oil viscosity is 5w40 at the moment.
Like i said in the video..i have never experienced this issue myself...even though the circumstances/variables has been excactly the same througout the 2.5 years ive owned the car..so its definetly something that has "developed"over time.
Maybe oil weight can affect things..i havent thought about that....IF it is actually the oil seal getting worn ,and letting blow by oil vapor into the distro cap area...then i guess thicker oil can affect things..in a better way.IF the weight is heavier..the oil film will be thicker and seal just a tad better i reckon..
By the way-.---the insulators where perfectly cleaned..and tested for oil residue inside the insulators..by letting them sit in front of my heater oven...for 24 hours..and there where NO oil residue seaping out of the insulator.So now..they are clean,and dry..and so is the rest of the area where the distro caps sit-.so i can further check this in a couple of months to see how it developed
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I used this one https://megaflis.no/nordsjo-decomax-spray-bensinfast-klarlakk-400ml.html
It`s in Norwegian but it says it can withstand fuel.
I don`t know anything about the 3M product but try it and see if It works.
It`s in Norwegian but it says it can withstand fuel.
I don`t know anything about the 3M product but try it and see if It works.
Stefan, you mentioned timing in your video....is the timing affected when rotor brackets are reaplaced or removed?
Nice video btw, I personally believe it’s a combination of oil vapor residue coming from camshaft seals and/or very tiny water bubbles in the back and inside the insulators.
It can be one or both.
I personally saw the tiny water bubbles and felt them wiping them off in one of mine 500E’s.
That’s why they are called “insulators”.
What did you use to clean the insulators?
My old insulators after removal:
Nice video btw, I personally believe it’s a combination of oil vapor residue coming from camshaft seals and/or very tiny water bubbles in the back and inside the insulators.
It can be one or both.
I personally saw the tiny water bubbles and felt them wiping them off in one of mine 500E’s.
That’s why they are called “insulators”.
What did you use to clean the insulators?
My old insulators after removal:
Attachments
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hey mister
no the timing is not affected..but i was "Afraid" of the possibility screwing with the timing IF the fastener bolt for the rotor bracket was not coming loose..but it did come loose very easily.it was only fastened with a small amount of torque..so it was no problem at all loosening it...but make sure you have a torque wrench available when tightening that bolt.9 nm of torque
i used brake clean to clean the insulators..and cleaning them 2 or 3 times..to make sure they were perfectly clean and dry...and like mentioned before,,i also heated them up to make sure they did not have any moisture inside them
thank you for kind words by the way
no the timing is not affected..but i was "Afraid" of the possibility screwing with the timing IF the fastener bolt for the rotor bracket was not coming loose..but it did come loose very easily.it was only fastened with a small amount of torque..so it was no problem at all loosening it...but make sure you have a torque wrench available when tightening that bolt.9 nm of torque
i used brake clean to clean the insulators..and cleaning them 2 or 3 times..to make sure they were perfectly clean and dry...and like mentioned before,,i also heated them up to make sure they did not have any moisture inside them
thank you for kind words by the way
Stephan,
I can’t view the video at the moment but will ASAP! But the pic looks like an emulsion of oil and water caused by the blender action of the spinning rotors. If there is any oil in there I would be changing the shaft seals behind the rotors. That’s the only place that could possibly let oil seep into the area. At those low temps the seals tend to srink. I think new seals would at least eliminate the oil part of the problem.
Take Care
I can’t view the video at the moment but will ASAP! But the pic looks like an emulsion of oil and water caused by the blender action of the spinning rotors. If there is any oil in there I would be changing the shaft seals behind the rotors. That’s the only place that could possibly let oil seep into the area. At those low temps the seals tend to srink. I think new seals would at least eliminate the oil part of the problem.
Take Care
Hey mister .that is what I think also ��but for now ,it's just inspection and investigation work .will open it up once more closer to spring ��thanx ��
Maybe to just re-assure anyone who has suffered a misfire problem that they may not have to rush to have those camshafts seals renewed, could I add that it can also be caused simply by "genuine" (i.e. not oil-based) condensation in the "front" cap part of the distributor, and may not always emanate from oil "vapour" seeping past the camshaft seal, as described by Stefan.
I have in the past experienced a couple of misfire situations after using the car following a lengthy (i.e. 1 or 2 months winter) layup. I have always managed to "drive through" it, and after giving the car a really good run i.e. an hour or so, I find the problem does not repeat itself - as long of course, as the car is then used fairly regularly. On each occasion, as a precaution, we did inspect the caps and insulators and found them to be completely free of the oily/emulsion type of contamination described by Stefan.
Stephen
I have in the past experienced a couple of misfire situations after using the car following a lengthy (i.e. 1 or 2 months winter) layup. I have always managed to "drive through" it, and after giving the car a really good run i.e. an hour or so, I find the problem does not repeat itself - as long of course, as the car is then used fairly regularly. On each occasion, as a precaution, we did inspect the caps and insulators and found them to be completely free of the oily/emulsion type of contamination described by Stefan.
Stephen
These insulator failures or moisture problems are a very common occurrence on the forum. Each time one comes up it’s resolved by replacing them with new items. I’ve read posts where people are noting yellow fluid running out of the insulator disc itself.
There are 2 things happening here to my mind-
1: Plastic degradation. These parts are 26 odd years old now and subject to very hot temperatures and engine oil vapour / atmospheric moisture. The constant high heat then cold temperature changes will have taken their toll on the plastic discs after so many years & miles. I have had one fail on my 300E-24 on the past and on VERY close inspection I could see fine fissures / carbon tracks where the spark could make it’s way through the cap itself. This was viable because the parts were bright red – on Black ones like Lowmans any carbon tracking; if present will be much harder to identify.
2: Contamination from Engine Blow by. There will always be some degree of engine oil vapour & blow by gasses including fuel present in the distributor area. Usually there is a fine oily film on the back of the insulator discs. This will be having a long term impact on the plastic and could perhaps break it down. Which would be indicative of the fluid sometimes observed running out of the discs.
IMO the time spent cleaning these and re-installing would be better spent fitting new ones instead because of the reasons above and the age of the parts involved. We see countless times how installing new insulating discs does cure the problem. Cleaning the back of the discs will cure the problem on the short term but as that atmospheric moisture makes it’s way back in behind the discs – which it will – the problem will re-occur with ignition leakage through the failing insulator discs. If ANY fluid is observed coming from the discs themselves they are junk for sure. Their purpose is to insulate the grounded cylinder head(s) from ignition spark – moisture is the no.1 enemy of that function. My 500E has not suffered this problem yet but I will be pro-actively replacing those insulating discs and also the cam Oil Seals this year regardless.
There are 2 things happening here to my mind-
1: Plastic degradation. These parts are 26 odd years old now and subject to very hot temperatures and engine oil vapour / atmospheric moisture. The constant high heat then cold temperature changes will have taken their toll on the plastic discs after so many years & miles. I have had one fail on my 300E-24 on the past and on VERY close inspection I could see fine fissures / carbon tracks where the spark could make it’s way through the cap itself. This was viable because the parts were bright red – on Black ones like Lowmans any carbon tracking; if present will be much harder to identify.
2: Contamination from Engine Blow by. There will always be some degree of engine oil vapour & blow by gasses including fuel present in the distributor area. Usually there is a fine oily film on the back of the insulator discs. This will be having a long term impact on the plastic and could perhaps break it down. Which would be indicative of the fluid sometimes observed running out of the discs.
IMO the time spent cleaning these and re-installing would be better spent fitting new ones instead because of the reasons above and the age of the parts involved. We see countless times how installing new insulating discs does cure the problem. Cleaning the back of the discs will cure the problem on the short term but as that atmospheric moisture makes it’s way back in behind the discs – which it will – the problem will re-occur with ignition leakage through the failing insulator discs. If ANY fluid is observed coming from the discs themselves they are junk for sure. Their purpose is to insulate the grounded cylinder head(s) from ignition spark – moisture is the no.1 enemy of that function. My 500E has not suffered this problem yet but I will be pro-actively replacing those insulating discs and also the cam Oil Seals this year regardless.
OK so a real life circumstance for me. I had the issue last Christmas (2016) whereas the E500 was in the garage for 2 months prior. Ambient temps fluctuated from 70F to 28F. I changed out original insulators to new, and kept caps and rotors (save for new bolts that are 4mm). Now this week we had lows in the high teens, and on Saturday, I opened up the car to start it. It was now 72F and the car was very cold in the closed garage so the temp of the steel was most likely in the mid-40's while the air was in the mid low 70's. My car cover was wet - think of a can of beer on a hot day. The condensation build up on the can (in this case the sheet metal) was enough to saturate a paper towel. I started the car up without issue and let it idle for about 45 minutes.
The C126 which was outside was reviewed. The engine was also saturated in dew - almost like I hosed it down. It also started right up but the steam cleaning began as the engine heated up the water, turning it to vapor.
SO my point here is along the lines of what Stefan was saying, that the condensation due to ambient temps changes can create excess moisture. So in this basic experiment, my experience was cold steel forming condensation.... symptoms presented again this year of temp changes producing condensation but no misfire with new insulators. YMMV (no oil seal leakage either)
Admin edit: Bold font added to clarify post.
An after the fact additional statement: if you don't have records that these were changed from original, my experience says change it and forget it
The C126 which was outside was reviewed. The engine was also saturated in dew - almost like I hosed it down. It also started right up but the steam cleaning began as the engine heated up the water, turning it to vapor.
SO my point here is along the lines of what Stefan was saying, that the condensation due to ambient temps changes can create excess moisture. So in this basic experiment, my experience was cold steel forming condensation.... symptoms presented again this year of temp changes producing condensation but no misfire with new insulators. YMMV (no oil seal leakage either)
Admin edit: Bold font added to clarify post.
An after the fact additional statement: if you don't have records that these were changed from original, my experience says change it and forget it
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It may be coincidence, but the few black insulators I've encountered (made by Doduco) were generally in much better condition than the orange (Bosch) insulators. I've also seen some Bosch insulators turn that sickly yellow color as seen in Eno's post above, and I'm pretty sure they were not this color when new.
I'm having a hard time with the blowby theory. There should never be enough pressure inside the crankcase to push oil vapor out through the cam seals. However, a slight leak of liquid oil could theoretically get vaporized by the high voltages present in the distributor. Vehicles which show absolutely zero signs of oil leakage (not even light brown residue/varnish below the cam seals) that have fluid back of on the insulator would likely have a different source for the liquid. Another possibility is liquid oil leaking into this area from either the cam advance solenoid (very common leak) or the valve cover gasket.
Also of interest is the color of the liquid both on the insulators, and on the aluminum cover that the distributor caps bolt up to. Used engine oil is dark brown (some new engine oil is similar color). Pull out your oil dipstick and wipe it on a clean paper towel. Compare the color to what is shown in Eno's photos, which is typical (IMO) as to how the insulators and aluminum look... with a light colored, almost clear liquid.
If the insulators are old / original, it's cheap insurance to replace them (new Bosch insulators are under $50 USD each now), ESPECIALLY if new caps/rotors are being installed. Before installing, clean every trace of oil from the entire area to ensure it's bone dry. It would be interesting to remove the parts for inspection after a few thousand miles and see how they look.
reading posts here...it still baffles me ,that people are STILL talking about "replacing" the insulators to cure the problem. those of you that want to replace the insulators ...go ahead im not.I cant see HOW in the world they can cause a moisture problem..UNLESS they contain moisture.
With that said...in my case..they are perfectly fine..they do NOT contain ANY moisture in them at all,so replacing them is pretty much pointless(even though im a super fan of replacing parts that DOES NOT NEED replacingLaughs
It will be up to each and everyone to determine if THEIR insulator contains moisture INSIDE the material...and i also do point out EVERY part of this in the video....but i reckon not all people did not bother to watch the whole video,as i do understand it is quite alot of babble in there..
i also mention in the video, that the pure nature of temperatur changes DO result in a condensation situation.cold/hot air WILL result in condensation.
Like i also mentioned....is that putting on new insulators MAY help...but that is probably a temporary fix..as it is the nature of the job....which is putting on NEW parts,kinda fixes it temporary IF there is another cause to the problem causing you to replace an item.
So...if you have a blow by issue...the new insulators will do nothing to prevent future moisture build up
Another thing that Gixxr mentiones...is that the Bosch ones seem to be the ones "failing"...that is also one of my reasons for NOT replacing mine.Cause the ones in my car is Doduco ones..and does not have the coating on them.
But this is of course just my personal view.AND i do plan to remove the insulators once more in a couple of months..to re inspect the area
im not.I cant see HOW in the world they can cause a moisture problem..UNLESS they contain moisture.With that said...in my case..they are perfectly fine..they do NOT contain ANY moisture in them at all,so replacing them is pretty much pointless(even though im a super fan of replacing parts that DOES NOT NEED replacing
Laughs It will be up to each and everyone to determine if THEIR insulator contains moisture INSIDE the material...and i also do point out EVERY part of this in the video....but i reckon not all people did not bother to watch the whole video,as i do understand it is quite alot of babble in there..
i also mention in the video, that the pure nature of temperatur changes DO result in a condensation situation.cold/hot air WILL result in condensation.
Like i also mentioned....is that putting on new insulators MAY help...but that is probably a temporary fix..as it is the nature of the job....which is putting on NEW parts,kinda fixes it temporary IF there is another cause to the problem causing you to replace an item.
So...if you have a blow by issue...the new insulators will do nothing to prevent future moisture build up
Another thing that Gixxr mentiones...is that the Bosch ones seem to be the ones "failing"...that is also one of my reasons for NOT replacing mine.Cause the ones in my car is Doduco ones..and does not have the coating on them.
But this is of course just my personal view.AND i do plan to remove the insulators once more in a couple of months..to re inspect the area
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I'm having a hard time with the blowby theory. There should never be enough pressure inside the crankcase to push oil vapor out through the cam seals. However, a slight leak of liquid oil could theoretically get vaporized by the high voltages present in the distributor. Vehicles which show absolutely zero signs of oil leakage (not even light brown residue/varnish below the cam seals) that have fluid back of on the insulator would likely have a different source for the liquid. Another possibility is liquid oil leaking into this area from either the cam advance solenoid (very common leak) or the valve cover gasket.
you should watch the video(if you havent) ,dave..as the "leak" on my car is definetly NOT a LEAK...either from cam seal OR cam solenoid...it is 99.99 percent certain that it is vapour
I did watch the video. There is a discolored area below the seal, which is odd (screen shot attached). I understand you believe this is from oil vapor, but I still don't believe oil vapor is being pushed past the seal. If there was that much pressure in the crankcase, you'd also get oil vapor passing the front and rear crankshaft radial seals, and probably leaking from the PCV hoses & valve covers, and anything else open to crankcase pressure. As I mentioned above, it would make more sense if it were liquid oil leaking into that area, which is then vaporized by the high voltage. Maybe. I really don't know. We'll see how your Doduco insulators look when you check them again later on.you should watch the video(if you havent) ,dave..as the "leak" on my car is definetly NOT a LEAK...either from cam seal OR cam solenoid...it is 99.99 percent certain that it is vapour
Attachments
definetly looking forward to recheck the insulators.
and when it comes to "if there was blowby in the crankcase..you would also get the vapor passing on the crankseals and such....." Well...the crank seal ,rear front, does not live in an enclosed area like the insulators do...meaning..vapor would not have anywhere to "collect"...
The whole Area around the seal is "covered" in the same "vapor"...its not just in the lower area where you pointed the arrows..but obviously it is a tad more there..because of gravity...
anywhoooo...each to their owni was not trying to say "im right"...but i did try to enlighten the subject..and at a later stage be able to MAYBE show that replacing the insulators to cure a moisture issue may not be the solution..other than a short term one..as they pretty much do nothing to seal this area. the only option for them to be TOAST...are IF they are full of moisture...which will have to be determined by the owner of the example which DOES have a insulator that is full of moisture
and when it comes to "if there was blowby in the crankcase..you would also get the vapor passing on the crankseals and such....." Well...the crank seal ,rear front, does not live in an enclosed area like the insulators do...meaning..vapor would not have anywhere to "collect"...
The whole Area around the seal is "covered" in the same "vapor"...its not just in the lower area where you pointed the arrows..but obviously it is a tad more there..because of gravity...
anywhoooo...each to their own
i was not trying to say "im right"...but i did try to enlighten the subject..and at a later stage be able to MAYBE show that replacing the insulators to cure a moisture issue may not be the solution..other than a short term one..as they pretty much do nothing to seal this area. the only option for them to be TOAST...are IF they are full of moisture...which will have to be determined by the owner of the example which DOES have a insulator that is full of moisture
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Some additional pictures
Condition of the insulators when coming off the car.Right hand side(worst side)
Left hand side,
Doduco insulator
Condition of the aluminium on the backside of the insulator when insulator has first been removed.This is the right hand side,and the "worst" looking side,when it comes to moisture.You can clearly see here that the complete surface is "covered" with damp oil vapor,as it is also ABOVE the cam seal
Aluminium "housing" on the left hand side..the "best" looking one.
Dirty/wet insulator to the left....clean one to the right
Aluminium side,cleaned.Also carefully cleaned the sealing ring
finally,Both insulators and rotors cleaned.and ready to go back to where they belonginto the mighty NON misfiring beauty of a v8 German style
Condition of the insulators when coming off the car.Right hand side(worst side)
Left hand side,
Doduco insulator
Condition of the aluminium on the backside of the insulator when insulator has first been removed.This is the right hand side,and the "worst" looking side,when it comes to moisture.You can clearly see here that the complete surface is "covered" with damp oil vapor,as it is also ABOVE the cam seal
Aluminium "housing" on the left hand side..the "best" looking one.
Dirty/wet insulator to the left....clean one to the right
Aluminium side,cleaned.Also carefully cleaned the sealing ring
finally,Both insulators and rotors cleaned.and ready to go back to where they belong
into the mighty NON misfiring beauty of a v8 German style
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Im Schmutz..may i help you
They are clean..the stuff you see on the side ..are scuff marks from them seating onto the aluminium
Finally got round to taking the caps off mine this morning. It's been sat in the garage for three years now and I need to cure the hot misfire and get it registered.
I've had the dehumidifier going in the garage for four weeks now and the car has not been started since last August so you would not expect that much moisture inside the caps but it was damp in there. The contacts in each cap are corroded and there appears to be minute cracking in the plastic so I'll be ordering new caps and arms tomorrow. Does anyone have any idea if Bremi parts are as good as Bosch?
The insulators are original Merc items so likely never been changed at 280,000 kms. The orange seal on the right bank is broken and both are flattened so I'll be getting new O rings as the insulators are ok otherwise.
Main reason for replying is to throw this question into the ring... why are the insulators not O ring sealed on their back side against the head? I can only conclude that they are not sealed so that any condensation building up in the recess and back side of the insulator can drain out between the insulator and the head. It is quite obvious that there will be a natural build up of condensation inside the distributor due to the temp variations and zero ventilation.
It would seem that this design is inherently weak, most owners are having problems every 20-40,000 kms which is poor for a Merc and painful considering the price of replacement parts compared to more popular engines.
Once I've replaced the arms and caps and cleaned everything up I'll report back on the misfire issue.
Gareth
I've had the dehumidifier going in the garage for four weeks now and the car has not been started since last August so you would not expect that much moisture inside the caps but it was damp in there. The contacts in each cap are corroded and there appears to be minute cracking in the plastic so I'll be ordering new caps and arms tomorrow. Does anyone have any idea if Bremi parts are as good as Bosch?
The insulators are original Merc items so likely never been changed at 280,000 kms. The orange seal on the right bank is broken and both are flattened so I'll be getting new O rings as the insulators are ok otherwise.
Main reason for replying is to throw this question into the ring... why are the insulators not O ring sealed on their back side against the head? I can only conclude that they are not sealed so that any condensation building up in the recess and back side of the insulator can drain out between the insulator and the head. It is quite obvious that there will be a natural build up of condensation inside the distributor due to the temp variations and zero ventilation.
It would seem that this design is inherently weak, most owners are having problems every 20-40,000 kms which is poor for a Merc and painful considering the price of replacement parts compared to more popular engines.
Once I've replaced the arms and caps and cleaned everything up I'll report back on the misfire issue.
Gareth
hey mister
MY view on WHY they are not o ringed on the backside against the alu side...is like i mentioned in my video...the o ring is ONLY there to make sure that the insulator sits TIGHT between the distributor cap AND the aluminium .Cause the o ring seats against the edge of the distributor caps..where the ventilation grooves are...so they are certanly not there to SEAL.They are there only to provde a tight fit between the distributor cap and the seating point against the aluminium side.
AT LEAST ..that is my 2 cents..looking forward to your update....as i do look forward to my own update on this subject.Still a way to go though until that happens
thanx for commenting
That will ne nice once the final culprit to this wet distributor insulator is determined, as well as what a good solution is.
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I have Bremi spark plug wires, caps & rotors in my 500E. Bremi wires have been in car prior to my ownership. Bremi caps & rotors (replacing Bosch) have been in service since April 2016.
No issues.
Thanks guys,
Found Amazon to have good prices here in UK,
Can anyone confirm Bremi part numbers?
Cap 6018R, Arm 7027. £55 for the pair is cheaper than fleabay!
Lowman... Agree with your view, I wonder if there is room between the aluminium and the insulator for some anhydrous absorbent material?
Found Amazon to have good prices here in UK,
Can anyone confirm Bremi part numbers?
Cap 6018R, Arm 7027. £55 for the pair is cheaper than fleabay!
Lowman... Agree with your view, I wonder if there is room between the aluminium and the insulator for some anhydrous absorbent material?
hey mister
i did actually get a tip on my youtube video..this guy drilled a small hole in the bottom of the distributor cap...attached a hygroscopic filter to the end of the hose...go into the video..and check the comments...much easier than me describing what he did
but yes..it is a "good idea" in some way with the absorbant material...would be fun to try it out though.
But me personally..im gonna stick to my plan..and re check the distributor caps in a couple of months...cause the car is in storage now..and when i take it into the workshop...it would be the perfect time to check moisture build up.
thank you for suggestion..ill keep it in mind
copy / past from video comments:
Trausti Elliðason
Thank you for your videos.
Both my 400E and E500 were suffering from the problem of condensation inside the distributor caps which rendered the cars useless in worst cases.
I laid a 6mm. pipe (with an inline Air Filter) from the caps to the Air Cleaner. Easy, just drill four holes press the pipes in and voila, problem solved.
Thank you for your videos.
Both my 400E and E500 were suffering from the problem of condensation inside the distributor caps which rendered the cars useless in worst cases.
I laid a 6mm. pipe (with an inline Air Filter) from the caps to the Air Cleaner. Easy, just drill four holes press the pipes in and voila, problem solved.
Sounds like Trausti has the solution. I think I will try cleaning up the caps and arms and drilling them as described and see how the car runs on the old parts versus the new one's when they arrive. The thought of drilling brand new caps without a trial run is a bit daunting!
While I remember,the last time I started the car the rev counter died so that is another for the list!
While I remember,the last time I started the car the rev counter died so that is another for the list!
Sounds like Trausti has the solution. I think I will try cleaning up the caps and arms and drilling them as described and see how the car runs on the old parts versus the new one's when they arrive. The thought of drilling brand new caps without a trial run is a bit daunting!
While I remember,the last time I started the car the rev counter died so that is another for the list!
While I remember,the last time I started the car the rev counter died so that is another for the list!
Hello,
are the newer orange insulators any better? I have this black ones from year 1992 never changed. Recently I cleaned them but I stil have misfire when hot on idle. Strange thing is then when I restart engine missfire goes away for a few kilometers or minutes on idle.
are the newer orange insulators any better? I have this black ones from year 1992 never changed. Recently I cleaned them but I stil have misfire when hot on idle. Strange thing is then when I restart engine missfire goes away for a few kilometers or minutes on idle.
Did your black (Doduco) insuators have liquid on the back side, or were they dry?
How bad is the misfire at hot idle? The misfire being discussed related to the insulators is a severe misfire, where the engine barely runs, and is almost undriveable. An occasional hiccup at idle is more likely to be cured by increasing the spark plug gap from 0.8 to 1.0-1.1mm.
Thanks for a quick reply.
They had like a kind of dry oil on a back and I wipped it of with alcohol. Car has occasional misfire but after longer driving is permanent misfire like on one maybe two cylinders. I changed rotors and caps for original Bosch and is same.
Is it possible that fuel pressure can be the problem on idle? However pumps sounds great and fuel filter is new.
They had like a kind of dry oil on a back and I wipped it of with alcohol. Car has occasional misfire but after longer driving is permanent misfire like on one maybe two cylinders. I changed rotors and caps for original Bosch and is same.
Is it possible that fuel pressure can be the problem on idle? However pumps sounds great and fuel filter is new.
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Fuel pressure is almost certainly not the problem, although if you have a fuel pressure gauge it wouldn't hurt to check.
I know this doesn't help much but I had a brand-new Bosch cap defective out of the box, which caused a misfire when hot. Took me a very long time to diagnose as I thought the new cap should be fine. Replaced that cap and it cured the problem. Do you have spare caps / rotors to try swapping?
It will also help if you can narrow the problem to either left or right distributor. If you have SDS or other digital scanner, you can often determine the cylinders which are dropping out by viewing the live data (voltage for each cylinder).
I know this doesn't help much but I had a brand-new Bosch cap defective out of the box, which caused a misfire when hot. Took me a very long time to diagnose as I thought the new cap should be fine. Replaced that cap and it cured the problem. Do you have spare caps / rotors to try swapping?
It will also help if you can narrow the problem to either left or right distributor. If you have SDS or other digital scanner, you can often determine the cylinders which are dropping out by viewing the live data (voltage for each cylinder).
I hope you can understand all this text!
Translated with www.DeepL.com/Translator and me to correct some deepl's words!
Concerning the moisture in these caps, I have another theory that I am testing.
For the moment, it's positive.
First of all, as some of you, I changed my caps; the caps seals, the orange cups, and even the camshaft seals.
I still have more or less the same moisture problem.
--> caps full of moisture after 1015/min. of engine start-up.
My idea is that:
as it is always the same caps that tends to make moisture the passenger side one.
So the caps on the left when you look at the engine.
this head is in front of the fan.
And that this moisture problem occurs after the engine is hot.
the problem is more important in cold and humid weather
I think it is the condensation linked to the thermal choc (hot/cold) that causes this internal condensation.
In fact, the fan is blowing cold air on the ignition cap, while inside this cap, the air temp is hot, since the engine is hot.
This thermal choc would cause the moisture to bead from the moist air inside the caps.
As before, when we didn't have double glazing, when it was cold outside, it was not uncommon to have fog on the tiles inside the houses.
So, of course, there is a plastic protection that covers the spark plug wires and protects the cap from draughts.
however, the bakelite with which the ignition caps is made is supposed to be a good thermal insulator.
I think this bakelite may no longer be of the same quality as the old caps, produced in the 90's)
So I had the experiment of putting thermal insulation around my ignition cap, trapped under the cover that encloses the spark plug wires. only on the left side (looking at the engine).
I also think that the other caps is less exposed to the cold drafts of the fan.
so, It condenses less.
for the moment, my test is positive.
To be continued.....
In the pictures, I used ACTIS triso super 10 multilayer insulation.
http://www.insulation-actis.com/multifoil-insulation/triso-super-10-plus.html
This is called thin insulation, which is equivalent to several centimetres of glass wool.
Maybe you can try it with simple glass wool.
Well I'm not pretending that this is the solution, it's just a test I'm doing that I wanted to share with you.
it's very easy to do, it doesn't cost much, you probably all know how to find some glass wool in your house to try yourself.
Translated with www.DeepL.com/Translator and me to correct some deepl's words!
Concerning the moisture in these caps, I have another theory that I am testing.
For the moment, it's positive.
First of all, as some of you, I changed my caps; the caps seals, the orange cups, and even the camshaft seals.
I still have more or less the same moisture problem.
--> caps full of moisture after 1015/min. of engine start-up.
My idea is that:
as it is always the same caps that tends to make moisture the passenger side one.
So the caps on the left when you look at the engine.
this head is in front of the fan.
And that this moisture problem occurs after the engine is hot.
the problem is more important in cold and humid weather
I think it is the condensation linked to the thermal choc (hot/cold) that causes this internal condensation.
In fact, the fan is blowing cold air on the ignition cap, while inside this cap, the air temp is hot, since the engine is hot.
This thermal choc would cause the moisture to bead from the moist air inside the caps.
As before, when we didn't have double glazing, when it was cold outside, it was not uncommon to have fog on the tiles inside the houses.
So, of course, there is a plastic protection that covers the spark plug wires and protects the cap from draughts.
however, the bakelite with which the ignition caps is made is supposed to be a good thermal insulator.
I think this bakelite may no longer be of the same quality as the old caps, produced in the 90's)
So I had the experiment of putting thermal insulation around my ignition cap, trapped under the cover that encloses the spark plug wires. only on the left side (looking at the engine).
I also think that the other caps is less exposed to the cold drafts of the fan.
so, It condenses less.
for the moment, my test is positive.
To be continued.....
In the pictures, I used ACTIS triso super 10 multilayer insulation.
http://www.insulation-actis.com/multifoil-insulation/triso-super-10-plus.html
This is called thin insulation, which is equivalent to several centimetres of glass wool.
Maybe you can try it with simple glass wool.
Well I'm not pretending that this is the solution, it's just a test I'm doing that I wanted to share with you.
it's very easy to do, it doesn't cost much, you probably all know how to find some glass wool in your house to try yourself.
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My 500E was put away for winter in my carport. Rather than cold startups etc I choose to let the car hibernate and start her up this evening for a first drive of the year.
Fired up right away as always- perfectly smooth. Drove it to a filling station a mile away and half filled tank with fresh super unleaded. Cranked up fine and drove off on up the road.
Next junction around 5 miles later- pop fart dead. Stone dead. Cranking and popping that was all. Pushed her off into a hard shoulder and phoned GF to come get me (to get tools at home) whilst my brother who happened to be with me stayed with my 500E.
Came back 20 mins later - pulled the dist caps and they were laced with water condensation inside. (My very first suspicion is that it was dizzy cap related) All leads, plugs, caps and rotors are brand spank new less than 100 miles on them - fitted about a year ago.
Dried out the moisture with a cloth, sprayed WD40 inside the cap and in the rotor area as best I could - problem solved. Drove home as is nothing happened. Some WOT action confirmed I was on all cylinders again with a puff of tyre smoke.
Lesson? If your 500E is stored outside or in less ideal conditions for months on end it would be prudent to check moisture before first trip out. Dont take cold start behaviour as a given - if moisture is in there it will show its face after 10 or 15 mins of driving.
Lesson no 2 - always have a rag, 5mm Allen wrench and a small can of WD40 in your 500E's trunk.
I will monitor this and keep checking caps periodically and apply WD40 each time to displace moisture from in there.
The picture was taken at the side of the road with the moisture I found in RH bank cap. Both were the same level.
Sucks breaking down - especially in a gleaming 500E! I'll not lie - it pissed me off, imagine how good a 500E would be with coil packs....... dont like distributors and my other HFM models never miss a beat. The 500E will have to gain my trust again somewhat
Fired up right away as always- perfectly smooth. Drove it to a filling station a mile away and half filled tank with fresh super unleaded. Cranked up fine and drove off on up the road.
Next junction around 5 miles later- pop fart dead. Stone dead. Cranking and popping that was all. Pushed her off into a hard shoulder and phoned GF to come get me (to get tools at home) whilst my brother who happened to be with me stayed with my 500E.
Came back 20 mins later - pulled the dist caps and they were laced with water condensation inside. (My very first suspicion is that it was dizzy cap related) All leads, plugs, caps and rotors are brand spank new less than 100 miles on them - fitted about a year ago.
Dried out the moisture with a cloth, sprayed WD40 inside the cap and in the rotor area as best I could - problem solved. Drove home as is nothing happened. Some WOT action confirmed I was on all cylinders again with a puff of tyre smoke.
Lesson? If your 500E is stored outside or in less ideal conditions for months on end it would be prudent to check moisture before first trip out. Dont take cold start behaviour as a given - if moisture is in there it will show its face after 10 or 15 mins of driving.
Lesson no 2 - always have a rag, 5mm Allen wrench and a small can of WD40 in your 500E's trunk.
I will monitor this and keep checking caps periodically and apply WD40 each time to displace moisture from in there.
The picture was taken at the side of the road with the moisture I found in RH bank cap. Both were the same level.
Sucks breaking down - especially in a gleaming 500E! I'll not lie - it pissed me off, imagine how good a 500E would be with coil packs....... dont like distributors and my other HFM models never miss a beat. The 500E will have to gain my trust again somewhat
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Was this the passenger side cap or driver side?
Location of cap described in my post above! (Read post #42 fully PLZ…..)
Makes no difference to this issue how fast the engine warms up IMO……
I have my own theory on this issue. We know that behind the insulating cups is an alloy section of the cylinder head. The coldest surface in this assembly due to the thermal mass of the alloy head material. This area is also not sealed from the distributer cap – due to the hole recess (In the insulating cup) to allow the rotor arm mount to pass through and that the cup is freely floating against the head (No seal) and only seal is an O Ring to the distributer cap. This distributer cap O ring seal is more locating function than seal and this is confirmed by the fact the Distributer caps have vent slots in them at this O Ring seal junction.
Remember that it is very typical in this problem for the car to cold start just fine – then at a certain warm up stage start to stumble / cut out….. Correct? Which was exactly my situation yesterday.
I believe that atmospheric moisture readily makes its way in behind said insulator cup and condenses on the aluminium head. This is also where people primarily see liquid spotting on the back of the insulator cups. Then as the motor begins to warm up this moisture is displaced / evaporates / moves into the distributer assembly to the next coldest surface – the inside of the plastic distributer cap and condenses again causing the misfiring / stumbling.
Yes the insulator cup(s) itself can be defective / have micro fissures perhaps – but that is NOT the case in my car as the photo proves with excess moisture sitting inside the distributer caps to the point the car was dead – where it ran 100% perfect minutes previously at cold startup. (The moisture was NOT on the underside of the distributor caps at startup is what I am pointing out!)
So to me the void behind the insulating cups IS the primary weak point. And I am trying to think of a material to seal / fill that void - foam would need to be applied carefully and possible hazard due to the engine temps. Unless I use Pink Fire rated foam…….. a bead of RTV won’t be enough either there will still be void space. I also want to avoid a situation of glueing or adhering the insulating cups to the head wherever possible. I would place a tube inside the rotor hole area to protect the cam oil seal ring from the pink fire rated expanding foam. For those wondering about the foam – yes it will clean off and dissolve with appropriate cleaners should I wish, and have a backup new pair of insulting cups on the shelf for this experiment – to swap back in if required.
WD40 is bashed on most forums since it is a less than ideal lubricant. Lashing WD40 inside the distributer caps is a temporary solution at the moment which after all is exactly what that product is most suitable for (Water Displacement 40th Formula) Has anyone used WD40 before in the M119 caps? It does work………. It was my brother who suggested it yesterday, he is a top fuel crew chief and uses it on the Mags when the dragster is stored outside overnight before racing. The WD40 spray layer will not last indefinitely, indeed it may only last a few weeks and evaporate off but whilst that coating is inside the caps the water condensation cannot condense and cause issues. Moving forward, foam or not I also intend to upkeep the WD40 spray inside the caps as additional protection.
EDIT- further reading on TFTSNBN https://www.benzworld.org/forums/r129-sl-class/1638170-m119-distributor-caps-moisture.html
PS I have my own ideas and theories developing on this issue ranging from how any vapour can escape from the caps etc and I will create a new full thread of my own
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JC220, thank you for relaying your thoughts.
Perhaps a neat test of your theory would be to use a vented distributor cap (i.e. drill a small hole in one of your many spares) and run around with that vented cap for a while?
Tom and Ray Magliazzone (Click and Clack on NPR) make reference to vented caps: https://www.cartalk.com/content/our-pontiac-lemans-piece-junk-theres and doing a google search of "condensation distributor cap vented" yields a tonne of results, and not just isolated to M119s.
https://www.google.com/search?clien.....0.63.186.3......0....1..gws-wiz.3s-6MOxiedg
As well, here is a reference to vented distributor caps on marine engines - https://forums.iboats.com/forum/eng...oisture-or-condensation-inside-distributorcap
I'd suppose that the whirling distributor rotor would be able to dry out the interior of a moist cap if it were vented.
Just thinking out loud because it seems that this kind of issue cannot possible be the exclusive domain of MB M119s engines...
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Note the M119 caps are vented, via slots at the bottom.
The odd part is that if a car is not stored long term, but parked outside in extremely humid conditions, this problem doesn't seem to occur. Why does it take weeks to happen? Perhaps the cap vent slots are small enough that it slows the condensation process?
The odd part is that if a car is not stored long term, but parked outside in extremely humid conditions, this problem doesn't seem to occur. Why does it take weeks to happen? Perhaps the cap vent slots are small enough that it slows the condensation process?
Exactly! This is a problem.....
I have an experiment planned later when I get home to demonstrate what I mean very clearly with photos. My first mod is appropriately placed vent slots of my own to disperse rising water vapour that may (and does) occur
I keep reading about the insulator O-ring as being a problem, and that replacing it will somehow fix things. I don't think anyone understands how little that O-ring does. AFAICT, it primarily is a dust seal, and provides a soft barrier between the cap and insulator. There was a lot of speculation, SWAG's, and not much useful info in that thread. Drilling a hole in the oil fill cap to relieve excess crankcase pressure was an awesome suggestion. (Not!)
I'm not convinced the bottome vent slots are a problem to be "fixed". We've already proven that the mystery liquid which collects on the back of insulators is not water - if the damp insulator is removed and left to sit out for days, the liquid never evaporates. I'm also not entirely convinced the liquid is condensed oil vapor being pushed out the seal, but that is a possibility.
If it is water condensation inside the caps, I'm not sure what the solution is. But again, as mentioned above, this only seems to happen when a car is parked in a humid environment for months. Why doesn't every M119 in a tropical environment have major problems? I mean, you'd think every one in Florida or Hawai'i would spend most of the time in the shop if not driven daily.
I don't know the solution, and I'm still not sure of the root cause, but the more experiments are performed & recorded the more it will help narrow down the root cause.
