I've been driving a pair of E420s for the past 5 years or so and have rarely been so pleased with other cars I've owned. I visit the local wrecking yards quite often and am always disturbed whenever I happen upon a W124 coupe, I see these way more often than I'd like to. Before all the coupes end up in the crusher I'd like to pick one up for a V8 conversion. I've done the research and it's well within my ex-mechanic, ex-fabricator capabilities; upper bulkhead and cross member being the biggest hurdles. The question is, what would you guys include in a V8 coupe recipe? Easiest course of action would be to obtain a battered E420 to use as a donor, but should I go with a 5.0L instead? A later coil-on-plug M119? Could one even make that work with a minimum of headaches?
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How would you do a V8 coupe?
- Thread starter Dan O.
- Start date
If you're going to build one, absolutely build a 5.0L coupe. The 5.0 engines are no more expensive than 4.2 engines. Get a 1993-up motor for the automatic belt tensioner and other goodies. You'll also need to determine if the recipient will be ABS or ASR, different modules are needed. It will be cheaper to get a complete V8 donor/parts car and swap all the parts needed, rather than buying everything piecemeal. Plan on completely re-sealing the V8 engine & tranny before installation, and also replacing the chain rails (maybe chain too). 100x easier with the engine on a stand compared to in the car. Probably need to swap over the CAN box and all the wiring. Don't forget to upgrade the rest of the chassis to handle the power (best to use a .051/.052 coupe as a donor, NOT the .050).
I wouldn't consider a later 119.98x engine with coil-on-plug unless you are prepared to deal with a LOT of wiring / electronic headaches. To date, I don't think I've seen anyone who has done this, or even attempted it.
BTW - welcome to the forum!
I wouldn't consider a later 119.98x engine with coil-on-plug unless you are prepared to deal with a LOT of wiring / electronic headaches. To date, I don't think I've seen anyone who has done this, or even attempted it.
BTW - welcome to the forum!
IIRC, to Really do it right you need to section out the old front cross member make for the I6 and put one of the V8.. @ least that was how the one example I Know about was done.
COP is where it's @..! You might even consider stand alone..Woo!
jono
COP is where it's @..! You might even consider stand alone..Woo!
jono
A Norwegian build ce420.
From page 18 he starts the v8 build part.
http://translate.google.no/translat...tklubb.no/smf/index.php?topic=13781.0&act=url
From page 18 he starts the v8 build part.
http://translate.google.no/translat...tklubb.no/smf/index.php?topic=13781.0&act=url
sec's are not th same as the same as the M119 motors and I don't like the extra countours on the body. The shape of the windows at profile when the windows are down, are perfect proportions. The 300ce proportions are a littel off and rear side widows a bit truncated. Plus, it's not a W124 ! BAM! A gut in Santa Monica California already did the same, he used the 400e motor, all he has to do now is look for a 500e M119 and transplant it.
There would be less electronic hassle that way. Probably need a .051 donor chassis for this swap. I like the LH injection but KE/CIS-E would be easier.
Appreciate the feedback. I knew about the guy in Santa Monica, I liked his approach because it seems the most cost effective even though he got a bit of static about not going to a 5.0L; which raises the question...exactly how much more trouble would the 5.0L be? Regardless of which M119 I go with I know I'm gonna start with a E420 donor, I'd probably source the 5.0L from a W140 (pre-coil on plug). Oil pan, exhaust manifolds, etc from the E420 will be needed but what about electronics, what would be needed to make the 5.0L play with the transferred E420 wiring? I'd prefer a non-ASR car, but didn't all the W140s have ASR as standard? If (big IF) it were possible to use the E420s throttle body on the 5.0L and plug the 5.0L ECU into the E420 harness would I not get codes for missing features (ASR and who knows what else)?
Also, not quite up to speed on the finer points of my chassis numbers, is the .051/.052 coupe post facelift and are there actual structural differences vs the .050? I'm pretty sure the Santa Monica swap was on a pre-facelift coupe, personally I like the later style but it's all cosmetics isn't it?
Using the KE Jetronic M119 is an interesting idea, I don't think I've actually seen one of those in the yards; would that have to come out of an early R129 500SL? Being in California I'd be restricted to an engine that post-dates the recipient vehicle, to be legal anyway.
Also, not quite up to speed on the finer points of my chassis numbers, is the .051/.052 coupe post facelift and are there actual structural differences vs the .050? I'm pretty sure the Santa Monica swap was on a pre-facelift coupe, personally I like the later style but it's all cosmetics isn't it?
Using the KE Jetronic M119 is an interesting idea, I don't think I've actually seen one of those in the yards; would that have to come out of an early R129 500SL? Being in California I'd be restricted to an engine that post-dates the recipient vehicle, to be legal anyway.
There is no more hassle with 5.0 compared to 4.2 which is why it doesn't make much sense to do a 4.2L, unless it's strictly to save money. But IMO, a 5.0L coupe will be more valuable (not to mention more fun) than a 4.2L coupe. Only differences are the 5.0L EZL and LH module. All the 500SEL/S500 did have ASR standard. 4.2L and 5.0L use the same ETA (throttle body), only difference is ASR vs non-ASR, again the computer module must match the ETA.
.050 = 1988-1989, M103 engine, small differential, 3.07 axle ratio, small brakes
.051 = 1990-1992, M104 CIS engine, big differential, 3.27 (1990) or 3.06 (1991-92) axle ratio, medium 295x22 front brakes
.052 = 1993-1995, M104 HFM engine, big differential, 2.65 axle ratio, larger 294x25 front brakes as of mid-1993
KE/CIS-E M119.960 was only used in 129.066, 1990-1992 500SL. Possible swap if your engine is 1992 and you use a .051 recipient coupe.
.050 = 1988-1989, M103 engine, small differential, 3.07 axle ratio, small brakes
.051 = 1990-1992, M104 CIS engine, big differential, 3.27 (1990) or 3.06 (1991-92) axle ratio, medium 295x22 front brakes
.052 = 1993-1995, M104 HFM engine, big differential, 2.65 axle ratio, larger 294x25 front brakes as of mid-1993
KE/CIS-E M119.960 was only used in 129.066, 1990-1992 500SL. Possible swap if your engine is 1992 and you use a .051 recipient coupe.
Oh man, I like how this is shaping up. Yes, the 5.0L does seem like the obvious choice now. I have not yet taken a serious look at the W140 electronics but I was under the impression that because of that models higher bells and whistles count the LH module would need a lot more inputs that would end up getting ignored in a W124 swap, apparently this is not the case. So since a non-ASR LH module for the 5.0L is nonexistent it looks like I'll be stuck with ASR...maybe that would be for the best, not a deal-breaker anyway. The KE Jetronic/.051 swap is out.
I should have known Mercedes would not assign chassis number variants based only on cosmetic differences, I'm definitely on board with using the .051/2 as the recipient. Speaking of brakes, I recall reading something about certain R129 brakes being a direct bolt-on upgrade for certain W124s, is this just akin to piecing together a .052?
Should you do a search for "W124 V8 coupe" talk of 6.0L engines pop up, as far as I know these are pretty rare and if you do find one you're talking about parting with an arm and a leg to get it in your hands (hand?).....should these engines not even be part of a sane discussion?
I should have known Mercedes would not assign chassis number variants based only on cosmetic differences, I'm definitely on board with using the .051/2 as the recipient. Speaking of brakes, I recall reading something about certain R129 brakes being a direct bolt-on upgrade for certain W124s, is this just akin to piecing together a .052?
Should you do a search for "W124 V8 coupe" talk of 6.0L engines pop up, as far as I know these are pretty rare and if you do find one you're talking about parting with an arm and a leg to get it in your hands (hand?).....should these engines not even be part of a sane discussion?
FYI. LH is totally separate from ASR. Different modules. Non-ASR cars have an ABS module, ASR cars have an ASR module. The 400E and 500E share the same ASR module (in USA) so you could use a 400E ABS module, if you want a 5.0 with LH injection and ABS only (not ASR).
6.0L motors are $$$$. A conversion would likely be $10-$20k on top of the cost of the 5.0L motor. It would be awesome, but not cheap....
6.0L motors are $$$$. A conversion would likely be $10-$20k on top of the cost of the 5.0L motor. It would be awesome, but not cheap....
I would recommend that you keep researching this imagined swap.
One would be crazy, if doing an M119 swap, NOT to do a 5-liter. A six-liter car wouldn't be an issue, outside of machine-shop and piston/ring work, to achieve. The stock CIS-E system on the early M119 engines can easily handle the extra fuel needs and HP associated with boring out a 5-liter motor to six liters.
With the CIS-E motor, you won't have the hassle of the entire CAN system and its associated computers. The wiring will be much easier and more straightforward from a rewiring/layout perspective, particularly if the car it's going into is a CIS-E inline-six (M103 or early M104) car.
Not having the CAN system (which is located underhood, in the traditional battery area) also won't require moving the battery to the trunk, and all of the wiring hassles associated with that. The battery can be retained in its normal position, and the KE-injection computer can fairly easily be relocated to the interior passenger footwell, where it resided on the later M104 (and I think M103) cars.
The brakes you are talking about would be the R129 "Silver Arrow" brakes, which are tecnically a direct bolt-on, but would require late-style lower control arms and different brake shields (or to cut the existing shields), and at least 17" (or is it 18", I can't remember) wheels to clear the larger diameter rotors. It would be a highly recommended part of the overall project, though. The fitment and requirements for the Silver Arrow brakes are very well documented on this site - just use the search function and you'll learn everything you need to know about this upgrade.
Cheers,
Gerry
One would be crazy, if doing an M119 swap, NOT to do a 5-liter. A six-liter car wouldn't be an issue, outside of machine-shop and piston/ring work, to achieve. The stock CIS-E system on the early M119 engines can easily handle the extra fuel needs and HP associated with boring out a 5-liter motor to six liters.
Don't be so hasty to condemn a KE motor swap. The KE/CIS-E makes a lot of sense and you are not losing any power whatsoever by going CIS-E over LH injection.
With the CIS-E motor, you won't have the hassle of the entire CAN system and its associated computers. The wiring will be much easier and more straightforward from a rewiring/layout perspective, particularly if the car it's going into is a CIS-E inline-six (M103 or early M104) car.
Not having the CAN system (which is located underhood, in the traditional battery area) also won't require moving the battery to the trunk, and all of the wiring hassles associated with that. The battery can be retained in its normal position, and the KE-injection computer can fairly easily be relocated to the interior passenger footwell, where it resided on the later M104 (and I think M103) cars.
The brakes you are talking about would be the R129 "Silver Arrow" brakes, which are tecnically a direct bolt-on, but would require late-style lower control arms and different brake shields (or to cut the existing shields), and at least 17" (or is it 18", I can't remember) wheels to clear the larger diameter rotors. It would be a highly recommended part of the overall project, though. The fitment and requirements for the Silver Arrow brakes are very well documented on this site - just use the search function and you'll learn everything you need to know about this upgrade.
Cheers,
Gerry
gsxr: Forgive my ignorance regarding how the modules are sorted out, having both w/and w/o ASR cars for as long as I have you'd think I'd know all the important stuff by now. Truthfully, I've had such a good time just driving, maintaining and dealing with very minor issues that I haven't devoted the time to do all the reading I should; thanks for setting me straight.
Gerry: Just when I was settling into a definite course of action you go and throw a 6.0L wrench into the works. I forgot about the adaptability of KE Jetronic, that and the other points you bring up make it a compelling choice. I don't even want to start researching which M117 crank I'll need or looking into rod offset because once I start down that road.... Maybe I'll save the KE Jetronic 6.0L for a W124 wagon.
Regarding 5.0L LH modules, it there a cutoff year for WOT enrichment like with the 4.2L? I was pretty lucky to find a pair of WOT LH modules for my E420s, I swapped one in on one car and left the other stock, I like the noticeable difference.
Gerry: Just when I was settling into a definite course of action you go and throw a 6.0L wrench into the works. I forgot about the adaptability of KE Jetronic, that and the other points you bring up make it a compelling choice. I don't even want to start researching which M117 crank I'll need or looking into rod offset because once I start down that road.... Maybe I'll save the KE Jetronic 6.0L for a W124 wagon.
Regarding 5.0L LH modules, it there a cutoff year for WOT enrichment like with the 4.2L? I was pretty lucky to find a pair of WOT LH modules for my E420s, I swapped one in on one car and left the other stock, I like the noticeable difference.
My $0.02: Complete the swap with a 5.0L engine first. If you want to do a 6.0L in the future, great. You can build a 6.0 at your leisure, and it's a relatively simple swap to pull an existing 5.0 and replace it with a 6.0 (other than locating the 6.0 LH module, which make hen's teeth appear commonplace, or figuring out how to adjust a KE/CIS-E to properly fuel 6.0 liters).
Also - all .051/.052 chassis come with the late LCA's needed for the Silver Arrow brake upgrade, however if they are original, they'll probably need replacement anyway.
Also - all .051/.052 chassis come with the late LCA's needed for the Silver Arrow brake upgrade, however if they are original, they'll probably need replacement anyway.
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