question about "valve adjustments"

[jano]

Hi,

I'm sort of new to the whole engine stuff. I've seen in various manuals, etc, that certain benzes require a valve adjustment as a regular maintenance item. My 1984 300sd turbo diesel, for example has it, and I've seen the AMG DOHC variations of the m117 need this, too, but they are like ferraris and might need shims whereas the diesel just needed a wrench.

Does the m119 need this? And what exactly is it?

 

[gsxr]

Engines which do not have hydraulic cam followers (aka valve lifters) need to have manual adjustment of the cam-to-follower clearance. This pretty much came to an end by the late 80's. The M102, 103, 104, 119, 120 gas engines all have hydraulic lifters which do allow any adjustment. Ditto for all OM60x diesels. I think the last chassis to need valve adjustment was the W123 and W126 diesels, and of course the M117 AMG DOHC. AFAIK, everything since then (definitely 1990-up) is hydraulic and non-adjustable.

 

[jano]

Okay, thanks.

A bit of a diversion here: does the m119 have four cylinders per valve? Why would that better than having one humungo one?

 

[valvfloat]

turn in your man card now...it has been suspended...

you must now study >>> how an effin engine works

there will be a test later...don't post again until you've been contacted...

 

[bing]

let's not be harsh..let's just say it was a typographical error So, Jano if the answer is "4 valves per cylinder" how should your question be?

 

[Glen]

Okay, thanks.

A bit of a diversion here: does the m119 have four cylinders per valve? Why would that better than having one humungo one?

In a nutshell, the M119 has 4-valves per cylinder as opposed to say an M103, which uses 2-valves per cylinder. In a 4-valve design, two valves are used to let air/fuel into the cylinder and the other two are used to expel the exhaust, in a two valve design, one valve is for intake and one for exhaust. The reason to use more valves is because two smaller valves can flow more air than one larger one. Also, depending on the size of the cylinder bore, you can only make a valve so large in diameter...again, multiple smaller valves fit better and flow more.

 

[gerryvz]

The aluminum-block M117s and M116s (from circa 1981 onward) also utilize hydraulic cam followers (aka "valve lifters") and do not require any manual adjustment -- they are self-adjusting. I'm talking about the M116 380 and 420 motors and the M117 5.0 and 5.6 liter motors (i.e. 560SEC, etc.).

Cheers,
Gerry

 

[jano]

To the canadian, that's a cool site, thanks!

Now before I put on my tootoo and go back to ballerina class, Glen, that's really helpful, too. I now need to research and find out why those valves need to be cylindrical instead of, say, a half-cylinder or cubicular.

 

[gsxr]

I can see this discussion drifting rapidly towards things like oval pistons with eight valves per cylinder... which, despite your intial reaction, are not fictional!

http://objetpart.blogspot.com/2010/02/p ... iston.html

 

[jano]

I think I'd prefer donut shaped. Mmmm donuts.

 

[valvfloat]

To the canadian, that's a cool site, thanks!

you're welcome...

now for the test...

http://www.funtrivia.com/playquiz/quiz89969a4f200.html

 

[gsxr]

now for the test...

http://www.funtrivia.com/playquiz/quiz89969a4f200.html

I bet #7 was your favorite, Doran!!!

 

[valvfloat]

you know it...!!!

no doubt GVZ will like #14....

 

[jano]

HEY.. NO HINTS.

I missed #12 because I re-clicked while reviewing my answers. Pffft.

 

[DerFuror]

turn in your man card now...it has been suspended...

[to man in 500Espot forum]
Jake: [fakes accent] How much for the little 500E? How much for the car?
Jano: What?
Jake: Your car. I want to buy your car. The little car, your 500E... sell it to me. Sell me your Mercedes before it it too late.

 

[Christian_K]

The Brabus 3.6L M103 had manual adjusting valve lifters. A friend of mine did drove that engine in a MB W201 190E. Quite some Power/Torque for that 1300kg car. It did beat a E420 easily up to 180km/h, then his E420 slowly was winning.

I have had a discussion in germany long time ago about pros/cons of hydraulic lifters and he said that especially on higher RPMs and on tuneed or *true* sport engines, there should be manual adjusting lifters, as the hydraulic ones are "too slow" ??? Dunno if i got that right....