Front crank dampener delete?
 

Hi all,

I have fitted a manual transmission on an early M117.960 euro 5.0L and I used a 3.5 M116 flywheel. The engine is stock other than a Megasquirt fuel and spark (EDIS) setup. I just sourced a pair of AMG spec camshafts and I thought I would lighten the flywheel to help the engine rev better. Unfortunately the design of that flywheel (24lb) makes it difficult to take any substantial weight off without weakening it. Ideally I should have an aluminum flywheel made but I would prefer to keep that for a later stage.

The dampener in the front is a big heavy steel wheel, and mine doesn't have that rubber band inserted I've seen on others, so I wonder how it dampens anything. As I believe all elements are balaced separately on these engines I thought I could delete that "dampener" as an ersatz of flywheel lightening. I would just have to work out a spacer so that the pulley still aligns correctly with the belts.

Any experience on this? Is it a good idea?

Thanks in advance!

my engine is a 103, but, i removed the damper on the front so i could fit the toothed wheel for my megasquirt build.
not had any problems.

Were there any benefits, similar to lightening a flywheel?

The purpose of the vibration damper is to reduce the torsional vibrations in the crankshaft ...

It comes in handy to offset any harmonic...it's there to prevent stress to the crankshaft..

Personally I wouldn't remove it...all part of the engine design.

This.

Thanks!

there is a guy on another forum marketing a lighter front vibration dampener for the M104 AMG. and report show that many have suffered crank failures

Thanks all. This is unvaluable information and advise. I can't imagine my face the day when I would have faced a serious crank problem.

what type of failures? barings or actual snapping, ive done 5000 miles so far and all seems ok, hope i aint gonna run into problems?????

Nick, the throw on your M103 crank is so much smaller than the 3.6L crank
8.25mm Vs. 92.4mm. and your pistons and rods are also lighter, thus the stresses are nothing compaired to what the M104 3.6 goes thru. i would still say your better off with a dampener. IIRC the failures where due to the dampener getting lose. so may be by having it completely off your lucky so far :)

cheers jay, but dont forget my crank is the 3.2 and i have forgies and h beams in there, do you think they will they be lighter?

btw, i dont experiance any vibrations or anything like that, another thread spoke of it, and the guys were each suckin eachother agreeing obout there lightend engines having vibrations, i dont have any at all...

i also have the hardest shells the dealer offerd, oh and apr rod bolts.

i couldnt imagine the crank snapping just by removing the vib damper, and i'm sure others on hear remove theres when they put megasquirt on.

i reconed that the damper was only for smoothness for when the cars were new and neede to be benz smooth.

it has got me stressin though, i dont want to have to replace the whole engine, the car will be sent to its maker if that happens!!!

did u get the internals balanced? it seems they are since others speak of vibrations, and urs runs smooth. and i had totally forgot u had the 3.2 in. but as i said, i think its the modded dampener the guys were using coming lose that must have caused the crank breaking. its the wobble it creats prolly as it starts moving around before finally falling of.

OK, i dun some research since last post, apparently, all 6 cylinder engines are very well balanced, but suffer from harmonic resonance at certain rpm's. it just so happens that the usually range is from around 6000 rpm to 6500 rpm... just where the sweet spot is on my engine.

i am gonna try to refit the damper as soon as i find time. it may well interfere with the toothed wheel though.

Most crankshafts have one or multiple critical speeds which need to be pushed through as rapidly as possible to avoid crankshaft damage. On the old nissan L28 it has two, one around 6200 rpm and iirc one around 6700rpm. If the crank is held at these speeds for any extended period of time, the engine life is drastically reduced.

Just because the engine is balanced does not mean it does not need a damper. I can only think of a few instances where the engines are run without a damper, and none of those engines are designed to last very long, just put out gobs of power and live short, violent lives.

interestingly, the only engines that i have found that dont use harmonic balancers are Porsche rs engines.