Fse Part , What is it , and where is it from ???

[Gerko]

Hi Gents can anybody identify the below part, Whilst fiiting the new timing chain i removed the plastic tensioners and found this just behind the bottom timing chain gear.

I cannot see anywhere it has come from and the service manual shows nothing like it, It looks like the chain has been rubbing it for a while so i presume its been there for a while.

Its obviously from somewhere ? has to be from the head down to the bottom gear , small area really. It looks like it sits on a lug or pin and is possibly retained by a spring.

Any Clues

[gasgasman]

It is off the cam shaft, part of the automatic compression release.

[Gerko]

Thanks alot that makes perfect sense now. This looks like its been like that for ages, but its hard to tell. Do you know exactly what it does (when does it release compression) ? Will it run without it .

[gasgasman]

At cranking/kicking engine speed, it holds open one of the exhaust valves to lower the compression.
Once the engine starts,the centrifugal force disables the compression release.

[iancp5]

Originally Posted by Gerko

Thanks alot that makes perfect sense now. This looks like its been like that for ages, but its hard to tell. Do you know exactly what it does (when does it release compression) ? Will it run without it .

Do you have trouble starting it? GG's aren't great starters at the best of time but without the decompressor working must be harder still. I'm not sure what effect missing that part will have. If it means it doesn't decompress then it wont hurt when running. If it's always decompressing then it might not be good. Would certainly be down on power and if it means you get blow by the exhaust valve it could be damaging the valve and seat. The decompressor is designed to lower compression only during low rpm while starting so that the lightweight starter and battery can turn the engine over. Once it fires it should spin fast enough that the decompressor stops operating - I assume it works on some sort of centrifugal basis like the PV but to be honest I don't really know.

[Gerko]

It s been hit and miss to honest when starting, i think ill try and source a second hand cam, Thanks guys. This liitle incident is turning out very expensive

[hannesd]

maybe look for other missing parts that could have fell down in the crank case...
can't you refit it?

[Gerko]

Im pretty sure its only half round , Plus ive found all the other bits and the stud that holds it on had snapped off, found that aswell. So its un repairable.