yanmar valve cover

[rperret]

Hi

First - I own a 1GM10 - and want to cold adjust the valve. (I own a manual and have instructions - but one item is not clear.)

Is there a valve (rocker) cover gasket that I need to replace when removing the cover to adjust the valve? Would like to know before hand and order the gasket if need replacement.

Thx

Rick

[Omatako]

There will definitely be a gasket between the rocker cover and the cylinder head. Whether it needs to be replaced depends on how long it's been there and how it was put on. If it wasn't put on with a lot of gasket cement it will generally be re-usable.

[Sapperwhite]

There is a bonnet cover gasket that is cheap and easy to replace. Torresens has the 1GM gasket listed at $4.29 each. I would change it with new, that is the only place my engine has ever leaked oil. They get a lot of heat from the cylinder head and become brittle. I would bet that once you take the bonnet cover off some of the gasket may stick.

Once you take the bonnet cover off (the cover that has the oil fill cap on it) turn it upside down. You'll see a chanel that receives the gasket. It's really more of a big O-ring than a gasket.

I have a 2GM, and have done similar work myself. 1GM and 2GM are very similar.

Here is the p/n at Torresens:
1GM Bonnet Gasket

Call them and double check it. The part numbers have changed over the years, particularly with gaskets as the materials have changed.

[Rockter]

RP...

You have got two valves in there to adjust now, not one. The manual will tell you how. Be careful. It's not a difficult job but they must be right. Whatever you do, do not under-gap them. Over-gapping makes a wee bit more noise, but it doesn't hurt anything. The valve likes to breathe a little. It detests being under-gapped.

The motor must be stone cold when you do it.

The old gasket probably will do. Just put a wee bit of sealant on it when you re-assemble. If it leaks, buy a new one, or put a new one on there now. In the motors I have worked on, I have very rarely bought a new one. It's not a lot of work to change the gasket if it leaks, unlike some other gaskets.

[rperret]

thanks all - my service manual was clear on the procedure- but did not mention gasket.

will check Torrensens.

thx.

[timebandit]

Always replace gaskets.

It just is not worth the time and effort to redo.

Be sure to remove all traces of old gasket and if you have to stick the new gasket to anything, stick it to the part that is removable.

Rick