Valve Shims

[Zag]

Checked the clearances on mine yesterday, have 1 that definitely needs doing and a few more that are borderline. Couple that with a minor leak from the cam carrier it is something I am going to do shortly (when it warms up a bit) Is the library available to be passed on?

[Cliffords]

Yes I have them. If you pm me your address, I am happy to post on.

David

[Zag]

Pm sent, many thanks.

[Cliffords]

Just passed on today. We have a good collection now around 40 shims. Thank you for the loan .

[rbgosling]

Zag, do you have the shim library still? Any chance you could send it my way?

I spent ages checking and re-checking my shim clearances when I rebuilt my engine 7 years / 30,000 miles ago. Haven't checked the clearances again until now. Quite shocked that all but one of the inlet valve clearances are well below spec - should be 0.13 - 0.18 mm, some are 0.04 or below. Not checked the exhaust side ones yet, but they are probably just as bad.

[Zag]

Still got them, pm me your address and I'll send them on.

[lambert.john]

After replacing a camshaft oil seal, I have had a persistent tapping noise which I think is a loose tappet. However, my mechanic has rechecked the valve clearances and has assured me that they are all within book spec.
On a Vauxhall Viva I had years ago I had to reset the valve clearances with the engine ticking over (very slowly) in order to resolve a similar issue. I am wondering if it would be possible to do likewise with the Lotus engine. Any comments, please?

[Alan_M]

The only comment I would make is there will be a lot of escaping oil. I started the engine with the oil filler cap off once - that was bad enough!

[Hawaiis0]

Sorry to hijack

The only comment I would make is there will be a lot of escaping oil. I started the engine with the oil filler cap off once - that was bad enough!

A friend is mentioning a similar thing happens without the dipstick !!

[Pete Boole]

Try using a mechanic's stethoscope to determine if the noise is really coming from the cam housing. If the clearances are measured carefully it is hard to be more than about 0.001" - 0.002" out. Are you sure all the shims are flat - ie no dimples from valve tip contact. How much end float do the cams have?

Pete

[MetBlue]

reset the valve clearances with the engine ticking over (very slowly) in order to resolve a similar issue. I am wondering if it would be possible to do likewise with the Lotus engine. Any comments, please?

Am I missing something, or about to state the bleeding obvious.

The 9xx engine has shims under the bucket that can't be accessed without taking the cam shaft off.
I can see it might be just possible with the thread and lock nut system used on many engines, but not the 9xx.

[rbgosling]

Make sure the bolt holding the sprocket on to the end of the camshaft is tight, and there is no free play between the sprocket and camshaft. That was the source of my knocking noise, and I was lucky to catch it in time!

If you do need to re-shim, I should be finished with the shim library in a week or so.

[lambert.john]

Many thanks for those responses, guys; (I've got a mechanics stethoscope on order)!

[LotusMonkey]

Idiot question… what is the shim library moving around the forum? Is the idea that people do their shims with it and add back into the library the shims they no longer need on their car?

[rbgosling]

Pretty much. It doesn’t claim to have every thickness, but there’s a fair range. Use the shims you need, add back into the library any you don’t use or remove from your engine. If you need a thickness that’s not there, Lotusbits have a good selection of used shims for purchase.