twin cam valve clearance question

[Europa73]

Hi all,

As this forum is a fantastic knowledge base, I am hoping someone out there can let me know if I am completely out in left field with this question on the twin cam engine.

I am also restoring a 69 Elan plus 2 with a weber head and sprint cams.

I have not yet started the engine and it has not started for about two years.

Here comes the noob question.

I took off the cam cover for painting and thought I would check the valve clearances.

They are all very tight and out of tolerance.

Question – Could this be because the car has laid idle for so long?

Or is this s dumb question and lack of inactivity should make no difference?

Many thanks,

[BDA]

Surely you've heard the old saw that there are no stupid questions - only stupid answers. It's true. I'll try to make sure not to provide a stupid answer.

There is nothing about a motor sitting up that would tighten (or loosen) valve clearances. It could also be that the seats have worn a bit from normal wear before the engine was stored. What are your valve clearances? Are the intakes off by the same amount? Exhaust? I have known of people who adjust the valve timing and lift a little bit by monkeying with the valve lash. I don't think that's a good idea.

I assume you're doing it correctly but just to be sure: You are measuring the gap between the follower and the HEEL of the cam is what you're measuring, right? See the attached picture from Section E page 7 of the TC shop manual addendum.

The specs for valve lash are (from the Technical Specifications Section of the TC shop manual):
Intake: 0.005 - 0.007
Exhaust: 0.009 - 0.011

If they are more than a thousandth too tight, I think I would re shim them. Especially if the exhaust is 0.007 or tighter (part of the gap is to give the valve time to get rid of heat through the seat and water jacket). You especially do not want a tight exhaust valve.

[4129R]

You can actually reduce the thickness of the shims by gripping them with your nails, and rubbing them up and down on Emery paper, if they are close, but not exact.

It takes a while, but if you cannot access the proper ones, it works well.

[BDA]

Alternatively, I'm sure DBE or r.d. enterprises will have them. Lotus Ltd (the Lotus club on this side of the pond) used to run a shim exchange. I don't know if they still do but it might be worth checking out.

[Europa73]

Many thanks for the information.

Cheers,

[Europa73]

I have shimmed a the Lotus 907 engine with a timing belt - but - never a over head cam with a timing chain.

Is there a step by step out there for re-shimming the twin cam?

Many thanks,

[BDA]

I doubt it's much different.

First, you need to know about http://lotus-europa.com/manuals/. All the Europa manuals are there in searchable PDF format. There is also a lot of other information that is very helpful.

Now, for your specific issue, go here (http://lotus-europa.com/manuals/tcwork/e/tce.pdf) and go down to section E.7. That should tell you everything you need to know.

[Europa73]

Many thanks,