Lotus Elan

TC Valve Spring renewal?

PostPost by: Matt7c » Sun Jul 10, 2005 7:56 am

Hi there,

My Elan S2 is going strong since its return to the road after 14 years of rest. However, I do have 2 small timing issues, which after many hours of study and checking I have traced to the valve springs. After 14 years stationary, I think that the 2 springs that were squashed are now lazy - others on the forum warned me this would happen. In particular, the inlet on cyl 2 often spits back, and as I get regular back firing through the exhaust, I am thinking that an exhaust valve is similarly lazy. The problem is most accute when cold and in the 2300-2900 rpm range.

I don't have the time, the space or the inclination to do a full engine rebuild, although I am sure that will be required at some point. However, I was wondering how feasible it would be to just renew the valve springs? Can it be done without the valves dropping into the cylinders? How long might it take (1st time!) and what else must I renew while I am in there? Any special tools required? I have a workshop manual and the Wilkes TC book, but I'd like to hear from somebody who has done the job, or similar.

Any advice gratefully received.

Matt
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PostPost by: types26/36 » Sun Jul 10, 2005 11:47 am

I've done this many times but not on T.C. engines, I used to work for VW and to replace the valve seals (a common problem) the golf/passat range has a similar valve/spring arrangment to the T.C.
We had special tools which was basically a tube which would compress the valve spring, it was levered by a another fitting that was bolted to the head.
You need a fitting that screws into the plug hole and a pipe attached,this is connected to a compessor and pumped with air to keep the valves held against their seats, the engine needs to be set at TDC and left in gear with the hand brake on (to prevent the piston going down)
Its easy to make the plug fitting from an old spark plug, also easy to make the tube bit but you would have to work out how to lever it to compress the spring. (not to difficult)
Brian
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PostPost by: twincamman » Sun Jul 10, 2005 1:19 pm

the head comes off in 20 minutes ----do it right ----ed
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PostPost by: Fred Talmadge » Sun Jul 10, 2005 8:38 pm

Pulling the head is easy and recomened but then you will see other problems that will cause you to want to do a valve job at least. So if you want to keep your Elan on the road at least for the summer then I suggest you avoid it and do the "mickey mouse" repair of just replacing the springs. But be prepared for a proper job during the winter.
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PostPost by: storrar54 » Sun Jul 10, 2005 11:22 pm

There is an old trick to replace valve springs/seals without removing the head which goes as follows. Take out the sparkplug with engine at BDC so the piston is at its lowest. Feed in through the spark plug hole as much waxed twine as you can. bring the engine up to TDC. The twine will compress up against the valves and keep them on their seats whilst you effect the replacement. Turn the engine BACK to BDC and remove the twine.Job done.
Richard
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PostPost by: Matt7c » Tue Jul 12, 2005 6:40 pm

Thanks for the suggestions, fellas. I have to go away to Italy for a while, but I'll let you know what I decide to do.
Regards,
Matt
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