Lotus Elan

Twin Cam Problem

PostPost by: pereirac » Fri Mar 19, 2004 5:55 pm

I am finally putting my Elan together after it has been off the road for a number of year :-(

The engine has not been run for a long time although I did put oil into the bores. I have started turning it by hand with the plugs out just to loosen everything up...

It almost rotates freely but just around TDC it seems to stop as if it's reached a stop. If I turn it backwards the same thing happens just the other side of TDC. I don't want to take the head off unless I have to but if anybody has any suggestions I would welcome them. The cam followers all seem to go up and down properly so no problems there. I don't want to force anything as that would probably be expensive...

Any ideas?
Carl

72 Elan Sprint
87 Excel SE
97 Alpina B10

http://www.lotuselan.co.uk
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PostPost by: types26/36 » Fri Mar 19, 2004 7:02 pm

Pereirac,
You say the cam followers go up and down but you cannot check the compleat movment as you cannot pass TDC, I had a simlar problem with an engine. In my case one of the tappit shims had "jumped" out of it location in the retainer and was jamming the valve, try taking off the cams and checking the shims are located correctly.
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PostPost by: john.p.clegg » Fri Mar 19, 2004 7:33 pm

try checking the valves are closing as well as opening,if one is stuck open!!!!
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PostPost by: pereirac » Fri Mar 19, 2004 7:35 pm

Oh well, off with the head then!!
Carl

72 Elan Sprint
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97 Alpina B10

http://www.lotuselan.co.uk
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PostPost by: pereirac » Sat Mar 20, 2004 8:25 pm

Cams removed, no slipped shims but the engine now turns so it looks like it was a stuck valve. Hopefully when it goes back together the engine will continue turning!!
Thanks to everybody who left me suggestions or emailed me

Carl
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97 Alpina B10

http://www.lotuselan.co.uk
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PostPost by: gobw2 » Sat Mar 20, 2004 11:43 pm

:) Be sure to try all the valves before reassembly - make sure open & close. George
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PostPost by: khamai » Sun Mar 21, 2004 2:38 am

Strongly suggest doing a compression check. Leak down is best just to be sure you didn't bend a valve. Even the slightest piston-to-valve contact can bend it enough to lose compression.
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PostPost by: gjz30075 » Sun Mar 21, 2004 7:27 pm

Pereiac,
Turn the engine so all the pistons are halfway down/up in their bores. Remove cams. That way you won't have a problem diagnosing valve issues. Then put one cam in and rotate 360 degrees, checking for movement and clearances. Remove, and put the other cam in, checking same. If you think its a stuck valve, this way can determine at least what side its on. Good luck.

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PostPost by: pereirac » Mon Mar 22, 2004 10:14 pm

I have reassembled the cams and everything now turns smoothly but just to be certain I will do a compression check (as soon as I can get hold of a compression tester)

Carl P
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97 Alpina B10

http://www.lotuselan.co.uk
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