Lotus Elan

timing chain cheat...

PostPost by: RichC » Sun Aug 06, 2017 11:35 am

after the thashing the motor has had driving around castle combe and on long motorway journeys this summer I detected what I thought is a very slight rattle on the overrun , really only noticeable with bonnet up.
the motor is a very quiet one with a quiet exhaust and so i'm not talking heavy chain noise .
I didn't really want the faff of removing the cam cover so i decided to see if tweaking the chaintensioner screwthread would make any difference .... I took it round just a half turn and it's now rattle free .

The motor probably hasn't done more than 3000 miles since the engine was rebuilt in 1996 .
Anyone care to comment on whether this is appropriate and how much chains stretch in time?
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PostPost by: UAB807F » Sun Aug 06, 2017 4:02 pm

Chains don't stretch, the rivets/rollers wear and that's what gives the increase in length and hence folks say "it's stretched". Given the TC chain is running in oil I would expect wear on the actual chain to be minimal and I can't imagine a chain showing actual wear in 3000 miles. Bike chains which are exposed to the elements and not cleaned show wear in that sort of mileage but a chain on our engines should last from one rebuild to the next.

Given the low service life I'd look elsewhere for the reason, perhaps the adjuster has slackened off a touch ? Half a turn isn't a lot to move over 20 years, is it ?
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PostPost by: RogerFrench » Sun Aug 06, 2017 7:49 pm

I wouldn't look anywhere. You fixed the problem, now forget it.
1967 Elan S3
1972 Europa Twin Cam
2005 Elise
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PostPost by: RichC » Mon Aug 07, 2017 7:21 am

so if anything it's a tiny bit o wear/ movement maybe in the tensioner itself ,,, happy with that!
there's quite a bit of thread sticking out from the block as I presume you'd anticipate after a rebuild .
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