Is the American turbo engine an interference engine?

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Is the American turbo engine an interference engine?

Postby dkellis » Wed 11.07.2018, 03:40

I can hear the groans already, given that this thread goes back more than a decade, but a San Diego guy is shopping for an M100 and has seen conflicting opinions online.

If the cam belt breaks, does the American turbo motor break?

The only thing I see in the Lotus Service Notes for the model is in the Precautions section in "EC.4 - CAMSHAFT DRIVE BELT", to whit: don't rotate the crankshaft or camshafts with the belt removed or damage may be caused to the valves and pistons. (This has been previously quoted in this forum.)


Dave Ellis

PS: Being a belt and suspenders guy, I just had the 120K service (including cambelt) done on my car, at 98,000.

Update: after some more searching I found the "Timing belt" topic which provides the answer...from years ago. Thanks to Brit-Car-Nut, among others. -Dave
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Re: Is the American turbo engine an interference engine?

Postby tedtaylor » Sat 25.08.2018, 14:59

Y E S !!!!!!
why the delay in answering this?
"Driving a Lotus is a triumph of bravery over intelligence." Stirling Moss

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Re: Is the American turbo engine an interference engine?

Postby sideways » Sat 25.08.2018, 18:01

Dunno, but the Japanese turbo engine is... :D

Doesn't necessarily mean a disaster, last time it happened to me (907 engine) the car was in the driveway, idling and when the dust settled, I only had 12 bent valves. :o
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Re: Is the American turbo engine an interference engine?

Postby John_W » Sat 25.08.2018, 22:56

It looks like I was lucky when my timing belt on a 907 engine slipped a couple of teeth (worn camshaft pulleys and wrong cam belt tension). I only ended up having to replace the belt and one valve (on a Jensen-Healey). I was still appalled at the cost!

As far as why it’s taken so long to reply, I think it’s a case of stating the obvious. But you’re right - somebody should have said yes.

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