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Valves bent?

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Well my luck is in again - after having a great run down to Newlands corner in the Esprit and after just having it serviced... I drove to see a friend on Sunday evening. Put my foot down to over take, throttle jammed wide open.. so switched off and coasted to a halt... Then checked throttle linkage for jamming and it all seemed to be ok, re-started and it ran and then started to make Not A Good Noise. AA man said it looked like I had jumped teeth on the Cam belt - so my question is, what do we think on damage and more importantly the cost of repair - I assume I have bent some valves on one camshaft / valve guides... anyone have any experience on this? CANNOT believe it, just before Christmas, which as we know is such a cheap time of year....

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My suggestion

Check the cambelt doesn't line up. Set to TDC on the flywheel mark, the two dots on the back faces of the camwheels should be adjacent . If they are not then the AA man is right. I'd be tempted to put a new cambelt on (you'll probably want to do that if its more serious anyway?) then I would turn the engine over by hand. If any knocks or noises then stop as it will be a head off job.

Assuming no probs I'd do a compression test. It that passes then you have been lucky. Any compressions not up to scratch will mean head off and survey the damage

I have a spare cylinder head but its for an LC turbo and I think yours is an NA?

Fingers crossed

John

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Hi John, mine is a high compression NA - It was definitely making a bad noise though so I am assuming that something is damaged? but maybe lucky - so is a new cambelt essential here? I assume it would have been put under stress if it jumped teeth?

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as I said better safer than sorry and you'd replace it if you had the head off as its a job that you might as well do 'while you are there'

John

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Good point, agree its always best to err on the side of caution with the belt - I just really really hope it is nothing to serious.

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You going to take it to Chuckle & Co or get Sparky to have a look?

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Am taking it to the usual place as they just serviced it...

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Sorry to hear of your problem. If it has just jumped one or two teeth then you may not have done any damage but your timing will be off. Is it a mechanical noise or does it sound like missfiring.

If mechanical then you will have to be prepared for a strip down but as others have said line up the timing and check the dots on the camwheels.

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TAKE IT TO SPARKY

Henry sorry to hear about your problem

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I guess Henry would do but having just had it serviced he needs to find if it is an issue for them and also they rebuilt the engine not long ago.

Trevor.

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Am taking it to the usual place as they just serviced it...

Surely, If it's just been serviced then it shouldn't have jumped teeth as the tension would have been set correctly???

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Sorry to hear of your woes. But I doubt cambelt jumping teeth is the issue. Don't forget once the engine is warm, the thermal expansion of the engine should be enough to keep it tight - unless it was slackened it way too much during the recent service!

If the throttle jamming was the first sign of somthing amiss, maybe something got stuck in the carb butterflies?

Once you've checked cam pulley alignment, it could be worth doing a cold compression test.

At least that way, you're armed with information before you take it back to the garage who serviced it.

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Well, it is a good question - if it has jumped teeth and it was just serviced, would that have been possible? The cambelt was new last year. Also, to clarify the engine was not rebuilt just installed. So is it possible for a throttle jamming wide open for a couple of seconds to have caused the belt to jump?? Anyway it is in the garage now so I shall no doubt find out soon what the issue is...

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Hopefully you'll find out soon and the result WILL be a pleasant surprise for you.

When I first bought my car, I was unaware that the tensioner was shot, and later found out that the noise on decelleration was the belt flapping against the inlet pulley snubber!

So, what seems to happen is that belts tend to jump if tension is too low, when the throttle is released and the belt slackens.

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Having the the throttle wide open shouldn't cause the belt to jump, you should just be bouncing off the rev limiter. Been there a couple of times myself.

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As it is a High Compression engine which was fitted from excel and I am not sure what distributor it has in it - would the rev limiter still be fitted?

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I should be - although non-limiting rotor arms are a cheap alternative.

Having said that, when one of the springs broke on mine (causing it to cut out at 3500rpm), I removed the remaining spring and on one occasion I took it to nearly 8k, without issue. Not that I'd recommend repeat it too often.

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I suppose I have to see what the issue is and then work out whether it something which perhaps should have been picked up in the service. The garage in question is normally really good so I would hope not.

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Entirely possible for the cambelt to jump teeth; it happened to me....I had an inexplicable loss of power, kept on driving and finally it slipped again and that was the end of the inlet valves! So...check the valve timing as has been said. The snubbers aren't there for show, so make sure that they are set correctly, as is the cambelt tension. Hope it turns out to be a cheap fix, whatever it is!!

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no compression on one cylinder, so they are stripping it down tomorrow....

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Hope it's just valve damage, and pistons are OK!

It is easy to bend valves - turning the engine over by hand can do it, if the cam timing is out..............

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Yup, hopefully just valves on one cylinder so not too expensive!

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Be careful with what the garage tell you - they are hardly likely to admit the belt or tensioner was set incorrectly as that would make them negligent. Make sure they show you the damage rather than just go ahead with a repair. For instance, if it is a burnt valve or a hole in the piston then it is just bad luck but will be an expensive repair as most of the cost will be strip down (you really should consider a full top end service).

However if the valve has bent then others are likely to have been damaged and would almost certainly point to wrongly fitted/adjusted cambelt. Also if they did fit the belt wrongly in the first place I would certainly not want then to refit another one.

Is it a Lotus experienced garage

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Henry - is it confirmed that the belt jumped?

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