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Mr_John111

Cambelt Snapped

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Well, the title says it all.

Sue's lovely 84 TE decided to celebrate in an unusual way after passing its MOT today.

Just a few hundred yards from home the car stalled whilst coasting to a stop at some traffic lights.

Fortunately at low speed but still prepared to find 16 bent valves when I take the head off.

The only comfort is that I wasn't driving it at the time otherwise the thread would be entitled "I broke it yet again"

John

Edited by Mr_John111

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Really sorry to hear that John. I know its in good hands though.

How long was it since the belt was last changed, is it just one of those freak things?

Edited by Nelly9000

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Yet to see if there is an obvious cause, I'll have a good look at the weekend.

The belt was changed last summer (August) as the head was off to replace a melted exhaust valve. Whilst the first belt had only done 14000 miles and 18 months of service it seemed only right to change it whilst the engine was out.

John

Edited by Mr_John111

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As I drove up behind it tonight coming home from work, I could see one end hanging down under the car :(

Bending down to have a look (wearing my suit so not a 'proper' look) I could see the end was ragged.

John

Edited by Mr_John111

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I was told by my local specialist that its a cambelt change every 2 years on a G Esprit mainly as the belt is held under tension, so you are within that (not that it will be any consolation at all),

Mines due for change when it goes back on the road in the next week or so, and part of me is wondering if I should trailer her to Sailsbury. All it needs to do is make it down there, but after reading this I am not sure if I should risk it!

Edited by Nelly9000

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I am curious to know whether the cam timing on an Excel SE engine is the same as the 910.

The HTD belt fitted to the excel looks much more robust and if it was a straight swap I would think of donating the cam wheels from my car to give the esprit the better set up

Must fish out both manuals

Any one know for certain?

John

Edited by Mr_John111

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That's incredibly unusual (and unfortunate), John. I'll follow this with interest, as I can't help feeling there might be some other reason...

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That's really unlucky John. As Sparky will recall, a couple of years ago I drove 50 miles over to his place to get my cambelt changed not knowing that the tensioner bearing had seized while the car had been in storage for a year. When I arrived the smooth upper surface of my belt had been "polished" almost through to the fabric and the stresses and heat generated had induced a crack in the tensioner body. The belt was still intact but was probably minutes from snapping so they can stand up to some extreme treatment.

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John,

Unfortunate situation. However I am glad to hear that you were not driving at the moment...What mekes it even more frustrating for you I imagine is that you have done all to keep up on the maintenance cycles. Best of luck and will be following the progress as well...

Otherwise I do hope that all is finding all of you well..

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Really shocked to read this John - its very very bad luck. I only get mine changed every 4 years (ABAC services, one per year) which is about 7000 miles total. Never had one even look a bit worn let alone close to breaking. Would suggest a really careful check of the whole area and path cos it just seems like something must be up for that to have happened, rather than it just failed after 6 months. Do you remember where/when you got it? I guess it could have been new old stock and have time expired on the shelf of whoever sold it to you...

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Guest WausauLotus

May sound strange, but do cam belts come with an "user friendly" date of manufacture code or stamping?

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Hi John, what very unfortunate luck. Fingers crossed that damage is limited and not too costly. You may want to consider JAEs 'blue' Gates HTD belt if you do the sprocket swap.. I think they are good for 5 years or 100,000 miles. Best of luck.

Gav.

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Really shocked to read this John - its very very bad luck. I only get mine changed every 4 years (ABAC services, one per year) which is about 7000 miles total. Never had one even look a bit worn let alone close to breaking. Would suggest a really careful check of the whole area and path cos it just seems like something must be up for that to have happened, rather than it just failed after 6 months. Do you remember where/when you got it? I guess it could have been new old stock and have time expired on the shelf of whoever sold it to you...

Belt was from S J Sportscars and not had any indication it was old stock.

May sound strange, but do cam belts come with an "user friendly" date of manufacture code or stamping?

Don't think so

That's incredibly unusual (and unfortunate), John. I'll follow this with interest, as I can't help feeling there might be some other reason...

Me too, when I changed the belt I also did the tensioner bearing. The belt had caught a coolant hose that runs near it and rubbed a small groove into the hose. The belt looked absolutely fine and being so new I may have taken a chance that I shouldn't in not changing it.

Edited by Mr_John111

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Bummer. Hope it's not too bad once you get inside the engine.

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I had a belt snap in the first week of ownership...back in 1988 before I knew anything about Esprits and before the web was here to disseminate all the info. Happened at idle, and the engine survived unscathed. I was very careful not to cause any further damage, once I got the beast back home..although I had had to park the thing when it went bang, and had got it away from the traffic lights using the starter motor, so the engine had revolved many times. Just lucky that the valves had stopped in a position where they emerged undamaged! I remember fitting the new belt outdoors in the snow.....fortunately, all went well and the beast ran for several years before I did anything else to it! I still have the broken belt; there is no sign of any damage or deterioration other than the break across the thing. Inspection would have been useless. As for the belt wearing away the hoses...I assume it was the hose to the waterpump? ... that has been a continuing hassle. A week or two after I had changed the belt, it wore through that hose and left me by the side of the road...managed to limp around to a friend's house and replace the hose a day or so later. Quite an introduction to Lotus ownership(!). I've never found any belt problems from contact with this hose, and it's happened time and time again...difficult to get a hose position which provides consistent clearance; last MOT I had a grovel underneath whilst on the ramp, and there was no sign of any contact after 3000 odd miles, so - hopefully - that bit's OK...

I have also run a belt for 4 or 5 years...during the time I was respraying...and that did show deterioration when examined after changing it; there was definite signs of break up at the inside edges of some of the teeth. So it gets changed to the service schedule now.....and the tension is critical, too. O for a nice duplex chain.....in an oil bath....

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Thanks to everyone who has replied with their commiserations and sympathy.

I have a plan........ What do you think?

If I get the engine 'lined up' i.e crank 90 deg back from TDC and the marks on the camwheels aligned. then move crank to TDC

Then fit the new belt with the engine in situ. (after checking for stones in the pulleys, mangled vee belts etc)

Then tension it

Turn the engine over 'by hand' using the crank pulley bolt.

If, and only if, it turns over freely and nothing 'catches'

then try a compression test.

If at any stage it 'catches' or won't turn then the engine will have to come out for a ''head off'' look to see how unlucky I am (pick a number from 1 to 16?)

If it fails the compression test then I'm really no worse off than I was before as the engine will have to come out anyway.

If it passes the compression check breathe a sigh of relief and tell my kids they won't have to clean chimneys for a while.

Is that reasonable?

Encouraged by what John (Molemot) said as similar circumstances (at idle) and he then ran for years with no ill effects.

However nagging doubt is that if stressed a valve head could drop off and make even more of a mess (but then if I do inspect the valves it will be visual only anyway as I dont have an x-ray machine. If I did I would probably sell the x-ray machine and buy 16 shiny new valves but I don't have a thousand pounds to throw at it).

So as always its a balance between doing a good quality, reliable job that will last but at as low a cost as possible.

John

Edited by Mr_John111

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My first Excel was purchase with a snapped belt and known bent valves. I rebuilt it with parts from Mike Taylor, started it and it ran for a few seconds. Then it stopped, well, sort of suddenly. The belt slipped (semi-auto tensioner) but luckily didn't hit valves to pistons again. This time a cam bucket which had been cracked by the initial belt failure had broken up and jammed in the cam tower so locking that cam shaft and so the engine carried on by slipping the belt over the teeth of that pulley.

Moral of story, if there has been any piston to valve impact check all components. Buckets can be checked by a light tap with a small metallic object and listen for the tone.

Oh, and yes the round tooth cams are a direct swap, they are the same as used on the later Esrit but timing may be different (which you suspect), Excel is 107 exhaust and 104 inlet (I have the manual to hand), you'll have to check the TE manual for Esprit timings.

Mike Taylor would be a good source of the pulleys/ sprockets and he's be able to advise if the timing is the same

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It's a good idea to check the valve gaps after fitting the new belt and before starting...if they are all within tolerance, you're in with a shout. Were the valves bent, the gaps would be significantly too big.

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Of course! What a sensible suggestion, thanks John

Edited by Mr_John111

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Does sound like a fluke thing to me. I have the Gates blu-belt on my '87 HC and it will get done with my major at the end of this driving season. It will have about 3.5 years on it(changed in spring of 2009) and roughly 16K to 18K miles. The car gets driven regularly and I do visual inspections here and there. The belt still has good tension and looks fine.

If anything, Im probably doing it too soon - the Gates blues are rated for longer service life but I figure its good to do it even though Im discarding a perfectly good belt :)

The belt issue for sports/exotics has always been an issue and the arguments for/against frequent changes have and will go on forever. It does make sense to do it a little earlier than normal but doing it every two years? REALLY? That would kill any desire I have to own a car like this then. I mean.... two years seems absurd. Auto belts, especially modern performance-oriented ones dont go bad after two years. The tensioner could go bad I suppose but regular use and no abuse takes care of that, IMO.

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Isn't there a part of the equation your'e missing? It is neither difficult or expensive for a competent mechanic to change a cambelt on an esprit. (Even if you are paying somebody, it should not be prohibilitive). I pay vastly more on my daily driver to keep a 'stamped' service history than I do fastidiously maintaining my Esprit to a minimum of factory schedules.

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What he said. It's not much harder than changing the other belts.

Who would have thought a supercar would be onerous to maintain... :turned:

I'll be changing mine every 2 years as it's ~£65 of belt plus a bit of work.

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What he said. It's not much harder than changing the other belts.

Who would have thought a supercar would be onerous to maintain... :turned:

I'll be changing mine every 2 years as it's ~£65 of belt plus a bit of work.

Onerous to maintain is one thing. We expect that. Buit, if its that fragile and easy to do, why not every year or every 6 months then?

And, Ive always thought a major service consisted of replacing all the C-service parts, not just the belt. So, now there is a D service where just the belt gets renewed? I dunno. I dont get it.

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