Cam Belt - What do you think?

[Roger 912]

It is now 4 years since I had a genuine Lotus Cambelt replaced in my Red Turbo Esprit and so far the car has traveled 11 000 kilometres on the new belt. On inspection it still looks as good as new. The engine has never been thrashed except for a couple of short blasts whilst tuning the E.F.I. on a dynomometer.

Now the question. Is it time yet to replace it or do you think I can take it a little further, say up to 20 000 kms.??

[jonwat]

I'd have thought so as long as you keep a close eye on it, so, if you're a plodder then it's fine but if you like to hit the rev limiter every now & then you'll always be afraid to because of the belt.

[Nelly]

I was told (by Sportomotive I think) that the cambelt needs to be every 2 years because its under tension - nothing to do with mileage. That was for an S2 but I can't see it being that different for an S3?

If it was me i would not risk. Better safe than sorry.

[Sir Paolo]

I did hear that under test conditions Lotus did over 100,000 miles on one belt. But this was subject to regular tension testing.

I appreciate your situation is somewhat different as it is to do with age not use.

However, rubber still deteriorates with age, probable more so with lack of use. The tensioner piston could also seize, but again with a regular tension test you should be able to see that this is still working.

[s2mikey]

The old belt replacement issue! My current Gates blue-belt in my '87 Hci has about 20K on it and it was replaced in 2009. I was planning on driving the car next driving season and then replacing it at the end of next years driving season. I know Lotus says 2 years but that quite frankly is stoopid, especially for a car like mine that is driven regularly. I do 5k to 6K a year. Mostly regular driving with plenty of highway cruising and occasional spirited driving. Ive talked to a few people, including Jeff at JAE and he thinks I'll be fine until the end of the next driving season. Ill have about 25K on the belt and about 3 1/2 years.

I know that age and sitting kill these belts probably more than driving does. I also know that the blue-belt is specifically engineered to deal with hotter environments and withstand higher temps. They are also very strong.

I dunno - the belt issue has always been an area of consternation for Esprit owners. Hardly anyone ever gets to the mileage Lotus says to change it at so everyone uses the age of the belt. The problem I have is that belts can sit on the parts shelf for a year before being sold. What happens then? Does that belt now have 1 year of wear on it? Is it only good for one year now? Do belts actually last longer if they are run regularly? Some think so. Its a tough argument either way. It just seems silly to have to do such a big job every two years ...... I mean.... thats a HUGE job every two years!

I know that having a belt go is bad news.... but that doesnt mean changing it too frequently is required either. I say if you drive your car regularly and arent beating the crap out of it, you can go 3-4 years and 25K miles before having to replace it.

[Roger 912]

I know when I contacted Gates about the belts that I have on my green Turbo Esprit (square tooth) and on my Excel (round tooth), they stated that it should be changed every 100 000 kms. are Lotus belts that more unreliable. I wonder if it is known who actually makes the Belt that Lotus put their name on.

I do check the tension and condition every month on all of the cars and I have had to make no adjustments at all on any of them. I have a feeling that on the Esprits, the tensioners were modified from the original design.

I will give the red one another season and then change it. I will keep a rabbits foot and piece of coal in the car as a precaution and keep my fingers crossed at the same time.

[GavinT]

From all the research I found on how long to leave between belt changes the underlining fact was that lack of use was more of a concern than mileage. My belt was 2 years old and the car had only covered about 2000 miles during that time period. I was debating to change it or just leave it for another season. In the end I completely over analysed the situation and decided to step up to the challenge of doing my first Esprit belt change. In fact it was my first timing belt on any engine. It took most of the day to do but was a complete success and now I'm good for another 24 months. I put one of JAE's new HSN belts on the engine. I have been told that the HSN was the next step forward in belt technology that Lotus employed for the turbo engine. A far superior belt to the original A prefix # belt that was fitted to the S1 and S2, which is still available from Lotus. Ultimately the relative cheap cost of the belt coupled with a day of my life spent playing mechanic in the engine bay of my S1 was a better option than throwing salt over my shoulder everytime I turned the key. The risk of a timing belt failure is just not worth the headache. Remember assumption is the mother of all **** ups, and as some have found out that means big $$$ on an Esprit engine.

Edited September 14, 2011 by GavinT

[rogerch]

How much is a new cam belt ?

How much is an engine rebuild ?

Sorry what was the question ?

[andydclements]

Now Roger, you know from the other forum that I think it's best to replace it rather than risk engine failure, but if you don't then you're a brave man to have gone beyond 3 years.

[Roger 912]

Hi Andy.

Point taken.

I have just ordered a new belt from my parts supplier and I will collect it tomorrow. The Gates belt is 10 pounds over here. I wonder how that compares to U.K. prices. Now all I have to do is to convince my Italian mechanic that he is looking forward to the job.

I meant to add a snippet about something that happened to a pal of mine.

His car was a company car and serviced regularly. He had a cambelt changed at the prescribed mileage and to his dismay, the new cambelt disintegrated at less than 1000 kilometres after it was fitted completely blowing his engine.

Sometimes, if it aint broke, don't fix it.

Edited September 14, 2011 by Roger 912

[Sir Paolo]

I recall from a chat with a techhie chap a Gates that another factor in the untimely demise of a cam belt is engine oil.

I understood from him that if oil gets onto the toothed side of a belt, it gets forced into the material under pressure and heat, which ultimately affects vulcanicity (if that's the correct word), leading to belt failure.

Moral is - check for leaks and keep oil away form your cam belt.

[molemot]

Setting the belt tension is more of an art than a science...the book method calls for several checks to be made at different points in the crankshaft rotation...and then you have to convince yourself that the gauge is reading accurately and that you have the technique spot on with regards to releasing the plunger to get a reading. I haven't tried the sonic method..... All this means that you can't be properly accurate when setting the tension with the sprung loaded tensioner. I believe it's because of this that the 2 year replacement period has been advised by Lotus. My cambelt broke the first week after I bought the car (knowing nothing of the possible problems, 'twas in the days before the interweb) and I have also run the car for five years on the same belt. When that one was removed, there was significant visible cracking across the belt where the teeth joined it...enough so that I always change the thing every two years now! I have a fine collection of secondhand belts....some of them seem fine, and some look a bit sus. I still have the one that broke...and it seems perfect...no obvious deterioration anywhere....but it broke straight across! I will always remember crawling into the back of the beast in the middle of Kingston, Surrey, expecting some minor electrical failure...and seeing the frayed end of this rubber belt out of the corner of my eye......ah. Hoping that there was no engine damage, I was very careful fitting the new belt to ensure I didn't cause any, and - amazingly! - all was well and she ran for years after.

Edited September 14, 2011 by molemot

[DanR]

There are a lot of different "factory" specifications for belt renewal.

In the 1899 page CD manual which, I assume most of us have, Lotus lists MY93-94 belt change being at 50,000 miles with no reference to age. It then lists the MY94 model as 100,000 miles again without any reference to age. (Pages 878 and 882.) That's for California and I'm not aware they use a different belt to the ROW.

As for checking the tension, the manual requires the average of three readings every 360degs and being 95 units on the cantilevered Burroughs gauge. That 95 units correlates with 95lbs on a generic Burroughs gauge. Both gauges can be easily calibrated by suspending a 95lb weight and checking that either Burroughs shows 95 when testing the tension of the taut line supporting the weight.

Regular visual checks, tension checks and no more than 50000mile (80000k's) should be ok but only for those in California. For the rest of us...

[s2mikey]

Hi Andy.

Point taken.

I have just ordered a new belt from my parts supplier and I will collect it tomorrow. The Gates belt is 10 pounds over here. I wonder how that compares to U.K. prices. Now all I have to do is to convince my Italian mechanic that he is looking forward to the job.

I meant to add a snippet about something that happened to a pal of mine.

His car was a company car and serviced regularly. He had a cambelt changed at the prescribed mileage and to his dismay, the new cambelt disintegrated at less than 1000 kilometres after it was fitted completely blowing his engine.

Sometimes, if it aint broke, don't fix it.

There is some truth to this. Any engine at the mercy of a belt could go poof at any time. Sure, regular changes and checks reduce the chances of that happening but there are NO gaurantees. The Gates blue belts are worth using since they are better quality and the change interval is increased. When mine gets changed at the end of next year, it will have about 25K miles and 3 1/2 years on it. I drive my car regularly.

[molemot]

There are a lot of different "factory" specifications for belt renewal.

In the 1899 page CD manual which, I assume most of us have, Lotus lists MY93-94 belt change being at 50,000 miles with no reference to age. It then lists the MY94 model as 100,000 miles again without any reference to age. (Pages 878 and 882.) That's for California and I'm not aware they use a different belt to the ROW.

As for checking the tension, the manual requires the average of three readings every 360degs and being 95 units on the cantilevered Burroughs gauge. That 95 units correlates with 95lbs on a generic Burroughs gauge. Both gauges can be easily calibrated by suspending a 95lb weight and checking that either Burroughs shows 95 when testing the tension of the taut line supporting the weight.

Regular visual checks, tension checks and no more than 50000mile (80000k's) should be ok but only for those in California. For the rest of us...

I think you'll find the spec. calls for measuring the tension at TDC and then every 120 deg of crankshaft rotation...I have a splendid cardboard template made to fit the camwheel with marks at 60 deg intervals...equivalent to 120 crankshaft degrees. This clips on and enables the rotation to be set rather more easily than peering at the crankshaft pulley from underneath or the flywheel through the inspection hole.... I also have a calibration rig for the generic Burroughs gauge consisting of an old cambelt, cut to get a single length with loops formed in the ends, two hooks and a known weight to hang on one of the hooks. Then you can check the gauge calibration...even after all that, once the engine is in the car, using the gauge is one of those things that one has to be convinced about. The reading you get depends on exactly how the gauge is squeezed and released...a slower release gives a lower reading due to stiction in the gauge mechanism. So it is a matter of "feel", no matter how many precautions you take regarding points of measurement and gauge calibration. A lot easier with the engine on a stand...! I have only ever used genuine Lotus belts and they come in sealed plastic bags..so ought to be immune from loss of plasticiser from the synthetic rubber mix used on the belt...as long has they haven't been hanging in the window in the sunshine!! After insecting the belt I left on for five years, I've stuck to the 2 year specification. The best advice to anyone buying an Esprit is to change the cambelt immediately, no matter what the PO might say...then you KNOW where you are!

[s2mikey]

The best advice to anyone buying an Esprit is to change the cambelt immediately, no matter what the PO might say...then you KNOW where you are!

Unless there is documentation that the belt was changed recently.... just saying

[esprit22]

if you find a crack in the belt, fill it with superglue and staple together..

[Sir Paolo]

if you find a crack in the belt, fill it with superglue and staple together..

With an MO like that you must be your local Lotus dealer's best customer (ha ha!)

[andydclements]

if you find a crack in the belt, fill it with superglue and staple together..

Why go that far, just a bit of gaffer tape on the back, that should be enough shouldn't it?

[esprit22]

Why go that far, just a bit of gaffer tape on the back, that should be enough shouldn't it?

Nuh, gaffer tape not strong enough...need to try that Solvite wallpaper glue, if it can stick some fool to the wing of a plane.....

[Roger 912]

One of the problems that we encounter in darkest Africa is the fact that no-one has ever heard of a Burroughs gauge. They all seem to adjust a cam belt by feel.

I have checked on the two Esprits and the Excel and they all feel about the same tension. I do check each belt as well as oil level and coolant before I take them out for a drive.

[Mesprit87]

Still, I think common sense should come to the rescue, my TT runs at vaporizing underhood temperature and still, the belt needs to be replaced at 160 000km (That is a little high if you ask me...).

When I bought my car, it had 20 000 miles on the clock and my guess is it was the original ( 23 years old). It was running with a missing teeth. Now that's stretching too much, there has to be something in between. I know it's cheap insurance to replace it but then again, who changes antifreeze or brake oil at recommended intervals???

[Iconic Ride]

I have replaced both my V8 belts with bespoke chains. The peace of mind was well worth the cost.

Of course, as they are exterior to the oil gallery, I must externally lubricate them prior to each drive, and limit my trips to ten miles or less per outing, but it's a small price to pay for knowing that they won't have to be changed out for the life of the car,

[andydclements]

One of the problems that we encounter in darkest Africa is the fact that no-one has ever heard of a Burroughs gauge. They all seem to adjust a cam belt by feel.

I have checked on the two Esprits and the Excel and they all feel about the same tension. I do check each belt as well as oil level and coolant before I take them out for a drive.

And what is wrong with adjusting them by feel? When cam belts were new technology I can understand needing a gauge to measure tension as people may not know how tight is right unless they've done several. Now (before current type belts disappear in preference to chains with auto-tensioners or belts that run in oil) you'd expect a decent mechanic to set the belt by feel and be within tolerance.