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timing belt change ?


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Hi all, firstly happy new year to you all,in a bit of a mix up here,come march my timing belt is 2 years old,only doing about 800 miles on the belt and new idler.trying to find a local garage to fit the belt,has anyone else used a local garage or does anyone know someone near dundee ,scotland to change the belt.is it that big a job too slacken the idler ,slip the old belt off,and the new belt on,its a S3 n/a with none of the turbo extras etc in the way.also reading other threads about the belts i thought the v-belt drives the crank,alternator,and waterpump as i`ve only one belt appart from timing belt,thanks

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Your right the V belt takes the crank drive to the alternator and water pump, with the alternator with the alternator forming the adjustment via the sliding bottom bolt.

With the belt and a few other parts out of the way the main obstacle (not a major one) is several components have to be perfectly aligned when the cam belt goes back on, the crank, both cams and the distributor drive crank. The cranks isn't going to move when there's no belt in place, the cams may or may not move easily when the belt is removed (depending on the position you stop the engine in), but the dissy will rotate freely, so who ever does it must stop the engine at the right point/ rotate it to the right point, then be very careful to align the various dots on the pulleys when putting the new belt on. A competent mechanic could do it, but if they're not familiar with where the dots are, or what they have to align with they may need to refer to a manual, similarly, if they're not familiar with which components need to be removed to get access they may not want to do the job.

So, look for a specialist, and be prepared to travel a fair distance to them, it's worth the effort for a job that will be more cost effective in the long run, then somebody who doesn't know the cars having to take a lot longer over the job due to inexperience.

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thanks andy,ye i agree to what you say its a catch 22 as its not just a normal belt to change,how critical is this 4mm pin to retain the idler when loose,i`ve contacted a classic car company who deals with a lotus guy and they told me it would take 8 hours too change the belt what do you think ? thanks again stu

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8 hours seems a bit excessive to me, it takes me about 4 hours including rebuilbing the automatic tensioner, (it is false economy not to replace the tensioner bearing with every belt, Sj sports cars are very reasonable on bearing prices). the locking pin is not strickly necessary for removal, however it helps a lot on fitting the new belt. i use a drill bit!!!

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Some specialists I've come across in the past will deliberately inflate the estimated hours to price the job up on difficult jobs they really don't want to do. They fig that if the guy pays over the odds then it becomes worthwhile to do the job even if its difficult and they don't really want to do it.

Regards

Mat

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hi andy,is it just the bearing you change is there bushes etc or just swap the bearing with the new one,i spoke too paul matty cars ,they said they just supply the bearing now and no kit which is obselste,2 year ago i bought the bearing and idler kit from chris neil,i have now bought a lotus belt from paul matty so i will buy a bearing,and the idler will be ok am i right thanks

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Not an 8 hour job. I've just done an S3 Turbo with aircon this weekend. (4 belts in total) I would say I took a very leasurely 6 hours and did some other stuff along the way. It would be significantly less for a professional with access to a lift etc.

The 4mm pin is simply to retain the idler tensioner, in a tensioned position. I also use a drill bit, but find 3.5mm is easier to insert & remove.

I believe SJ have the tensioner kit, however if its only 2 years since the last, I'm sure just a new idler bearing will be fine. Dont forget to make sure the earth lead is also OK. (to avoid static damage to the bearing).

I don't know what your circumstances or experience is, but its not a dificult diy job.

cheers Steve

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Others may have an opinion on this but you might consider going to the later "round" tooth belt upgrade. These belts are designed to give 90,000 miles of service. On my rebuild I did this and can recommend doing it as the sprockets are readily available.

Jeff

www.espritturbo.com

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Jeff

Ref the service interval for the HTD (round belt). This belt is considerably better than its predecessor but be Carefull!

The info from the Lotus Service notes states:

93 My onwards 4 cyl Esprit (except California) renew cam belt at 36000 miles (37500 miles (USA)) or 36 months,

93/94 MY 4 Cyl Esprit (California) 50000miles with an inspection of belt condition and tension every 12500 miles,

95 MY 4 Cyl Esprit (California) 100000miles with an inspection of belt condition and tension every 12500 miles.

From my knowledge the belt is the same in all the above applications and there were no fundamental differences to the engine that would reduce the belt loading and wear this significantly. This technology wasnt around then.

As a Primary Drive engineer with lots of experience of belt design, I might let the belt on my car go to 50000 miles for the kind of usage I put the vehicle through but I would check it regularly (monthly or before any major planned outing), but I would be very surprised that many would go past the 50000 and make the 100000 miles especially as you will be running a higher ambient in California. These engines also have a fixed tensioner which stresses the belt more.

If you are going to try to get that sort of mileage out of your belt please check its condition regularly, particularly looking of tooth cracking and tooth flank wear. Please also note that there is no time frame for the belt change in California spec vehicles. Does this mean that there is something unique about the Californian climate that prevents the rubber from ageing. I suspect the Californian belt service limits are more to do with local legislative practices involving cars with non free wheeling engines so be extra carefull.

You will probably find that most Lotus garages were picking up worn belts earlier than this mileage and changing them anyway. You will be more aware of local practices. However if you have a genuine 100000 miler belt and can warrant the mileage, I would love to see it.

Regards

Ralph

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hi andy,is it just the bearing you change is there bushes etc or just swap the bearing with the new one,i spoke too paul matty cars ,they said they just supply the bearing now and no kit which is obselste,2 year ago i bought the bearing and idler kit from chris neil,i have now bought a lotus belt from paul matty so i will buy a bearing,and the idler will be ok am i right thanks

That depends on the condition of the bushes. mine have not been changed in 13 years, i just change the bearing every 2 years with the belt. I always strip the tensioner and inspect it though as they have been known to crack. So far so Good.....

If you are thinking of changing to the round profile make sure you get the right pulleys as the cam timming was different of some of the later cars.

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Ralph,

I did keep my original tensioner when I changed over the belts and pulleys. Have no idea how that may or may not extend its life. I do plan to keep tabs on the condition and belt tension as I drive.

I believe you are right about the California belt service limits (mandate) and I am not sure if Lotus had to warranty any cars that failed to go the distance.

On a side note, it is amazing to how strong these belts (cam belts in general) are. In auto dismantling yards I have seen them used as slings to pull engines!

Jeff

www.espritturbo.com

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I suspect the mileage limits may have more to do with Californian emission legislation than with the Californian climate. The laws changed the major service intervals for anything to do with emissions from 50,000 to 100,000 miles in the 90's, I think.

S4 Elan, Elan +2S, Federal-spec, World Championship Edition S2 Esprit #42, S1 Elise, Excel SE

 

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Jeff

You're right, most people think belts are weak but I have had belts and chains compared and I can think of one application where I designed both applications to use the same belt. One remained a belt drive and the other was converted to a chain as it was predominantly for the American market. On a tensile strength rig, the chain broke at 32000N and the belt broke at 49000N. I think I would have preferred the belt in my car.

The belts you are using are quite an old spec and there are now much better specs. I have the moulds to make some of these now and hopefully will soon be able to get a test run made. The work I have done in the past 10 years has allowed me to design a stronger longer life belt, but more importantly I have a process that also reduces friction by approx 50% and wear on my belts has been negligible (more power/fuel economy whichever floats your boat). If the economy wasnt in such a nasty state I would probably have pushed the go button.

With regards to the autotensioner, it would be difficult to guess but I have seen applications that have been marginal at 100,000miles with a fixed tensioner go easily to 150,000 miles on an autotensioner. There main benefits are maintaining a positive tension on the belt for all engine conditions. When the tension is able to drop to zero and below, it is then possible to shock the belt with the next torsional pulse giving a kind of shock you sometimes see when towing an inexperienced driver with a tow rope.

I am pretty sure that there was a bit of preventative warranty work done on some of those early belt applications as that spec is not a 100,000mile belt.

Good luck with your change, let me now how you go if you take the brave pill to 50,000 or more miles.

Cheers

Ralph

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i`ve contacted a classic car company who deals with a lotus guy and they

told me it would take 8 hours too change the belt what do you think ? thanks again stu

As stated, 8 hours to change a belt is way too much.

Maybe thats a quote for a cambelt service? A full C service with tensioner work and

maybe adjustment to valve shims etc would easily roll in 8 hours at a lot of specialists.

Maybe thats a fixed price for worse case scenario and they make their money on the

easy ones.

A lot of places for example allow engine out on their quote for turbo manifold replacement,

but it more often than not can be done with engine in situ. Some just quote for worse case.

:D

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I recently changed my timing belt (with the help of the Lotus Corps - group from IL area), and it took us about 5 hours - this was made a bit easier through the use of a lift, though.

I had not changed my belt in the 13 years I have owned the car...so I was certainly playing against the odds on this! I also put a new tensioner bearing on at this time.

Matt

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hi matt, i wish i was as brave as you but would it be a good test for the Lotus belt too let us run the car until whenever and then sort out the engine free of charge,maybe one day what sort of milage have you done in 13 years cheers stu

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My belt is now aproaching its third birthday. I have been very diligent about checking it. It has not moved one notch since it was installed. I have not touched it, and there are no cracks splits or wear of any kind. I am running an HC with round tooth HTD belt. I can't help to think that belt failures, aleast on round toothed belts, are largely due to installation problems. I considered changing it at the two year mark but it still looked new and the tension was the same as the day it was installed. I will replace it as soon as there is any sign of wear.

I used to consider these cars fragile, but my opinion is changing. A well sorted Esprit can be a reliable car.

Cheers

Clay

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I read a tip in a car mag for changing the belt.

It stated basically cut the old belt in half, i.e half its widith. Pull of one half leaving the otherside holding the pullies etc in place. Then slip the new belt on, once this is half way on width wise. cut the reamaining part of the old belt off and then push the reamaining width of the new one on. Job done.

Does this make sense and would it work?

Amateurs built the Ark

Professionals built the Titanic

"I haven't ridden in cars pulled by cows before" "Bullocks, Mr.Belcher" "No, I haven't, honestly"

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It could work, but I wouldn't.

The belt will not pull past the crank pulley, so you'd have to turn the engine over with only half a belt driving bits of it in order to get the second half out. I'd prefer to see the state of the tensioner bearing and other components before putting the new one on, and if you're replacing them you're going to have to completely remove them anyway.

Do it the normal way, the cut belt method may be fine on some engines, but I'd not do it to a Lotus on the basis it way too costly if it goes wrong to justify saving an hour ( most of the work to do it properly still has to be done with this cut method).

Andy

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hi matt, i wish i was as brave as you but would it be a good test for the Lotus belt too let us run the car until whenever and then sort out the engine free of charge,maybe one day what sort of milage have you done in 13 years cheers stu

Stu,

Not much mileage has been put on my car in the past 13 years. For three of those years, it sat not running (had two children during this time, so priorites changed). Currently my car has 56K on the odometer. Suprisingly, when I took the old belt off, it looked fine!

Matt

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