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Techspy

Crap.. Lost timing belt today while running... Now what?

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I will try to keep it short and to the point.

 

94 S4, 58k miles, last timing belt changes were around 2003 (30k miles) and approx 2009 (50k miles).

 

Heard a rotational noise and immediatly after that the engine died. Tried a quick turn over and could tell it wasn't right and just gave up and rolled to a stop. Car was going about 20mph and at about 2500 rpm when it happend. Timing belt is trashed (see picture).

 

So, questions are;

 

- How to tell if the valves, pistons are damaged? I assume I will have to pull the head to see. That can be done without removing the engine correct? If I don't see any damage, I can put it back together and replace the timing belt correct? Would a video scope like this have any luck in looking for any damage via the spark plug holes? http://www.mcmelectronics.com/product/22-13245

 

- If there is damage I will need to pull the engine, replace the damaged valves and pistons. I have seen different opinions but I think the concensus is that I can simply replace the damage piston(s) and not the whole set? Will I need to have the liners honed or leave them as is? Last compression check a year ago was good.

 

- Looking at the timing belt it seems a groove has been gouged in it. Is this how they normnally fail or has something come in cotact with it? If so, what could it be?

 

Well, if anyone has a set of pistons and valves I may be in the market for them. I have quite a bit of parts I could offer for trade if intersted (used stock turbo, Tubi exhaust and test pipe, etc).

 

The fortunate part is that I was only 2 miles from home. Still cost $90 for a rollback ride. But at least she is home.

 

I am going to pour another drink now.....

 

a6065614-212-IMG_20130830_201524.jpg

Edited by Techspy

John
94 S4

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You can do a leak down test now as is.  That will give you some idea of how much damage to valves.  You could also use a borescope to look inside.

 

Otherwise, have the head removed and inspect the head, valve, seats, cylinders, and pistons.  

 

Looks like you might have caught a rock in the belt or something like a nut, bolt, or tool from previous work?  COuld just be from skipping a tooth due to being too loose.

 

Your tensioner might have seized?


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Thanks for the info Travis. I have a borescope on the way. I will see how it goes from there. I may just source a new short block, swap it and rebuild this one or sell it as-is if I find damage.

 

But, how can I do a leak down test like it is? Wouldn't I have to replace the belt first?


John
94 S4

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The short block is mot likely not needed...  or available... 

 

The cylinders are removable on the 910, so usually unlikely that the block is damaged.  The head could be damaged, along with pistons, and cylinders...

 

Don't start ordering stuff until you see the extent of the damage!

 

You can do a leak down without the belt, turn the crank back 90 deg from TDC to prevent the valves from hitting the pistons as you turn them to close each cylinder, or just remove the cam towers so all the valves are closed by the spring force.


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Well, I will check with the borescope and if that is inconclusive I will try a leak down test or just pull the head. I have already found another engine and if I find any damage would rather just swap it out as I can do an engine swap but dont have the tools for a rebuild. Even if I end up with this engine as an extra, I wouldn't mind. I can take it slow and have it rebuilt as I get the time.


John
94 S4

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Bad luck sounds like you're in for a very expensive time. :thumbdown:

 

I had the alternator mounting bracket (the piece with the steel tube through that the alternator swivels on) split apart & that gouged a groove in the timing belt but as I checked the engine every week I caught it in time.  :thumbup:

 

When you're rebuilding the head you'll also need to check the guides of any bent valves as they can split due to the force of impact.

 

Commiserations & good luck.


Cheers,

John W

http://jonwatkins.co.uk

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Im with Travis looks like a stone or a bolt got in there? Do you have an under tray fitted? How loose was it when you took it off? I mean it hasn't broken completely so you may have been lucky and skipped a couple of teeth?

 

Best of luck.

 

Buddsy


 

"Belief is the enemy of knowing" - Crrow777

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It is broken, just pressed back together for the picture. Undertray is installed. I will get under the car soon and remove enough stuff to try and look for a cause of the failure. I will probably just trade this engine in on an already rebuilt one as I really don't have the setup for a rebuild.


John
94 S4

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Well its out. I didn't see anything out of the ordinary looking at the places where the belt goes. Nothing out of place or anything that looks like it could have come in contact with it. Maybe it was just a bad belt.

 

Anyway, now to try to figure out doing a rebuild etc. I haven't pulled the to look at the damage as I am planning on a total rebuild anyway.

 

Holy crap what a job that was......

 

a6082754-140-out.jpg

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John
94 S4

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Sure didn't seem like it... I imagine I worked on it a total of 5 hours per day/evening (not including tool runs etc) so about 25 hours total? I did a lot of referring to other threads etc so I definitely was figuring stuff out as I went. While it is being rebuilt I will remove the gas tanks and inspect/recoat them etc. I am also going to clean the hell out of the engine bay and refurb a bunch of stuff. At least it will be a cleaner job going back in.

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John
94 S4

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Hope it all goes well for you. At least you are going to take the opportunity to do some other stuff that is easy to do while the engine is out so some good news there.


All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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Yeah pretty much. I'm not too bummed at this point. A few years ago and I would have probably had a stroke. I am fortunate that I have the funds to have it rebuilt with a few nice upgrades at the same time. Also, when it broke I was just a couple miles from home on the way back from an errand in the middle of the day. Tow truck was there in 15 min.

 

Yeah it sucks but it has always been a possibility in my mind and it will be as good as new and worry free driving when done (hopefully).

 

Anyway, I am driving the engine to the mechanic that will be doing the job tomorrow. He is basically going to balance everything, port the head, upgrade to green dot pulleys and replace all the standard things (water and oil pump etc) as well as check the clutch and turbo (WCE turbo with about 12k miles on it and as S4s clutch and lightened flywheel with about 20k miles). So, hopefully there will only be a couple valves and guides that need replacing and the parts cost won't be too high.

 

So I am going to use the time to refurb the engine bay (header tanks, engine bay side panels, etc), pull the gas tanks to check them and properly mount my electric chargecooler pump. Probably replace the shifter links too as they are pretty rusted and stiff. I am also going to get a set of silicone hoses as well. And I am sure there will be a few more things that come up.

 

By the way, anyone have a link to a set of silicone hoses that they have used? I have seen several sets on eBay but am not sure about which are better and fit correctly. Also, anyone have a source for the orange engine paint?

 

Thanks


John
94 S4

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http://www.colorcote.co.uk/

 

Right opposite the Lotus factory in Hethel for the paint!


88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

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FYI, dropped the engine off and took the timing belt. My mechanic said the belt was deteriorated but he had to look closely to see it was in bad shape. It was either old stock that the mechanic that fitted it had a long time or was old stock received from his distributor. Really sucks as there was no indication before it went. I will definitely be using the blue belt from JAE on it after the rebuild.


John
94 S4

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My mechanic said the belt was deteriorated but he had to look closely to see it was in bad shape. It was either old stock that the mechanic that fitted it had a long time or was old stock received from his distributor

 

I see at the top you had the belt in for 4 years. I know on my 85 turbo the belt should be changed every 2 years. Is it different on your car or were you running a belt for twice the recommended period? 

 

Buddsy


 

"Belief is the enemy of knowing" - Crrow777

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I just purchased the car back a year ago and was told it was replaced during the time period I didn't own it, which was 4-5 years. It had at most 10k miles on it.

 

In any case, it was determined that it the belt was in much worse condition than its reported age.


John
94 S4

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I think milage lower than the recommended change distance is irrelevant as is age of the belt prior to fitting. Its once its fitted and goes through the heat cycles and stretching. I'm not having a go by the way just would be interested in determining any thing that would save others...well me from the same fate!

 

Buddsy   :(


 

"Belief is the enemy of knowing" - Crrow777

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I really feel for you - as it is something that is so easy to put off - because it is expensive and/or time consuming - but can really cause a lot of stress if it does go. I have lived by the rule of 2-3 years (no longer) or 24,000 miles. As Scott says they degenerate more once they are on the car through the heat etc. If I have had no supporting paperwork for the Cambelt - I get the belts done. You are not the first and certainly not the last who have had a belt on longer than the ideal time and sadly it let go. The tensioners can have the same effect if the bearings go too - ask for them to be replaced as well - a bit more expense but at least you have a line in the sand. It is also very difficult to tell the age of a belt unless it has visible signs of wear or you have supporting paperwork. Feel bad for you - here's hoping your tale prompts at least one forum member to change their belts before the inevitable happens!

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I recently put off buying an S4 that had been through 5 owners in 5 years and nobody ever bothered to change the belt on it. They all kept saying "aah but it's only done like 5000 miles on the belt!". Maybe send the old belt for analysis to determine cause of failure?

 

But kudos for keeping a positive attitude through it all, all things considered. I'd probably have to be committed if it happened to me.


Vanya Stanisavljevic '91 Esprit SE | '91 Elan SE | '97 XK8

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We all know the timing belt is a big weakness of our engines. Has no one thought of a modification to fit a chain instead? Surely would be better?


Signature not working...

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Not sure why the belt hasn't been significantly improved.

Changed my vectra diesel @ 95k miles. Apart from being a bit glossy it looked like it could easily do another 95k. Tensioner and water pump changed at the same time but they were smooth running too.

Isn't there a new improved Blue belt in circulation in the states or something?


Chunky Lover

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