Disastrous Clatter From VR6 - tensioner bolt causes rebuild!

[Kevin Bacon 5]

It's all in the Wiki mate. There's a chain replacement guide on there.

[MikLSP 0]

Update on this, while progress has been somewhat slow things are coming back together now.

 

Had the head reconditioned, 8 new valves, cylinders re-honed, new piston rings, bottom end rebuild, oil pump rebuild, all new chains and tensioners.

 

I think we may have found the original cause of the problem too, the tensioner bolt was unable to retain oil pressure so the seal must have gone as Andy & Kev wisely mentioned. This has seemingly resulted in a loss of chain tension and skipped teeth on the cams :(

 

Ultimately we have here a £1500 cost due to the failure of a £40 part! :mad2:

[Kevin Bacon 5]

Bummer, but at least a reason was found.

 

That's the way it goes sometimes. You could say the same of cambelts. A £40 belt can also cause catastrophic failure! At least your engine was salvagable though :D

[andy 0]

Glad you've found the cause, it would be worrying to put it all back together without knowing what had caused it. Dare I say it, you could have replaced everything else but used the same bolt . . . Anyway she should be really good now!

[MikLSP 0]

Yeah, certainly glad to have found a cause otherwise it would have been a worry as to whether it might happen again even though everything has been rebuilt.

 

Funnily enough, I bought my chains and tensioners from vwspares.co.uk and they could not supply the tensioner bolt. I asked my mechanic about the existing one and whether we could re-use it hence him testing it and finding that it cannot hold the pressure. Imagine if I had gone with the old one unknowingly and had the same thing happen all over again! :shock:

 

I'm really looking forward to getting the car back now and yeah ok I've spent a fortune on it but I'm now going to have a Corrado with and engine, gearbox, clutch and brakes I can rely on (touch wood!)

[Kevin Bacon 5]

Did you use the later "MK4" style upper tensioner pad? If so, you can't reuse the old bolt anyway as the newer pad uses a redesigned bolt, which is sprung loaded aswell as hydraulic.... so no chance of the cams slipping :wink:

[Roger Blassberg 0]

I would say that £1500 for all that work was a very competitive price indeed - you would expect to pay that for the head and chains job alone. Did you have a new clutch as well whilst the gearbox was off ?

 

Best wishes

 

RB

[Toad 0]

Did you use the later "MK4" style upper tensioner pad? If so, you can't reuse the old bolt anyway as the newer pad uses a redesigned bolt, which is sprung loaded aswell as hydraulic.... so no chance of the cams slipping :wink:

 

Although I've had a broken Mk4 tensioner bolt.

[MikLSP 0]

@ kev

I got this one which I think is the original style.

 

@ Roger

Yeah, already had the clutch done the first time the gearbox was off, it looked like the one on there was the original.

[MikLSP 0]

Another bad update on this, I've posted details in my car topic here, any advise? :(

[dukest 0]

...subsequently a very lengthy rebuild including having the head reconditioned, 8 new valves, cylinders re-honed, new piston rings, bottom end rebuild, oil pump rebuild, all new chains and tensioners the car was finally up and running again. At this point it was still with the mechanic as he had a few other little things to sort out......

 

Yesterday I received a call from him, expecting to hear that everything was now done and I could go get the car back, but no, the news couldn't have been much worse!

After the engine had apparently started first time after the rebuild and run very well since, he left it idling yesterday to get up to temperature and await the fans coming on. Suddenly the engine just stopped and would not restart, not even turning over and could not be cranked by hand!

 

He told me he had taken the rocker cover off again to inspect the cams and valves, all ok, same with the chains. Also the sump is off and the bottom end looks to be fine so now the engine has to come back out to find what is wrong.

 

Surely though if either end seems fine and the engine cannot be cranked the only explanation is a seized piston?!

What could have caused this and what sort of outlook am I going to be expecting?

 

if you've paid for what amounts to close to a full rebuild then i wouldnt be expecting any issues - not casting aspersions but for something to suddenly seize when just idling it sounds like somethings gone wrong/not been checked/not been done properly in the rebuild?

[MikLSP 0]

Well that is the natural thing to assume isn't it :(

 

A friend just suggested that maybe he over-torqued some bolts and the crank nipped up when it got warm.

[muppetlab 0]

Jeez mate thats some bad luck. Was it the same Garage that did the clutch etc first time round? If they have rebuilt an engine to that extent i would say its down to them to make sure its thorughly checked over before starting work. If they forgot to check something the blame can only be all theirs. Hope they are going to sort it out for you as i would be going mental at this point :bad-words:

[barrowfordred 0]

I'm going mental and it's not even my car, (he is my son though) :lol:

[MikLSP 0]

Yeah all done at the same place. Really just waiting to hear from the garage again now before forming an opinion.

 

I'm going mental and it's not even my car, (he is my son though) :lol:

:lol:

[MikLSP 0]

Update: The engine has been stripped down again and despite the mechanics initial thought that the bearings looked ok with the sump off, it turns out the #3 crank bearing had indeed nipped up. The crank has now been sent off to be polished and new bearing on the way.

 

Not sure what would cause this to happen but I'm at least glad that nothing has happened to the cylinders or pistons.

[barrowfordred 0]

I might get the chance to drive it more than 300 yards when it eventually comes back. I've forgotten what colour it is :lol:

[Kevin Bacon 5]

@ kev

I got this one which I think is the original style.

 

Not a good idea! You should have used the redesigned part. Oh well. Too late now.