Need help, engine rebuilt, having issues...

[Dodger 10]

Ok, so the G60 is all back together with the exception of the super charger. It starts and idles fine, but as soon I try to give it throttle the timing belt strips? I have been through two timing belts now, and don't want to waste another one. Here is what I think it might be; because the super charger is not installed, and I have the oil line plugged. I am thinking that because there is no where for the oil to go, the lifters are overcharging? So they are stalling the cam when I accelerate? Anyone have any experience with this?

[Trev16v 0]

You have a severe mechanical problem if the timing belt is stripping. It's nothing to do with oil pressure or blocking off the charger oil supply.

 

How well does the engine turn over by hand? Specifically, how well does the head alone turn over by hand?

 

It could be that your head has been overheated in the past and now the camshaft no longer turns as freely as it should, or something. Did you refit all head bearing caps in the correct orientation and location?

 

The only time a belt will lose teeth is if it has been very perished by oil contamination and it is old, and / or valves have met pistons (16V engine). There's something horribly wrong with your cylinder head if two brand new timing belts have stripped.

 

Or... thinking about this a little more, are you sure you have tensioned the timing belt propery, or is the belt starting to slip on the crank sprocket that should be driving it? Or is it definitely tensioned properly, but the belt's teeth are literally being ripped out?

Edited May 27, 2012 by Trev16v

[Dodger 10]

The engine runs fine below 2k rpm. The tension is set by the bently manual. Both were new timing belts, and yes the teeth come off. Everything spins fine by hand. I have already gone back and looked at all the cam bearing caps, they all look good. If it did not run at all I would agree that the cam might be binding or is seized, but that is not the case, this starts right up.

[Rustynuts 0]

Have you tried twisting the timing belt, 90 degrees either way is spit on, any less is too tight, any more is too loose.

[daleyboy 0]

Perhaps a seized tappet may have cause it........

 

Its a strange one thats for sure. maybe if you could work out which wheel stripped the belt that would help, did you look for any marks on the wheels ?

[Dodger 10]

The belt stops at the crank pulley, both times the cam would spin freely with the stripped belt. So that rules out a seized cam. Seized tappet could most certainly be the culprit. I put it all back together again, starts right up, runs below 2k rpm wonderfully. Kind of afraid to hit the gas pedal this time.

[daleyboy 0]

Maybe you could wait until the charger is back on before you start it, i would have the car in a fully built up state and then go from there. Without an intimate knowledge of oil flow it'll be quite difficult to make any definitive diagnosis, however if the engine is fully built then the problem is what you have got, rather than what you haven't got, if that makes any sense.

 

Oil pressure would be quite low below 2000 revs and, would increase a lot, further up the rev range.

 

It is possible that if any components are taken out of the oil circulatory system, then strange things may happen, as you are liable for too much or not enough oil pressure.

 

 

Let us know how you get on, because i for one would like to know the outcome.

Edited May 28, 2012 by daleyboy

[Roger Blassberg 0]

I'm not familiar with the G60 engine, but by stripping the belt the first time, have you not now bent a valve or two? Would this cause resistance to turning which would increase with rate of rotation causing the second belt to fail ? (Of course that doesn't answer the question, "Why did the first belt fail?") How tightly did you do up the camshaft bearing caps? Certainly on a 16V ABF engine the caps are done up to "only" 11 ft.-lb. which surprised me.

 

Are you using belts of a known good quality and correct specification? (Sorry, but it has to be asked.........)

 

Best wishes

 

RB

[steveo29 0]

id not worry about not having a charger on , many folk "bypass" the charger when its blown and run the car without it

[Dodger 10]

I just ran it for an hour, ran great, hit the gas, timing belt slipped. The bently manual calls for 20 ft lbs. The PG engine will not bend valves if the timing belt fails. I am going to try new lifters with another timing belt, and a different torque wrench.

[dannyboy 0]

Id say the pressure caused by pluging the line is causing the lifters to overfill with oil causing hydrostatic lock.lifter locks out,camshaft cant turn,belt strips.Have you had a look for problems with the intermidate shaft?

[owen g60 10]

Run the oil feed for the charger straight back into where the return goes in the block this will solve any hydro lock issues.

It's what is usually done when the charger is deleted due to failure.

I remember reading it on vortex some while ago

[Dodger 10]

BINGO! problem solved! It was the no.1 intake tappet/lifter. Timing belts all over the world can sleep soundly now that my car is not killing anymore of them.

[phantom corrado 10]

this may not help but i had a 1.8i mk2 scirocco and when my oil pump siezed momentaraly it sripped my cambelt of teeth.i would check this and replace if unsure,they are pretty cheap.i believe they are run off the cam belt.