T4 Timing Belt Issue

[CRH71]

All,

2000 - W - V40 T4, originally with B4204T5 engine until it self-destructed and now sporting a shiny B4204T3 lump, known perfect runner before it was removed from the donor car.

Whilst it was "in between cars" we thought it a brilliant idea to change the cambelt, tensioner(s), waterpump and auxiliary belt - such jobs are a lot easier when you've got room to work in!

My friend, who actually changed the cambelt admitted that he didn't have the tools to lock the cams, but set the crank to TDC, locked it and then marked the cam pulleys before removing the old belt. He swears "nothing moved" and the marks were still exactly as they were when he replaced the belt.

Fast forwards a lot of naughty words and skinned knuckles and the lump's back in the car now.

Gave it fuel, sparks and prayer and it started, but very, very lumpy - a definite mechanical misfire (recorded code P0300). General conclusion is that the cam timing's out and I wondered if it could be something to do with the VVTI pulley on the exhaust cam?

On the plus side, the engine DID run, fairly happily, without making any nasty metallic noises so we're reasonably happy a valve isn't bent as a result of this and, logically, the cam timing can't be THAT much out because it actually did start.

It hasn't been driven since, or even started whilst we scratch our heads in sheer frustration.

Question to all you timing belt gurus - how can we get ourselves out of this mess? Obviously it's out of use at the moment, so getting it to a garage is out of the question and his financial circumstances really don't allow for this option.

Thanks in advance for your time.

[Biotoxic]

As I can see, you have read my guide... so just make sure he set crankshaft and camshaft to TDC.. make sure that he adjust tensioner correctly, if there is some problems, try to move timing slightly (+-0.5cm) to left or right, as per my Adjusting timing section in http://volvoforums.org.uk/showthread.php?t=118618

Is it petrol? make sure that there is spark in spark plugs

[Clan]

Firstly the mark on the crankshaft is NOT TDC it is a mark where the pistons are all down the bore so that the camshafts can be turned without the valves touching the pistons .

have you checked the cam timing marks ?
Lined up the crank pulley mark and the two cam pulleys factory scribed marks align with the slots in the upper plastic cover housing? This is what you should aim for ..
Have you got the right belt ?

[CRH71]

Thanks, guys.

Yes, it's a petrol, and it's got sparks. Clan, I am told that yes, everything was lined up as you describe and the belt was bought for the engine, not the car (it's a newer engine than the original) and he assure me it was the correct one.

Biggest problem here is that I'm trying to diagnose the car from a distance (he's 20-odd miles away) and listening to an engine running (badly) over a mobile phone is less than ideal!

Finally, he got some more time to look at it. He took the timing covers off and made sure all the marks aligned - so we could be sure there would be no damage from carrying on further - then I got him to run a few more tests for me.

Cut another pretty long story short, this "misfire" it's got is just that - it's got a definite 'mechanical' misfire and we've so far been able to rule out crank/cam sensors (got spares from the original engine), throttle body, O2 sensor. He read the live data from it last night, at both tickover and 3000rpm and our initial thoughts from the results of that were that there was a massive airleak.

He's checked more today and found, in fact, that it's not firing on cylinders 1 and 2 and is running as rich as Hades.

However, disconnecting the VVTI soleniod made the engine run MUCH smoother and I'm almost 100% certain he's got the valve timing wrong.

Question time again - what's the best way of locking the crank (it's an auto) without the tools? It's a B4204T3 lump, if that makes any difference - I am told there's some sort of "access point" in the flywheel housing. Ideally, I want to lock the crank, then check the cams are correctly aligned by using some flat steel plate in the end of the cams and a laser level to ensure they're spot-on level.

I'm almost convinced that the exhaust cam's 1-2 teeth too far advanced and, with the VVTI connected, it's advancing it still further and holding the exhaust valves slightly open - hence it running smoother with the VVTI disconnected and the cam (theoretically) retarded fractionally.

I'm not going up there until the weekend, through time constraints, but I really want to nail this once and for all whilst I'm there.

Biotoxic - your guide was really, really helpful, and ingenious! That's an inspired bit of thinking, there. If all else fails, we'll ahve to do it that way, but I really do want to avoid lifting that top half of the head off if I can.