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I have this pulley (OEM no. 074 105 251 AC S1 - 074 105 251 AC) fitted since april this year as the original was starting to break up.

The old one original VW 074 105 251 T
 

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Discussion Starter #42
Cheers Zmok....the apology was needed.

I have the old, original damper pulley and one other new damper pulley that I put on a year ago when I noticed I had imbalance problems. That new damper pulley made everything worse, so replaced it for an oem quality damper which cured the problem. I have tried all three of these over the weekend with no luck. These damper pulleys have the same exact dimensions. I even put four washers on the allen bolts between the damper pulley and the crank sprocket to put the sprocket in alignment with the cam sprocket etc.. This cured the belt problem, but I wouldn't want to try and run the engine with the washers on. It was an experiment to rule out tensioner and water pump issues. Hopefully you can see the copper washers in the photo.


This is why I'm reluctant to swap other parts such as tensioner and water pump etc...

Why, why, why is the crank sprocket 3mm off????? Zmok, you mentioned that most T4's timing belts run off and away from a usual central position. Could it be that this very crank sprocket location is the culprit. On top of which, any slightest play in the bearings of the other auxiliary parts can cause the timing belt to run in a very bad position. Mine is overhanging the cam sprocket by a good 2mm.

I'm still cool with everything at the moment, haven't had a psycho bash on the van with the sledge hammer just yet. Believe me I'm holding it together, even after just recently replacing a leaking clutch slave cylinder. Engine/gearbox out and replace the very expensive DMF at the same time. Issues with the cylinder head and weak valve springs....hopefully cured that. Touch wood, everything will come good when the key is turned. Not just yet though, tooooo much effort gone in to it to f**k up at the last stage.
 

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Discussion Starter #43
Cheers Interslice, missed your input just then. As I've just mentioned, I have tried three damper pulleys. Two German oem quality and one god knows what quality, and they are all the same dimensions and have the same effect on the crank sprocket location when everything tightened up. Also like yourself, I wondered about the tightening sequence of the four allen bolts, and the main, big stretch bolt. After experimenting with different tightening sequences, it makes no difference to the final outcome.
 

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Discussion Starter #44
bluezie came up with a good likely explanation.....crankshaft bearings shot, therefore crankshaft being forced out by the clutch operation. If this were possible, it would explain the position of the crank sprocket. Can't find any longitudinal play in the crankshaft though!
 

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Years ago I had a T4 with the AJT engine, and I changed the belts twice on it, and the belt definately ran completely on all pulleys, it may not have been absolutely dead center, but there was visible pulley showing on both sides of the belt as you would expect.
 

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Well i thinks its time to find a similar engine known to be ok (maybe someone on here can help ) take measurements of the bare crank shaft distance sticking out from the block / oil pump casing & compare these with your engine ? At least you can rule this theory in or out :*
 

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Discussion Starter #47
Well i thinks its time to find a similar engine known to be ok (maybe someone on here can help ) take measurements of the bare crank shaft distance sticking out from the block / oil pump casing & compare these with your engine ? At least you can rule this theory in or out :*
Couldn't agree more. Exhausted all other avenues!
 

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Discussion Starter #48
Quick update......decided to put everything back together (minus the timing belt covers, belt sticks out too far for those to go back on) and get the old boat running again. Thankfully, and touch wood, at least the engine sounds and runs great after the head rebuild. Keeping a close eye on the head gasket....always a bit weary for the first couple of hundred miles. The timing belt still overhangs the cam sprocket by 2mm which looks well dodgy. Until I can see another acv engine to check measurements of the crank sprocket it will have to remain a mystery. Thank you for everyone's input on this.
 

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Discussion Starter #50
Still running engine without the belt covers. Runs great, but no idea what the problem is. Need to see another acv engine to check position of crankshaft and take measurements. Cheers for asking.
 

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Hi there. Im in Plymouth towards the north park and ride and have an AJT complete bottom end engine if ur not to deep into cornwall ur welcome to come and take some measurements.
 

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Discussion Starter #52
Cheers for the offer. I'm near Penzance so a bit of a round trip, but would have been very helpful.
 

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Discussion Starter #54
Still running my van with timing belt off center and covers removed! Runs good a few thousand miles on. Would need to take measurements from another engine to help diagnose problem. I do wonder if the camshaft is machined differently...cam sprocket sits closer to engine block maybe!!!??? What do you reckon? How bad is yours?
 

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Mine looks pretty similar to yours - it is touching the guard (just). The worse thing is its making a squealing sounds when engine runs. I think it may have prior by markings on guard when I removed it - which may have caused my recent cambelt failure?

I was thinking about new damper pulley and crankshaft gear but mot sure this will help? :confused:
 

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Discussion Starter #57
Bit of an aside Geoman ~ what was the problem with the head mate ?

My AJT is as tappety as hell now (done all the usual stuff), wonder if a rebuild is in order :ILU:
I had the usual tapping noises too so decided to replace the cam and followers. Then I decided to go the whole hog and give the head a degunk....inlet ports were caked so cleaned the lot and reground the valves and replaced springs and oil seals. Got the head skimmed too. With everything back together and timing bang on there was a big difference in performance. The engine could breath again and no more irritating tapping noises. I only had one issue and that was the timing belt fiasco. I swear it was originally like this and the new camshaft is exactly the same dimensions as the original!
 

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I had the usual tapping noises too so decided to replace the cam and followers. Then I decided to go the whole hog and give the head a degunk....inlet ports were caked so cleaned the lot and reground the valves and replaced springs and oil seals. Got the head skimmed too. With everything back together and timing bang on there was a big difference in performance. The engine could breath again and no more irritating tapping noises. I only had one issue and that was the timing belt fiasco. I swear it was originally like this and the new camshaft is exactly the same dimensions as the original!
Cheers mate T:

I understand that the stem seals are quite deep in the head ~ will I need a special tool to change them ? :ILU:
 

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Discussion Starter #59
Cheers mate T:

I understand that the stem seals are quite deep in the head ~ will I need a special tool to change them ? :ILU:
I got the lads that skimmed my head to remove them after bodging the first one! New ones go in easy. All the best if you go aheadT:
 

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I got the lads that skimmed my head to remove them after bodging the first one! New ones go in easy. All the best if you go aheadT:
I'm weighing /pricing up the pros & cons i.e. tools, time, hassle vs. buy brand new AMC head with warranty (more money...) hmmm..
is
Then again, the engine has done 190k, do I go for a complete rebuild... I hate decisions like this :D
 
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