Club 80-90 Forums

I have just bought a 97 aaz engine and as I was stripping it down noticed that the crank nose that locates in the timing belt pulley was a bit chewed up. I have read that people think it is a better idea to go for another engine, but how do you know that the next one will not be the same?

I was thinking alobg the lines of cleaning it up and replacing the pulley and using some engineers adhesive to provide some additional locating strength. As far as I can tell the exact location of the pulley is not critical on the nose of the crank as there is enough adjustment on the other pulleys.

Has anyone else thought along the same lines?

That usually means they are f**ked and it's the first thing you check before you put one in.
Use some chemical metal if you want, thats what people tend to do when they are selling them! just for them to behave just long enough to sell the car.
Buy another engine, or fit a TDI crank.

Waste of time trying to sort it, get another engine or a tdi crank, nothing else is goint to sort it.

Thats what i have read, but with these modern adhesives is it not possible to assist the crank bolt by literally glueing it on? I actually drove around in the car for a while before I pulled the engine and all seemed ok.

I have had prior experience with these engineering adhesives and they are pretty tough. I think I will give it a go and see what happens, if the engines scrap anyway I have nothing to lose!

Thanks for your input, if it all goes pear shaped I will report back.

Cheers

cabs wrote:Thats what i have read, but with these modern adhesives is it not possible to assist the crank bolt by literally glueing it on? I actually drove around in the car for a while before I pulled the engine and all seemed ok.

I have had prior experience with these engineering adhesives and they are pretty tough. I think I will give it a go and see what happens, if the engines scrap anyway I have nothing to lose!

Thanks for your input, if it all goes pear shaped I will report back.

Cheers

Proper metal is stronger than any adhesives i know of, that broke.

I shall watch out for your report back of 4 smashed pistons.

Thats very interesting, thanks for the link. I was thinking about the design of the pulley and can only see that the key just locates the pulley in the right position and kept from rotating, ie not shearing the key, is the friction between the two mating surfaces. So if the surfaces are flat and mate up properly there will be no problems?

The pins are a good idea as a precaution but if the surfaces are not correct they will be subjected to a shearing action and possibly fail.

This was why I was thinking of adhesives as they can fill in any minor imperfections in the surfaces. The aerospace industry uses adhesives so I guess they are strong enough.

As a belt and braces fix you could use the pins and some adhesive!!

the use of something like loctite bearing fit and the mod in the link from simon should work fine?

cabs wrote:Thats very interesting, thanks for the link. I was thinking about the design of the pulley and can only see that the key just locates the pulley in the right position and kept from rotating, ie not shearing the key, is the friction between the two mating surfaces. So if the surfaces are flat and mate up properly there will be no problems?

The pins are a good idea as a precaution but if the surfaces are not correct they will be subjected to a shearing action and possibly fail.

This was why I was thinking of adhesives as they can fill in any minor imperfections in the surfaces. The aerospace industry uses adhesives so I guess they are strong enough.

As a belt and braces fix you could use the pins and some adhesive!!

VW realised they had severe issues with this pulley, the pulley and bolt are not at fault, there are severe pulsations due to auxilary belt setup there is a simple cure but once nose of crank is damaged its never going to be right without a new crank or modified to take a tdi pulley.

Thanks for all your comments, just out of interest how is the TDi pulley different and is it difficult to modify the nose of the crank to fit it? I have a pulley from a 220000km N/A diesel engine and it was perfect so would the problem be less likely to occur if I used the alternator and water pump set up from the N/A diesel engine?

cabs wrote:Thanks for all your comments, just out of interest how is the TDi pulley different and is it difficult to modify the nose of the crank to fit it? I have a pulley from a 220000km N/A diesel engine and it was perfect so would the problem be less likely to occur if I used the alternator and water pump set up from the N/A diesel engine?

Tdi pulley has no key, it is D shaped, even loose it would take alot of abuse. The t25 diesel belt setup will be much nicer to crank pulley. The AAZ, 1Y, and all tdi's have the belt problem just does not kill the tdi's.

Thanks, so would it be worth me trying to modify the nose? are the pulleys of similar dimensions or is it like too much much work?

cabs wrote:Thanks, so would it be worth me trying to modify the nose? are the pulleys of similar dimensions or is it like too much much work?

Never tryed it myself but crank will need to come out and be machined accuratly, should be cheaper than another engine or tdi crank.

Ok thanks for all the info, will have a good think about what to do.

Cheers

The Maybe Worth a Go link was a good idea. And easy to do.

I have just fitted a 1Y engine but could not get hold of a pulley in time so I have left the original one there undisturbed - but naturally am concerned.

I have used the golf fan belt set up, but have machined of the outer steel pulley as it was not going to be used in my conversion.

I have also read on here that VW upgraded the bolt at some point and you can tell this via a nipple or dome or something special about the bolt - any idea's?