Gti-6 Timing Problem

[Daxed 7]

Hi All,

 

My car came home on the back of an AA truck. I wasn't driving it when it went wrong but the report I received from the driver was that they had pulled out from a junction, was just changing into 2nd then heard a loud screech followed by the car stopping

 

The AA guy told me he thought it was a timing issue, that it turned over without proper compression and made a large backfire.

 

On removing the cover the belt looks fine, no stripped teeth and although I don't have a proper understanding of the tensioner system I can't see anything that looks amiss and the belt seems properly taut in all places I can reach.

 

On turning the engine over by hand to set a crank pulley timing pin in place I felt a lot of resistance in certain parts of the cycle (hardly able to turn the engine over with a std size 3/8" ratchet), assuming this was compression I removed the plugs but the resistance remains.

 

With the crank pin in place (I don't currently have suitable size items for the cranks) the inlet cam alignment hole is a mile out as can hopefully be seen in this pic.

 

 

I guess you can't really see the miss-alignment due to the angle of the photo but it is a long way out.

 

I have the Lynx/Rich_W ally crank pulley fitted so assume any possible miss-alignment due to a deteriorated outer pulley is not a possibility.

 

 

I can't see the alignment of the exhaust cam and as I said don't have a suitable pin at present.

 

Is it safe to assume that any possible damage has already been done (the car was cranked over on the starter by the AA chap following the breakdown) and that I can't cause anymore grief by doing a compression test?

 

Should I remove the crank pulley and check the bottom timing belt drive? Head off?

 

I guess I'm really asking what to do next

 

Cheers,

[Toddy 7]

1) Having alot of resistance turning it over suggests the valves are hitting the top of the pistons, can you borrow a bore scope and take a look, if not it's your choice to do a compression test, personally I would, be cheaper to get another engine if fubared.

 

2) The inlet cam is a far bit out, looks like a tooth at least

 

3) ask whoever was driving whether it sounded like a sewing machine/ metallic tapping.

Edited October 9, 2011 by Toddy

[Anthony 1,003]

Unlucky Steve

 

Chances are that any damage that is going to have occurred will already have done so if it was being driven when it failed, and then spun over on the starter by the AA man. Certainly looking at that inlet cam pulley I'd be surprised if you've not bent some or all of the inlet valves, assuming that the crank pulley was lined up with the timing hole when the picture was taken.

 

The double valve springs on a GTi-6 head do add considerable resistance when turning the engine over, but it still shouldn't be that hard with the plugs removed - my guess is that as per Toddy's reply above, you're kissing the pistons and valves, which would make sense with the inlet cam that far advanced.

 

Do a compression test to see what cylinders are showing no/low compression (all of the I'd guess), and then head off time to see what a dogs dinner you've made of it. I think that I'd be tempted to get a replacement engine rather than fix that one, as the pistons aren't the strongest on GTi-6's either, and having taken a whack from the valves I'd be concerned with them subsequently failing - especially with the stress of forced induction. GTi-6 engines seem to be silly cheap at present, especially as you don't need the management, manifolds etc and thus a Phase 2 Xsara one would be fine.

 

How many miles had it done since the last belt change out of interest?

[Daxed 7]

Thanks for the replies gentlemen.

 

I will do a compression test tomorrow.

 

Pretty gutted if this is the failure Anthony as new belt, water pump and tensioner fitted within the last 5k miles from memory and probably a fair few less than that.

[matty_gti 20]

Can't one of the cams be atleast one tooth out and not have any problems?, some people alter the cam timing ever so slighty (maximum one tooth IIRC).

 

You'll have to see what the exhaust cam is like then see what the alignment is really like.

[welshpug 1,657]

Its around half a tooth you can get away with, its more the proximity of the valves to each other as well as the pistons that causes issues.

 

Is it a 136 or a 137 timing belt on there? I see that its the later cam pulleys.

 

An M5 bolt can be used to check if the cam timing is out, M8 for the crank pulley.