Slipped Timing Belt

[LC5F]

Timing belt slipped last night after accelerating out of a roundabout.
Worse still it was preventable, my ancillary belt got damaged while fitting the intercooler, this frayed and a strand got sucked into the timing belt - lets just say that was a very expensive lesson learnt

I have stripped off the cam cover to reveal that:
Exhaust cam still turns with crank, but all 8 valves are stuck fully down that all followers have fallen over, one hydraulic lifter was out of its hole.
Inlet cam does not turn with crank but followers still in position, some loose.

Without removing the head I can tell that exhaust valves are all mashed, plus a enough intakes as well to snap the chain. Other than 2 cam lobes scratched there is no other obvious damage.

Unless someone can offer any hope that the head and bottom end and head are salvageable -but then always worry that a piston will let go - it's looking like I will be needing a replacement long engine.

Need a bit of advice on:
Should I only look for the same BWA engine type?

When I get a replacement lump I plan to do:
Timing belt kit + water pump
Cam chain
De-carbon intake
Clean out oil pickup
- Anything else I should be doing while everything is out and accessible?

[bobby_fodge]

Take the head off and have a look at the pistons first.

I'd then get some quotes for getting either just the head sorted or head and bottom end fixed.

Depending on how long you can have the car out of action for but at least you should then have a known good engine.

I fitted one of these last year or year before, maybe worth considering.

https://www.akstuning.co.uk/shop/home/550-2217-tfsi-oil-pump-balance-shaft-delete-modification.html#/417-balance_shaft_delete-i_am_sending_you_my_pump_1st

[LC5F]

Thanks Bobby - I'm still on the fence with this, the free wheel is tempting.
I do have access to another car, all the work I had been doing on it was for a trip away...I was on my way to get a pair of new tyres & AC fill booked for the next day!

Last night I found a humblemechanic video where only the chain snapped on a GLI jetta, unusual for him he suggested just new valves/guides/seals and then send it on its way.

Rather than strip the head off, I am still more inclined to just swap out the whole engine saving on time, head gasket kit & bolts, plus the cam chain is relatively easy to get at - with a lower mileage engine I would hope this could wait.
Doesn't help that the Golf is currently out in the street, once it's in the drive I can pick away at it.

[Jons1001]

Sorry nothing good to add but hope you get it sorted that's rotten luck.

[chimp400]

Problem is what state will the new engine be in?
If it were me I’d just strip your head and get it done if the pistons are ok, you will have chance to de coke it all and add new gaskets and timing belt etc.

[LC5F]

Sorry nothing good to add but hope you get it sorted that's rotten luck.

Thanks Jon

Problem is what state will the new engine be in?
If it were me I’d just strip your head and get it done if the pistons are ok, you will have chance to de coke it all and add new gaskets and timing belt etc.

Yes - that's always the gamble with a pre-loved engine
- but if I stuck with the current engine, by the time I add head gasket set, head bolts, valves, lifters/followers and then possible machining for new guides that would be well over £400 and a long way to used engine.
I will strip it down, but first need to get the Golf into the drive to work on it properly - so far in the street I have got the HPFP off - at least the follower was looking good! - and most of the intake manifold is undone.

[pudding]

Ouch 

Maybe I've misunderstood your OP, but I can't get my head around how a frayed serpentine belt took out the cambelt?  Aren't the cambelt covers there to protect the belt from foreign objects?

In any case, I doubt the bottom end is game over unless the valves thumped the pistons with such force, the con rods got bent. The valve stems are pretty thin and will bend way easier than bending a rod or cracking a piston. I guess only a full strip down and inspection will confirm, but you might be surprised.  Generally, the lower the engine speed when that happens, the more chance of survival.  Was it a low gear, high rpm failure?

If the engine was sweet prior to this incident, I would personally just plonk a new head on it and carry on.  Swapping it with a used engine could open an even bigger can of worms as already mentioned, especially as most second hand engines will almost certainly have been tuned/mapped, and therefore unknown history/condition. 

Good luck with it.  Hopefully it's not as bad as you think under there.

[LC5F]

Cheers Pudding -
RAC guy said that this was an issue with these engines and he had seen this before with the cover allowing foreign objects in - I also seem to recall reading some random thread on here where this happened to someone else.

I was on about 65% send coming out of a island at 40 - so will see how much carnage there is.

I was thinking used head, it's the same price as a set of aftermarket valves, seem to recall reading they are all the same part number, with different engines having lower compression from pistons.

Edit - different part numbers

[pudding]

Ah OK.  Maybe the knackered alternator belt chewed its way through the cambelt cover over time?  It is only wafer thin plastic after all!

Hmmm, OK, a fair bit of rpm and load then.  I reckon you will just have some contact marks to smooth off the piston crowns and you'll be OK.  The compression ratio isn't massive on the BWA, 10.5:1 iirc, so valve cloutage shouldn't be too severe.  If all the pistons are at the same height in relation to the block surface at TDC, theres a good chance the rod(s) didn't bend.

There are some head and cam differences between K04 and K03, but afaik, all K03 heads are the same.

What a pain in the rump.  At least you have access to another car for work, which is the main thing!

[LC5F]

Thanks again Pudding - I found an excellent thread you contributed to https://www.mk5golfgti.co.uk/forum/index.php?topic=109982.0
AXX & BWA heads are interchangeable.

Progress today was getting the Golf into the drive way, no small feat as its got a slight slope, shuffling it over to one side was a complete mare!

Started stripping it down, confirmed my theory of frayed drive belt, there was 2 or 3 rows of "rope" stripped before, it must of kept un-ravelling:


Top cover off and found this:


under the timing belt I found more:


The extracted foreign objects:


Would love to show the bottom cover removed...but one of the 6 bolts in the crank pulley decided to round out - I'm thinking drill the head off

At least my plans for the intake de-carbon was definitely due, this is number 3:


Current state is only turbo oil feed and a coolant line connected + all the head bolts left before head and turbo off in one lump:

[LC5F]

The butcher's bill is in.
All 16 valves bent:

Opened up the timing chain and was confused as everything looked great. instead of ripped chain and destroyed tensioner - they were both good, what happened was the locating pin in the VVT ring sheared, and the bolt had started to undo itself:

But cam follower still mint!

More drive belt found, the spindly thread middle left was jammed behind the cam wheel:

must have been rubbing behind the pulley before gaining entry:


I was a bit annoyed to find the head bolts are a special socket 10mm polydrive -ordered one, be here in 3 days - but left me stuck with head still attached - fortunately a T50 torx grips the head bolts just enough to remove them.

Pistons look OK -
No.1

No.2&3

No.4


Close up angle view of No.3:

After some brake cleaner and scotchbright, not even sure if there is even anything I can hone down & all the pistons come to the same height and damage is a lot less than I was expecting:


All 4 done:


So the upshot is I am happy to stick with the bottom end, getting a cheap second hand head, need to find another VVT ring and have a close review of the current lifters and followers.
Will speak to machine shop to get the upper cam pulley removed from the exhaust cam - it won't come off so the woodruff key has jammed + price out tank wash and possible valve guides.

[chimp400]

I'd find a company that can refurb yours, shouldn't break the bank and will come back all nice and shiny.

[LC5F]

I'd find a company that can refurb yours, shouldn't break the bank and will come back all nice and shiny.

Thanks - I did and yes it is very shiny: