Author Topic: Oops - piston and valve contact suspected...advice needed! (Read 3393 times)

vwt4 · « **on:** November 19, 2008, 10:19:03 am »

ok guys, well, since I did my timing belt and the T4 (1.9TD ABL engine) has run sweetly, until the other week when it started limping (literally) and running like a dog.
it just got me home and was smoking like a chimney and no power!

I tried to start it a few days later to move it on to the ramps and it sounded nasty so I took the key off and we towed it!

I was deeply suspicous the timing had slipped (like the first time) and these are my findings -

1// I tried to set the engine to TDC to remove the cambelt...it wouldnt! It would rotate freely for about half a turn and then there was an obstruction (bent valve(s))
So I removed the timing belt anyway as I knew what was to come.

2/The crank pulley did not appear to be loose and the gear that the cambelt runs on seems rigid? (I was expecting the woodruff key must be the cause and the timing had slipped?.. but as I couldnt rotate the engine to check the timing I cant be sure if it was still right)

3/The timing belt tensioner and belt were in perfect order

4/ Camshaft out and this is what I found... (a faint scratch on the lobe for cylinder 4 that correspods with the lifter that is stuck and has the dent on the top (see pictures)

The next job is to remove the head and see what lies in store....but Im seeking some advice if anyone has any...

Also, how the heck can I get the big bolt off the end of the Crank (holding the pulley on) as I cant lock the engine? ive tried putting it in gear and it just turns!!! (is my clutch also b*ggered? its never slipped that Im aware of..)

vwt4 · « **Reply #1 on:** November 19, 2008, 10:20:00 am »

All the other lifters seem to be fine...not sure if this means just a coupoe of bent valves or not!

arb · « **Reply #2 on:** November 19, 2008, 11:18:14 am »

Advice ? Count on a full teardown and replaceing a few parts... then use the opportunity to rebuild the engine. :-)

Quantum TD · « **Reply #3 on:** November 19, 2008, 11:53:51 am »

Oooh. Looks like you sucked/bent a valve. I guess the big question would be, why would the valve get sucked/stuck and bent?

Either way, it won't be pretty. Figure at least a piston, and valve work. Hopefully, the valve didn't completely fall in and mangle the head.

vwt4 · « **Reply #4 on:** November 19, 2008, 12:01:21 pm »

Quote from: "arb"

Advice ? Count on a full teardown and replaceing a few parts... then use the opportunity to rebuild the engine. :-)

Thats the problem arb!!

I badly need this vehicle working asafp (I use it for my work) and basically I dont have a nice warm dry garage where I can do a relaxed rebuild! (the garage hass a project car in already and loads of other stuff and the T4 is on the driveway so Im trying to minimise the work I have to do...especially so because Im planning on a 1z transplant from a Golf TDi early next year. So basically this engine only needs to run until then!!

I know Im looking at a partial top end rebuild, but Im seriously hoping the bottom end is still solid!!

vwt4 · « **Reply #5 on:** November 19, 2008, 12:03:38 pm »

Quote from: "Quantum TD"

Oooh. Looks like you sucked/bent a valve. I guess the big question would be, why would the valve get sucked/stuck and bent?

Either way, it won't be pretty. Figure at least a piston, and valve work. Hopefully, the valve didn't completely fall in and mangle the head.

Thanks Quantum,

my thoughts exactly. What would make the valve bend or snap?
The only thing I can think of is the crank pulley woodruff key failing, maybe its too tight to spin it by hand but a torquey derv engine can make it move!!

Im not counting my chickens that the piston has had it...not yet anyway! These engines are very hardy indeed.... but Im aware that its not going to be a fun job.

arb · « **Reply #6 on:** November 19, 2008, 12:09:24 pm »

Well, when you pop the head take a very close look at the crown of that piston. Spend a few bucks for the 2 part crack detection spay can product and test the crown in the bock. The first is a spray that will penetrate cracks you can't see. Then you clean the metal and spray a developer on it and the crack will show up, if present.

If no cracks, roll the dice that the piston was able to decelerate to zero w/o damage while breaking stuff made out of steel... Maybe, but I would not hold my breath.

vwt4 · « **Reply #7 on:** November 19, 2008, 12:13:35 pm »

Quote from: "arb"

Well, when you pop the head take a very close look at the crown of that piston. Spend a few bucks for the 2 part crack detection spay can product and test the crown in the bock. The first is a spray that will penetrate cracks you can't see. Then you clean the metal and spray a developer on it and the crack will show up, if present.

If no cracks, roll the dice that the piston was able to decelerate to zero w/o damage while breaking stuff made out of steel... Maybe, but I would not hold my breath.

Will do Arb,havent seen the crack detection spray you mention over here...
Might have to use the Mark 2 eyeball instead

(I kid, I kid)... I will try and get hold of some of it.

Also, I dont know what Im going to find with regards to the cylinder head yet....

But I dont think its going to be pretty :cry:

addition// Does anyone have any info or even better does an ABL engine tech manual exist? (in pdf ideally!) I would be soooo grateful if anyone has one that they could send to me. (if you can pm me I will give you email addy)

I will happily send you the one I have if its any use to you!

Im guessing I need to remove the exhaust manifold completely and also the inlet manifold, but is there any hints or tips anyone can offer on removing the head please?

Im just going to use the bolt pattern sequence that Ive used on petrol engine rebuilds in the past if I cant get hold of an ABL manual (torque settings, procedures etc)

I have the Eurovan manuals in pdf but the engine is different.

arb · « **Reply #8 on:** November 19, 2008, 12:41:06 pm »

The kit I bought was from Production Tool & Supply ( http://www.rocol.com/lubricants/english/metalworking/flawfinder/ ) But I just searched their site and they don't show it.

Here's a 3 step - I have not used this. I cleaned the metal with Trichlor. brake cleaner...

http://www.rocol.com/lubricants/english/metalworking/flawfinder

But I think I'd trust Magnaflux system - http://www.sacskyranch.com/crack.htm

Quantum TD · « **Reply #9 on:** November 19, 2008, 01:06:13 pm »

I don't imagine any belt/cam slippage. You said everything looked fine. If it had slipped, then I'd expect that more than one valve would be mangled.

I'm thinking some other type of failure: stuck lifter caused by low oil pressure, glow plug tip broke off and got jammed in the valve seat, etc.

No point in speculating, you'll know when you get the head off.

Be sure to follow the instructions for head-bolt removal (loosen outers and work in to the center).

Let us know.

vwt4 · « **Reply #10 on:** November 19, 2008, 02:15:30 pm »

Quote from: "Quantum TD"

I don't imagine any belt/cam slippage. You said everything looked fine. If it had slipped, then I'd expect that more than one valve would be mangled.

I'm thinking some other type of failure: stuck lifter caused by low oil pressure, glow plug tip broke off and got jammed in the valve seat, etc.

No point in speculating, you'll know when you get the head off.

Be sure to follow the instructions for head-bolt removal (loosen outers and work in to the center).

Let us know.

Thanks Arb :wink:

Quantum - I hope your right and its not the cambelt :? but Im not counting my chickens yet!!

Oil pressure has been fine all the time going on the gauge
Glow plugs are all A1 and almost brand new...I removed them all to turn the engine over easier by hand.

10/4 on the head bolt removal procedure.