HELP!!!

**Nath43** · 11th November 2011, 03:54 PM

I have blown a water pipe on my D2 V8 and stopped as soon as I saw the temp drop off. Long story, but I was watching the temp gauge quite often as it had a small radiator leak and was booked in to have it fixed two days after the pipe burst. DOH!!! Unfortunately I have done some further damage and I am unsure of what it could be. I have cylinder pressure in all but cylinder 2. Which is puffing through the oil filler when running. First thoughts were a head gasket or cylinder rings gone. It doesn't burn oil and there is no water in the oil. We've stripped it down to the point where the rocker cover is off and I have just spoken to a mechanic at a reputable place in Perth and he said it is less likely to be a hole in the piston top or rings gone (our current thoughts) but more likely a valve issue. Can anyone give me any advice or has anyone experienced this? The valves seem to be acting as they should but is there a possibility the intake valve just isn't sealing/seating???

**PhilipA** · 11th November 2011, 04:04 PM

Broken Rings /cracked or holed piston.
Ouch.
Shouldn't puff if burnt /stuck valve as there is no direct connection between the inlet or exhaust manifolds with the crankcase.( and umnlikely to have enough gas going up valve stem to puff, unless a valve has completely disintegrated and drpped into the cylinder , then refer to Piston).
Regards Philip A

**Blknight.aus** · 11th November 2011, 04:13 PM

pull the plugs and do a rough leak down test...

roll the engine over by hand till the piston you want to test "puffs" air at you then blow air down that cylinder with a rag wrapped around an air duster or a propper rubber bunged job for doing it.

IF a piston doesnt puff air at you when you wind it over then its leaking and badly.

The really poor mans version is.

pull the plugs, fit them to the leads and then earth the plugs to prevent damage to the coil packs. disable the fuel pump/injectors

wind the engine over 2 turns to ensure its mechanically free

crank the engine on the starter while you place your finger over each plug hole the one that produces the least puff is your suspect pot, refit its plug, remove the dipstick. crank the engine again.

With both tests

Air into the inlet means inlet valve seal failure
air into the exhaust means exhaust valve seal failure
Slow air into the crankcase means ring
big air into the sump means piston failure
Air into the cooling system means head/gasket

If youve got one throw an endoscope with a 9mm head into the suspect bores and that'll show you the piston crown use the 70 deg mirror attachement to look at the valves.

**Nath43** · 28th November 2011, 11:21 PM

Thanks all,

Did the leak down test and found heaps of air coming our of the PCV hole. Oh no!!! Already had the left bank rocker cover off so continued on and took the head off. Found that the head gasket had blown but into the valley so that the air could escape straight through. Thankfully!!! I had the head skimmed very slightly (back to flat) and got all the new gaskets and head bolts to put it back together. It's back in one piece now but still isn't running correctly. I found that the plug from the bad cylinder was fouled so I replaced that and the leads are really difficult to put on correctly. Anyway, it feels like it is still missing. What I am wondering is if there is a chance that the coil packs might have got a hot joint when the engine got hot? If so, is the best fix to get another pair and then test it that way? And I'm guessing that it means pulling the intake and plenum off to get to them again?

Thanks for your help in advance and above.

Nath

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