Blog Title: '97 TSi AWD Auto 2.4 Build Project
Project log following my 2.4 build.
Head Gasket
Posted 05-26-2011 at 04:12 PM by VETDRMS
Well, the 2150s work great and E98 is a blast, but it started pushing coolant. After a re-torque and lowering timing it stopped but when brining the timing back up it pushed again so it was time to pop the head!
Here is the last pull before pulling the head (attached):
It was running really well at 25-26psi, ~58lb/min. It scratched it way to ~3.2s 0-60 spinning, full weight, full tank of gas and a passenger. It launches pretty well and doesn’t squat too much, I can’t wait to get it to the track on a sticky surface.
I never ran excessive timing. Timing near the torque-peak range of 4500-5500rpm timing was below 10* on the "high" timing map and ~5-6* on the low timing map. I never registered more than 1.8* of knock retard but it still lifted.
The #2 cylinder leaked on the block side of the gasket. Upon disassembly we noticed an issue with how the valves were un-shrouded: there is an overhang of the gasket that creates a hot spot, which would explain its low tolerance for timing (6* peak) on pump gas. I am looking for a gasket solution but unfortunately the chamfer in the combustion chamber comes very close to the fire ring. Cometic cannot move the fire ring and I am waiting to hear back from Fel Pro about the fire ring starting diameter. If neither of those will work a copper gasket is a possible solution, but not one I want to try very much. Another option would be to weld the chambers and re-machine it but that will be a last resort.
All of the cylinders looked good, perfect cross hatch and minor scuffing from the skirts but no gouges or signs of material in the cylinders. The ethanol was just starting to clean all the carbon up from the piss gas it was running on low boost.
Hopefully it will be back on the road in a week or less and I can turn it up!
Here is the last pull before pulling the head (attached):
It was running really well at 25-26psi, ~58lb/min. It scratched it way to ~3.2s 0-60 spinning, full weight, full tank of gas and a passenger. It launches pretty well and doesn’t squat too much, I can’t wait to get it to the track on a sticky surface.
I never ran excessive timing. Timing near the torque-peak range of 4500-5500rpm timing was below 10* on the "high" timing map and ~5-6* on the low timing map. I never registered more than 1.8* of knock retard but it still lifted.
The #2 cylinder leaked on the block side of the gasket. Upon disassembly we noticed an issue with how the valves were un-shrouded: there is an overhang of the gasket that creates a hot spot, which would explain its low tolerance for timing (6* peak) on pump gas. I am looking for a gasket solution but unfortunately the chamfer in the combustion chamber comes very close to the fire ring. Cometic cannot move the fire ring and I am waiting to hear back from Fel Pro about the fire ring starting diameter. If neither of those will work a copper gasket is a possible solution, but not one I want to try very much. Another option would be to weld the chambers and re-machine it but that will be a last resort.
All of the cylinders looked good, perfect cross hatch and minor scuffing from the skirts but no gouges or signs of material in the cylinders. The ethanol was just starting to clean all the carbon up from the piss gas it was running on low boost.
Hopefully it will be back on the road in a week or less and I can turn it up!
Total Comments 3
Comments
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Damn...how does head lifting like that occur? It would appear that happened to me: http://vm01.zi0x.net/misc/IMG_0268.JPG - but I was only around 20psi. For me personally it was a botched HG install - I didn't set the headgasket perfectly flush and went with it. Also my 7 bolt head was never drilled for 6 bolt ARPs...I just threaded them down with the head already on, some bound up others didn't.
When I replaced this HG I put all but 2 of the arps on, made sure the head HG aligned correctly, put the head on and the 2 in. Torqued down in 3 stages (just oil, no moly lube) - and I'm probably at about 1k miles and no issues. No longer pushing coolant. I hope it doesn't happen again though as I will be moving to a HX40 here soon.Posted 05-26-2011 at 07:25 PM by ziggo0
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Better invest in some L19 head studs!!Posted 05-30-2011 at 01:10 AM by 400hp93talon
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I'm not sure why it happened, the initial torque may have been too low. This was with L19 head studs.Posted 08-02-2011 at 03:58 PM by VETDRMS
