VETDRMS
15+ Year Contributor
- 340
- 21
- Jun 1, 2006
-
Vancouver,
Washington
As the title implies I just finished removing my 2nd Cometic gasket after it started to pressurize the coolant system.
The first failure happened at relatively low boost (24-25psi) and conservative timing for E100 (14* total, 7-8* @ 5000).
Both the head/deck were prepped for MLS to a mirror finish. The block deck was checked for flatness. I am using A1 H11 studs torqued to 95 ft/lbs (30-60-95).
The first gasket was a Cometic 87mm (.066" thick), the second gasket was 87.5mm (also .066" thick). Copper spray was used on both.
The first time it failed it was mostly at the back of cylinder #2, right in the middle. After cleaning the deck surface it also leaked in the front of #2 and the front/back of #3. Each point of failure was directly in the middle and directly in line across the cylinder (front to back).
Upon the first disassembly there was some overhang of the gasket into the chamber due to too much material being taken off when deshrouding the valves. The head was welded up, seats replaced, and re-machined.
It failed at the same boost/timing on the 2nd gasket. It held fine at 22psi. It failed in the same spots as well.
I've attached a few photos of the first failure, but the second one is about the same. Any ideas of what could be causing this?
Also, what other gaskets suggestions are there for the 2.4?
I was considering using an OEM Galant composite and having the head machined for SS o-rings. Can this be done on the 2.4? I have heard that it is difficult and not recommended to machine the 2.4 block for o-rings due to the larger bore.
Thanks, hopefully the third time will be more charming.
The first failure happened at relatively low boost (24-25psi) and conservative timing for E100 (14* total, 7-8* @ 5000).
Both the head/deck were prepped for MLS to a mirror finish. The block deck was checked for flatness. I am using A1 H11 studs torqued to 95 ft/lbs (30-60-95).
The first gasket was a Cometic 87mm (.066" thick), the second gasket was 87.5mm (also .066" thick). Copper spray was used on both.
The first time it failed it was mostly at the back of cylinder #2, right in the middle. After cleaning the deck surface it also leaked in the front of #2 and the front/back of #3. Each point of failure was directly in the middle and directly in line across the cylinder (front to back).
Upon the first disassembly there was some overhang of the gasket into the chamber due to too much material being taken off when deshrouding the valves. The head was welded up, seats replaced, and re-machined.
It failed at the same boost/timing on the 2nd gasket. It held fine at 22psi. It failed in the same spots as well.
I've attached a few photos of the first failure, but the second one is about the same. Any ideas of what could be causing this?
Also, what other gaskets suggestions are there for the 2.4?
I was considering using an OEM Galant composite and having the head machined for SS o-rings. Can this be done on the 2.4? I have heard that it is difficult and not recommended to machine the 2.4 block for o-rings due to the larger bore.
Thanks, hopefully the third time will be more charming.