Eric Hsu posted some intruiging headgasket testing results on his blog that I haven't seen posted to this forum:

"... we take some expensive *** pressure film and sandwich it in between the block and head gasket. Obviously, all sealing surfaces must be perfectly flat and free of imperfections. Then we torque the head on top of everything with the head bolt/stud of choice. The pressure film creates a color coded imprint that shows how well the clamping force is distributed. Obviously you want a high clamping force around the cylinders. Of course you can’t forget the water/oil jackets either. The higher the pressure, the brighter the imprint. We’ve found some very surprising results. A leading US multi-layer stainless steel gasket manufacturer actually manufactures some pretty weak gasket designs. In some instances they are worse than stock.

Here are some results from a popular Japanese 2.0L in-line 4 cylinder iron block/aluminum head factory turbocharged engine. No names, models, or manufacturers in this blog post. You figure out which engine. If you can’t, you’re probably either a dumb **** or a non-enthusiast in which case I’m not sure why you’re reading this. Ok, here’s a hint: it’s four wheel drive. No not the one with the flat engine.



This test was performed with 8740 ARP 11mm studs with torque at 90 ft./lbs.

LEFT: This US made multi-layer stainless gasket has a thin sealing line around the cylinder and distortion right around the head bolts which compromises the strength seal. You’ll also see the color is dull which means the clamping force is low. The funny part is that the primary seal (immediately around the piston) is very light whereas the secondary seal (around the primary) is darker and wider. They got it reversed.

CENTER: The OEM multi-layer stainless gasket. It only needs to seal 280hp so the engineers don’t seem too concerned with with a perfect band around each cylinder. However, you can notice that the clamping force is significantly higher than the Co…(oh **** sorry, no names, huh?) the gasket on the left.

RIGHT: The best of the bunch. The sealing area around the cylinders are round, consistent, wide, and the force is the highest. What does this mean to you? Proper cylinder sealing whether your engine is stock or you’re running 40psi boost on methanol with L19/H11/MP studs."

 

I cannot say I've had too many issues with cometic. *shrug*

 

how thick is the oem gasket?

 

Ill throw something that could be construed as ignorant into th equation. Is it possible that the same head studs were used repetitively on each test? This would cause an issue if the studs were stretched. The test would have had to be done in the reverse order than was shown to boot.

 

interesting results. great post!

 

I am not surprised I could have told you that yrs ago.

Sean

 

Double post sorry

 

Done with ARP studs so stretch shouldn't make an appreciable difference

 

ive had alot of issueswith cometic for an old b17 engine, first 2 that i got were deformed and didnt line up over one of the pistons, and the 3rd i got was shot after 2k miles and we usedbrand new arp studs.. Id never buy another cometic ever again justbecause of the problems with the honda

 

Yeah, i know, but even ARP's recommendations require one to only torque their studs 3 times, so it could be plausible.

I am giving scenarios, not creating mischief. The above data is important. Some people might overlook head gaskets in their build if not informed properly.

 

as far as i know AMS uses the stock head gasket on their race cars.

 

i have had issues with honda cometic gaskets.they would always push coolant under high boost.i switched to an oem gasket and didnt have a problem.same thing with my evo,i am running a stock headgasket,run 37-39 psi on high boost and doesnt push any coolant ,perfect!

 

45-50psi on OEM gasket NO issues..

 

46 psi + 100 shot and stock head gasket has hold fine.

 

Great info!!