fetl vs mls compression change?

[crazy_quick]

I was just wondering if there is a compression change in the two head gaskets. It looks like the mls is a little bit thicker then the felt crap.

The reason that I am asking is because I just purchased a 2.3 stroker it and it is a 9:0:1 compression and I think it is a little high..

 

[Bender]

The MLS is thicker, and it does lower compression. But IMO it is a lot better than the graphite, especially for a race engine. No longer do you need to scrub the head and block whenever you take the head off. The MLS's are a little bit harder to seal initially. (block and head both need a machined finish-or wet sanding with low abrasive paper if your careful) You also need to to torque them down a bit higher. I have mine torqued to 85 ft lbs. Also don't use a copper sealer. (even though some people recommend it, it is not needed, and the head gasket was designed to be used without it)

 

[crazy_quick]

well i went ahead and got the block decked for the mls and arps. So there will be no problem sealing. And about how much drop in the compression will it be, seeing how its 9:0:1. 8:5:1 or 8:8:1?

 

[Bender]

I wouldn't imagine that much even, the headgasket compresses when torqued down. Unlike the graphite ones, these seal by compression, so they are almost impossible to blow. My dad has spiked 30lbs of boost with detonation for about an 1/8 mile before he let off the throttle. The MLS headgasket handled it no problem. After all is said and done, I would imagine it would drop your 9.0:1 to around 8.9:1. Again this is just kind of a rough estimate, but when I put my on, I hardly noticed the compression change lower end. Only thing I noticed was being able to run higher boost. And since they are almost impossible to blow, if they do start to leak after sealing, just give them a heat cycle, and they should seal back up. (depending on how bad you detonated) As I said before, the tricky part is to get them to seal initially. Mine leaked a little at 75 ft lbs, so I torqued it to 80 ft lbs. It was better, but still there. So then I went ahead and torqued to 85 ft lbs, and it is still strong.

You said you had your head and block machined. Look at it carefully when you get it back. A lot of machine shops smooth them "rough" so the graphite headgaskets have something to "bite" into. If it is rough, wet sand it with a block and 800 grit sandpaper. Be sure to sand it even with no high or low spots. A metal yard stick comes in handy for this. You don't want your tolerances to exceed 0.001 of an inch. Check like this: <br><br> <img src=http://crx.honda-perf.org/articles/blockguard/images/Head08.gif><br>It also wouldn't hurt to check horizontally across all cylinders in the middle. As well as vertically on the cylinder walls between the cylinders.