Bump from a few months ago...
I pulled off the heads yesterday and, although I can't say exactly why, I'm not sure that those Mr. Gasket MLS head gaskets actually sealed properly. I can't put my finger on it, but I think it's because they both looked kind of wet (coolant seepage?), which didn't seem normal to me.
The purpose of using MLS head gaskets in the first place was because the re-hone as part of this build didn't use torque plates. The machinist said the existing .060" oversize bores distorted too much with the torque plate and did a quick touch-up hone w/o it, so I figured an MLS would reduce some of the distortion vs the typical composition gasket I'd use. The block & head surfaces certainly appeared smooth enough to use an MLS, especially w/ Mr. Gasket saying their nitrile coating was more forgiving of surface irregularities.
Haven't decided on the best option for when the heads go back on:
1. Coat the Mr. G MLS parts w/ "something" and re-use them (and does this require disassembling them and coating all the layers?)
2. Buy a set of Cometic MLS gaskets, since they seem to have a better reputation in this thread
3. Use some of my tried-and-true orange Detroit Gasket "Competition" composition head gaskets
Thoughts?
One engine I had built had Mr. Gasket MLS gaskets and I was told that they seeped until after the initial engine break-in/heat cycles even though the surfaces had the proper finish. It sealed ok for the short time I ran it, but after I got water in the engine from another problem, I switched to more conventional composition gaskets for peace of mind on my 360 (Fel-Pro 1008).
What REALLY caught my attention was your engine builder not honing with torque plates because he said that the +.060" walls were too thin and distorted too much with a plate.
The whole purpose of torque plates is to simulate the heads during the honing process so when the heads are actually bolted on and stressing/distorting the block, the bores remain round! (Some also use the same type of gasket to help duplicate all of the influential factors.) I'm not sure how much the deck plate affects head gasket seal, perhaps a little, if any, but it certainly would affect the ring seal.
NOTE: Are you saying that the
initial build didn't use torque plates? I would be curious how much, if any, a head gasket style affects the deck even though it can't hurt to use one during honing.)
