extreme01ta

iTrader: (2)

well for one I used head studs. and I have a lift so IMO it would prabably save time and I'm sure a lot of headache to just drop it out and do it on the engine cradle and then just put the car back on. But I will let you know what I find with the clearance. my head gaskets are suposed to be here today or tomarrow so I will stay late and try to complete it in one night. It should all be fresh in my mind ( I just frigin did it!!) I believe the cometics I have are .051 compressed so going with the gm gaskets I should pick up a little clearance.

1LEFirehawk

Has anyone used copper head gaskets that you can have custom made whatever thickness needed? I haven't done the scientific way of measuring but we did the clay in the valve recess trick and came up with around 20 to 25 thousanths clearance. Or what about using 2 felpro gaskets stuck together with the copper gasket sealer? I know these aren't the proper way of doing it, but I really don't have the money to buy new LT4 heads and then have them ported and polished to match the intake.
Thanks,
Andy

Cal

iTrader: (1)

.065 here which is the least I want to go. It's survived a few 7000 rpm blasts so far.

PREDATOR-Z

Bottom line guys,
.080 intake and .10 exhaust should be your street limit. All else is borrowed time, especially on M6.

bigdsz

iTrader: (1)

Play it safe and notch those pistons. You're only talking a few hours, and with the engine out, a piece of cake.

extreme01ta

iTrader: (2)

well I got the engine out and tore down here the other day and no signs of any problems so I reassembled engine with G.M. graphite head gaskets and still have a coolant leak from the head surface on both heads. Not as bad as before but still a leak none the less. Has any one ever seen the surface finish on a set of heads that was so rough that it leaked even with the graphite gaskets? It seemed pretty rough to me but I assumed that the machine shop knew what they were doing. Was I suposed to have used some kind of sealer? I need to pull it back out for the 3rd! time now and get the surface finish checked/smoothed out and try it again. thinking about using J.B. weld for gasket sealer just to be sure this time! LOL!!!

extreme01ta

iTrader: (2)

Well I got the engine out again and pulled the heads and took them back to the shop that milled them. I think the surface is way too rough. I know this isn't very scientific but I put a razor blade's edge down on the head surface and could see day light in the low spots of the head surface finish. they are going to smooth them out for me but as close as my p to v clearance is any may be too much. I measured the head thickness and determined that they were unmilled before I milled them .030". But I decided to go a head and flycut my pistons for clearance. Maybe this leak problem was the engine gods way of saying "Notch those pistons dumb a$$" all along. Now I already had the intake manifold port matched to the heads, how much more can I take off of the heads (to smooth them out) before my port match gets affected? also there would be no down side to notching for just the intake valve would there? I have plenty of clearance on the exhaust side and don't plan on changing the cam in this engine, Forged, stroker, FI motor in mind for next project.
thanks for the input

bigdsz

iTrader: (1)

Man, I can't believe what you've gone through with your engine. In a way this very well may be a blessing in disguise to get you to notch your pistons. Not doing it is nuts. If Iwere you I'd also notch the exhaust maybe .025. Though not necessary better safe than sorry, and you may want a bigger cam later on. I obviously don't know what the deck finish on your heads looks like, smoothness is measured in RA and is very critical with MLS gaskets, much less so with the graphites. I would be leery about going back to that machine shop, Imean if they didn't mill the heads right the first time, who's to say they will do irt right the next time. A .005 clean up mill. I wouldn't think would mess up the intake/ head alignment.

extreme01ta

iTrader: (2)

Yes I thought the graphites would seal it up also, they did slow it down alot. When I pulled the heads this time I could see the lines left in the gasket by the surface finish on the heads. I really don't have much choice around here but to take them back to the same shop which I already have. I've had a business relationship with this shop for about 5 years, they are pretty sharp on the older stuff but not so on the newer stuff. They already got them cleaned up (they thought) I went in to look at them and they looked pretty good except right around were the coolant flows to the head wich still had some of the texture. So I said "Try it again boys." Do you think this shop should reimburse me for wasted gaskets and my time to R&R heads once or twice? I run a boat repair shop so I have been on his end of the stick before, (not to this extent) so I can feel for the guy. I feel funny asking for upto $700- $800 for each time on a $100-$150 mill job. But at the same time it was his mistake that caused all of this trouble. There is an R.A. spec for the surface, he said he has the tool to check it and didn't. If I didn't inspect them closly this time they still would have leaked around that coolant passage! Man hopfully a few more weeks and this thing will be finished!

66deuce

iTrader: (1)

man,sorry to hear about your troubles.when i installed my cometics,i sprayed a thin coat of copper gasket sealer on them.this might help.i've seen different surface finishes from two shops,the difference was almost like night and day.not all shops are equal,i guess.you should have no problems with intake alignment on your heads with just a cleanup cut.i have almost .045 milled off my heads and haven't had any problems.