Ok question for thoe who run copper head gaskets. I have always ran them on the blown alky stuff and have a butt load of them. Most are .040 and up. Wondering how thin I can get away with.

Yes I know mine is Hemi and most here are bbc,gasket has no idea name on block just how much clamping pressure is holding it in place and how much pressure trying to push it out of the way.

So whats thinnest you have run or someone you know has run.

quote:

Originally posted by wideopen231:
Ok question for thoe who run copper head gaskets. I have always ran them on the blown alky stuff and have a butt load of them. Most are .040 and up. Wondering how thin I can get away with.

Yes I know mine is Hemi and most here are bbc,gasket has no idea name on block just how much clamping pressure is holding it in place and how much pressure trying to push it out of the way.

So whats thinnest you have run or someone you know has run.

So it sounds like you should know this! The o-ring thickness is determinded by the head gasket thickness!

quote:

Originally posted by TOP38:

quote:

Originally posted by wideopen231:
Ok question for thoe who run copper head gaskets. I have always ran them on the blown alky stuff and have a butt load of them. Most are .040 and up. Wondering how thin I can get away with.

Yes I know mine is Hemi and most here are bbc,gasket has no idea name on block just how much clamping pressure is holding it in place and how much pressure trying to push it out of the way.

So whats thinnest you have run or someone you know has run.

So it sounds like you should know this! The o-ring thickness is determined by the head gasket thickness!

Do what?

O=ring is in the head and receiver groove in block or this case sleeve .O-ring simply compress gasket into groove. Gasket thickness has nothing to do with it. I have run everything from .040 to .110 gasket with same head oring, Now it makes huge difference on intake mating surfacess.

We never ran anything less than .050 on our roots and screw stuff. BNR and BAE both

I ran .040 on mine for over a year, never had any reason to run anything thinner. O ring in head receiver groove in sleeve. 30lbs boost

I've ran .040 with no issues, but have been running .050 for a while now.

Well I have found some .021's/Answer question of hos crazy to try. It is NZ motor.Reason for wanting to go so thin is I have gotten huge deal on two sets of MGP rods at one and two runs and less than half price. I have known guy selling them for 30 years so figure odds are he shooting it straight. Problem is they are 7.175 and mine are 7.195. Compression already lower than I want and dropping almost .7 not to my liking. Plan on getting bigger bore ,higher compression pistons this winter and no issue then. Not sure I would want to run .021's with bigger load in tank for nostalgia race, but with just alky I don't think it would be issue.

As for running with blower I ran .040;s 90% of time with 50 lbs on 12.5:1 and no issue related to gasket. We did burn cpl heads and blocks but was more detonation or broken pushrod and trying to hydraulic it that cause neighboring cylinder to burn out.

If you are going to try to run more compression and more Nitro I do not think it will work. From my experience Nitro does not like compression. Also I think on say an 850 HP motor the difference on horsepower from compression change from 12.5 to 15.5 is only like 12 horsepower. If you were running Pro Stock and you were required to run certain cubic inches then you need everything you can get. But if you can run Nitro, lower your compression and throw some fuel to it. You can get WAY more power from Nitro than you can from 2 points of compression. And you can not really run both high compression and Nitro.

Stay with lower compression and make it easy to tune and relativity easy on parts. And it gives you the option of putting Nitro in the tank.

If you know people who run Nitro ask them what compression they run.

quote:

Originally posted by Curly1:
If you are going to try to run more compression and more Nitro I do not think it will work. From my experience Nitro does not like compression. Also I think on say an 850 HP motor the difference on horsepower from compression change from 12.5 to 15.5 is only like 12 horsepower. If you were running Pro Stock and you were required to run certain cubic inches then you need everything you can get. But if you can run Nitro, lower your compression and throw some fuel to it. You can get WAY more power from Nitro than you can from 2 points of compression. And you can not really run both high compression and Nitro.

Stay with lower compression and make it easy to tune and relativity easy on parts. And it gives you the option of putting Nitro in the tank.

If you know people who run Nitro ask them what compression they run.

Funny we are running 95% with 13.6:1 in a/fuel car. According to Jimmy( sry will take his word for it) we need to get closer to 15:1. Same car just went 5.40 at 250's and dropped cylinder at 3.2 because lean cylinder. Was on a 5.28 run last month at regional in IN
ndy except driver lifted because close to centerline. Noway my deal can near the volume it is running.

Where do you get 12.5 to 15 is 12 HP? Plus the .125 larger bore alone is worth 3 times that.

As I have been told all combo are different and mine being Hemi with totally different combustion chamber will react different than a chevy. Bottomend is stronger just by design and has some of best parts made for Hemi short of TF.Bottomend has always been Hemi's biggest advantage over Chevy,top end not so much.

If I get compression to 15 with .040 gasket and I want less its simple gasket change and adjustment on intake to realign runners to ports all of which is very simple with this deal. Getting 15:1 is a push and probably not get qall of it. With a gasket change I can drop 2.-- out of it Like you folks keep telling mine is not typical of anything else on site,but does have few benifits with the odd parts on it.

Will not run nitro in normal trim anyway. Big load requires different converter,more mag and probably dbl the pump of going above 50% along with differnt 3rd mem ber with higher gear. In other words getting to that point is a ways down the road. Plus second motor sitting here could be totaly different setup altogether. Hey I love running the stuff but its not for bracket race mode. Hell at 40 per gallon its notr for run ning lot of laps. Back to topic .I have no plan to run nitro with .021 gaskets. They are just for running for while till I get new pistons that will allow me to run higher compression with a .040.

Before lots of comment about nitro thing. That is just a play or nostalgia show thing and not part of running any kind of bracket race deals.

I was just replying to Curly commenting on it with compression.

Lil Brotehr is cutting me a set of .021s next week.If Rods get here I will give them some test soon/ I forgt he had run the 21's on his VR6 with 42 lbs boost before blowing one,but then he did not have oringed setup at the time. So if last with 40 lbs ,NA should have zero issues. Plus will put compression back to where it is now.

If can find TNT with enough time I might just make hit with gasket and piston in it now then swap to 21's and see how much that picks car up.Only takes about 30 minutes to pull heads and swap gaskets and reassemble. Heck last trip the small tire guys take that much time to pick the track between pairs down track.

Well didn't get gasket yet.Seems lil brother has gone democrat and using covid as ecuse for not getting stuff done.

Told him fine and works out because I want bore diamter xhanged to 4.260 instead of std 4.360.Yea not much but its free compression and maybe cpl horsepower.

Hoping he can get them out next week.Would love to try them with old setup before swapping rods. According to calculator they will give about .6:1 more than i have now.

When new rods are inI should be exactlt where I am with .040 gaskets. Can't get ABA results.Well could but need longer time at track for swapping gaskets. Beside pulling heads at a local bracket deal seems to caue lots of commotion. So well have to settle for different weekends to see difference .6 makes. Guessing maybe cpl hundredths.As long as air in close should be decent indicator.