Are there any negatives to going with the thinner .029" impala head gaskets? I understand that there is a bump in compression, and i would have to keep the motor running cooler (i already have a 160* thermo and manual fan switch). Are there any other problems i should be aware of. I plan on ordering a ton of parts here as soon as i get my tax rebate, and i want to get all my ducks in a row.

I also talked to the shop that is doing my heads, and they said that with the thinner gasket, i won't have to go with shorter pushrods...they're right, aren't they??


thanks
trav

 

was posted here awhile ago but no you will not need a longer pushrod

 

There is one other concern. I'll alert you to it, but you can probably find more information under the "search" feature.

The Impala head gasket was designed to be used with an iron head/block combo. Your car more than likely has aluminum cylinder heads and you're also more than likely using an iron block. The differening specific heats of the two substances may or may not cause the gaskets to fail or not operate properly.

I'm not saying don't do it, but as far as "negatives" go this is probably one of the only ones unless you suffer from KR after the fact, due to pinging/detonation from a poorly tuned/running engine with the increased compression ratio. More knock retard probably won't be a concern nor the gasket's sealing performance, but they are possibilities nonetheless.

Ben T.

 

well then what gasket from what company would be a better choice where you wouldnt have to deal with the two different metals with similar gasket thickness to the .029?

 

Don't sweat it, dude. People use the Impala stuff all the time with no problems. I had mine on for over 3 years with no problems at all.

-Chris

 

No issues with the Impy gaskets on my stroker.

 

I'm using Fel-Pro 1074. Compression thickness .039". Nice head gaskets and a nice alternative.

 

i think i am gonna go with the impy's from ls1speed.com. They are only 35 bucks a piece..cant go wrong.

thanks for the info

trav

 

The process is called brinneling. Basically the gasket is designed to work on Iron heads, and it can leave a imprint on aluminum LT-1 heads when used. Most gasket manufacturers do not reccomend it. I suggest fel pros

-Shannon

 

Mr.Gasket has a 0.026" gasket I belive. That would put quench at a near-ideal 0.051". Shoot for 0.045 to 0.060 for quench benifits.

The slight increase in C/R from a gasket swap isn't worth the effort, but if you're already in there you might as well shoot for higher C/R and better quench. Stock quench values suck. With a piston-deck height of ~0.025" in most LT1's, and a stock LT1 gasket compressing to ~0.045", the quench is a large ~0.070".

Increased quench will help with detonation resistance, and any gasket swap is BARELY going to affect C/R on a 350.

Many people use the felpro gasket and like it, while others have used the Impalla gasket with success. Depends what you're goals are I guess.

I'm planning a 383 build-up right now and am looking at ~0.005" piston-deck clearance... which would make the Felpro gasket an ideal choice for me... if I can get all the dimentions right (particularly the piston's compression height).

 

I ran the Impy gasket with 10.5 CR and blew the gasket after 1 season of racing. The gasket blew between #3 & #4. The result was a nice little groove cut in the heads connecting the combustion chambers together. Heads are being welded up and redecked but I won't be going the Impy route again. As stated, they are for CI on CI application.

Steve

 

what it work out to with stock bottom end Mr. Gasket head gakests and heads that have been milled .010?
do you have the part number for those gaskets, maybe know the price off the top?

thanks
Steve

 

That's a very important point.

Aluminum heads won't tolerate combustion gasses escaping the chamber.

I know a guy with a late model harley that has an aluminum motor. He blew a gasket on the highway and rode 15-20 miles home. By the time he got there, the jug and head were ruined.

I blew a gasket on my older harley with an iron engine, and it was so bad that you could SEE the escaping gasses pulsing out the front of the engine even if you were sitting ON the bike and looking at the engine from several feet away.

When I got home I pulled the head and other than a carbon residue on the external surfaces, the jug and head were unharmed. I just installed a set of cometic copper gaskets and it never happened again.

The moral of the story is that when you have an aluminum head, you want to be especially careful not to create a situation where the head gasket blows out, because the heat and pressure from the combustion chamber will destroy the head far more quickly than most people realize.

 

i've been talking to a few machinists and they were telling me that the gasket would work out fine as long as i never use cheap gas and keep the engine temps at ~180* or lower.

What do you guys think of those suggestions?

Also, if you can shoot me some part numbers for popular alternatives, i would really appreciate that.

thanks guys,
trav

 

Those suggestions are good for any performance engine.

Like I said, no Impala gasket problems whatsoever on my nitroused stroker, and I'm sure my engine sees pretty substantial cylinder pressures.

Blowing a head gasket is like blowing a fuse. Usually the gasket goes before the rest of the engine. You could run a copper gasket that would probably never go out on you, but leaning out a motor with copper gaskets will likely destroy a lot of stuff!