Steel shim gaskets?

Posted By: polkat

Steel shim gaskets? - 04/10/09 07:14 AM

How much will the Mopar steel shim gaskets raise compression on an otherwise stock B block engine (stock gaskets)? And should some kind of sealer be used on the gaskets?
Thanks!

Posted By: 70AARcuda

Re: Steel shim gaskets? - 04/10/09 07:29 AM

have you checked the price on the new steel shim head gasket?

Posted By: polkat

Re: Steel shim gaskets? - 04/10/09 07:39 AM

I have a set that's about 10 years old and never been out of the package. How much will these raise compression above stock? Also, if I use them, will I have to shorten the pushrods? These gaskets are about .020" thinner then the stock gasket, can I shorten the pushrods that much? Thanks!

Posted By: 70AARcuda

Re: Steel shim gaskets? - 04/10/09 07:42 AM

good deal..cause the new ones would not be a cost effective deal...

Posted By: polkat

Re: Steel shim gaskets? - 04/10/09 07:46 AM

70AARcuda, we crossed posts. How about my pushrod question? Thanks!

Posted By: DusterKid

Re: Steel shim gaskets? - 04/10/09 11:32 AM

I think the .020 difference is 1/4-1/2 compression. Someone with more knowledge will chim in, but it does make a fairly large difference

Posted By: Anonymous

Re: Steel shim gaskets? - 04/10/09 11:57 AM

This swap was worth a tenth in the eigth on my boys car when i switched with no other changes.

Posted By: Florida_70Bee

Re: Steel shim gaskets? - 04/10/09 12:22 PM

Quote:

I have a set that's about 10 years old and never been out of the package. How much will these raise compression above stock? Also, if I use them, will I have to shorten the pushrods? These gaskets are about .020" thinner then the stock gasket, can I shorten the pushrods that much? Thanks!

I currently have a set of old Fel Pro 8280 SH-1's (steel shim) gaskets on my 383 Bee with no issues. They compress to .020 and have been on the motor for 5 years with no issues.

The key to using them I found is to make sure both the head and block deck are completely flat (a pass or 2 on a milling machine would true both surfaces up). I my case I milled the block to the point where the pistons are .006 below the deck (they were .040 down in the hole from the factory) and the heads I had milled down to 80cc (they were 88cc from the factory) this combined with the steel shim gaskets give me a CR around 10.2. I did however compensate for the milling on the heads and block by adding shims under the rocker arm shafts (I think .050) to get the lifter preload right with the hydraulic cam.

Also before installing them I would coat the gaskets with copper coat spray.

Hope this helps

Posted By: Mr.Runum

Re: Steel shim gaskets? - 04/10/09 12:52 PM

Find an engine calculator like the one on Chenoweth Racing Enterprises LLC. Just plug in your spec change around the gasket thickness and it will show you changes in compression. Without guessing.

Mr.Runum

Posted By: RapidusMaximus

Re: Steel shim gaskets? - 04/10/09 01:46 PM

I too still have a set hanging on the wall in the package...no telling how old they are

used to use them on all my engines with iron heads...never had any problems, always sprayed them with silver high temp paint. No pushrod change was ever made...never calculated the compression change, just knew it raised it and back in those days that's all I was after...

Posted By: moparniac

Re: Steel shim gaskets? - 04/10/09 02:16 PM

Quote:

Find an engine calculator like the one on Chenoweth Racing Enterprises LLC. Just plug in your spec change around the gasket thickness and it will show you changes in compression. Without guessing.
Mr.Runum

http://www.csgnetwork.com/compcalc.html

Posted By: dodgefarmer

Re: Steel shim gaskets? - 04/10/09 03:30 PM

The steel shim gasket is worth a bit less than 1/2 a point on compression, and it is the stock gasket.

Randy

Posted By: Cab_Burge

Re: Steel shim gaskets? - 04/10/09 04:09 PM

Quote:

and it is the stock gasket.

Randy

There where two different thgicknesses on the gaskets depending on the motor and the year and vendor, .017 and .022 usually on the B&RB. I have measured some used 426 Hemi gaskest that where .020

Posted By: moparmattkos

Re: Steel shim gaskets? - 04/10/09 04:16 PM

I just ordered the a set of Mr gasket part number 1135 .20 steel shim head gaskets from jegs for 19.00 for a old iron head motor i got. They are what i need to bump the compression up what i figure about a 1/4 of a point. for the money its worth a try!!

Posted By: JohnRR

Re: Steel shim gaskets? - 04/10/09 05:54 PM

Quote:

Quote:

and it is the stock gasket.

Randy

There where two different thgicknesses on the gaskets depending on the motor and the year and vendor, .017 and .022 usually on the B&RB. I have measured some used 426 Hemi gaskest that where .020

X3 , that motor should have steel shim gaskets it its STOCK so changing will net you alot of work and a big GOOSE EGG for compression increase .

Posted By: polkat

Re: Steel shim gaskets? - 04/10/09 06:13 PM

Okay. Well, in this case I was thinking about using them on a 400 from a '73 truck (original engine). But if that engine came stock with the steel gaskets (doesn't seem to have ever been apart), then there wouldn't be any compression advantage to using them...right? Or am I missing something here? Thanks!

Posted By: JohnRR

Re: Steel shim gaskets? - 04/10/09 06:24 PM

Quote:

Okay. Well, in this case I was thinking about using them on a 400 from a '73 truck (original engine). But if that engine came stock with the steel gaskets (doesn't seem to have ever been apart), then there wouldn't be any compression advantage to using them...right? Or am I missing something here? Thanks!

No you aren't missing a thing , I have never seen anything but steel shim gaskets on original BB mopars , the first with a composite gasket was my crate hemi .

Posted By: Florida_70Bee

Re: Steel shim gaskets? - 04/10/09 06:29 PM

Quote:

Okay. Well, in this case I was thinking about using them on a 400 from a '73 truck (original engine). But if that engine came stock with the steel gaskets (doesn't seem to have ever been apart), then there wouldn't be any compression advantage to using them...right? Or am I missing something here? Thanks!

That is correct. the original motors came with the steel shim gaskets in those years. Mine was steel shim when it was pulled apart the for first time. For that engine you could gain compression by either a different set of pistons, milling the heads and or the block deck.

But since this a low compression 400 you would probably have mill a ton off the block and heads (and intake) to get the compression anywhere useful. Those pistons are probabily .090 to .100 down below the deck. So if it were me a another set of pistons (higher compression pistons that is) is what I would consider.

Posted By: polkat

Re: Steel shim gaskets? - 04/10/09 10:17 PM

How about a closed chambered head? I assume that a '73 400 came with open chambered heads like the 906 or similar. What kind of compression increase could I get with...say, 516 heads? Thanks!

Posted By: JohnRR

Re: Steel shim gaskets? - 04/13/09 04:48 PM

Quote:

How about a closed chambered head? I assume that a '73 400 came with open chambered heads like the 906 or similar. What kind of compression increase could I get with...say, 516 heads? Thanks!

not enough