Head Gaskets Block Coolant Passages

Posted By: GTX MATT

Head Gaskets Block Coolant Passages - 04/11/13 05:54 AM

I bought a set of Mr Gasket steel shim gaskets for my 440 with Stealth heads. When checking the fit around the combustion chambers I noticed a severe blockage of some of the coolant passages. I'm thinking Whiskey Tango Foxtrot, stupid aftermarket junk. So I dragged a 906 out from under the bench, same deal. Stupid Mr Gasket [Edited by Moparts - Family Friendly Site - Keep it clean]

So I got out one of the fel pro 8519PTI gaskets (standard gasket) and guess what? Same deal, worse actually. I wish I kept my original head gaskets to compare, the witness marks on the 906 heads from the original 1967 date coded gaskets look like it wasn't interfering before but of course the marks are from the embossings.

I ran a set of that same gaskets I believe when fixing a burned valve on a buddy's 383 over the summer. I had bought them 3 years ago, but it was the same kit. I'm ashamed to say I never checked the fitment to the head, or if I did I don't recall seeing this, but it was the same kit and I assume the same gaskets.

Is this okay? Should I mod the gasket? Anyone else know anything or noticed this before? I can't be the only one. I don't see how it could be okay its blocking a head to block passage, but my buddy's 383 didn't have any cooling issues.

On a side note my first combustion chamber CC'd 79 cc

Posted By: GTX MATT

Re: Head Gaskets Block Coolant Passages - 04/11/13 05:55 AM

Pic 1

Posted By: GTX MATT

Re: Head Gaskets Block Coolant Passages - 04/11/13 05:55 AM

pic 2

Posted By: GTX MATT

Re: Head Gaskets Block Coolant Passages - 04/11/13 05:56 AM

pic 3

Posted By: 340SHORTY

Re: Head Gaskets Block Coolant Passages - 04/11/13 06:59 AM

The restrictions in the gaskets are there to slow the coolant down so the there is better heat transfer to the coolant.

Posted By: Cab_Burge

Re: Head Gaskets Block Coolant Passages - 04/11/13 07:16 AM

Quote:

The restrictions in the gaskets are there to slow the coolant down so the there is better heat transfer to the coolant.

OP, your good, put them babys on

Posted By: therocks

Re: Head Gaskets Block Coolant Passages - 04/11/13 10:35 AM

I agree install them.Why try to out figure the factory engineers.Rocky

Posted By: TooMany62s

Re: Head Gaskets Block Coolant Passages - 04/11/13 11:29 AM

Those big holes are sized that way to get the sand out of the casting in the foundry. This is true of both the block and the heads as they are "sand castings". The gasket reduces them to what they should be for cooling. I never tried opening them all up to the casting size to see what would happen.

Posted By: RapidRobert

Re: Head Gaskets Block Coolant Passages - 04/11/13 02:31 PM

go to www.moparchat.com then scroll down to & click on "circle track chat" then peruse Sanborns' cooling mods that are in a sticky at the top & that info may better help you make an informed decision. He's a SB guy but the info is still applicable to BB's with some differences.

Posted By: 80fbody

Re: Head Gaskets Block Coolant Passages - 04/11/13 02:37 PM

Are you sure you're supposed to use steel shim type gaskets with aluminum heads?

Posted By: GTX MATT

Re: Head Gaskets Block Coolant Passages - 04/11/13 02:44 PM

Quote:

Are you sure you're supposed to use steel shim type gaskets with aluminum heads?

You're not supposed to but many guys are running them and getting away with it. I think with the superior head clamping design of the Chrysler big blocks and Chevrolet small blocks and big blocks that most people would be fine (17+ head bolts rather than 10).

I'll probably copper spray them, although the instructions say that you shouldn't because they already have a coating on them. It looks like they're aluminum painted.

And thanks guys, I guess I've never actually really looked at this before. I figured its supposed to be since both gaskets were this way, but it didn't make sense. Since my detective at Moparts have explained the reasoning I feel comfortable with them now. Thanks

Posted By: 80fbody

Re: Head Gaskets Block Coolant Passages - 04/11/13 02:47 PM

I'd be more concerned with the the steel gasket ruining the head surface but I've never run aluminum heads.

Posted By: GTX MATT

Re: Head Gaskets Block Coolant Passages - 04/11/13 02:50 PM

Quote:

I'd be more concerned with the the steel gasket ruining the head surface but I've never run aluminum heads.

I've heard this noted before, but theres quite a few threads on here about steel gaskets with aluminum heads. They say multi-layer steel is okay, so what difference would that make on the surface of the head that the regular steel shim wouldn't? Not being a wise guy, just wondering if you'll learn me something new

Posted By: 80fbody

Re: Head Gaskets Block Coolant Passages - 04/11/13 03:25 PM

Dis-similar metals, aka steel & aluminum, don't generally mix well. Not sure the technical term but over time the steel sort of eats into the aluminum head surface. Also the steel gasket is a harder material than the aluminum head which means the gasket could imprint itself into the head.

Doesn't seem worth the risk with high dollar heads.

Posted By: JohnRR

Re: Head Gaskets Block Coolant Passages - 04/11/13 03:38 PM

Quote:

Those big holes are sized that way to get the sand out of the casting in the foundry. This is true of both the block and the heads as they are "sand castings". The gasket reduces them to what they should be for cooling. I never tried opening them all up to the casting size to see what would happen.

I agree with this but the fly in the ointment is that around 1973 they changed the holes in the block to a figure 8 shape which ends up having a round hole right in line with the round hole in the head, BUT they changed the gasket from the rectangle to a slit.

Posted By: JohnRR

Re: Head Gaskets Block Coolant Passages - 04/11/13 03:40 PM

Quote:

Dis-similar metals, aka steel & aluminum, don't generally mix well. Not sure the technical term but over time the steel sort of eats into the aluminum head surface. Also the steel gasket is a harder material than the aluminum head which means the gasket could imprint itself into the head.

Doesn't seem worth the risk with high dollar heads.

BUT BUT BUT ....

People run MLS Cometic gaskets with alum heads ??????

The fire ring , if that is what it is called , on a felpro gasket is STEEL ????

Coat the gasket with copper spray and he should be fine ...

Posted By: Supercuda

Re: Head Gaskets Block Coolant Passages - 04/11/13 11:51 PM

Quote:

Dis-similar metals, aka steel & aluminum, don't generally mix well. Not sure the technical term but over time the steel sort of eats into the aluminum head surface. Also the steel gasket is a harder material than the aluminum head which means the gasket could imprint itself into the head.

Doesn't seem worth the risk with high dollar heads.

It's called bi-metallic corrosion.

I wouldn't sweat it if you use coolant and not straight water as the coolant has corrosion inhibitors. Also, it really doesn't matter what head gasket you use, in regards to corrosion, they all will have a dissimilar metals issue.

Posted By: JohnRR

Re: Head Gaskets Block Coolant Passages - 04/12/13 05:13 AM

Quote:

Dis-similar metals, aka steel & aluminum, don't generally mix well. Not sure the technical term but over time the steel sort of eats into the aluminum head surface. Also the steel gasket is a harder material than the aluminum head which means the gasket could imprint itself into the head.

Doesn't seem worth the risk with high dollar heads.

Can't ... resist ...

He doesn't have High Dollar Heads ...

...

Posted By: HemiRick

Re: Head Gaskets Block Coolant Passages - 04/12/13 07:31 AM

Ive been running a set of steel shims under alum heads for 6+ yrs now with no problems at all.

Posted By: GTX MATT

Re: Head Gaskets Block Coolant Passages - 04/12/13 03:22 PM

Quote:

Quote:

Dis-similar metals, aka steel & aluminum, don't generally mix well. Not sure the technical term but over time the steel sort of eats into the aluminum head surface. Also the steel gasket is a harder material than the aluminum head which means the gasket could imprint itself into the head.

Doesn't seem worth the risk with high dollar heads.

Can't ... resist ...

He doesn't have High Dollar Heads ...

...

HEY

I was actually going to say that myself, but I guess 1000 bucks is more than a stock set of 906 costs in most cases

Posted By: 451Mopar

Re: Head Gaskets Block Coolant Passages - 04/12/13 04:09 PM

The MLS gaskets are coated. The chemical reaction between dissimilar metals is called "Galvanic corrosion". The small holes/slots restricting coolant flow are by design. The coolant is supposed to flow from the front of the block to the rear of the block, up through the big hole at the rear of the cylinder head then to the front of the cylinder head. The restrictions in the gasket help force the coolant to the rear of the block, but also allow some cooler coolant up to the head to equalize the themperatures through the cylinder head.

Posted By: dogdays

Re: Head Gaskets Block Coolant Passages - 04/12/13 05:17 PM

Thank you for a sane response.
R.