Building a 1725

[V6 JOSE]

Sometimes the damned things blow for no apparent reason. Mine went in Matilda 15 or more years ago, but the replacement has given no trouble. Someone, a year or so ago (Jose?) mentioned treating the mating surfaces in a way that roughens them, to provide extra grip for the gasket. I don't recall the details, or the procedure, but it made sense. Anyone remember what I'm referring to?

Hi Nick,

If you have the head surfaced with a rougher finish, the gasket has a better surface to get hold of, so less probability of a blown gasket. It is even better, if you had the surface of the engine block done with the same surface too.

Jose

 

[jumpinjan]

I disagree with this rough surface thinking. One can never get a good seal with a rough & grooved surface. We just got very $hity head gaskets.
The GM engineers recommend a very fine surface finish (like on the order of 10micron finish) on the Quad4, when replacing a head gasket.
I am experimenting with coating the new Alpine head gaskets with the copper-coat spray, and not installing dry. We will see how that goes.
I'm also wondering about the age of our head bolts and they could add to the problem by their cumulative stretch over 40 years and a million heat/cool cycles.

 

[ozzie alpine]

just out of interest, are Wills Rings ever fitted to the Alpine motor instead of a standard head gasket?
I have them fitted to my high performance imp engine (infamous for head gasket failure), with great success.

 

[alpine_64]

just out of interest, are Wills Rings ever fitted to the Alpine motor instead of a standard head gasket?
I have them fitted to my high performance imp engine (infamous for head gasket failure), with great success.

brian Holmes on this site has ringed his head on his turbo 1725. Ringing the head is not so easy in the alpine, i believe he had to do both head and block on a CNC. Also the heads are quite soft, a better solution i found was to weld up the cresent shaped water passage near the CC and replace it with 2 holes.

 

[V6 JOSE]

Jan,

I sisn{t mean a rock and gravel surface. When I said rough, I meant wirh a surface that you can feel with your fingernail. I am not familiar with the Quad Four, so don{t know what worls there, buy I havw been soing this procedure for years, and I don{t have problems with blown head gaskets.

I have never built an alpine engine either, but since it is old technology, I think it would work very weññ-

Jose

 

[RootesRacer]

I have had good luck on the alpine by running an oiled coarse whet stone across the block face (put oil rags down the bores), the after cleanup, using copper gasket spray on both sided of the gasket and allow to fully dry before application.

The stuff is hell to get back off though.

 

[Bill Blue]

Jose, I'd pay close attention to what GM has to say about head gasket sealing. The Quad 4 was notorius for blown headgaskets and at one time had nearly a 100% failure rate that probably lead to that engines early demise in production.

On second thought, maybe that means you SHOULDN'T pay attention! I suppose it depends if they ever solved the problem.

Bill

 

[jumpinjan]

All the shops are using new & better flat surfacing machines now that leave the smoothest finish that I have ever seen (no groove patterns even). There must be mandatory requirements on surface smoothness for engine rebuilds now, or the gasket makers are requiring a very fine surface (less than 10 microns).

 

[RootesRacer]

All the shops are using new & better flat surfacing machines now that leave the smoothest finish that I have ever seen (no groove patterns even). There must be mandatory requirements on surface smoothness for engine rebuilds now, or the gasket makers are requiring a very fine surface (less than 10 microns).

Many new OEM head gaskets use a multiple layers of stamped metal, raised in all the right areas. These gaskets want the smoothest surface possible, since the gasket wont flow into surface scratches and imperfections.

The older gaskets like we use are softer materials, and arent as rigid as the new solid metal gaskets are, so having scratches for the gasket to "bite" into keep the gasket from walking helps with longer term sealing and prevents gasket walk.

Using a hylomar coat will probably help keep a gasket in a sealable condition, even if the gasket is prone to gasket walk. Id call this a bandaid because it not going to last forever.

 

[jumpinjan]

Many new OEM head gaskets use a multiple layers of stamped metal

I think that the Jap's import engine technology, and not the domestic technology because I had to pull the head on the '98 Escort DOHC Mazda engine to check & fix bend valves (from a shredded timing belt incident) and thats what was on it (By the way, it was a real bitch to work on)
I haven't seen these multilayered,sheetmetal, head gaskets on a GM engine yet?

 

[RootesRacer]

I think that the Jap's import engine technology, and not the domestic technology because I had to pull the head on the '98 Escort DOHC Mazda engine to check & fix bend valves (from a shredded timing belt incident) and thats what was on it (By the way, it was a real bitch to work on)
I haven't seen these multilayered,sheetmetal, head gaskets on a GM engine yet?

The LS series engines now use them, and Ive seen some of the modular fords using it too. The LS seems to still have some silicone for sealing some areas, whereas the stuff I see for subarus is all metal, no silicone.

Its a pretty good technology, wouldnt be surprised if all the new stuff goes this way.

 

[Jay Laifman]

Many new OEM head gaskets use a multiple layers of stamped metal, raised in all the right areas. These gaskets want the smoothest surface possible, since the gasket wont flow into surface scratches and imperfections.

The older gaskets like we use are softer materials, and arent as rigid as the new solid metal gaskets are, so having scratches for the gasket to "bite" into keep the gasket from walking helps with longer term sealing and prevents gasket walk.

Using a hylomar coat will probably help keep a gasket in a sealable condition, even if the gasket is prone to gasket walk. Id call this a bandaid because it not going to last forever.

I can confirm that years ago, with my original head, I had quite a few blown head gaskets, even after smooth surfacing of the head, until I had it surfaced by a guy whose surfacing put radial grooves through the surface. I never had a blown head gasket after that - and my torquing techniques and frequency remained the same throughout. My Holbay head has never blown a gasket either.