if money is no object, which head gasket?

[turtlevette]

I've blown head gaskets twice on my high mileage goodwrench 350. Because i continue to drive long distances once its blown up, i think the deck has probably erroded away some between the cylinders. It looked ok to the naked eye but who can see thousands.

i used the zz4 head gaskets .051 thick thinking they would compensate for a slightly wavy deck and they have been holding for about a year. I suspect that eventually they will go again and want to be ready. I see copper head gaskets for around $100 each up to .060 thickness. What i've read say the deck has to be o ringed and the copper does not compress and does not conform to deformaties in the deck and head so i don't know. I would think it would be fairly blow out proof though and the silicone o-rings built into the gasket should hold the water back.

Why wouldn't a copper gasket hold up in my lowly street motor?

There are also new multi layer steel gaskets. Would they be more appropriate for a street engine? I don't know what is between the layers.

I just don't like the way the fire ring on composite gaskets blow out so easy.

 

[redvetracr]

I've blown head gaskets twice on my high mileage goodwrench 350. Because i continue to drive long distances once its blown up, i think the deck has probably erroded away some between the cylinders. It looked ok to the naked eye but who can see thousands.

i used the zz4 head gaskets .051 thick thinking they would compensate for a slightly wavy deck and they have been holding for about a year. I suspect that eventually they will go again and want to be ready. I see copper head gaskets for around $100 each up to .060 thickness. What i've read say the deck has to be o ringed and the copper does not compress and does not conform to deformaties in the deck and head so i don't know. I would think it would be fairly blow out proof though and the silicone o-rings built into the gasket should hold the water back.

Why wouldn't a copper gasket hold up in my lowly street motor?

There are also new multi layer steel gaskets. Would they be more appropriate for a street engine? I don't know what is between the layers.

I just don't like the way the fire ring on composite gaskets blow out so easy.

look into Cometic, I think they are the "latest greatest" thing to come along. No I`m still using the $35 a piece Fel-Pro head gaskets.

 

[big_G]

I just don't like the way the fire ring on composite gaskets blow out so easy.

They don't. You're asking them to something they weren't designed to do.

 

[Twin_Turbo]

You have shaved heads right? Your problem is a non straight deck, possibly with corrosion indeed and a thin decked seat of heads that are milled too. You will keep having these problems if you don't fix the cause.

Also, the steel gaskets, they require a certain deck roughness (roughness average) to bite, you will never have that with a wire brushed deck.

 

[turtlevette]

Also, the steel gaskets, they require a certain deck roughness (roughness average) to bite, you will never have that with a wire brushed deck.

i've been looking around on this. Here is a quote from one site.

"For aluminum heads, the numbers are even lower. The typical recommendation today for an aluminum head on an OHC bimetal engine is a surface finish of 30 to 60 RA, with the preferred range being from 50 to 60 RA, unless, of course, it is one of the Japanese engines already mentioned with the MLS steel head gaskets which requires an even smoother finish (typically 20 to 30 RA)."

Here is a quote right from the Cometic webiste:
Good machining is critical in achieving a proper seal when using a Cometic MLS gasket a recommended, a RMS 36 or 80 MA finish is recommended, any quality machine shop can achieve this finish quality and it shouldn't cost any more.
They're saying you need a smoother finish for MLS gaskets. I'm thinking i should pick up a set of these. They make a 400 gasket that is 0.060 thick. I would think the more layers and thicker the better to conform to any wavyness and irrigularities. I doubt this solid steel gasket will blow out like the composite ones with the wimpy SS fire o-ring.

Here is something else i found. http://www.hotrod.com/techarticles/engine/hrdp_0603_cometic_cylinder_head_gaskets/index.html Fire rings that dynamically conform to the head/deck. I guess in extreme FI applications the head moves away from the deck for a short amount of time.

I'm going to need a new engine soon anyway. This one has about 10psi or less at idle. Its just flat wore out like everything else on my car.

 

[turtlevette]

Well i bypassed my heater core a few days ago and its not consuming coolant anymore. Still good for now. This setup may last a couple more years if i be really carefull to constantly check the coolant level in the rad and be vigilant about not getting it hot < 200 degrees.