[Chris Uratchko]

Originally Posted by Tom Vaught

If the studs are properly selected and torqued for the rings and the head/block, the heads will not be able to move upward away from the rings and the block.

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That's not accurate. The fastener is not the issue. The column of aluminum under the fastener is the weak link.

If you ever have a chance to do a pressure map on a deck(which everyone building engines should do) you might be surprised at how much a cylinder head bends when you torque the fasteners. And where clamp loads on the gasket surfaces actually occur. More load on the fastener does not equal more clamping force in most instances. Most castings I have tested are not able to withstand the torque that people try to apply with larger studs and higher loads. Instead the head deforms and bends and you have isolated clamping right under the fastener column, and nearly zero clamping force anywhere else..... due to the column compressing and not distributing load across the deck....

In other words, these types of scenarios are what are driving things like sealing rings.... improperly designed castings, and improper assembly methods.

[Elarson]

Originally Posted by Chris Uratchko

That's not accurate. The fastener is not the issue. The column of aluminum under the fastener is the weak link.

If you ever have a chance to do a pressure map on a deck(which everyone building engines should do) you might be surprised at how much a cylinder head bends when you torque the fasteners. And where clamp loads on the gasket surfaces actually occur. More load on the fastener does not equal more clamping force in most instances. Most castings I have tested are not able to withstand the torque that people try to apply with larger studs and higher loads. Instead the head deforms and bends and you have isolated clamping right under the fastener column, and nearly zero clamping force anywhere else..... due to the column compressing and not distributing load across the deck....

In other words, these types of scenarios are what are driving things like sealing rings.... improperly designed castings, and improper assembly methods.

Exactly right! Everyone needs to absorb that. I'd also add that the "bridge strength" of the head between studs is a big deal too. Our billet funny car heads seal terrific across the whole gasket. No water jackets, approx 1" taller than a stock head and a minimum .25" wall around all studs makes it way stiffer than typical.

Eric

[Tom Vaught]

Originally Posted by Chris Uratchko

That's not accurate. The fastener is not the issue. The column of aluminum under the fastener is the weak link.

If you ever have a chance to do a pressure map on a deck(which everyone building engines should do) you might be surprised at how much a cylinder head bends when you torque the fasteners. And where clamp loads on the gasket surfaces actually occur. More load on the fastener does not equal more clamping force in most instances. Most castings I have tested are not able to withstand the torque that people try to apply with larger studs and higher loads. Instead the head deforms and bends and you have isolated clamping right under the fastener column, and nearly zero clamping force anywhere else..... due to the column compressing and not distributing load across the deck....

In other words, these types of scenarios are what are driving things like sealing rings.... improperly designed castings, and improper assembly methods.

The post was accurate, The Palbykin/Earhart rings were originally designed to seal up a cast iron head. There was a reason why that head was chosen and worked well for several years with the ring. The best performance of the little 406 cid pontiac engine was with the cast iron head vs the later tried Aluminum head.

So the head being a poor design, (column strength wise) is not a ring problem. It is a head design problem as you said. I stand by my post and the info posted.

A Custom Head like Mike and Eric run will seal fine and a head with column strength issues will have head gasket issues. A Pontiac Guy cut away a bunch of the head bolt columns material during a porting job and had sealing issues on a NA application, forget about a Boosted engine. Blamed it on the head, the issue was he took away what little strength that the head was designed with.

Food for thought. You only have so much room to put stuff inside a given bore spacing head. When you increase the bore spacing you can make the dimensions larger on the internal column parts. A solid head is another choice.

There was a reason why the Chebby boys went to the larger bore spacing dimension in the early 60s. The Pontiac guys will have to design band-aids to fix these issues if the bore spacing (no wiggle room) does not change OR AS ERIC HAS SAID, CAST UP A GOOD CAST IRON HIGH FLOW HEAD.

Tom V.