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crazy head idea


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Ok bear in mind I know this guy has crazy amounts of hours into the head machine work to get it this far. I personallly dont see this as being to difficult but if you read the guys post you can understand he loves himself ALOT!


Do you guys think if one was to surface grind each section completely flat that a gasket would be needed in between the sections of head? Most airplane engines used in light aircraft dont use any gaskets and sometime use tiny o-rings simply because everything is surface ground FLAT! I started asking a bunch of questions related to this to the guy and it turned into a flame war by other members. So, I wanted to see what you guys thought. peace.


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First off, aircraft reciprocal engines don't use cast iron blocks. The dissimilar metals (aluminum vs cast iron) expand and contract and different rates, which would eventually cause a gap. In weeks if not hours. For a throwaway drag engine that probably wouldn't be a big deal, but for a street or long-term race engine, not so good.


Second, aircraft engines use "fire rings" to seal the chamber. Notice on a head gasket the metal rings around each cylinder? That's the fire ring- it's compressed by the torque of the head bolts. It's why you should never re-use a head gasket. Without the fire ring, any little gap becomes an escape point for the combustion gasses and the space between the cylinders is quite close. It'll blow between the 2.


I've seen in happen in a Rolls Royce Merlin V1650 areo engine- which you can't get anymore- they had to send the head to Jack Rousch to be repaired (welded up and re-machined) to fix the burnt hole between 2 cylinders.


Another problem of course is with a Datsun head, the spacing between the cam and crank sprocket is critical. No gasket means a .5-1mm (average) difference- that's equivalent of taking .020/.040 inch off. How much can you mill a head before cam spacers are needed? Not that much. That isn't as critical with a pushrod engine, of course. Even more obvious is what it does to the compression ratio.

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Oh. I can't get to the other forum due to corporate firewalls, so I was assuming eliminating the gasket altogether.


So long as he has 4 head bolts surrounding each cylinder, it would work. Problem is, the "segments" run right through 2 pairs of head bolts which means the load is half n half.


I don't think a gasket will help- the expansion when heated will cause a gap to form when it cools unless the 3 segments are bolted together. Or better, WELDED together.


The comparison to aircraft heads doesn't work here- those are designed to be segmented so each segment is cooled independantly. Not a KA head. I assume you're talking the coolant galleries and maybe the cam jube galleries. O-rings would work here- you'd have to have recesses on both sides machined in, of course, around any galleries you're trying to seal. But you still need to tie the segments together.

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thats exactly what this guy did he bolted them together the thing that I cant understand though is he claims that he and his dad put hundreds of hours into designing the bolts when to me it looks like he just had them ground then cut to the apropriate length. I dont think welding is a viable option otherwise what you were talking about will be a problem and head gaskets wouldnt mattert anyway, lol. Its reassuring to hear that the sections wouldnt require a gasket but then again I havent testged it so I wont know until I try it. To me it would also seem that more dowel pinning would be needed the way this guy has it set up at least one more dowel persection would help it locate and keep from twisting. Tie bolted or not that thing still gonna move especially being aluminum and like you were saying the heat expansion rate would be intense. I hope for this guys sake it runs and works well but I just think he is blowing somethings out of proportion and telling people that they wouldnt be able to re-create his work. peace.

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