Quote:
Originally Posted by jwick
Is there a reliable head gasket option for high horsepower built blocks?
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Cosworth has HR/VHR headgaskets which I *believe* are manufactured by Cometic for Cosworth USA.
These are the gaskets I am going to try out on this build. My favorites have classically been HKS gaskets, but they only have DE style gaskets for the VQ.
What is very important is that you get proper head bolt or stud clamping force. This was the biggest problem for built DE's for a while, and cost the community a ton of money and gave VQ's a terrible name for high power. Everyone was using the standard ARP2000 head studs which had too low of a torque spec to hold up in the 500s and 600s, and head lift was a big problem. Nobody quite understood at first because it felt like the headstuds wouldnt be the issue after having just "upgraded" them. But it turned out it was the problem, and once people got the 1/2" studs done or L19 studs that could handle 90-100lb-ft of torque, the head lift issues and headgasket issues mostly subsided.
The VR engine uses a thread that is 1mm larger diameter than the VQ. Normally you couldnt machine a thread to just 1mm step-up because you wouldnt have removed the old threads yet. But I am pretty sure the PITCH is the same between the two, so very very carefully, it may be possible to oversize the threads up 1mm, but it would be a critical procedure and probably not recommended to bother. But I might try it, maybe. L19s havent been tearing out of the stock threads at high torque, but I would feel better with a larger thread in the block.