VHR Billet Block

Originally Posted by phunk

When you sleeve a block, you can sleeve it wet or dry. The reference is to whether or not the sleeve is in direct contact with the water.

If you dry sleeve the block, you would basically just be boring it out large enough to eliminate the factory liner and into the aluminum, then you would press in a new, stronger/thicker sleeve.

When you wet sleeve it, you install sleeves that are so large, they are in direct contact with the water around the cylinder. In the VQ, this means removing the entirety of the floating sleeve. Then you press in the new sleeves.

A wet sleeve process is an interesting one, because you go from a block that was essentially one complete unit, to a block that is now just a chassis for individual sleeves that are just resting inside it. You have sacrificed some overall integrity of the foundation for the sake of individual cylinders that can handle much more pressure.

For a VQ block, this sacrifice is minimal since the sleeves were floating anyway, you remove very little of any structural part of the block. You are also adding some sleeve stability since the wet sleeves contact the block horizontally at the deck, when the stock sleeves last touched the block at the base.

There is lots of argument back and forth about the potential side effects of large masses of dissimilar materials when you put these giant ductile iron sleeves into aluminum blocks. There is no argument that the wet sleeved block will hold a LOT more power than the standard VQ block. The argument is to longevity, most specifically the headgasket.

Attached are photos of a VQ37VHR block prepped for a wet sleeve install, and a wet sleeve before installation.

If anyone wants a wet sleeve setup, I am practically next door to the guy who does the wet sleeves for most powerful GT-Rs, and as you can see from the photo, he has VHR experience as well now

Originally Posted by jwick

Is there a reliable head gasket option for high horsepower built blocks?

Originally Posted by jwick

Is there a reliable head gasket option for high horsepower built blocks?

Originally Posted by phunk

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.