Speed 6 water journals

[Night Rider]

Can someone please explain why half of the water journals are blocked by the head gasket and why the remaining ones are restricted by a reduced hole compared to the actual cast in the head & block?

The old gasket in the pic is the same as the new Cometic gasket I’m about to fit…maybe.

[clive f]

an expert will be awake soon, but I`d guess that the small holes, with some of the bigger holes blocked off will increase the pressure of the coolant, therefor coolant moving around the cylinder head quicker.

a bit like putting your finger over the end of a hosepipe.

[dvs_dave]

No idea, looks very odd and if it's supposed to be like that a shockingly bad design. Since when has blocking/restricting flow through the water jacket ever been a good idea? It looks like it's maybe a bodge solution to increase the coolant flow around cylinder six which is known for running hot.

Does the head have corresponding holes for the water to flow through?

Edited by dvs_dave on Wednesday 12th October 00:23

[Geoff Ashcroft]

I think you need to be talking to Jason at Str8Six or Dom at TVR Power, to see what it's all about. Their knowledge is essential with such an important aspect and you don't want to create a problem. You just need to know what's right.

[plasticman]

I think you will find that using the gasket to bias the water flow to hotter parts of the engine is a lot cheaper and easier than recasting the head till youi get it right .

[dvs_dave]

So it is a bodge job fix to get more coolant flow to cylinder six. This is fair enough but what I don't understand is why some of the ports are completely blocked off. Surely this must cause all sorts of airlock issues and consequent hot spots?

[cinquecento]

There is an article in this months SPRINT which echoes details on RND's website about the original design for the head gasket... which has all gasket holes open on the inlet side of the gasket. The exhause side has all holes open.. however they are the smaller ones as opposed to the inlet side side, where holes match the block/head casting.