head gaskets

[john 4d]

Any one know why there are holes in the engine block and head gasket and blank faces on the mating cylinder head?

John

[V Mad]

imported post

I suspect Triumph put holes in the block in all positions that they might need, but the heads were developed (changed) to direct coolant to equalise temperatures. They didnt need to block off the unwanted block holes.

[alan_thomas]

imported post

I studied this in depth on the TR7 which is almost the same and found there are some holes in the head that don't match with holes in the block. There are holes in the block that don't match any in the Head and finally, most interestingly, there are holes in the head that match holes in the block but either have no hole or only a very small hole in the gasket.
It seems that they continued to develop the water flow after the head tooling was in production and modified the coolant flow thru the head with changes to the gasket design.
- Alan

[john 4d]

imported post

The reason I ask is that I've just strippedthe heads off ofthe block of my engine, to find that the only erosion in them that has taken place is not where I expected it to be, that is not around the water galleries. Instead the blank faces exposed to the openings in the engine block and gasket is pitted to the depth of 5 to 10mm, at one point braking through to an adjacent in-let manifoldtapping hole. This necessitates an attempted aluminium weld repair and re-skim if successful. In addition the associated build up of aluminium oxide and other detritus apearing to be a jelly like substance of primeval quality had grown back into the engine block severly restricting the water passage way at that point. No wonder we have cooling problems.

Potentially, because of these unnecessary holes, my cylinder heads are scrap!Hasn't this been raised before? I can understand the reasoning behind the holes in the head being therefor core removal during the casting process to provide internal galleries, but the gaskets! Were else are these gaskets used? I can understand if they were mass produced for several engines, but I thought the stag engine was unique. If it has been raised before why hasn't someone suggested designing the holes out of the gaskets used today, to protect these exposed surfaces,we can't be usingstock gaskets left over from thirty years ago?

[Sheepdip]

imported post

john 4d wrote:

we can't be usingstock gaskets left over from thirty years ago?

I also question where the stock comes from.

During the last 10 years I've always specified "Payen" head gaskets and they came plastic covered on a Payen backing card.

Recently I spotted a friends newly purchased Payen gaskets and these differed with a thin rubber sealing strip around the edge of the gasket (I have seen these before on more modern cars, usually sealing around waterways).

I questioned the supplier and he noted this type had been around for several years. So are the others just very old stock items?

Sheepdip