Cylinder Head water gaskets

[SteveW]

My gasket kit appears to have two gaskets for the water galleries in the cylinder head. I assume that one is for the blanking plate at the rear and one for the top water elbow at the front. One is cork and one is paper - which one is which? My engine had been stripped and then put back together dry for sale when I bought it so none of the gaskets were in place.

[Steve Simmons]

In my experience, nothing but cork works in the rear. So paper up front.

[Tom Lange, MGT Repair]

Original is paper up front, cork at the rear. But I have found that using cork at the rear is a mistake. The cork gaskets tend to compress unevenly and break down, and so I use paper gaskets in both places, without leaks. I supply only paper gaskets with my stainless steel plates for the rear of the head.

Tom Lange
MGT Repair

[Steve Simmons]

Interesting Tom, I've had the opposite experience. I've had paper gaskets leak more than once even with sealer. It probably has everything to do with the condition of the head. A lot of them after 70 years are less than perfect sealing surfaces. The cork should be tightened evenly and only snugly, never super tight. Being an unpressurized system, there is no advantage to going tighter than necessary to make a seal. I suspect paper gaskets are original up front because of the flex and vibration between radiator and engine. Cork would probably not hold up well, and it seems like the bolts might loosen as the cork compressed and released with each movement.

[Tom Lange, MGT Repair]

Steve - I think you are right. I should have made clear that paper gaskets are what I supply with my guaranteed-flat stainless plates at the back of the head - since the stamped factory plates are often warped, they might require a cork gasket to seal well.

I highly value hearing different perspectives, and always learn something!

Tom lange
MGT Repair

[SteveW]

Thanks for the clarification. Interestingly, when I was cleaning the threads for the front I noticed that the top right thread (as you look at it) goes all the way through to the boring for the No. 6 cylinder head stud (counting in tightening sequence order). This shouldn't be a problem as long as the gasket holds but I think that I'll put a small dab of gasket compound on the thread when I reassemble just to be sure.

[Steve Simmons]

Personally I put sealer on ALL the water plate threads. It helps protect from corrosion. Even if the holes don't go through, sometimes a bit of water leaks in, especially if there is a tiny crack. It also acts as a thread locker.