Rear sump cork gasket thickness?

I fit sump on my 3.8 yesterday and am a bit concerned about the rear seal. My block was done up with a rear main seal conversion and I think the channel for the seal is a bit deeper than stock. With the original rear housing there was a nice crunch on the standard cork gasket, but with this one the sump just kind of sits on the cork without much compression. It seems like a leak waiting to happen.

I’m thinking it would be smart to replace it with something 1/8" thicker so it gets a good smoosh. But I’m not sure what the stock cork is and am not near the car. Am I correct that it’s 1/4"? I did some searching for 3/8’ cork, and unfortunately it looks like it’s going to be pretty spendy since it’s not sold in small quantities.

It used to be that FLAPS sold sheets of cork: perhaps they’d have whatcha need?

And, I’d personally do this–and I know you don’t like the suggestion, but it works-- a thin layer of RTV, laid down between the pan and the seal, and allowed to cure before tightening down, will prevent any leaks.

I can find 1/8" there all day, not sure about thicker but I’ll check. I could also glue an 1/8" layer to the bottom of a 1/4" one.

I actually did end up using silicone and afterward started feeling a sense of dread that hasn’t gone away so I think I’d better redo it.

Oh, good grief, woman!!


I can tell you that gluing two cork pieces together will work just fine…OR…you could just add the bead of silicone to the existing cork, as already suggested. Many of the Ford FE (390, 428) guys don’t even use the 2 cork gaskets originally supplied by Ford to seal the front and rear of the intake-to-block bulkhead because getting the mani to seal to the heads properly is often compromised by those rather thick cork pieces…they just use a thick bead of silicone instead…partially cured at assembly…creating a sort of self-adjusting, perfect seal.

I did that, a lot, on various engines. Done correctly, it works perfectly OK.

So I think I figured this out. The gasket sent from XKs is not actually 1/4". After measuring it, it was just .19". Hence no squish at all. Best to source you own 1/4" cork/rubber gasket material and cut a strip.

I have just replaced the sump on my MK9. This car also had a rear seal conversion. The old gasket and the nos replacement was 5.6 mm thick.

Erica why not use the later rubber seal?
Peter B.