MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - Necessity for Sump Gasket

A recent thread about gasket quality has led to discussions of materials used for attaching sumps, i.e., gaskets and cements. I believe that the gasket thickness is considered in the sealing of the front and rear ends of the crankshaft. Is it feasible to attach the sump to the block with only a sealant? Bud
Bud Krueger

Good question Bud. I used a new gasket from Moss, but had to modify the front by narrowing it where it touches the crank seal. Fortunately I kept my old gasket for a pattern, no leaks. I wiped the gasket with Permatex Copper sealant.
I never heard of using just sealant on a sump, but very possible. PJ
Paul Jennings

I don't think it is a good idea on the XPAG as suggested above. Sealing around the oil pickup hole would be a big problem, etc. George
George Butz

I agree with George, there are too many places where the oil can get past (ends of the gasket, front and back, etc).

Rolls Royce never used gaskets on their engines, just Halomar sealant on the surfaces. That said, the consumers paid for that kind of precision (far more than I can afford). Cheers - Dave
DW DuBois

I'm on the same side. But, let me play Devil's Advocate for a moment.
Looking at Mort's images, and going through a whole lot of images taken while in the midst of engine redoing, I see a few things that make me wonder. I see very few areas where there is oil under pressure with a passage to the surface of the sump.
The first is the passage from the sump to the block where the oil is being picked up from the sump and is feeding the oil pump. I'm unclear of what sort of pressure would be there.
The only other areas where I see an avenue from a pressurized area to the sump is the underside of each of the main bearing caps. I've never heard of sealing that space.
Those are the only pressurized areas that I can see. I see a number of un-pressurized areas, e.g., The hole for the dipstick, the cork over the rear main bearing seal, the seal (cork or otherwise) at the crank pulley.
Otherwise it's just the splashing of the oil do to the motion of the crankshaft and rods.

How much pressure is present in the oil that's being slung about in the sump? How much of our leakage is coming from oil that is going around, under, or over the sump gasket???? What am I missing?

Bud

Bud Krueger

Yes, it can be done. A friend of mine uses some kind of modern sealant used on Volkswagens to seal up the pan on his TC. It has worked for many years.
Steve Simmons

Hi Guys,

I don't use gaskets on sumps. I seal with silicon but other sealants are probably just as good.
However there are some important issues. George makes an important point .... the oil gallery which joins sump to block is not under pressure but suction. Any leak there and air will be sucked in. Also, any sealant squeezed into the gallery might become dislodged and damage a bearing etc. To solve this problem I drill out the block and sump to take a short piece of (half inch OD) tube. I glue it into the block but it protrudes into the sump. This prevents the loose sealant issue. It is a bit tricky because the gallery in the block is at a slight angle.

The cork gasket at the rear seems to be thick enough to accommodate the lack of gasket but the front could be a problem. I machine the sump and timing cover to take a modern lip seal and that solves the problem for me.

There is no need for sealant under main bearing caps EXCEPT for the rear of the rear cap. Sealant applied there prevents the leakage of oil, possibly under pressure. This applies whether it is original seal, Moss seal, my seal or whatever! (See image, ignoring all but the red arrows)

Bob Schapel

R L Schapel

Thanks, Bob. Very interesting. May I ask which sealant you favor? Bud
Bud Krueger

Hi Bud,

I use "Silastic" or "Permatex" silicon sealants. They come in various colours etc. I have used a variety ... all seem to be ok. They are a pain to clean off when the sump is removed, but I figure that once together, an engine should stay together for a long time.

Bob
R L Schapel

Best general purpose sealer I've used so far is "Right Stuff". Terrible name, excellent sealer. I prefer it to all the types I've used in the past - Blue, Black, Grey, Aviation, Seals All, etc.
Steve Simmons

This thread was discussed between 14/02/2017 and 16/02/2017

MG TD TF 1500 index

This thread is from the archives. Join the live MG TD TF 1500 BBS now