Silicon sump gasket

[John Mason]

Job done. Easy to fit and oil tight I should have fitted one when I had the engine apart 18 months ago. Next time it's apart will also fit the crankcase to block silicon gasket although at present no leaking oil from there. Thanks everybody for the help and advice

John Mason

[John P]

HI,

Just wondered about using one of the silicone gasket makers which are rather like a silicone bath sealant but apparently designed for automotive use.

I could do with fitting the sump tomorrow and could pick some of this up locally rather than having to order a pre-cut silicone gasket.

Has anyone any experience of using this?   Do you use it as well as a paper gasket (which I already have)?

Finally, if I do go for one of the pre-cut sheet silicone ones what's the best place to get it?

John.

["Slack Alice" Simon]

Some on the forum love the silicon goo, I cannot use it without finding oil-jet sized blobs in the engine when I come to look inside again.

If you can find a cooking supplies shop they might have the silicon sheets I used before the cherished suppliers produced the sump gaskets.

It is really easy to make gaskets using silicon sheet, particularly if you have hole cutters.

If you don't have hole cutters, sharpen a bit of mild steel tube - it will do well enough for one gasket.

[Zetomagneto]

Jamie, Seven Workshop, he will send it for next day.Worth waiting for to do a nice hassle free, tidy job.
Assemble absolutely clean and dry on both sump and crankcase then it won't squidge out.
No grease, oil, or goo

[Hedd_Jones]

I used a Sainsburys silicone baking sheet as a gasket on my traction engine for its hydraulic test. I wasnt impressed. Far too squishy and needed serious pain to make it seal. We are talking 6no 3/4 BSW studs of tension.

[John Mason]

I got mine from Seven Workshop and when I ordered I put my thread on the forum. Some members said they put there's on dry without problems however Jamie on seeing my thread took the trouble to ring me and advised using a very thin smear of silicon sealer or Blue Hermatite. I used silicon gasket sealer but not that much that it would squish out into the sump. When all fixed none had to be wiped off on the outside so I presume that none either on the inside.

John Mason

[Ian Williams]

Interesting, whats the logic behind the sealer, to my mind it will lubricate the gasket and allow more to exclude from the joint. I have not had a problem fitting them completely dry and oil free, but that said always keen to learn from those who have better solution's, can someone please explain the reasons behind the sealant advice. Jamie perhaps?

[John P]

Obviously I can't speak from experience which is partly why I asked the question.   

I have however just bought a new tube of Blue Hylomar which is extremely sticky and I suspect a different formulation from the old tube I had which was more the texture of toothpaste.

I can imagine the new Hylomar would help hold the silicone gasket in place.   Certainly when I used it on the core plugs I ended up having to use a solvent to get the excess off the block and that was only 1/2 hour or so later.

I think I'll order a cut silicone gasket today and then decide whether to add Hylomar as well.

The reason I was thinking about silicone sealant rather than a gasket as such is that if I press on the sump flange adjacent to the oil pump and between the bolts it visibly distorts and oil can be seen squeezing from the joint which is probably why I have a quite bad leak on my garage floor.  

The bolts are tight and the joint is currently a normal paper gasket with Hylomar but this was assembled some years ago.

John.

[John Mason]

John P, Yes a small thin film of sealant holds the gasket on the sump all lined up with the bolt holes and does not move when the sump is offered up to the crank case. Just a simple thing to put in the bolts. Warning though only just nip the bolts up otherwise to much and the gasket will spread.

John Mason.

[Ian Williams]

I have used a number of silicone gaskets and found that installing them dry with both flanges throughly degreased seems to help control creep and spread, I use acetone or brake cleaner which leaves no residue. This is why I have asked for the logic behind using sealant, surely it acts as a lubricant and exacerbates the problem???