Today I received a letter from a gasket manufacturing company regarding custom-made CNC-cut gaskets in paper and other materials.

Having just resealed a leaking engine, this got me wondering if there was a better alternative to a paper gasket and blue Hylomar?

I know various people have different solutions to this perennial problem, ranging from no gasket at all to copper sheet, but wonder what the consensus of opinion is on material and thickness. With today's technology there must be something better than paper.

Rick

Location: Deepest Norfolk

Rick I have used Loctite 5188 flange sealant and no gasket on my latest rebuild. Its not cheap but it doesn't leak and is reputed to have gaps filling properties up to 20 thou.

Location: Farnham

Loctite 518 any day, make sure that both surfaces are flat and throughly degrease with a non oily cleaner, such as contact cleaner or brake clean, no more leaks....works for me

Location: NZ

I have used Permatex aviation gasket sealant number 3 which can be bought on ebay. You can use it with or without the paper gasket ( I used a paper gasket as I think it helps with any slight unevenness of mating faces) this is an alcohol based sealant that is just brushed on with the brush provided. Leave for a few minutes and it gets very sticky. Bolt together and after about 10 mins and it is supposed to be oil tight however they recommend over night. It is then oil, water and petrol tight. It never dries hard so allows slight movement between surfaces without breaking. My seven has not leaked since I used it over 12 months ago.

John Mason

Location: Nottinghamshire

Thanks. Like the sound of Permatex plus a paper gasket. Has anyone else used it? Has it failed?

Rick

Location: Deepest Norfolk

I stopped using paper gaskets combined with other sealants over 25 years ago when it was explained to me that doing so would increase the number of surfaces and therefore the chance of leaks occurring.

I have used sealant only ever since over extensive mileage with very good success.

Thanks Ruairidh. My main reason for this query was to wonder if anyone could suggest a modern gasket material with enough flexibility/elasticity to render sealant unnecessary.

Was I hoping for too much?

Rick

Location: Deepest Norfolk

Could you share the details of the company making the CNS gaskets?

Location: United Kingdom

Sorry - should have done that first
Ferriday Engineering http://www.ferriday.co.uk 01559 37313. They are located in Cwmduad Carmarthen SA33 6AX

Rick

Location: Deepest Norfolk

Rick - the answer is no, you are not hoping too much. I know that Ruriadh uses Tiger Seal, I have used Sikkaflex with the same results. A bead of the silicone like material will give a degree of flexibility as it doesn't dry to a hard finish and will allow just a gnat's movement in the joint as the crankcase flexes.

Edit: Sorry, just re-read your posting and realised your point. Doh.. Anyway, the above still stands. Hth...

Location: Cambridge

Thanks Hugh.

Rick, last year I read that some of the Australian Clubs were experimenting using silicon baking sheets, they were hand cutting them the same shape as the paper gaskets and found them to be very successful. I am keen to try these out myself, would you be interested in this? If so perhaps you could ask the company you have details of? The material used in Oz is nothing more special than run of the mill silicon baking sheets and are readily available.

Ruairidh, I'd be quite happy to take this further and, if the price is not too silly, order the minimum number and make those I don't need available at cost.

Have you any idea of the ideal thickness of the silicone, or even what thickness the guys in Oz are using?

Rick

Location: Deepest Norfolk

Just inspected the wife's Silicon baking tray sheets, they look as if they could do the trick just fine found them on E-Bay Item No.1117120229825 LARGE SHEETS PURE SILICONE/ GREASEPROOF BAKING SHEETS
PROFESSIONAL BAKINGS PAPER SHEETS(39gsm -approx.) 15" x 18" 375mm x 450mm (approx) would they be big enough?

Location: Piddle valley, Dorchester.

Peter, it's unlikely that a commercial firm will use individual sheets of material bought on ebay - I think they will buy it by the roll. The question is as to thickness - 39gsm sounds pretty thin to me, bearing in mind that common A4 printer paper is 80gsm. But that may be thick enough, I really don't know, which is why I would like to find out what thickness the Oz guys use.

Rick

Location: Deepest Norfolk

http://pub25.bravenet.com/forum/static/show.php?usernum=2099944454&frmid=5&msgid=972475&cmd=show

Previous thread here, note that the Aussie guys use a mat with an integral weave.

With the apparent difficulty and cost of getting them made commercially, I would suggest the best way if you wish to experiment is the use of baking sheets as in Doug Bakers article.

Enter Tony Press, stage west.....

Location: NZ

Ian,

Since this silicon gasket suggestion was mentioned last year I have not had any reports from anyone trying it.

I would be a little wary of a thickish gasket, preferring to rely on a good gasket cement and close fit between block and crankcase.

Tony.

Hi Rick,

I will get in touch with you once I am home again.

Location: Nottinghamshire

Location: Auckland

Hi All
My chummy has finally thrown his 1 1/8" crank, ironic that I had already bought a phoenix for the winter project.
The question is, where are we with the silicon gaskets. Has anyone got anything to add to this thread or are we back to no gasket with sealant?
Many thanks.
Adrian.

Location: New Forest

Adrian,

The Seven Workshop now stock them.

https://www.theaustinsevenworkshop.com/products/e0122s-silicone-rubber-base-gasket

Jeff.

Location: Almost but not quite, the far North East of England

They are available here Adrian: https://www.theaustinsevenworkshop.com/products/e0122s-silicone-rubber-base-gasket of the dozen or so I have now fitted, all provide a completely oil tight seal, I can highly recommend them.

Hi Ruairidh
Thats great news, just use as is or with sealant?
Adrian.

Location: The New Forest

Clean everything and fit it dry - some will creep out of the joint slightly, you can either leave this protruding slightly or trim.

Hi Ruairidh
Many thanks for the information.
Adrian.

Location: The New Forest

I have a silicone gasket on the Ulster engine and so far so good. It has spread slightly on tightening down the block. It was fitted dry but I have since learned that every trace of oil should be removed from the joint as it is this that causes the silicone gasket to creep. If I was doing the job again I would use brake cleaner or similar to clean the top of the case and the underside of the block before fitting the gasket.

Location: North Yorkshire

I have also now had extremely good results with silicone sheet block gaskets, not the slightest sign of an oil leak. We even made one which cured a persistent block crankcase leak on Joss 12/4, all very promising and highly recommended!

Location: Auckland NZ