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SP250 Engine oil seals; cork or rubber?

Posted: Fri Mar 15, 2019 8:55 am
by wadams
Hi
Does anyone have experience of using engine oil seals made of rubber instead of cork for the SP250 please?
Thanks

Re: SP250 Engine oil seals; cork or rubber?

Posted: Fri Mar 15, 2019 9:32 am
by timmartin
I am assuming that you are referring to sump oil seals.

I do not have the personal experience to comment, but Russ Carpenter (who is currently rebuilding my engine) told me as recently as this week that he now prefers cork as it reacts to the oil better over the long term.

I have been told by both him and Philip Glenerster (spelling?) that it is easier than you might think to snap the sump when bolting it back on. Not something that I would have guessed, but might be irritating.

Re: SP250 Engine oil seals; cork or rubber?

Posted: Fri Mar 15, 2019 10:36 am
by A.N.Other
Cutting to the correct length is the trick and can be a trial and error operation.
As they compress radially to seal they expand laterally thus causing difficulties to get the length right. If too long then the sump does not pull up to the block face and can crack the sump if too much torque is applied to the retaining screws. If it is too short then gaps appear at the ends although they can be bodged with sealant.
Rubber can be difficult to push into position as it is a tight fit but a little grease can help. Cork should not be greased or oiled prior to installation as it will expand unevenly and swelling will make it difficult to fit.
Over time rubber may shrink but in saying that it is a consumable item that has a life span. Cork will shrink if it is not kept damp over long periods. All types of seals on all types of engines will never last for ever.

Re: SP250 Engine oil seals; cork or rubber?

Posted: Fri Mar 15, 2019 11:27 am
by wadams
Thanks for the great info on the seals guys, it is certainly really helpful.

Re: SP250 Engine oil seals; cork or rubber?

Posted: Fri Mar 15, 2019 5:04 pm
by wadams
One more question, can the seals be replaced with the engine insitu if you have the car on a ramp?
Cheers

Re: SP250 Engine oil seals; cork or rubber?

Posted: Fri Mar 15, 2019 6:04 pm
by A.N.Other
I have done it but it is not straight forward. The sump (my brother referred to it as the “camels ump”) catches on the chassis and back plate so the engine has to be lifted until the top of the bell housing touches gearbox tunnel. The engine internals stop you getting a good angle to manipulate the sump out. If memory serves me accurately a little metal removal was required as well.

Re: SP250 Engine oil seals; cork or rubber?

Posted: Sun Mar 17, 2019 3:49 pm
by Reedweaver
My SP sump came off with little trouble using adjustable ramps. I dropped both exhaust manifolds off at the same time as one was cracked. The starter was removed as well and replaced.

I couldnt believe the amount of sludge caught in the sump trap! The cork seals were leaking badly, but they were 25 years old!

I am going with rubber seals this time.

Re: SP250 Engine oil seals; cork or rubber?

Posted: Sun Mar 17, 2019 10:45 pm
by wadams
Hi Reedweaver
Thank you for your comments and pictures. Much appreciated.

Re: SP250 Engine oil seals; cork or rubber?

Posted: Mon Mar 18, 2019 11:03 am
by Reedweaver
You might as well drop the oil pump as well while you are at it. Mind you, not much goes wrong with it I am told. It throws a fair amount of oil around and needs little maintenance. Andrew from Carpenter Racing can refurb and rebiuld to exceed OEM spec but it wont cure low oil pressure due to bearing wear or other issues.

A few more pics...

Re: SP250 Engine oil seals; cork or rubber?

Posted: Mon Mar 18, 2019 11:21 am
by John-B
Reedweaver wrote: Sun Mar 17, 2019 3:49 pm I couldnt believe the amount of sludge caught in the sump trap!
I'd rather not look at mine. Are flushing oils any good at getting rid of sludge there?