BIG oil leak

Post by **Matt** » Sun Aug 05, 2007 4:21 pm

Im getting to my wits end with this car...

I have totally rebuilt the engine (1275 ital) with an overbore, new pistons and rings, new camshaft, mains and little ends reground, new bearings all round and its still peeing oil from between the sump and the backplate! it started after running for about 5 minutes.

The scroll looked to be okay, but it cant be that can it?? surely it would run into the bellhousing if that was the problem

Anyone got any ideas before (haha) I go insane?

Post by **picky** » Sun Aug 05, 2007 4:32 pm

have you fitted the cork or rubber gasket that is meant to seal the sump round the main bearing caps? sounds like the rear one is missing. also, what have you got setup for crankcase breathing? if there is too much pressure building up then you will have a high chance of oil leaks.

Picky

Post by **Matt** » Sun Aug 05, 2007 4:40 pm

Yes the cork gasket is there, it (a different one!) was before I rebuilt the engine... New gaskets everywhere. Breathing didnt make a difference before, but at the moment there is a vented cap in a rocker cover which is vented to the carb. There is a vent on the timing cover which is to atmosphere. Neither of the vents are blocked.

Post by **bmcecosse** » Sun Aug 05, 2007 6:10 pm

If it's coming down the backplate - then it is the rear sump pan seal. The cork (or better to use silicone rubber) seal must be left slightly long - so when the sump is bolted up it is compressed and seals completely. I know some will huff and puff - but I would also suggest a bead of silicone sealant on it - then bolt it up.

Post by **Matt** » Sun Aug 05, 2007 7:48 pm

BMC, I put sealant on it when I assembled it ;)

Leak is sorted, (dont critisise my choice of materials, it was all that was avaliable at 5pm on a Sunday, I will rectify it soon!) Attached the breather on the timing cover to the carb, and the rocker cover to the airbox. Also (as a v.temp bodge) put the oil filler cap in through a carrier bag to make it non vented, I will be looking for a non vented sort now though!

Post by **bmcecosse** » Sun Aug 05, 2007 9:02 pm

Just leave ot vented! The air flow will be negligible.

Post by **Matt** » Sun Aug 05, 2007 9:04 pm

Post by **bmcecosse** » Sun Aug 05, 2007 9:05 pm

Post by **Matt** » Sun Aug 05, 2007 9:15 pm

hmm I will see how a vented cap works, but it will reduce the vacuum!

Post by **bmcecosse** » Sun Aug 05, 2007 9:20 pm

It will allow a nice cooling flow of air through the engine ! Actually - only one of your breathers should be connected to the inlet system - the other should admit the air. But if your engine is all nicely rebuilt - there should be no 'pressure' in the crankcase anyway!