1275 midget oil leak

Post by **pskipper** » Wed Apr 01, 2009 6:59 pm

Hi,

We've got a leak from the back of our modified Panda car's engine, it's a 1275cc midget (we think) engine, does anyone know what length the pressure relief spring should be, is the backplate to block gasket the same as the 1098 (as we have one of those free) and will we need anything other than the flywheel locking washers and oil pump locking washers if we change the backplate gasket and check the oil pump?

Thanks,

Philip

Post by **PSL184** » Wed Apr 01, 2009 7:16 pm

Have you checked your breathers are clear and correct and that you don't have positive crankcase pressure - That will blow oil past the rear crank seal all the time....

Post by **pskipper** » Wed Apr 01, 2009 7:28 pm

Well if you blow into the breather with your hand over the oil filler bit off you can feel the air coming out, I can't think of any other way to check that?

Post by **PSL184** » Wed Apr 01, 2009 8:45 pm

Have you got a vent in the rocker cover and/or using a vented cap?

Post by **bmcecosse** » Wed Apr 01, 2009 9:41 pm

It won't be the oil pump! And it's nothing to do with oil pressure relief valve - or oil pressure for that matter. It's ALL to do with crankcase pressure - caused by blow-by on the piston rings forcing fume into the crankcase. Engine hot and idling - take the oil filler cap off - is there a plume of fume/smoke ? If so - there's the problem. If not - look for poor fitting sump - could be simply bad fit seal at the end of the sump. Easy enough to drop the sump and fit new seals. If there IS a plume - it can be helped by making sure one vent pipe is connected directly to the carb - so the engine consumes it's own fume. I have even connected directly to the inlet manifold - with a 1/8" hole restrictor to limit the pull. It worked well on a 1340 Mini engine which was in good enough condition - but was very prone to oil leaks and smells. However - the real cure will eventually be at least new piston rings, and glaze bust the bores - or a full rebore and new pistons.

Post by **pskipper** » Thu Apr 02, 2009 8:24 am

The vented cap is clear too, there are no fumes with the oil filler cap off either.

Post by **bmcecosse** » Thu Apr 02, 2009 9:38 am

Then check the sump end seals - if that's where the leak is from ? Is the leak at front or back of engine ? Is it dripping out of the little 'jiggle' pin in the base of the gearbox ? Is it just a little leak - or are we talking pools of oil under the car ?

Post by **Kevin** » Thu Apr 02, 2009 4:59 pm

it's a 1275cc midget (we think) engine

If its got the hanging down position oil filter it is, however if its angled upwards towards the back its Marina or Ital, can you confirm its got a breather outlet on the timing chest cover.

Post by **pskipper** » Thu Apr 02, 2009 6:04 pm

Yes it has the hanging down type oil filter and the breather on the timing chest cover!

Post by **pskipper** » Thu Apr 30, 2009 7:21 pm

Replaced backplate gasket, sump gaskets (makes it much easier to check the seal with the backplate off) and moved the breather vacuum connection from the carb to the manifold which gave a much stronger negative pressure and the car made it to Cambridge and back (~240 miles) without loosing a drop of oil.

Post by **bmcecosse** » Thu Apr 30, 2009 9:00 pm

The moving of the breather has done the trick - well done !