Crankshaft rear seal ?

[bmcecosse]

This post is on the same lines as my earlier one - but it is many years since I took a Minor crank out of the block - so could someone remind me how the rear main bearing seal works ?? The sump obviously has to seal against a matching section on the main cap - but what seals the top half - is there actually a seal there, or is it just a labyrinth - with the half circle section that bolts on the back face of the block completing the circle with the sump ??

[Kevin]

If I remember there is no actual seal just the scroll to return the oil which is why the leak with age / wear, there is a conversion unit but I dont know anyone who has one fitted.

[bmcecosse]

Thanks kevin - my aim is to convert a Mini 1275 block for use in a Minor - so details of the 'conversion' would be very useful. Can anybody help here ?

[rayofleamington]

The conversion is an Owen Burton one. If your engine is in bits already then it is less of a problem as it involves fitting the bottom bearing cap and having it machined square with the one on the block etc...
If you call the places that sell the conversion kit they should be able to mail you a PDF of the instructions.

For the average engine, I'd just put up with oil in the bellhousing, but if you have a new crank (hopefully without any slight marks on the backside of the flywheel flange) then it could be worth it.

[bmcecosse]

Hmm - quite a job to machine the rear main bearing cap. I was hoping for something bolt-on since of course the Mini block has nothing at the rear cap - the oil just flows down into the gearbox.

[jonathon]

Why not use the 1.3 Maestro block which has an excellent proper crank oil seal and an extensive breathing system.

[bmcecosse]

Because I have 4 perfectly good 1275 Mini blocks sitting on my bench !! One has a knackered Mini crank - but excellent bores and pistons - so this is the likely candidate. Looking at my spare Minor engine tonight - if someone has an old knackered Minor block lying around - could they consider selling me the rear half-moon seal and also the rear main bearing cap ?? Obviously the rear main won't fit - but from it I could maybe make a bolt-on bit to attach to the Mini rear cap to give the sump the correct shape to seal against. So- anyone got an old block I could have these bits off ?

[jonathon]

fair enough!!!

[turbominor]

Hey Jonathon

is the maestro lump a straight fit (same mods as a ital block)

i know they have a normal crank with a bold on flywheel as they were fitted to vw box in the maestro, to my eyes they seem to have a round deep back plate fitted to the back of the block?

[jonathon]

The Maestro unit is a simple fit ,just needs the enbine mounts swapping side to side, there is normally an alloy sandwich plate which incorporates the crank breather system,on the back of the motor. We manufacture our own flywheel to accept either Minor or Ford gearboxes. The benefit of the good crank seal is that big bore motors or turbo'd /supercharged units will not pose sump oil pressure problems. and consequent blow bye of the otherwise useless standard seal.
The after market oil seal from O. Burton alias MMC Bath will seldom be satisfactory as most cranks especially those in tuned motors will have been machined down in size. Even standard cranks vary wildly so the success of the kit is purely one of luck, good marketing and money maker though!