Oil leak

[Ryanhooley]

I am looking for a bit of help. I have an oil leak on a marina 1800 tc engine, from just behind the flywheel so suspect the bearing seal. Is this a easy job to do and where would i find a bearing seal, and is there any other jobs that should be done while i am underneath the engine? Thanks Ryan

[lil_red_roadster]

Re: Oil leak

A straightforward job...but engine out...follow the Haynes manual. Any MGB specialist will be able to supply a new crankshaft oil seal. Check/change the clutch while you have it all in pieces...remember the Law of Sod...!

[stevejgreen]

Re: Oil leak

B series engines are subject to all sorts of oil leaks and they manifest themselves generally at the front of the bell housing, the lowest point and where the oil gets blown to.
They also have a habit of blowing out any excess oil if they are overfilled, so check that the level is really dropping beyond the normal level.
Possibly the weakest seal is the tappet chest, behind the exhaust manifold. Don't overtighten the fixing bolts.

Jez is right, but I think that the gasket between backplate and block may also form part of the seal arrangement.
If you change the crankshaft oil seal and complete clutch assy, don't forget the crankshaft spigot bush, buried inside the crankshaft end. I have never understood why they are not supplied with the clutch kit!
All parts the same as MGB apart from clutch assy.

Hopefully it's not an engine out job, but if it is, other jobs that could be done easily at the same time, like draining, flushing and re-filling the gearbox and replacing the sump and tappet chest gaskets.
It's also an opprtunity, depending on mileage, to think about a new cam, or changing the timing chain to a duplex style, the same as an MGB.
Could be a winter project!

[lil_red_roadster]

Re: Oil leak

Spigot bush is a good call and worth checking...but iirc the MG/Marina are different. Doesn't the MGB have a larger diameter input shaft ..? Its a few years since I had a B box lying around so hopefully this isn't an early-onset senior moment..!

[stevejgreen]

Re: Oil leak

Same problem here. My memory says that spigot bushes were different OD's between old 3 bearing crank MGB's and later 5 bearing cranks. But that the ID's were the same.

Having said that an MGB parts list I have quotes a range of differ OD's available from std? to +0.060".

Does anyone else have better info?

The moral of the story is not to rely on declining brain power but to pull one out and then download http://www.bowman.co.uk/Resources/Sint%20Bearings%20%26%20Excel%20LO.pdf and search till you find the right one and then order it from Brammer at half the price an MGB parts man would charge.