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1275 marina rear oil seal
Posted: Wed Aug 30, 2023 7:39 pm
by Classiccars
Can you please advise where to get the above correct seal as a bit too much choice about and confused.
Re: 1275 marina rear oil seal
Posted: Wed Aug 30, 2023 8:27 pm
by philthehill
There is no seal fitted to the rear of a 1275cc Marina 'A' Series engine crankshaft.
Oil control is achieved by the return scroll as per the Minor 'A' Series engine.
The return scroll and oil thrower ring can be seen in the bottom photo.

- Marina crankshaft tail 1.jpg (82.97 KiB) Viewed 958 times

- Marina crankshaft 1.jpg (52.96 KiB) Viewed 957 times
Re: 1275 marina rear oil seal
Posted: Thu Aug 31, 2023 7:44 am
by Sleeper
It could be this you're thinking of
https://www.morrisminorspares.com/engin ... ly-p830198
Mixed opinions, I'm happy with mine , albeit with the midget guru mod..
John ;-)
Re: 1275 marina rear oil seal
Posted: Thu Aug 31, 2023 8:08 am
by philthehill
Sleeper
Can you please put up a link to the Midget Guro modification.
Fitting a rear oil seal kit without additional work is a waste of time and money.
If you must fit a lip seal to the rear of the crankshaft this is the one to use:-
https://www.med-engineering.co.uk/produ ... n-seal-kit
Re: 1275 marina rear oil seal
Posted: Thu Aug 31, 2023 8:57 am
by svenedin
Are you having an issue with an oil leak from there? It is a very common place for A-series engines to drip oil. As Phil says there is no "seal" as such. There is a scroll oil thrower. This is a spiral groove ("scroll") that throws oil back towards the engine. These are common on a lot of older engines, not just the A-series and actually I found one in the gearbox of an old Kenwood Chef mixer I overhauled recently. They are rarely perfect and a few drips of oil are to be expected because the "throwing" action is only working when the engine is running. On shutdown of a hot engine, a few drops often leak and so a drip tray or some cardboard on the garage floor is a good idea.
If the leak is more problematic than a few drops then the issue is most likely to be due to poor engine breathing. I remember you posting about the breathing system of your engine and it was not set up correctly. When there is crankcase compression (and there always will be some, more on a worn engine) that pressure must be relieved by the breathing system. The best breathing systems use engine vacuum to create slightly less than atmospheric pressure in the crankcase. If the breathing system is not working it overwhelms the ability of the scroll to throw oil back into the engine and oil leaks out. A more modern actual seal to replace the scroll system will not work if the engine breathing is still incorrect.
Stephen
Re: 1275 marina rear oil seal
Posted: Thu Aug 31, 2023 9:50 am
by Classiccars
Thank you all for the advice.As the engine now appears to have stopped throwing out oil I may just change the wet clutch and ensure there is a hole in the bottom of the clutch cae just incase of any oil..
Re: 1275 marina rear oil seal
Posted: Thu Aug 31, 2023 10:46 am
by Sleeper
Re: 1275 marina rear oil seal
Posted: Thu Aug 31, 2023 10:50 am
by Sleeper
Re: 1275 marina rear oil seal
Posted: Thu Aug 31, 2023 4:30 pm
by philthehill
Sleeper
Thank you for the links.
The conversion/modification in the link was discussed on this forum some time ago. My general opinion back then and still is - get the engine correctly built and running properly and then there will be no need for any conversion/modification.
Personally I would not undertake the conversion/modifications as described in the link as it is non reversible and needs some skill to achieve a successful outcome.
Phil