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MG MG Y Type - Crankshaft front seal

At present, I am fitting one of the Moss crankshaft rear seals plus speedi-sleeve. (see photo).
Once this job is done, I will replace the front asbestos strings that act as seals. Moss and NTG sell the appropriate rubber seals.
However, I will use a Viton Seal equivalent (36x47x7mm), since this type of material is more heat resistant. I bought it from a local supplier.

Question: how should I go about (sequence) when fitting the Viton seal. At present the timing chain cover and the sump are stripped off the engine - with the crank fitted.

Regards from Switzerland
Anton Piller
YT 4220



Anton Piller

Anton
It might pay to measure your crank pulley diameter, I think they're just under 35.5 dia.
and the groove the seal fits in is 9mm wide
a seal 35x47x9mm might fit better----
William Revit

William

Thank you for the warning, but a seal by 36x47x7 is the part to use - because the pulley shaft is 35.9mm (I am using a new pulley from NTG).

Yes, the groove is 9mm wide, but sports big radiuses, so a 9mm wide one would never fit. Please also refer to the scan of a MOSS seal.

all the best
Anton

Anton Piller

If I remember rightly, Anton, the seal has to be fitted to the crankshaft nose before fitting the timing chain cover or the sump. Needless to say this requires careful fitting of both of these with a careful use of silicon. Quite a lot of silicon is needed to fill the old rope slots but not as much as to squeeze out into the oil - a difficult job to judge. Of course all must be scrupulously clean to get the silicon to adhere and it all needs to be bolted up before the silicon has gone off. All in all a lot of care and the ability to work quickly is what is needed.
Good luck
Ian
ian thomson

Cheers Anton -- sorry for my misleading info.
Would it be worthwhile machining the front lip off the housings so that the seal can be removed/replaced without having to remove the housings from the engine'
I can remember from somewhere that someone had made up a cutter to slide over the crank snout to cut the housing true to the crank for a perfect fit for a seal.
William Revit

Found it---

https://www.mgexp.com/forum/t-series-and-prewar-forum.46/creating-a-concentric-cavity-for-the-front.4646024/

some pics--
https://www.flickr.com/photos/wendlinghorst/albums/72157717705327763
William Revit

Dear Ian and William
Thank you for your replies. Especially Wout Ram´s text, he published in "The MG-Experience", regarding the concentricity with the Crankshaft is VERY helpful !!!

I probably will go for the solution with the special cutting tool. I do have a German MG mate, who owns such a cutter :o)

Anton
Anton Piller

This thread was discussed between 31/05/2026 and 02/06/2026

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