Gaskets - to seal or not to seal?

Technical MGB discussion
Ian Fozzard
Posts: 653
Joined: Fri Mar 27, 2015 8:18 am
Forename: Ian
Surname: Fozzard

Re: Gaskets - to seal or not to seal?

Post by Ian Fozzard »

Dick - supplementary questions are the norm on this forum🤔

A couple of things to note:

I would be very careful in polishing any of the internals on the SUs. They certainly need to be clean and dry with no aluminium corrosion, but don't remove too much material from the surfaces.

You need to ensure the jets are centred, especially if you have fixed needles, not biased needles. If not this will hinder piston movement.
You also need to ensure that the correct piston and cover are retained (don't mix them up) and that the piston has the required amount of the correct viscosity oil.
It sounds to me like you have some binding of the components somewhere.....

Ian F
1972 BGT, Blaze, Navy trim, recessed grill
1961 Midget, 948cc, Clipper Blue, Blue trim and weather gear
Vic Butler
Posts: 618
Joined: Wed Dec 21, 2016 6:07 pm
Forename: Vic
Surname: Butler
Location: North West Hampshire

Re: Gaskets - to seal or not to seal?

Post by Vic Butler »

Any abrasive substance mustn't be used to clean SU carburettor parts. Brake cleaner or similar is best. If anything abrasive is used then it will wear away microns of the metal and alter the clearances. Cellulose thinner is very good but it must be used outside and away from any heat source.
If any part of the piston or dashpot is corroded the only answer is a new pair. You shouldn't buy a new dashpot or piston on its own.
1977 Stage 2 MGB GT
1975 SWB Series 3 Land Rover with a later 2.5 petrol engine
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