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MG MGB GT V8 Factory Originals Technical - Oselli 1995cc info

I have a 1995cc Oselli lump in my GT with a melted piston. Oselli tell me they are made of "unobtainium" so the big Q is - which pistons did they use. a Google search has come up with various piston makers (v. expensive for one-offs) but what I need is a catalogue or database of pistons used in other engines (bores are 84.25mm but calculation says 84.5 to give 1995cc) or even better Oselli pistons from a broken engine.
R.A. Furneaux

Are there any identification marks anywhere on the Oselli pistons?

I think you will find that the 2 litre "O" series engine from the MG Maestro or Monetgo of the mid 80s to early 90s had 84.5 mm pistons - could Oselli have used these?

Peter Burgess builds 1950 cc B series engines - have you spoken to him?

If you have to have to go along the remanufacturing route I would advise a full set of pistons rather than a singleton.

Accralite will make forged pistons, and they are not too expensive:-

Nigel Steward

We used to use Lotus Cortina pistons when building 2ltr. B-series engines. If your pistons have valve reliefs on the left and right sides as one would expect to see in a dual overhead cam hemi head engine, then you have the Lotus Cortona pistons.
John Perkins

Thanx for that guys, BUT have already explored the Lotus t/c route, that's not what they are. Lots of people do 1950cc engines (actually 1947 or 1948) using 83.5mm pistons, so mine could be oversizes of those.

Will have to look at "O" series pistons. Neil Cairns also said that Abingdon made experimental 2l. engines before the "O" series.

Have sent a query to Accralite, so am holding my breath!

Roger Furneaux

I expect you are looking for four ?


I am not an engine expert but when I last spoke to Oselli about an engine build the 1995cc was the same bore as the 1950cc. The extra capacity is gained by offsetting the crank/bearing and giving you an increased stroke.

Why don't you just ask Oselli what pistons they used and where you can get them?

Joe P

Give Chris Betson of Octarine Services a call. I'd use him over Oselli any day of the week.


This thread was discussed between 19/02/2006 and 22/02/2006

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