MGB Register Forum

Oselli 1950cc stage 2 engine, I am trying to locate a piston ring supplier to purchase replacement rings oversize 0.090 as stamped in the piston crown. So far all the maximum size rings go up to are oversize 0.060.
Does anyone know also the spec of the camshaft they fit to be able to correctly time it during the rebuild as Oselli are not being very helpful.
Jeff Lister.

Hi Jeff
I don't think you need to worry about the cam timing if all you need to do is replace a ring, as the pistons come out through the top deck of the block, so you would leave the crank in situ.
Of course you have a problem if you have stripped the engine without marking the relative position of all the components. A lot of engine builders don't like people to 'mess' with 'their' engines, so it doesn't surprise me they are a bit secretive. They may be more forthcoming if you go and see them.

Try Peter Burgess (01773 520021) and see if he can help.
Or
Try Thornton's in Shrewsbury (see http://www.fwthornton.co.uk/8.html) who are legendary for being able to sort out odd size rings. You would probably have to go there though and take them a piston and ring sample.

Someone else will need to confirm this, but I think the 1900cc and 1950cc conversion use Lotus Twin Cam pistons.

Hi Peter,
Appreciate your comments, however I am having to strip and rebuild this engine because after approx 20K miles I thought 1 pint of oil per 100 miles excessive plus the pretty blue haze emitting from the exhaust was not as it should be. I installed the engine in my roadster in Oct 2011 thus it is out of warrenty.

On stripping down the bores were glazed over and the camshaft followers are showing signs of wear to the base also the cam lobes had a ridge appearing on the lobe peak. This was verified by a competent MG and race car preparer.

The other reason for being dissatisfied with Oselli is the advert for the engine stated that a vernier cam gear was fitted, not so mine has a standard cam gear, according to Oselli they only fit a vernier if the cam and crank gears dots don't line up when timing the valve operation.

I don't believe I was asking much of Oselli to reveal where they obtained the piston rings or the camshaft spec. Suffice to say I have located the correct rings which by the way are Ford and have purchased a new camshaft from Kent cams.I am disappointed that the Oselli built engine failed so early and that they chose to ignore my requests, you can draw your own conclusion.