Morris Minor Owners Club

Hi Guys,

I'm looking for some information on a suspected low compression 1098cc engine. The engine in question is a "Genuine" BMC Gold Seal Engine (the transfer on the rocker cover tells me so). However, when stipping it down for rebuilding, I find that it has deeply dished pistons and a 12G1456 cylinder head fitted. According to Vizards book, these heads were fitted to the 803cc and 948cc Minors (amongst others)

Would this be correct for a low compession engine? It seems odd otherwise, and I can't believe BMC would rework lower spec heads to a higher spec.

I intend to fit new pistons and rings to the engine. Should I have the block rebored or would glazebusting be a better option? I can't feel any ridge at the top of the piston travel, but that's not a guarantee that there isn't one.

What do you suggest?

Also, what size is the camshaft securing nut?

Regards

John

The compression ratio was in the pistons. The l/c engine had a deeper bowl in the pistons. Can't comment on head nos. because I don't know anything about them.

Are you sure it's not a 948 engine ? Check the bore sizes. That head is certainly useless on a 1098! Cam nut I think is 1 5/16" AF or near enough 33mm if you are 'metric'.

Dont know much about the numbering of Gold Seal engines but I have a genuine low compression 'van' engine that I am rebuilding as a high compression engine replacement for Matilda
My engine number is 10V/451E/L 5621 I think the clue is in the L as in low compression instead of H
Quite easy to tell when you have the head off it has pistons like soup bowls
If you dont have access to a micrometer take the block to your local machine shop and ask them to check it for ovality

The 948 engine has 950 cast on the side of the block below the front tappet chest. The 1098 has a plate with 1100 on it in the same place.

Good point MP! Just because the rocker cover sports a 'transfer' - dosn't necessarily mean the engine has been 'reconditioned' !