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MG Midget and Sprite Technical - Interesting head? What is it?

Hello. I'm a new member and have recently got myself a 1972 midget, wire wheels and all. A lot of work done and lots or new/refurbed parts.

One thing I'm trying to establish is what head is this? It was stated as a "Cooper" head. It has 12G938 stamped by the thermostat housing, it appears to be an 11-bolt head but I notice there is no casting number and no "hollows" in the casting where a casting number would be. It's all a flat machined surface.

I can't see anything through searches that matches this in any way. Head thickness (machined top to block face, including head gasket is 2.765", if this helps.

It either rare or sporty (my hope) or common and not a good idea for a Midget.

Thanks, Dave.




D Price

Hi Dave and welcome to the forum - you'll find everyone is very friendly and eager to help.

I think you might have struck lucky.

My 1967 Mk IV Sprite has 12G938 stamped on it too.

According to my Google research a few years ago, the 12G938 heads were a special variant of the 12G940 head with extra 'meat' in certain areas to allow for porting etc. If yours is a Cooper one, it just might have received some special attention.

Sadly, as far as I am aware (emphasised by the lethargic performance figures) I'm pretty sure mine is unmodified.

Here's a link to the thread in the archive that I started a few years ago:

http://mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&access=&mode=archiveth&subject=97&subjectar=97&thread=2013102300024727529

Cheers and Happy Midgeting

Colin

PS. I just noticed that yours has pressed steel rockers whereas mine are forged. I think the pressed steel ones are what was fitted to the later engines.

C
C Mee

Dave..this is from spritespot:

by Mark T Boldry » Thu Jan 26, 2012 5:26 am

A friend asked me today to have a look at his early 1967 Ex UK Austin Healey Sprite and listen to the engine which he plans to put into his other car. I came across the stamping 12G938 on the head near the thermostat housing.. Having never come across this before, I've done some research.

It turns out it's quite a rare head, cast especially for competition use so that porting can be carried out without fear of breaking through into fresh air... Nice find...!

Does anyone else have one of these heads...?

Mark.

I have a 12G938 on my 1966 GAN4. It seems that the factory had problems with engines "back in the day" and my car didn't leave the factory with the engine [or rear axle] that was first fitted. Mine was sold via John Sprinzel Racing in Lancaster Mews so could have had a different head fitted at that time?
Dave
David Cox

Thanks for the responses.
The thing I find odd is that there are no recesses in the casting between the rocker gear posts. On all the heads I can search there are hollows and this is where the casting number would be.

So is this what a 1967 head would be like?

(PS the pressed steel rockers are from the 1972 original engine)
D Price

This thread was discussed between 03/03/2019 and 04/03/2019

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.