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MG MGA - Cylinder head - what do I have?

After reading a couple of threads on head identification numbers, I thought it might be interesting - to me at least - to see what mine is.

Certainly not original numbers!

I have:

12H650.
The word MOWOG with the number 4 immediately above it.
The letters/numbers D5 M2 at right angles across the head.

If this is any help I bought the head new in 1973.

Thanks guys

John
John Follett

Must be a typo, or misread. 12H650 is a valve spring. Wanna check that casting number again?
barneymg

Thanks Barney
Should have read 12H670
John
John Follett

Must have had a senior moment!! Identification number is 12H1670 which I think is a GA 1600 head.

Question is should I be considering changing it for an early MGB head, assuming a replacement 1622 head is virtually unobtainable.(highly likely)

Or what is the downside for retaining it?

Earlier threads seem to say my CR is likely to be a lot higher than with the 1622 head.

Is the possible reason why I seem unable to stop pinking between 2500 and 3500 revs, however much I retard the ignition, without affecting performance.

John
John Follett

Hi John,
I had a similar thing. I purchase an early MGB and that pinked badly and did not go very well. Ends up it had a 1500 head fitted to it so 39cc chambers and small valves. Now has a standard B head 43cc chambers and hey presto - runs like a dream with no pinking and pulls like a train.
Andy
A J Dee

1622 heads are available if that is what you want - they were fitted in abundance to the whole BMC range of cars so any Austin / Morris / Wolsey / Riley 1622 will do as core - you can then get it reconditioned and lightly tuned by Mr Burgess.....
Chris at Octarine Services

I have a 1622 motor (Austin A60 block) with an early MGB head. Not sure of the CR but it pulls very well.
Art Pearse

Many (if not most) of the "non-MG" 1622 engines use dished pistons and the "15" head common to the MGA 1500/1600 engines. It may be tough finding a "16" head on anything other than an MGA.

In Australia they had a 1622 engine with "1620" cast on the side of the block. This has the same 3.000" bore with 1622cc displacement, but has dished pistons and uses the crankshaft and connecting rods and "15" head common to the 1500/1600 engines.

Get an early MGB "18" head. That one is fairly common and nearly identical to the "16" head. It makes a very good substitute for the MGA 1622 engine.
barneymg

Thank you all.

I have been lucky enough to source a 1622 head! Bliss!!

John
John Follett

I come across 1622 engines regularly, and have one in my car (still waiting patiently for delivery of the 1950cc, but with 1622 +60 oversize and a supercharger that's not too big a worry.) They are not that rare in Europe, although getting harder to find as are all non-retro parts.

Dished 1622 pistons are no longer available - all are now flat top.
Dominic Clancy

All early MGB heads are functionally interchangeable with the MGA Mk 2 heads.
Bill Spohn

This thread was discussed between 12/06/2018 and 15/07/2018

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