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MG MGB Technical - cylinder head id.

hi,
does anyone know of a site that you can lead me to to find out what year car a cylinder head with number 12h 4738 came from.
thanks in advance.
bob 1970 bgt.
bob taylor

Bob

Try this site
http://www.autochart.com/MGB_Head.htm

Kent
DK McNeill

Are you sure it's not a 4736?

http://www.flowspeed.com/cylinder-ident.htm

Sean
Sean Brown

Bob,

you will not find this carsting in the official MGB cylinder head listings as it was a Austin 1800S item.

I use one of this heads on my B, ported and flowed to ralley/race specs and it works extremely well.

Seems that this carsting has enlarged internal water passages, as coolant temperatuers are lower than that with the normal MGB heads as i realized with a pricise mechanical temperature gauge.

Hope this helps

Ralph
Ralph

That chart is not that great. Just a few examples, the 12H1326 head is listed for the 1st 3 years, when it was actually a 12H906, and the 12H2923 head used from 72-74.5 isn't shown anywhere. Sean's article is more accurate.

Paul K

Ralph

The 1800S head is 12H2595, the 1800 landcrab had a 12H2709 head.

Peter
peter burgess

Does anyone know what a 1670 is?
Sean Brown

Peter,

i picked the head from a Marina with an 1800S label, that i found in the Netherlands some time ago. It did not look as if anything had been exchanged on this car, so i had to belive that it was fitted during the production run.
The head fits the 18V in the B and came with the larger valves and single springs as used between 1971 and 1974 on the 18V engines in the MGB. It seems to have a better layout of the water passages (i beleve) as is coolant temperature does not tend to rise as much as on the previous used heads on this engine, although the whole installation was identical in any way (bored to 1868, flat top pistons, lightened and balanced, 285-2 cam, HIF 6 etc.).
Up to now i did not find any further cross references that specifie details upon this carsting.

Ralph
Ralph

Peter,

forgot to mention... offset oil feed, chamber volume checked at 42ccm each, no bosses for smog installations carst on...

Ralph
Ralph

Ralph,

Early versions of the 4736 heads didn't have the smog bosses and look similar to the 2709 heads except for the offset rocker oil feed.
Chris at Octarine Services

How about a 4743 head? Anyone know what those are?

Sean Brown

Sean, a 1670 is a 1622 Morris Oxford head as far as I recall it has a little recess on the peak opposite the plug. usually runs small MGA inlet valve and MGB size ex valve.

Ralph, When 'they' built the engines 'they' used whatever parts were to hand even if they were not quite what should be on that particular build :) The Marina didn't have the 2595 only the 1800S front wheel drive car (pic on home page of my website)

Peter
peter burgess

Thanks Peter,

I've come across a few of the 1670 heads...

Sean
Sean Brown

This thread was discussed between 02/03/2008 and 18/03/2008

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