Cylinder head identification

[Propshaft]

Could someone please tell me what cylinder head I have see three separate photos[frame][/frame]

[Propshaft]

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[Propshaft]

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[Propshaft]

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[les]

Try reading the cast number on the top face of head, it looks partially machined but difficult to see. That's the view you should have shown.

[Chipper]

Looks like it could be a Metro Turbo head, judging by the extra rib at the thermostat end, and double valve springs - similar to the one in this thread (2nd post in, 3 photos down):

http://www.mmoc.org.uk/viewtopic.php?f= ... 40#p596844

What is the cylinder head number, stamped into the centre section, and is the heater valve port blanked off?

12G940 denotes a 1275cc head.

[Propshaft]

Guess it could be 12G940 see picture[frame][/frame]

[Propshaft]

Why do you think it needed to have the top scimmed ,must have been really bowed to need thar

[philthehill]

12G940
And appears to be a MG Metro Turbo head with that additional sculpting around the thermostat.
Checking the diameter of the valve stems will confirm.

[Propshaft]

Thanks will check diameter tomorrow

[Chipper]

I'm guessing someone may have skimmed the top to effectively lower the rocker pedastals down, in the aim presumably of giving higher lift to suit a peakier camshaft...

[RobThomas]

Turbo heads have 8mm exhaust valves, don't they?

[philthehill]

Rob
You are correct.
Metro Turbo exhaust valve stems are 7.955mm - 7.970mm dia.
And the stems are filled with sodium. That is why my recommendation above was to check the dia of the valve stems.
Consequently special valve guides have to be used.

Chipper
The cylinder head starts out ss only a rough casting and I understand that the first machining of the head is the head to block face and once that is done the rest of the machining uses the head to block face as the datum point.
To get the depth of the head to 2.75" nominal the top of the head is skimmed - quite often and not uncommon the head ends up with the number partially machined off.

Phil

[Propshaft]

Hi not had a lot of time today busy building another garage , but I have measured the top of the valve just above the collet this measures 7-02mm (.279) the thickness of the block is 2-744mm is this good enough or do you need me to take out a valve

[Propshaft]

Sorry should be 2.744"

[philthehill]

To be absolutely certain it would be better to take out an exhaust valve and measure half way down the valve stem.

[Propshaft]

Ok will get it done this week