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Cylinder head identification
Posted: Tue Nov 22, 2016 3:34 pm
by Propshaft
Could someone please tell me what cylinder head I have see three separate photos[frame]

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Re: Cylinder head identification
Posted: Tue Nov 22, 2016 3:35 pm
by Propshaft
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Re: Cylinder head identification
Posted: Tue Nov 22, 2016 3:36 pm
by Propshaft
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Re: Cylinder head identification
Posted: Tue Nov 22, 2016 3:37 pm
by Propshaft
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Re: Cylinder head identification
Posted: Tue Nov 22, 2016 4:38 pm
by 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.
Re: Cylinder head identification
Posted: Tue Nov 22, 2016 4:39 pm
by 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.
Re: Cylinder head identification
Posted: Tue Nov 22, 2016 4:58 pm
by Propshaft
Guess it could be 12G940 see picture[frame]

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Re: Cylinder head identification
Posted: Tue Nov 22, 2016 5:00 pm
by Propshaft
Why do you think it needed to have the top scimmed ,must have been really bowed to need thar
Re: Cylinder head identification
Posted: Tue Nov 22, 2016 5:06 pm
by 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.
Re: Cylinder head identification
Posted: Tue Nov 22, 2016 6:04 pm
by Propshaft
Thanks will check diameter tomorrow
Re: Cylinder head identification
Posted: Wed Nov 23, 2016 12:21 pm
by 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...
Re: Cylinder head identification
Posted: Wed Nov 23, 2016 12:57 pm
by RobThomas
Turbo heads have 8mm exhaust valves, don't they?
Re: Cylinder head identification
Posted: Wed Nov 23, 2016 1:16 pm
by 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
Re: Cylinder head identification
Posted: Wed Nov 23, 2016 3:16 pm
by 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
Re: Cylinder head identification
Posted: Wed Nov 23, 2016 5:06 pm
by Propshaft
Sorry should be 2.744"
Re: Cylinder head identification
Posted: Wed Nov 23, 2016 5:42 pm
by philthehill
To be absolutely certain it would be better to take out an exhaust valve and measure half way down the valve stem.
Re: Cylinder head identification
Posted: Wed Nov 23, 2016 6:01 pm
by Propshaft
Ok will get it done this week