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Longman head markings?
Posted: Sun Oct 09, 2011 10:36 pm
by towners
Hi all
Came across a ported 940 11 stud head (stamped 12g1805) today
It was stamped 12g1805 above the thermostat and also a capital "S"
The other end of the head has a L stamped in
any ideas? early Longman?
Cheers Paul
Re: Longman head markings?
Posted: Mon Oct 10, 2011 1:04 pm
by sandman
I've seen this on '1805' heads too... but I thought it was something 'standard'... ?
Re: Longman head markings?
Posted: Mon Oct 10, 2011 2:33 pm
by Vegard
Yup, bog standard markings.
Re: Longman head markings?
Posted: Mon Oct 10, 2011 3:14 pm
by towners
Cheers for info Vegard
Re: Longman head markings?
Posted: Tue Oct 11, 2011 12:12 am
by ivor badger
Pretty certain the L is something like a quality inspection marking. If Longman worked the head, it normally loses the L because they used to face the head on both surfaces and all the marking disappeared.
Re: Longman head markings?
Posted: Tue Oct 11, 2011 7:12 am
by JC T ONE
ivor badger wrote:
If Longman worked the head, it normally loses the L because they used to face the head on both surfaces and all the marking disappeared.
The head on my race engine, is suppose to be a Longman, and it had been skimmed/faced, on both sides, and lost those markings.
Re: Longman head markings?
Posted: Tue Oct 11, 2011 7:31 pm
by ricardo
I've seen heads with R, S and K stamped near the 12G1805 stamp. These are standard markings, but don't know what they mean... if they mean anything at all.
Re: Longman head markings?
Posted: Thu Oct 13, 2011 11:47 pm
by Red1967
The 12G1805 is a MKIII S head with 35.6mm intake and 29.4 exhaust. They were used on other cars. 1275 GT I believe and Austin America 1300. Earlier versions cracked between the valves. The 1805 has the smaller exhaust valve leaving some more meat between the valves which fixed the cracking. That is the head I have on my engine. I had it converted to unleaded gas though with hardened valve seats.
Re: Longman head markings?
Posted: Fri Oct 14, 2011 12:58 am
by ricardo
Not fitted to 1275GT, but to 1300GT. It's a different car. Also fitted to the late MK2 Minis.
Re: Longman head markings?
Posted: Tue Oct 18, 2011 9:45 pm
by scooperman
Longman stamped the head with three sets of numbers. Looking down on the cylinder head, thermostat to the right and heater outlet to the left, the numbers are stamped on the left end of the head. Two of them are on the flat area just to the left of the #4 exhaust pushrod. The three digit number closest to the exhaust manifold is the refacing figure (how much was milled off the head). The second three digit number is the chamber capacity, where the first two digits are the ccs and the third digit is tenths of a cc. The third number is the serial number. This stamping is rotated 90 deg, and is on the flat area at the end of the head so it can be read with the valve cover installed.