You are right, that makes more sense. But the holes are definitely not
drilled, and I can't even tell precisely where the "water port" would have
been (not being familiar with RBB engines) -- there is no sign of it.
Thanks for the information. I was mainly concerned about the valve details,
if I had to disassemble it, and decided to go all the way and rebuild it. My
inclination would be to just slap on a new gasket, if it seemed to be
straight, and the valves looked OK.
I'm pretty sure it has single valve springs, but I ought to take another
peek, since I wasn't particularly examining those.
on 11/17/08 2:25 PM, Barney Gaylord at barneymg@mgaguru.com wrote:
> At 12:59 PM 11/17/2008 -0800, Max Heim wrote:
>> Well, I just went out to take a look at it again, and there is no
>> sign of a water choke block-off (and no air injector holes for that
>> matter), so we are looking at an early style head.
>
> Not necessarily early. Later European spec heads and some later
> replacement heads had no air injection ports. Sometimes the ports
> were not drilled even though the casting was configured for air
> injection. Ditto for the late model heads with a water port on top at back.
>
>> ....
>> .... markings on top surface of the head are (from rear):
>>
>> PAT NO
>> 585384
>> (cast)
>>
>> 16N9 (maybe "H")
>> 5 (very large)
>> (cast)
>>
>> 12H4736
>> (stamped; the 6 is very out of alignment)
>> ....
>
> This casting looks like a 1975-1980 Euro spec or replacement
> head. It should have the casting bosses for air enjection and top
> water port, but the holes may not be drilled.
>
> Engine year/ OEM Part/ Features
> Engine type Casting no.
> 75-80 North American spec
> 18V797/18V798 BHM1062/ Air injection ports
> 18V801/18V802 CAM1106 Single valve springs
> 18V883/18V884 43cc chamber volume
> 1.5625" inlet, 1.343" exh.
> Type "B" valve hardware
> Single valve springs
> Water port, top at rear
> Rear pedestal oil hole offset
>
> 75-80 Replacement ---/
> 12H4736 Similar to CAM1106 except:
> Air injection ports (usually drilled).
> Dual valve springs in most cases.
> Patent number relocated inside.
> Water choke outlet hole drilled or not.
> 43cc chamber volume
> 1.5625" inlet, 1.343" exh.
> Type "B" valve hardware
> "18" on top at back
>
> Barney Gaylord
> 1958 MGA with an attitudehttp://MGAguru.com
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires
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