Hmm...
My motor is a BMC "Gold Seal" rebuild of unknown internal configuration. I
found it in a 72 GT, sporting sidedraft Webers and headers. The parts broker
stated that the previous owner claimed less than 10K on the motor (this was
in 1989 or 90), and a look at the bottom end bearings seemed to confirm
that. Since then I have around 60K street miles on it, running unleaded
premium and no additives. I haven't noted any signs of valve recession. This
leads me to surmise that BMC replacement engines were equipped with the late
"cat"-era heads...
As for Phil's experience, the 1500 head may well have different metallurgy
than the 1800 heads.
Just musing...
on 1/8/04 11:49 AM, Dodd, Kelvin at doddk@mossmotors.com wrote:
> Dave:
>
> These would be engines fitted with catalytic converters. I can guarantee that
> a 1972 will have recession problems under normal daily use running straight
> unleaded fuel. It won't happen overnight, and you don't gain anything by
> worrying. My family ran a fleet of 1973 Austin Marina's and once the exhaust
> valve clearances started to move, the seats eroded pretty quickly. I think my
> brother went through 3 used heads in as many months being too cheap to get one
> fixed correctly.
>
> note "daily use" above. These were cars that were driven daily and did not
> get the best mechanical attention. YMMV
>
>
> Kelvin.
>
>
>>
>> Kevin,
>>
>> Did your source say what year engines this started?
>> A BL mechanic told me I didn't have to worry about that with
>> my 72 when they
>> changed over to unleaded gas here in the States. However, I
>> still put a
>> lead additive in with each fill up.
>>
>> Dave 72 B
--
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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