Mark,
I'll support Your try to get a decent, and technical, thread going...
And cylinder heads is a nice and technical thread to start on this
forum I think.
As far as I know, on Spitfire/Herald heads:
One can distinguish two different heads used on the standard SC-
(SC = Small Car) engines (and three rare types used on racing engines)
during the time between circa 1962 and 1980. They have been seen in
many different applications with different valve sizes and compression
ratio related measurements on head thickness and combustion chamber
volume.
The original head on the 1147cc engine in Herald 1200, 12/50 and in
Spitfire Mk1 and Mk2 had two inlet ports, four exhaust ports, eleven
head studs, a brass pipe fitted into the head as "cooling water
distributor" and exposed pipes for the push rods to pass through.
This head was supplemented by the rare types, all for 1147cc engines:
The three types of eight port heads used in racing, rallying and
tuning of the 1147cc engine.
The one most commonly seen is the so called "Stage II head" with its
spark plugs leaving the head at 90 degree angle to the longitudinal
line of the head. This head was cast in iron and sold as an accessory
to people and organisations wanting to tune the 1147cc engine.
To be able to accomodate the extra intake ports they cut two of the
head studs short, about 3/4 in, and put the nuts on them in two small
niches grafted into the head, below the intake ports! How genuinely
British! They are rare but not extinct. I've seen at least three, all
at the same time...
The other types are rare. No, make that VERY rare!
These heads are the two types made for the factory racing/rallying
effort in the mid sixties. They are most easily distinguished by the
fact the spark plugs exit the head at another angle to the longitudi-
nal line of the head. They were cast in both iron and aluminium alloy.
The alloy heads were used on the rally cars and the iron ones on the
racing cars. Not much in common with the Stage II heads, exept the fact
the factory homologated them via the declared sale of enough
numbers of Stage II heads. Probably a slight exaggeration... ;-)
They are extremely rare. I've never seen any of them. If anyone have
one for sale, call me!!! Collect call from Brisbane, Bolivia, what
ever... I'll accept it!
Then there is the so called later head, used on the Herald 13/60,
the Spitfire Mk3, MkIV and 1500. (And on lots of other cars that
Triumph blessed with the 1296cc/1493cc engines.) They had four intake
and four exhaust ports, 10 head studs. It had no separate water
distributor as it, and the pushrod tubes, were integral in the casting.
It was delivered with different valve diameters along the years as
well as compression ratios and exit holes for the heater feed, but
it was essentially the same head all the time.
I've probably forgotten something so if someone have more details to
add to this, please feel free to jump in. I'd love to read them!
I probably just scratched the surface of knowledge about the SC-type
cylinder heads. For instance I'm not that knowledgeble on the 803cc
and 948cc versions of SC-engine and would love to learn more on this.
Now it's someone elses turn to tell us the different types of heads
used on the six cylinder engines and on the four cylinder wet liners...
And why not - on the poor Acclaim... ;-)
/Odd
Mark Stahlke wrote:
> My 71 TR6 (CC61289L) has engine number CF18842UE. My limited
> reference material indicates this is a 74 engine. The car is
> fitted with a single pipe exhaust system as appropriate for a
> 71 model.
>
> I seem to recall someone mentioning that port locations were
> different on later engines. Or was that Spit heads (carefull
> how you spell that!)?
>
> What are the differences in the heads on various model years?
>
> Is there any way to tell what head is on the engine without
> disassembling it?
>
> There are several sets of numbers on the right side on the head.
> Some are cast in, others are stamped. Any clue as to what they
> mean?
>
> Thanks for your help,
> Mark Stahlke
> (desperately trying to start some new, more interesting threads)
--
Odd Hedberg
Pomonagatan 4
S-74236 Östhammar International liaison secretary,
Sweden Triumph Club of Sweden
'70 Spitfire Mk3 FD82497LO Signal Red
E-mail: odd@triumphclub.se / odd.hedberg@bigfoot.com
Club URL: http://www2.passagen.se/triumph/
Home Telephone: Int+ 46-1731 7131
Geographical Position: N 60deg15min E 18deg23min
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