I wasn't able to pick up on this thread owing to other pressures. I'm
assuming the thread refers to an earlier post where someone queried the
existence of a number on a wet liner four pot? If I'm looking at the same
hymn sheet, these raised numbers cast in the head are usually found in the
middle-ish of the head adjacent to the valves and are not an alternative
part number, nor will you find them in any parts catalogue. You can see the
raised number on a little plinth which is visible underneath the rocker
arms. I know from more recent experiences with the six cylinder engine that
this same 'number' is about adjacent to valve stem three and/or four. The
same may apply to the four pot. That number is not a part number per se but
an engineering reference number for use in production - and no other
purpose! If I had been a Wise Virgin some fifty or more years ago and kept
my engineering change reference guides, I'd be able to tell you chapter and
verse on any head produced by the company for any market from 1946 to 1973.
However, long, long before the days of the internet, I looked at those
numbers in their manual and wondered "who on earth would ever want these?"
and they went in the trash. Sorry, everyone!
For those of you who have the 2.5 litre six cylinder, bear these two numbers
in mind - 219015 and/or 219016.
These identify the very last head ever re-worked for that engine and it is
by far the best head in terms of porting, port diameter, gas flow and swirl
within the combustion chamber. AFAIK, it was never fitted to North American
cars as they had lower CR's from 1971 onwards but if anyone is ever in the
UK or Europe and at a Triumph parts fair and you see one available that's
undamaged, GRAB it! Not many enthusiasts realise the true worth of this head
and I fitted one to my 2.5 injection saloon and the performance improvement
was amazing.
Jonmac
-----Original Message-----
From: Triumphs <triumphs-bounces@autox.team.net> On Behalf Of Randall
Sent: 30 November 2018 14:04
To: 'Dave' <dlhogye@comcast.net>; 'Andrew Uprichard'
<auprichard@uprichard.net>
Cc: triumphs@autox.team.net
Subject: Re: [TR] TR cylinder heads
> Does anyone have anything to add about the information I provided
> about a what looks like a 5th casting for 4 cylinder TRs? I hope the
> message came through with the attached photos.
> Dave H.
>
Perhaps I am confused. The information you supplied seems to match the
information TeriAnn has listed for (some?) TR3B through CT21470E TR4. P/N
511084 is listed in the SPC as being a cylinder head (less valves and
springs) for TR4 through CT21470E. It takes the same exhaust valves as
earlier TRs, with the 3/8" stem rather than the 5/16" stem used later on.
The SPC I have is not explicit about the change from triple exhaust springs
to double; but it's my belief that it happened around the same time as the
change in exhaust stem diameter.
The book says the later double springs can be fitted, but is somewhat
confusing on the topic of "collars", since the same term is used both for
the spacer that goes under the triple springs, and for what I call the
"retainer" that goes above the spring. I believe the sets with double
exhaust springs take a different retainer (142137 vs 105083) for both intake
and exhaust; and should be used without the spacer (108242). Both inner and
outer springs have different part numbers between the two sets, and I
believe the dimensions are different.
It also mentions the "conversion" guides to use the 5/16" exhaust valves in
the earlier heads. The earlier heads actually have a larger hole for the
exhaust guide, so these conversion guides are thicker to fill the larger
hole.
-- Randall
56 TR3 TS13571L once and future daily driver
71 Stag LE1473 - awaiting engine rebuild
71-2-3 Stag - awaiting gearbox rebuild
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