> From: tallen <tallen@csc.sctboces.org>
> Subject: TR3 Head?
;
>Anyway, it seems the car has a TR3B or TR4 head on it (is this a 2.2 liter
>engine as opposed to his 2.0?) The head doesn't mate properly with the
;manifold, and there are vacuum leaks, rich running, rough idle, etc. What
>are his options? Can this head be made to work? Could he get a used
;head? Swap the manifold? Anybody got parts lying around we could deal
>for? Again, I'm not on this list, so please e-mail me directly, and
;thanks for helping in advance,
;
Tom,
Starting around '58, according to a parts book suppliment I have, 86mm
pistons and liners were optional, while 83mm pistons remained standard. To
confuse matters further, 83mm, 86mm and 87mm pistons and liners were
available for anyone doing a engine rebuild.
Here is a primer on TR2 through 4A heads:
TR2 to engine number 9349E, 83mm, 8.5:1 1-3/8" dia intake ports.
TR2-3 engines 9350E through 13051E, 83mm, 8.5:1, 1-3/8"? intake ports
The above two heads are called low port heads. If you look at the side the
intake is on, there will be no rises in the head for the intake passages.
The head is basically a rectangle with a theromostat adaptor at the front.
The difference between the two heads is the porting. The later head, also
known as the Le Mans head, was added for better breathing.
After these heads, Triumph went to the high port heads to enable the heads
to breath better. A high port head has four ridges there the intakes enter
high in the head.
Engines 13052E to ? 83mm, 8.5:1, 1-5/5 intake openings. The underside of
the water inlet has a rounded hemispheric shape.
Engines ? to ? look like the early high port heads with two exceptions:
1) the underside of the head has more metal. The earlier heads tended to
crack, esp. if they were shaved for higher compression or resurfaced too
many times.
2) The underside of the water inlet has a flat diagonal on one side. If
you shaved the earlier heads, the underside of the rounded water inlet ran
aground on the rest of the engine.
Engines ? to 21470E. 86mm, 9:1, 1-5/8" intake ports. A champher was added
to each squish area. This campher kept the compression down to 9:1 with the
larger dia pistons and provided better fuel flow in the cylinder.
The top of the ridge above the #1 intake port is flattened. A serial number
may or may not have been stamped there. If the head is on the car, look
for the flatened area on the first intake ridge to identify it as a head
for 86mm pistons. If you are looking at the underside, look for the
camphers. Except for the camphers and flat ridge, the heads are identical
to the late TR3A high port heads.
Engines after 21471E came with the last head modifications, 86mm, 9:1,
1-1/2 inch intake ports, champher on squish areas. This head has two
exhaust valve springs per head. All the previous heads have 3 springs per
exhaust valve. This head has smaller dia valve stims. The smaller stim
dia lightens the valves.
Triumph went to the smaller intake passage diameter to pick up better low
end and mid range power. This head is not quite as good as the earlier
high port heads at the high power range but is superior throughout the rest
of the power band.
The very late builds of this head have aluminum push rod tubes. All the
previous heads have steel push rod tubes. Aluminum expands more under heat
and provides a better seal to keep oil from leaking.
Now getting back to your friend's TR3. You now know how to tell which head
is which. You will have to measure the dia of the piston to tell what size
it is.
To the best of my knowledge, the port locations, and mounting hole
locations are identical for all high port heads. Any high port head should
be able to bolt to any intake manifold designed for a high port head.
I would suspect the following:
1) incorrect mounting. These are some specialized parts used in mounting
the intake and exhaust. If the car did not have all the correct hardware,
you wouldn't know the difference.
2) interference. You may have something interfering with the intake
manifold keeping it from seating properly.
3) warped surfaces. Check the intake, exhaust manifolds and head for
straightness.
You might want to do a trial assembly of the manifolds to the head, under
strong light while the head is on the bench. This will allow you to look
at the joining from all angles to see if there is any interference.
You didn't say were you are located. If you are near Santa Cruz
California, I have a spare 83mm high port head I would be willing to trade
for the late style TR4 head
TeriAnn Wakeman For personal mail, please start subject line
Santa Cruz California with TW. I belong to 4 high volume mail lists
twakeman@scruznet.com and do not read a lot of threads..Thanks
A citizen of the internet community since 1986
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