Hi, Folks,
I thought I might be able to a touch of clarity on this subject as I'm
currently in a long-term (1.5-year+) project of fitting some Volvo HS6
carbs to my TR4.
Background:
I have a '62 TR4 with the original H6 (long body) SU carbs fitted to a
later 4a inlet manifold using the original H6 linkage. The original H6
linkage pretty much sucks <snicker> from a variety of reasons. It is to be
avoided.
These H6 carbs work, but the bushings are well worn and I know that as
RPMs increase my mixture is getting all fouled up from air entering the
bodies of the carbs at the throttle shafts. But they work, and they've
been working for forty years....
Over time I've kicked around the idea of the 'dream induction' setup, and
aquired here and there a bunch of different bits depending on my current
state of mind. I got an old set of Cannon intake manifolds for dual-webers
as part of a trade with a fellow on the list, and after a while I got a
pair of 40 DCOEs to go with 'em. I never fitted them, however, as I THEN
decided that the carbs that would give the best punch off the line would
be SUs. Besides, there's a hump in the hood to accomdate SUs and Kas
could make an SU motor make just as much power as a Weber motor, so I
decided I'd get a pair of HS6s and rebuild 'em.
Well, if you can find a set of TR HS6s on a 4a manifold with linkages, I'd
jump on it with both feet. Me, I went the hard way buying the manifold
from one guy, the linkage from another, and a pair of HS6s from a Volvo
B20 from yet another.
So now I have all the parts, right? Well, not quite.
See, on the B20 setup, the float bowls are between the carbs, on a 4a
setup they are outside the carbs. So the carbs get swapped from front to
back. Then I found that there's a little bushing that goes between the
float bowls and the carb body that determine the angle of the float bowl
to the carb body. The float bowls are supposed to be more or less level,
and the SUs angle up a bit. That angle differs between a B20 and a TR4a
motor. So I had to scrounge some bushings which I got from a pile of SU
bodies a friend had.
Okay, so now I'm set, right?
Nope. I then discovered that the throttle lever which attaches to the
butterfly shaft is different between the Volvo and TR as well. I'm
currently looking at modifying mine to relocate the arm that the return
spring mounts on (by cutting it off and welding it back on a different
place).
Oh, and by the way, the choke mechanism is operated via twin cables on the
Volvo and via a cable operated linkage on the TR. Um, haven't crossed that
bridge yet.
When I eventually get all this squared away, I still need to rebuild these
HS6 carbs. Prices for doing this range from $150-500 depending on who does
it for you. The MAIN part of the rebuild is rebushing the bodies.
Then there is jetting to consider and I think there are about a million
different needles for HS6 carbs.
So while people will tell you "All HS6s are the same" I can promise you
that all the linkages, levers, springs, needles and cables to operate them
can vary quite a bit, and while most of those little bits and pieces are
available, they are not cheap.
It is at this point that the HS6 'conversion kit' from Moss motors for
$599 (the last time they were on sale) actually starts looking good.
Remember, the stingy man spends the most.....but he might have the most
fun if he likes to tinker.
-jeffrey
/// triumphs@autox.team.net mailing list
/// or try http://www.team.net/cgi-bin/majorcool
/// Archives at http://www.team.net/archive
|