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RE: HS6 carbs for TR3A

To: <triumphs@autox.team.net>
Subject: RE: HS6 carbs for TR3A
From: "Randall" <tr3driver@comcast.net>
Date: Mon, 3 Oct 2005 14:34:06 -0700
> I have a pair of HS6 SU carbs in great shape that came with a
> bunch of parts when I bought my 58 TR3A. Someone told me that
> these carbs (probably from a TR4A) will work great on my TR3A if
> I have the TR4A manifold. My car is running fine with the H6
> carbs it has on it but the carbs have some air leaks at the
> throttle shafts and really need to be rebuilt. This is going to
> be a winter project but I am wondering if maybe switching to the
> newer carb would be an improvement.

IMO yes, even on your TR3A manifold.  The HS6 design eliminates those
troublesome cork O-rings on the jet, and the likewise short lived rubber
mounts for the float bowl.  In addition, the throttle shaft bushing should
last much longer, since there is a lot less force on them.

Preliminary measurements on my car indicate I might have clearance problems
running the HS6 carbs with the 4A intake, which moves the carbs closer to
the inner fender.  But I already have trouble running the TR4A filters on my
H6 carbs, so YMMV.

> I don't have a choke linkage
> for the HS6 units and would need to obtain this as well as
> manifold and air filter housing. Any advice from the list?

In addition to the choke, you'll also need a substantially different
throttle linkage.  The TR4A carbs need the linkage attached between the
carbs instead of way out in front, and the shafts turn the opposite
direction to the H6 carbs.  I saw (briefly) a local club members TR3A last
Tuesday where he had made up a rod to run between the choke levers, so he
didn't need the "two headed" choke cable used on the TR4A ... it looked
slick (but I expect nothing less of Bob, he's very good at that sort of
thing).

Paper element filters are available from TRF et al, no housing required.

The HS6 carbs reputedly flow a little more air than the H6, but on a stock
engine I doubt it will make any real difference.

Randall


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