View Full Version : TR2/3/3A H6 Throttle Linkage

01-04-2018, 10:44 PM
As I'm having my carburetors rebuilt by Joe Curto, I want to make sure everything around them is in fine working condition. The original linkage feels a bit "sloppy," it may well be the pivot/bellcrank on the manifold is worn. It feels like the forward part of the linkage binds or hits the manifold as a result, so I've purchased a very nice replacement throttle linkage from Britsport (they sell them on eBay). It's so nice, new and shiny, it qualifies as under the bonnet bling...

My question is this: There are four threaded ball joints on the linkage. They feel "tight," you can adjust them to loosen them up. How loose or tight should they be? Move freely or with some friction? Also, I imagine they should be lubricated, if so, with what?

01-05-2018, 12:12 AM
A small amount of friction is OK. The book calls for an occasional drop of oil; but with the original type that can be disassembled, I start out packing them with grease. (I don't know if Britsport sells original type, or the more modern ones that can't be disassembled. Used to be you could buy those pivots from a semi truck dealer, but I haven't shopped for them in many years.)

Geo Hahn
01-05-2018, 09:52 AM
An aside - I know a TR3 owner whom I have watched as he checked his oil. His routine was to pull the dipstick as usual but before he wipes and reinserts it he touches the end to each of those pivots.

I just use an oil can but his method had a certain elegant quality to it (elegant as dirty oil can be).

01-07-2018, 03:31 PM
Those balls get egg shaped over time, so if you do have new ones, nice. Plus Joe would be a good guy to ask about those ball joints. I have been collecting them for a while off eBay and parts cars. They used to sell something similar at parts stores, but they were a little bigger. For oil, I am using that Teflon stuff because oil will gather dirt and small chunks of sand.

The return on H6 carburetors has always been a problem for me. Don, E. who bought his tr3 new said he has always had an idle return the problem as well and pull the linkage back with his foot. I still do that sometimes and have fought it for 45 years. My experience has been a good distributor helps the idle come back.

01-07-2018, 06:00 PM
Attached is a photo of the Britsport linkage. I think it's is very well-made. The also make the pivot set-up only, but the difference in price makes it worthwhile to get the whole linkage.

I took my old one off, then matched the new one to length by adjusting the outer linkage housings. I took them apart and lubricated with grease around the ball joints inside (there's a spring and two cups, one is adjustable by screwing down to maintain slight pressure on the ball). I intend to install it in the next day or so. I also checked the pedal return, which is obviously freer without the linkage attached, but I think this will help. I don't want to take the pedal apart at the moment. I'm hoping the combination of new linkage and rebuilt carbs (and the distributor, which is on it's way to Jeff Schlemmer) will do the trick.



Geo Hahn
01-08-2018, 11:11 AM
Those balls get egg shaped over time...

One of mine did this and was popping apart at the most inconvenient times. As a temporary fix I took it apart and added a washer which changed the orientation of the tightened fitting by 90°. That 'temporary fix' was about 10 or 12 years ago - you know how it is once a problem stops being a problem.

01-08-2018, 11:49 PM
That 'temporary fix' was about 10 or 12 years ago.

Maybe in a couple years you can turn it 45 degrees to get a few more decades out it.
I have a "round-tuit" for those type of fixes, but I can never find it.

Somehow these cars are a combination of "if it works don't fix it" and "as long as you're in there...".

01-09-2018, 12:11 PM
On the TR2 I welded the balls back up and ground them round again. Should be good for another 60 years?!? Of course that was after I bought new ones...that turned out to look entirely non-original from one of the big three.

01-09-2018, 12:47 PM
That looks like a nice quality original set; I like it, and it is from Seattle. Time will tell how long they last; I am not sure how hard the steel balls should be, but my guess is a hardened material. I would tighten the ball spring combo tight enough so they do not come out and lose enough for free movement.

I had a 4 wheeler buddy of mine show me how a cotter key is finish out. They do not fold out --one on each side; they fold over the face. One leg is cut short and bent back and the other leg is left long and folded over the face of the nut and not over the flats, just a little detail. Look for a stock front wheel bearing picture.

If it is not too confidential, I am curious how much is Joe charging for complete rebuilds these days?

John I think Moss a special fine for most guys like us. I send half of it back.

01-09-2018, 03:19 PM
From the eBay description: “The bellcrank pivot plate and lever are machined from mild steel, the pivot pin and socket are made from hardened 4130 Chrome Moly, then silver soldered together, not brazed as original.”

I installed it yesterday and it went in fine and looks good, too. I lubricated the pivot joints with grease. We’ll see how everything works when the carbs come back.

Mr. Curto is charging $525 to rebuild an H6 pair, a bargain for someone like me, who is SU-challenged.

01-09-2018, 09:46 PM
Getting ready to send him my carbs.
I cleaned them up then replaced the needles, jets and all the seals then realized the butterfly bushes are worn. From what I have read doing the bushes takes more than a drill press. I gather he gets them setup as well as a complete rebuild. Been told they come back like new.


01-10-2018, 02:06 AM
Yeah, you've got to have the right kind of drill, too.

01-10-2018, 09:36 AM
And in line reamer. I think he sells the reamers but it is almost cheaper to get your carbs. done than buy the reamer.


01-10-2018, 07:38 PM
Tom Bryant has several excellent blog posts in which he describes the rebuilding of SU carbs in great detail with many photos. He includes sources for tools and supplies if anybody wants to DIY. I did a fresh rebuild last year and learned enough to be able to correct several things I did wrong the previous time. https://thosbryant.wordpress.com/2014/01/02/su-carburetor-rebuilding-hs-6/