TR2/3/3A TR3 Throttle linkage pics needed

[newmexTR3]

Hey all,

Long time no talk. Just finished up 3 months of work on the TR: reupholstered dash, added wood veneer to instrument cluster, installed new wiring harness, installed uprated heater, fixed throttle linkage bushings, etc etc... It was one of those, "might as well fix that bit since i'm doing this bit" jobs that snowballed, but I'm happy with the results. Got her back on the road just in time to drive from Brooklyn to Cape Cod for the holiday. Also sprung for the ferry ride out to Martha's Vineyard, which had great driving. Pics coming soon!

With everything back together I have a new weird problem- the throttle linkage is binding somewhere between the firewall and the front carb once the car warms up (at least that's where i think it is. When it's hot, the linkage wants to stay open about 10%. Interestingly, it's worse when I put it in reverse, which makes no sense to me.

While cold, the linkage returns to its proper place easily. All ball joints are new and lubricated and return spring is new, and I installed brand new nylon bushings on both sides of the linkage rod that runs behind and perpendicular to the engine, so I'm somewhat mystified. I have a feeling the geometry may be slightly off- ie the lengths of the two link rods may not be set correctly. So, does anyone have measurements of the long and short link rods and/or pics of their linkage that they could share? I'm particularly interested in the angles of the throttle lever that attaches to the throttle shaft and the lever assembly that attaches to the pedal shaft- I have no idea what stock looks like.

Here's two pics that hopefully illustrate what I'm talking about. Cheers in advance.

 

[mrv8q]

Here's one I have handy, HTH

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[newmexTR3]

Nice. Thanks Kevin!

 

[TR3driver]

Just a thought, since you didn't mention it. I found that wear in the bell crank pivot was letting the crank drag against the bolt head that holds the bracket to the intake manifold. You can see in Kevin's photo how the crank almost touches the bolt head anyway.

 

[newmexTR3]

Thanks Randall.

A question- how loose is the bell crank pivot supposed to be? I know there is supposed to be some play, but mine seems to have a ton. I think that may be the issue. It's not binding on the bolt head, but it does seem to be getting hung up on the shaft itself, probably because it's so worn.

Anyone else have a few more pics?

 

[newmexTR3]

Giving this a bump. Any pics would be appreciated. Thanks.

 

[CJD]

Sorry, I don't have any pics, but my bellcrank has almost no play.

 

[TR3driver]

Thanks Randall.

A question- how loose is the bell crank pivot supposed to be? I know there is supposed to be some play, but mine seems to have a ton. I think that may be the issue. It's not binding on the bolt head, but it does seem to be getting hung up on the shaft itself, probably because it's so worn.

I think it should have almost no side to side play, just loose enough to turn freely.
They don't seem to be available new, but I was able to file the pivot back to some semblance of round and use a piece of thinwall brass tubing to sleeve the lever to fit. Also filed a bit off the head of the bolt

But I'm still having some trouble in that area myself, so I can't really claim it's right yet. Just haven't taken time to revisit the subject.

 

[newmexTR3]

Thanks Randall & John- that must be the issue. Mine has a ton of play.I wonder if Mr. Joe Curto has some replacement bits laying around.

 

[martx-5]

Hey Gavin, good to see you come out of hiding.

Joe might be a source. You could just drop in, he's right around the corner from you.

I had a similar problem with a sloppy bell crank. I fortunately had a good spare on a manifold that I bought off ebay.

 

[luke44]

Resurrecting this old thread. I have the exact same problem. When cold everything is loose and moves perfectly. When warmed up the throttle binds to the point it’s actually almost dangerous. Let it sit an hour, went out to work on it and voila, loose and all normal. Did this “ok when cold, but binds when hot” ever get resolved? Thanks in advance,

 

[charleyf]

Resurrecting this old thread. I have the exact same problem. When cold everything is loose and moves perfectly. When warmed up the throttle binds to the point it’s actually almost dangerous. Let it sit an hour, went out to work on it and voila, loose and all normal. Did this “ok when cold, but binds when hot” ever get resolved? Thanks in advance,

To me when things get stiff when hot it means that there is expansion causing the stiffness. First check for all the moving parts and make sure they are loose and lubricated. That includes the little ball joints.
Second old springs get weak and do you have or can you add a spring to help overcome the problem?
Charley

 

[DavidApp]

How is the bell crank pivot? It wears out and may cause binding.
I bought a new bell crank and mounting bracket from one of the normal suspects and found that both parts were incorrect. The mounting bracket was too long and the wrong shape. The bell crank had the uneven legs the wrong way around. To add insult to injury the holes were not threaded.
I ended up making my own ones. I made a couple of extras so PM me if you need a set.

David

 

[luke44]

PM sent thanks

 

[luke44]

I’m rethinking on further investigation this may be where the problem lies. I’m replacing al the linkage
parts as I can find them (both the bell desk pivots are hard to find- David to the rescue!) and I’ll see.

 

[luke44]

To me when things get stiff when hot it means that there is expansion causing the stiffness. First check for all the moving parts and make sure they are loose and lubricated. That includes the little ball joints.
Second old springs get weak and do you have or can you add a spring to help overcome the problem?
Charley

The springs are good. Something seizes when hot. When it cools off it works perfectly!

 

[sp53]

Here are some pics I took of my engine. I am not sure what spot you need, or if I have mine the exact way the linkage should be set. I am curious what you mean about the linkage. Are you saying the mechanical parts of the linkage bind up when warmed up or the engine idle rises and will not come down after the engine is warm?

The rod that wants to rub on the manifold has always made me wonder if I have it correct, but I have had apart so many times that this seems to be the best orientation.

 

[luke44]

Everything works fine when cool, but it definitely got worse the more I drove it.

It's odd, at first I thought it had to be the Teflon balls on the firewall but the more I dug into it a lot of feedback indicated I should check the linkages first. The ball pivot piece has a lot of slop in it, instead of swinging left/right it almost twists up on an angle and very sloppy. So I've decided to replace all parts and levers that have a pivot point. Start with that first, as I really don't want to deal with the Teflon balls on the firewall. They don't have a lot of miles on them so it can't be wear. Does anyone lubricate those Teflon balls by chance? I did put them in dry.

 

[luke44]

Just to follow up on this thread. When I separated the linkage from the firewall rod it was obvious the Teflon balls were tight.

Loosening the 4 self tapping screws helps immensely but then you run the risk of the screws falling out.

In hindsight I wonder if the shaft shouldn’t have been painted at the Teflon ball point, I dunno.

So I replaced the self tapping screws with loosely tightened #8 threaded screws and double nutted them (triple nutted actually bc of the first wrench width) with the outer locking nuts loctited on the inside. So far so good fingers crossed!

 

[mrv8q]

TRF currently has TR3 carb linkage bits on sale, NFI.