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TR4/4A TR4 AUC878 vacuum connections

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Twit

Twit

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I'm reassembling an early TR4 CT2292. It was someone else's project and came totally disassembled except body, the block and the tranny(which is now out and off to add on an overdrive).

It came with a new AUC878 dual carb setup. I'm now trying to figure out the vacuum connection for this and its surprisingly hard to find any info. Shop manual is no help. Moss motors parts shots don't show enough. I think its a screw in connection to just the bottom of the front carb but I am not sure.

thanks Dave
 
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Hi Dave, I have an early TR4, but not as early as yours. The TR2/3 had a brass fitting on the bottom of the front carb that a steel line with a compression nut screwed to. The TR4 used a small copper line with a fitting that screwed directly into the bottom of the carb. Your car should use a direct screw-in connection to the carb but its possible there was overlap in the early TR4s. I have some TR3 carbs and fittings I can photograph & measure tomorrow. My TR4 is in storage but I do have a TR4 SU carb set to check.

I encountered the same confusion 40 years ago when I got a complete vac line from a junkyard TR3A and tried to fit it to my TR4 - the brass union from the TR3 carb was too big for the threaded opening in the TR4 carb. I think the Moss vacuum line 23 on their Ignition/Distributor page will work though.

Jeff
 
Jeff,
Same boat here, with my TR3B. I just had my carbs looked at and everything looks OK except the vacuum line connection. I have a new rebuilt distributor with a vacuum advance on the way. The distributor that came with the car had none. The fitting on the bottom of my H6 carbs was plugged. The fitting is 1/4" with a 1/8" hole, no threads in the hole in the fitting. I'm looking for a way to connect the carb and distributor. I'll measure the threads today when i get to my shop. I'm hoping I don't have to alter the carb to fit a larger fitting.
Fitting size and dimensions in the catalogs would be useful. I guess they don't put them in their description because people would purchase from a different vendor if they had that info.
Following this...
Jim
 
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I got off my butt and pulled the carbs off again. There is a threaded entry on the bottom of the front carb.

So now that I understand I just have the one connection I'm looking at the options offered by MOSS. My distributor has a slip on connection so none of the Moss configurations fit the setup. That is probably because the carbs and dist are both new so no guarantee they are both early TR4 versions.

I think what I need to do is get the option with the male and female ends and just cut off the female end. For now I'm plugging them as the motor has been rebuilt but never started and I can live without the advance for now. Getting parts into Canada with the COVID lockdown is pricy so I'm looking to do an order of all the little bits I find missing and I'm going to need all the overdrive stuff at the very least and some cables. I haven't even started on the dash as I want to put the tranny back in first so I don't damage anything.

thanks for the help Dave
 
Sounds good. You may be able to fit a short rubber connector (like the TR6 uses) to connect the Moss #23 line to the vac unit, then thread the female screw-on connector onto the rubber coupling.

Jeff
 
So the Moss pipe worked fine. The ends were press fit so didn't even need to cut the one off. But I did have to do a reduction from the distributor to the pipe. To do that I just nipped the ends off the rubber end covers and married them as they were just the right size.
 
Twit said:
I'm reassembling an early TR4 CT2292. It was someone else's project and came totally disassembled except body, the block and the tranny(which is now out and off to add on an overdrive).

It came with a new AUC878 dual carb setup. I'm now trying to figure out the vacuum connection for this and its surprisingly hard to find any info. Shop manual is no help. Moss motors parts shots don't show enough. I think its a screw in connection to just the bottom of the front carb but I am not sure.

thanks Dave
Click to expand...
Hey Dave... I have an early TR4 as well... CT2997 that I did a concourse
body off resto about 20 years ago... I have lots of pictures and can take more if you ever need any help...
PS My name is Dave too, and I live in Ontario...
 
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