TR4/4A Torque Reaction Arm

[TR Tom]

I thought I had finished bolting everything back up to my shinny new engine, when I came across what Moss calls the “Torque Reaction Arm” (#53 & 54 in the External Engine picture in the catalog) laying off in a corner. Of course I also forgot exactly where it went, and in the process of investigating, found that it appears to have only been installed on the TR4, but not the 4A or earlier 2 or 3’s. Is that true, and if so why? Were they on all the 4’s? And if discontinued, was it because they didn’t do what the factory expected them to do?

Everything on the engine has hopefully been sealed up good and tight by the machine shop, so I’m wondering if the bolt holes on the bottom of the front plate that holds the arm on go into a blind hole, or all the way into the crankcase, meaning I will have to seal them back up. And if so, what’s the recommended way to do that?

 

[charleyf]

I learned about them from Joe Alexander and bought them for my 2 TR4s. They are to prevent excessive engine movement to protect your engine mounts. It appears that a lot of them have been discarded by previous owners.
If you can wait a few days I will look at a TR block to determine as to whether the holes are dead end or not.
Charley

 

[TR Tom]

I learned about them from Joe Alexander and bought them for my 2 TR4s. They are to prevent excessive engine movement to protect your engine mounts. It appears that a lot of them have been discarded by previous owners.
If you can wait a few days I will look at a TR block to determine as to whether the holes are dead end or not.
Charley

I finally found some info on that part, and as you say, they look like a worthwhile item to have…still curious though why they were discontinued for the 4A.

It would be great if you could check that out Charley. I definitely don’t want to do something stupid and cause a new oil leak after going to all the trouble and expense of getting them all fixed.

And I can definitely wait a couple days - still plenty to do before I’m ready to fire it up.

Thanks
Tom

 

[charleyf]

I finally found some info on that part, and as you say, they look like a worthwhile item to have…still curious though why they were discontinued for the 4A.

It would be great if you could check that out Charley. I definitely don’t want to do something stupid and cause a new oil leak after going to all the trouble and expense of getting them all fixed.

And I can definitely wait a couple days - still plenty to do before I’m ready to fire it up.

Thanks
Tom

They did change the style of motor mounts from round to rectangular.
My best guess.
Charley

 

[Hamish Racing]

You shouldn’t need the torque bar if you have good engine and gearbox mounts.
Not sure is available in the US but in the uk there are specialist suppliers with harder rubber ( shore rating 70 I think)

MOUNT ENGINE ROUND TR4-4A

 

[TR Tom]

Good point about condition of mounts. Unfortunately, it seems quality has been all over the map lately, so “new” mounts doesn’t necessarily mean “good”.

I just bought my new ones from TRF, as they typically stock whatever is the best quality available at any given time. When I asked Albert for a recommendation between square and round style, he said only round were available…so that’s what I got - Will see how they hold up

 

[TR Tom]

So is the consensus that the torque arm was no longer needed with the switch to (upgraded??) square engine mounts on the 4A…or maybe the theory that it was no longer needed with the switch to the long bubble on the hood?

Anyway, looks like I might as well reinstall it. Just need to see what Charley (or anyone else) has to say about the mounting holes.