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I just saw a listing on ebay for a repro torque reaction arm. My TR4 is without one. I can imagine that it's purpose is to react the force of torque created by the engine, and prevents the engine from rotating. Question: how important is it? It seems like the engine mounts should do the same thing, although perhaps since the point of rotation is offset from the driveline, it causes add'l wear on the u-joints, etc. Do I need it? That's what I get for searching ebay without a purpose.
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TR4/4A tr4 torque reaction arm
- Thread starter derickson
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macino62
Jedi Hopeful
Offline
I would suspect it would cause less add'l wear on the U-joints, by keeping them in the same plane? Also, there's always going to movement from the rear suspension, being translated to the u-joints.
I haven't used one, but it seems like a nifty idea. Probably overkill for a street car?
If only airplanes had these to combat p-factor, haha
I haven't used one, but it seems like a nifty idea. Probably overkill for a street car?
If only airplanes had these to combat p-factor, haha
martx-5
Yoda
Offline
A little story here about the the first TR I ever owned. It was a '62 I bought in '64. It had about 22k miles on it. About a year after I got it, I was tearing around a left hand turn, and the steering locked up. /ubbthreads/images/graemlins/eek.gif I backed off the gas, and the steering was OK again. As it turned out, the left side motor mount was shot, and the engine pitched so much, that it caught on the lower steering knuckle U-Joint. You know, that fat fist sized rubber joint.
I replaced the bad motor mount...actually both sides, and installed a torque arm, so that if it ever happened again, I wouldn't be faced with another steering fiasco. I ran a 1/4" by about 1" flat stock from one of the rear head bolts over to a rubber mount that was bolted through that flat section under where the hood release mechanism is. The car felt so much tighter after I installed that, even after the mounts were replaced. I got the idea from the Saab two-cyles (my father had one). They had a torque arm going from the head to the inner fender.
/ubbthreads/images/graemlins/cheers.gif
I replaced the bad motor mount...actually both sides, and installed a torque arm, so that if it ever happened again, I wouldn't be faced with another steering fiasco. I ran a 1/4" by about 1" flat stock from one of the rear head bolts over to a rubber mount that was bolted through that flat section under where the hood release mechanism is. The car felt so much tighter after I installed that, even after the mounts were replaced. I got the idea from the Saab two-cyles (my father had one). They had a torque arm going from the head to the inner fender.
/ubbthreads/images/graemlins/cheers.gif
Alan_Myers
Luke Skywalker
Offline
[ QUOTE ]
Supposedly these were original equipment.
[/ QUOTE ]
Yup. There's always been one installed on my '62.
It's adjustable, by the way. And, necessary to keep the Webers and their air filters from knockin' against the underside of the hood.
/ubbthreads/images/graemlins/cheers.gif
Supposedly these were original equipment.
[/ QUOTE ]
Yup. There's always been one installed on my '62.
It's adjustable, by the way. And, necessary to keep the Webers and their air filters from knockin' against the underside of the hood.
/ubbthreads/images/graemlins/cheers.gif
trfourtune
Jedi Knight
Offline
alan,
can you please send photo of installed torque arm?
rob
can you please send photo of installed torque arm?
rob
Alan_Myers
Luke Skywalker
Offline
[ QUOTE ]
alan,
can you please send photo of installed torque arm?
rob
[/ QUOTE ]
Hi Rob,
Actually, I don't have a photo on file or online that shows it clearly and it's darn well hidden down on the RH front of the engine. I can't figure out any way to get a camera down in there. It's behind the rad/fan, under the cross brace/steering rack, and well hidden by the front pulley (harmonic dampener actually, on my car) and skid plate up from below.
Moss shows it illustrated online here: https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29116&SortOrder=75 It's item #53 on this illustration, with it's adjuster/buffer as #54.
Installation is simply under a couple of the front engine plate mounting bolts, and then the buffer is adjusted out until it is close to or contacting the frame rail. There is a locking nut on mine, to keep the adjuster/buffer from "re-adjusting" itself with vibration. The entire torque arm assembly needs to be removed when pulling the engine, or it gets in the way. Perhaps because of this a lot might have been lost over the years, it would be easy to forget to reinstall it.
It's my understanding that the later 4 cyl. cars didn't use it. Most likely it was discontinued at the time the rectangular engine mounts started to be used. Some think this is because the newer mounts were stiffer than the earlier round ones, and made the torque reaction arm unnecessary. I don't know if this is correct, or just an educated guess.
I think the torque arms being offered on eBay (and probably at Moss) are coming from Joe Alexander. I believe he started making replacements a while back, when they weren't available from other sources. TRF also carries a lot of Joe's parts, so might be another source, although I don't find it searching their parts database.
/ubbthreads/images/graemlins/cheers.gif
P.S. At first glance, I didn't find these parts illustrated in the factory (Stanpart) TR4 Spare Parts Catalogue. They aren't on the exploded views there.
However, looking a little closer I do find them listed (just not illustrated) as PN 133471 for the "Bracket, engine restrictor" itself, and PN 650325 as "Buffer, assembly, engine restrictor" that screws into it as the adjustable part. There is also listed PN 612067 "Buffer, rubber" which is replacement rubber end for the adjustable part. (Note: This part is important. The rubber cracks with age and then falls off, leaving the metal end of the adjuster to rub directly against the frame rail, eventually gouging it. Probably makes a pretty ugly noise, too.) PN 650325 "Buffer assembly"/adjsuter would actually be pretty easy to make, if necessary, it's not much more than a modified 3/8" NF bolt (head trimmed down so the rubber buffer or bumper fits over it).
Also listed are a spring-type lock washer and nut I'm sure are used to lock the adjuster in place. These are simply 3/8 NF nut and compatible washer, so part numbers are unnecessary. The only other consideration is the two bolts that mount it to the front of the engine might need to be a bit longer, although I don't see any differentiation in the parts catalogue.
My TR2/3 parts catalogues are packed away right now, so I can't check them to see if they list these items, too.
alan,
can you please send photo of installed torque arm?
rob
[/ QUOTE ]
Hi Rob,
Actually, I don't have a photo on file or online that shows it clearly and it's darn well hidden down on the RH front of the engine. I can't figure out any way to get a camera down in there. It's behind the rad/fan, under the cross brace/steering rack, and well hidden by the front pulley (harmonic dampener actually, on my car) and skid plate up from below.
Moss shows it illustrated online here: https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=29116&SortOrder=75 It's item #53 on this illustration, with it's adjuster/buffer as #54.
Installation is simply under a couple of the front engine plate mounting bolts, and then the buffer is adjusted out until it is close to or contacting the frame rail. There is a locking nut on mine, to keep the adjuster/buffer from "re-adjusting" itself with vibration. The entire torque arm assembly needs to be removed when pulling the engine, or it gets in the way. Perhaps because of this a lot might have been lost over the years, it would be easy to forget to reinstall it.
It's my understanding that the later 4 cyl. cars didn't use it. Most likely it was discontinued at the time the rectangular engine mounts started to be used. Some think this is because the newer mounts were stiffer than the earlier round ones, and made the torque reaction arm unnecessary. I don't know if this is correct, or just an educated guess.
I think the torque arms being offered on eBay (and probably at Moss) are coming from Joe Alexander. I believe he started making replacements a while back, when they weren't available from other sources. TRF also carries a lot of Joe's parts, so might be another source, although I don't find it searching their parts database.
/ubbthreads/images/graemlins/cheers.gif
P.S. At first glance, I didn't find these parts illustrated in the factory (Stanpart) TR4 Spare Parts Catalogue. They aren't on the exploded views there.
However, looking a little closer I do find them listed (just not illustrated) as PN 133471 for the "Bracket, engine restrictor" itself, and PN 650325 as "Buffer, assembly, engine restrictor" that screws into it as the adjustable part. There is also listed PN 612067 "Buffer, rubber" which is replacement rubber end for the adjustable part. (Note: This part is important. The rubber cracks with age and then falls off, leaving the metal end of the adjuster to rub directly against the frame rail, eventually gouging it. Probably makes a pretty ugly noise, too.) PN 650325 "Buffer assembly"/adjsuter would actually be pretty easy to make, if necessary, it's not much more than a modified 3/8" NF bolt (head trimmed down so the rubber buffer or bumper fits over it).
Also listed are a spring-type lock washer and nut I'm sure are used to lock the adjuster in place. These are simply 3/8 NF nut and compatible washer, so part numbers are unnecessary. The only other consideration is the two bolts that mount it to the front of the engine might need to be a bit longer, although I don't see any differentiation in the parts catalogue.
My TR2/3 parts catalogues are packed away right now, so I can't check them to see if they list these items, too.
Don Elliott
Obi Wan
Offline
All the guys who race TR4s have one. Recently they have been descibing how they have modified and beefed up their motor mounts too. On TR4 racer in Germany was getting 2 races out of his motor mounts even with a torque reaction bar.
Geo Hahn
Yoda
Offline
[ QUOTE ]
... PN 650325 as "Buffer, assembly, engine restrictor" that screws into it as the adjustable part. There is also listed PN 612067 "Buffer, rubber" which is replacement rubber end for the adjustable part...
[/ QUOTE ]
Interestingly, Moss lists the same part (p/n 282-130) as being the buffer for the torque reaction arm and elsewhere as the buffer for the TR4 bonnet.
... PN 650325 as "Buffer, assembly, engine restrictor" that screws into it as the adjustable part. There is also listed PN 612067 "Buffer, rubber" which is replacement rubber end for the adjustable part...
[/ QUOTE ]
Interestingly, Moss lists the same part (p/n 282-130) as being the buffer for the torque reaction arm and elsewhere as the buffer for the TR4 bonnet.
Alan_Myers
Luke Skywalker
Offline
[ QUOTE ]
[ QUOTE ]
... PN 650325 as "Buffer, assembly, engine restrictor" that screws into it as the adjustable part. There is also listed PN 612067 "Buffer, rubber" which is replacement rubber end for the adjustable part...
[/ QUOTE ]
Interestingly, Moss lists the same part (p/n 282-130) as being the buffer for the torque reaction arm and elsewhere as the buffer for the TR4 bonnet.
[/ QUOTE ]
Yep, I'm not surprised. I just checked and the part numbers are the same in the TR4 Spares Catalogue, too. That's the flat-type hood buffer that was used on the earlier TR4 (up to CT36xxx? or so, IIRC, and similar but not identical to the TR2/3 hood buffer).
Looking at the eBay auction, the one Joe is providing appears to use the cone shaped buffer that was used mid-TR4 and later.
Either one should work fine.
/ubbthreads/images/graemlins/cheers.gif
[ QUOTE ]
... PN 650325 as "Buffer, assembly, engine restrictor" that screws into it as the adjustable part. There is also listed PN 612067 "Buffer, rubber" which is replacement rubber end for the adjustable part...
[/ QUOTE ]
Interestingly, Moss lists the same part (p/n 282-130) as being the buffer for the torque reaction arm and elsewhere as the buffer for the TR4 bonnet.
[/ QUOTE ]
Yep, I'm not surprised. I just checked and the part numbers are the same in the TR4 Spares Catalogue, too. That's the flat-type hood buffer that was used on the earlier TR4 (up to CT36xxx? or so, IIRC, and similar but not identical to the TR2/3 hood buffer).
Looking at the eBay auction, the one Joe is providing appears to use the cone shaped buffer that was used mid-TR4 and later.
Either one should work fine.
/ubbthreads/images/graemlins/cheers.gif
trfourtune
Jedi Knight
Offline
it looks to me to be a poor design. it may limit the engine rocking but it pushes the engine up, putting the mounts in tension rather than compression. what it should be doing is compressing the motor mounts to limit movement. or i could be wrong and don't quite understand because i don't have one.
rob
rob
PeterK
Yoda
Offline
<<Looking at the eBay auction, the one Joe is providing appears to use the cone shaped buffer that was used mid-TR4 and later. >>
Joe Alexander used the cone rubber buffer on the torque arms he provides, becase he was unable to source the original type; works the same. Bought one for my 4A, Joe sells good stuff!
Joe Alexander used the cone rubber buffer on the torque arms he provides, becase he was unable to source the original type; works the same. Bought one for my 4A, Joe sells good stuff!