LT1/T56 JTR mounts, R200 mount and alignment questions

[gvincent]

Please don't flame me! I have searched and searched but I could not find a part # for the GM or equivalent transmission mount for the T56.

I read alot of posts saying the JTR trans mount will work and will not work with the T56 so what is it?

 

I intend on using the JTR motor mounts (LT1) without the lowering plates. I want to use the JTR trans mount as well and am now concerned about driveline angles and am paranoid about vibration.

 

I read all the old posts I could find and have read Pete's web page on this subject a couple of times over, He really drives home the 1 degree alignment being a must for no vibration.

 

Is it reall necessary to chage the diff angles to get the nose down and tail up more with the T56 and LT1 using the JTR trans and engine mounts? I also read about Pauls diff mount as well. Unfortunately most of the pictures or links to these discussions no longer work and yes I do think there has to be a better solution than wrapping wire rope around the diff. I could no longer find any drawings of the Ron Tyler diff mount either.

Somebdy has to have a 280Z with an LT1 and a T56 that is running and is aligned and vibration free and solved the diff lift problem under acceleration without using solid diff mounts?

 

I know I ask too many questions at once..

Thanks,

Greg

[strotter]

I have a '72 with JTR mounts all around, T56, no lowering plates, and I guess I just got lucky but I'm vibration-free. Comes from living a good clean life, and flossing. There *is* some vibration, but it's proportional to RPM, not speed or load - it's more about cheapo motor mounts than drivetrain alignment.

 

The wire-rope around the diff is one of those "looks dumb but works good" things, IMO - and of course it's a last resort, in case of broken components and diff swinging up & down wildly.

[78zlt1]

I don't know if this will help but here is the thread I started for my driveline angles

 

http://forums.hybridz.org/showthread.php?t=110503

[MikeJTR]

... I have searched and searched but I could not find a part # for the GM or equivalent transmission mount for the T56.

I read alot of posts saying the JTR trans mount will work and will not work with the T56 so what is it?

 

 

Is it reall necessary to chage the diff angles to get the nose down and tail up more with the T56 and LT1 using the JTR trans and engine mounts?

Somebdy has to have a 280Z with an LT1 and a T56 that is running and is aligned and vibration free and solved the diff lift problem under acceleration without using solid diff mounts?

 

Greg

 

The JTR book (page 5-11) recommends a flat bar for the T56 transmission crossmember.

Using the JTR crossmember with the T56 will cause the T56 to be about 1 " too high in the transmission tunner.

[gvincent]

Thanks guys,

78zLt1,

I already have the urethane moustache bar bushings but I could not find the details on Ron Tylers Diff mount, your pictures are great! How much did you lower the front of the diff? So you did not raise the back of the diff any? All the web links for the details on Ron Tylers or Paul's diff mounts are dead, anybody still have this information with drawings so I can get it fabricated? Anybody have one they want to sell?

 

MikeJTR,

I guess I have been planning this for way too long and my seventh edition manual that I bought back mid 2003 does not have a page 5-11:( it stops at 5-10, can I buy that page from you? I thought I asked for any differences between the 7th and 8th edition awhile back and sombody said it was the cooling sectiion only which was different and I was able to download that section from the JTR site. Anything else I am missing? God I got to get this done this winter before anything else including myself becomes obsolete!! ()

So I use a piece of flat stock? what is the GM tranny rubber mount #, I couldn't find that either.

 

Thanks again,

Greg

[Pop N Wood]

Well since no one seems to be ponying up with the exact answers you are looking for I will tell you what I know.

 

First off, the "flat bar" MikeJTR is talking about is just that, a flat bar bolted to the underside of the floor pans. I guess JTR doesn't sell a T56 specific bar because they probably rightly figured that no one was going to send them money for something they could get from Homers or their local steel yard.

 

As for the transmission mount, I have two copies of the JTR manual and neither one has a page 5-11. But I do know you can go on Summitracing.com and search for transmission mounts. Go though their search options until you find one for a manual V8 chevy. They will cross reference it to a 2000 whatever Camaro with V8. You can get a nice energy suspension urethane one for ~$27. Or hit the local Autozone and buy a stock one from a 2000 Camaro with a manual and V8.

 

Finally to drive line angles. IMO unless someone with the exact same set up comes on line to tell you exactly what they did, you will need to wait until you actually get the engine in the car to measure them. If I were you I wouldn't let making the Ron Tyler diff mount hold up your swap. The RT mount will let you lower the front of the diff maybe a half inch before it hits the stock cross member anyway. Just get the engine in there and make the mount later. My guess is you will have enough flexibility in mounting the back of the tranny to do the alignment.

 

1° is a nice goal, but when you figure how much the back of that diff is going to lift under full throttle I am not sure how much you should worry about it.

 

And even if the alignment isn't perfect, the vibration is more of nusiance than a problem. It is not like you are going to damage anything if it takes you 6 months following the swap to put one in. The stock mount might break, but it is not like anyone has ever driven around with one of those broken before.

 

One other suggestion, go to the FAQ section and look at the thread about using laser pointers to align the diff. Makes the whole process a visual one and very simple.

[78zlt1]

Thanks guys' date='

78zLt1,

I already have the urethane mustache bar bushings but I could not find the details on Ron Tylers Diff mount, your pictures are great! How much did you lower the front of the diff? So you did not raise the back of the diff any? All the web links for the details on Ron Tylers or Paul's diff mounts are dead, anybody still have this information with drawings so I can get it fabricated? Anybody have one they want to sell?

[/quote']

 

gvincent, you can find the diff mount on Pete's site, thats what I used.

 

http://alteredz.com/drivelinemods.htm

 

I didn't raise the rear of the Diff I just installed the urethane bushings and washers as the instructions as described, I wanted to to install everything to set a baseline to see what was needed to get everything in spec, It just happened that the rear mount was fine where it was, as for lowering the front of the diff , I used washers to space it up or down to get my angles, I'd say about .75 inches but you will have to play with it to get it correct , due to the tolerance stack of all the parts together.

 

as for the rubber trans mount I'm not sure , the one that was on the trans seemed OK so I just used it, You should be able to goto a auto parts store or on line and find it fairly easily , searching for the car the trans came out of.

 

I didn't like the JTR mount because bolting it to the floor pan just didn't seem beefy enough to me, but allot of people have used it to great success so it does work fine. I like to over engineer things

 

Since pictures are infinitely more Better , here are some.

 

CAD models of the tranny mount , these were bolted to extensions welded to the subframe connectors.

 

 

 

 

[gvincent]

Pop N Wood, exactly what I was looking for, Awesome! Thank you for answering my questions. The Laser setup is really quite simple actually!

 

78ZLT1 beautiful mounts, I wish I had the welding skills all you guys have.

I have AutoCAD experience (Not 3D though) and could draw something up I suppose but would still have to have somewbody fabricate it for me.

 

I think I will wait until I have the Engine and Trans in place and then start measuring and drawing. I will post my drawings for a sanity check with you guys when I'm done.

[Guest Mike]

Well executed... very nice. I'm going to have a fabricator/mechanic adapt this to my SBC w/ 700R4 and R200.

 

gvincent' date=' you can find the diff mount on Pete's site, thats what I used.

 

http://alteredz.com/drivelinemods.htm

 

I didn't raise the rear of the Diff I just installed the urethane bushings and washers as the instructions as described, I wanted to to install everything to set a baseline to see what was needed to get everything in spec, It just happened that the rear mount was fine where it was, as for lowering the front of the diff , I used washers to space it up or down to get my angles, I'd say about .75 inches but you will have to play with it to get it correct , due to the tolerance stack of all the parts together.

 

as for the rubber trans mount I'm not sure , the one that was on the trans seemed OK so I just used it, You should be able to goto a auto parts store or on line and find it fairly easily , searching for the car the trans came out of.

 

I didn't like the JTR mount because bolting it to the floor pan just didn't seem beefy enough to me, but allot of people have used it to great success so it does work fine. I like to over engineer things

 

Since pictures are infinitely more Better , here are some.

 

CAD models of the tranny mount , these were bolted to extensions welded to the subframe connectors.

[wheelman]

I just want to correct one thing Pop said in his post. The back of the diff will not lift the front will. Thats why those of us with high HP motors end up ripping the front diff mount relatively quickly, it's also why JTR suggested using wire rope to hold it down.

Pop is correct about it's affect on the driveline angles and that it will cause vibration until the front of the diff drops, if it does.

I experienced this myself and when I used the wire rope trick the vibration and wheel hop during burnout disappeared. I do intend at some point in the future to convert to the Ron Tyler front diff mount setup but for now things are working good.

If I was in the middle of the project again I'd take the time to do the Ron Tyler mount instead of putting it together then taking it back apart to redo it.

 

Wheelman

[Pop N Wood]

I just want to correct one thing Pop said in his post. The back of the diff will not lift the front will.

 

Thanks for correcting my typo. Meant to say front.

 

gvincent, thanks for the pics and the ideas. Love what you did with the front diff crossmember. I was going to splice two together but what you did should work just as well. I have saved all your pics to my hard drive.

 

Also like how sturdy your trans cross member is and the accessability it gives. Maybe I need to move up the schedule on adding subframe connectors.

 

One other thing, I did the JTR mod of drilling out the holes on the mustache bar bushings to raise the back of the diff by 3/16 inch. They helped me reduce the tilt on the engine increasing the ground clearance on the tranny. If you do that simple mod, then you may not need to mess with the front pinion angle to do your static alignment.

[gvincent]

PoP N Wood,

I would love to think I am that talented and take credit for the Pictures, But I couldn't weld my way out of a paper bag.

 

78zLT1 posted all that beautiful stuff. He deserves all the credit!!!

 

If somebody on the list had the time and resources and was good at fabricating this stuff fairly easily with a jig or something I would buy this stuff in a heartbeat!

 

Thanks all,

Greg

[Pop N Wood]

PoP N Wood' date='

I would love to think I am that talented and take credit for the Pictures, But I couldn't weld my way out of a paper bag.

 

78zLT1 posted all that beautiful stuff. He deserves all the credit!!!

 

If somebody on the list had the time and resources and was good at fabricating this stuff fairly easily with a jig or something I would buy this stuff in a heartbeat!

 

Thanks all,

Greg[/quote']

 

Thanks again.

 

I'm on a roll today.

 

Good work , 78zLT1

[Guest Mike]

PoP N Wood,

I would love to think I am that talented and take credit for the Pictures, But I couldn't weld my way out of a paper bag.

 

78zLT1 posted all that beautiful stuff. He deserves all the credit!!!

 

If somebody on the list had the time and resources and was good at fabricating this stuff fairly easily with a jig or something I would buy this stuff in a heartbeat!

 

Thanks all,

Greg

 

Yeah... I'd buy really nice complete conversion kits at reasonable prices too.

[jonus079]

that looks like a pritty nice set up. how far back is the cross member from the front of the diff? and where is it in relation to the original cross memeber?

[gvincent]

gvincent, you can find the diff mount on Pete's site, thats what I used.

 

http://alteredz.com/drivelinemods.htm

 

I didn't raise the rear of the Diff I just installed the urethane bushings and washers as the instructions as described, I wanted to to install everything to set a baseline to see what was needed to get everything in spec, It just happened that the rear mount was fine where it was, as for lowering the front of the diff , I used washers to space it up or down to get my angles, I'd say about .75 inches but you will have to play with it to get it correct , due to the tolerance stack of all the parts together.

 

as for the rubber trans mount I'm not sure , the one that was on the trans seemed OK so I just used it, You should be able to goto a auto parts store or on line and find it fairly easily , searching for the car the trans came out of.

 

I didn't like the JTR mount because bolting it to the floor pan just didn't seem beefy enough to me, but allot of people have used it to great success so it does work fine. I like to over engineer things

 

Since pictures are infinitely more Better , here are some.

 

CAD models of the tranny mount , these were bolted to extensions welded to the subframe connectors.

 

 

 

 

 

78zlt1, do you have dimensions available for the trans mount in those Cad file pics? How about AutoCAD DWG files possible maybe?

I want to get both the tans and diff mount made up locally.

Thanks again,

Greg

[78zlt1]

that looks like a pritty nice set up. how far back is the cross member from the front of the diff? and where is it in relation to the original cross memeber?

 

The tans xmember is approx 11" back center to center from the original xmember and center to diff mounting flange is approx 25.5"

 

Greg here is a PDF of the parts ( see attachment )

 

Its what i used to make mine, I use Unigraphics at work and design my stuff after hours, we don't have a PRT to DXF translator license so I cant distribute models.

 

I need to stress that these dimensions are for my setup , you will have to change some things to work for you depending how your sub-frame connectors are installed.

280Z_T56_XMEMBER.rar

[gvincent]

78zLt1 Thank you!

I will have these made up but a little longer so I can cut/grind to fit and then weld into place.

I am not sure what my frame rails are because they were done over by a previous owner, they are not Baddog rail caps but definately were welded over the original frame rails and run completely front to back from the TC rod cups to the end of the frame rail. They are much taller/wider than stock so that is good. I plan to continue the rails up the back slope and tie them into the rear sub frame assembly.

One last question, you did grind them to follow the contour of the floor and then welded them to the floor and frame rail , they are not cut through the floor correct?

Again thank you for the pdf file, I feel much better knowing I am going to have your custom mount inplace of a piece of flatstock bolted to the floor pan.

Greg

[78zlt1]

One last question, you did grind them to follow the contour of the floor and then welded them to the floor and frame rail , they are not cut through the floor correct?

 

Actually they do protrude thru the floor , they are the same 2X3 " .093 wall reqtangular tube that I used for the subframe, and they are welded all around to the subframe. I found this pic of the Xmember tack welded to the subframe ( I've since fully welded them in)

this view is the drivers side from inside the car. Make sure your cross member is very solid. Alot of bad things will happen very quickly if this comes loose.

 

[gvincent]

78 ZLT1,

Nice work!, But I was afraid you would say that. Do you think if I made the two side pieces out of U channel, welded a plate on one end of the channel and drilled the bolt holes into the plate for the crossmember to bolt and then ground down the U channel to match the contour of the floor and then welded it to the subframe and the floor it would be strong enough? Just like your underside picture but not cut through the floor. I am a little noid of cutting the floor.

Thanks,

Greg