Proper diff mount..

[ZR8ED]

All this talk of Kludge fix diff mounts has me thinking.

 

I have a solid stainless steel diff mount. It works very well, but transmitts too much gear whine into the car. Now that all the interior is back in the car is very quiet, and all I hear now is the whine of the diff.. even louder than my MSD fuel pump.

 

Anyone have a solution for shutting this thing up with out going back to stock...I'm afraid of breaking a stock one..since I already broke my solid mount once!

 

I have thought about wedging a piece of urethane between the mount and the crossmember to help dampen the noise...or maybe nylon...(heat and oil resistant and crush resistant, and I can get solid chunks that I can cut to size)

 

Any ideas guys? I have all winter to figure this out..hehe

 

Thanks.

[Guest Anonymous]

It seems Pete Paraska solved this problem with a mount that utilized a urethane GM tranny mount.. the details can be found in his amazing "how to do it website"

[pparaska]

Thanks for that compliment!

 

Check out my Driveline Mods Page under:

"Differential Front Mount", about halfway down the page.

[Guest JAMIE T]

Pete, The picks on your site of that mount are kind of dark, and don't show detail well. I was wondering if you had any other picks of the mount(or a drawing) I could probably whip one out with great ease.

[Scottie-GNZ]

Would there be any interest in an unbreakable urethane replacement mount? One is being developed as we speak for the RX-7 as theirs is just as bad especially with their hybrids. What would folks be willing to pay for something like that?

 

That is what I am using for an engine mount to stop my torque monster from coming through the hood.

[Pop N Wood]

Yeah, an "unbreakable" diff mount would be much aapreciated. Unfortunately, I don't think making it out of urethane will make any difference. It is the adhesive bond cementing the isolator to the top and bottom plates that fails.

 

What needs to be done is to redesign the mount to put int under compression instead of tension. There have been at least 3 different designs on this board for doing so. All require bending and welding some metal.

[PaulR]

Originally posted by Jim Powers:

What needs to be done is to redesign the mount to put it under compression instead of tension. There have been at least 3 different designs on this board for doing so. All require bending and welding some metal.

Yup, here's my version

Paul's Diff Mount Mod

[Scottie-GNZ]

If 540lb/ft of torque launching with slicks and a t-brake has not broken it, I doubt the diff will.

[ZR8ED]

I like both of those ideas!

 

Thank you very much. I can make either of those with no serious troubles. I will actually have a quiet car again!

 

Its a good thing there are always Z's at my buddies shop. I'll be able to fab something up over the next few months using a Z on the hoist...(mine is tightly packed away in non-accessable storage till April)

 

I'll most likely make extras though, as most of my buddies customers copy my mods anyways. ie brake swap, suspension tricks, bracing, etc... My car has sort of turned into a demo car to demonstrate my buddies mechanical abilities...ya know the ol story "I want what he's got".. good for his business, and I'm usually the first kid on my block to get the new toys...even though I'm always the guniea pig...

[Pop N Wood]

Thanks PaulR, now there are 4!

[Pop N Wood]

Looking back, I didn't mean to disrespect the urethane idea, just taking a SWAG at it. If someone has one that works, then by all means share it.

 

Looking at a different site I came across this idea:

 

http://zccw.org/Tech/Differential/MysteryClunk.html

 

Add this to the JTR suggestion of wrapping some wire cable around the diff and cross member and we are up to 7 suggestions. Trouble is past posts have said the cable will stretch, so one of the many top mounted designs look more permanent.

[Guest Anonymous]

Come on fellows,just when I get the urethane GM tranny mount to hammer out the "Pete mount", Paul comes up with a real cheap solution for pennies out of scrap. That I like... Now I will have to use the urethane elsewhere. I have no problems with the stock mount in an unfinished project

[pparaska]

You could make an INTERLOCKING urethane or rubber mount that could be a bolt in replacement for the Datsun piece, it that's what Scottie-GNZ is talking about. That'd be a nice solution, as it wouldn't have a ground clearance issue.

 

I'd like to point out one advantage to the "Ron Tyler" design mount that I have in my car:

For many V8 swaps, especially the JTR conversion, the pinion angle of the 240-280Z is very much nose-up compared to how the V8 and transmission shaft is installed. The Ron Tyler design allows the front of the diff to be lowered (in fact, it necessitates it) so that the pinion angle is closer to the transmission output shaft angle that the JTR installation typically results in.

 

This is an important detail, if you want low enough drive shaft u-joint angles to not have driveline vibration under acceleration. Check out my "driveline mods" page on my web site for details.

[Pop N Wood]

Then yet one more solution: Modify Paul's design to take the rubber out of the stock mount (the rubber above the cross piece). Could then lower the front of the diff more toward the cross piece since all of the isolation is coming from underneath.

 

Ground clearance should not be an issue since you will lose the exhaust first.

[Guest Anonymous]

Now somthing tells me that Pete took the urethane mount one step further to aid drive line phasing angles .Too many choices and too many variables and too late to restore the car to factory specs No loyalty here I am back to Pete's scheme

[pparaska]

Toma,

Actually, I WANTED to lower the front of the diff, as it was the last thing on my list to allow me to be able to get a 1 degree u-joint angle like I wanted. What happened was that my engine had scored bearings, I yanked it and while I was under there decided to take Ron up on his offer to make me that mount. As it turned out, the stackup of the mount bracket and the GM tranny (and replacement urethane mount) made it so the diff now was pushed down, so that it was about 1/4" above the 280Z crossmember I have in there. So Ron's mount forced me into doing something I wanted to do anyway .

 

It really is a joy to be able to hammer on the gas and NOT hear/feel those vibrations that I'd experienced in others V8Zs. They were unsettling to me and I didn't want any of that. Now I just have to worry about wheel spin .