shifter bobbing up and down on accel

[LGAFF]

Going to recheck the C-beam bolts, but under hard accel the shifter is moving up about 1/2" maybe more....any other possibilities? This is on the 90...pretty confident I torqued to 37 and 59

[XfireZ51]

Going to recheck the C-beam bolts, but under hard accel the shifter is moving up about 1/2" maybe more....any other possibilities? This is on the 90...pretty confident I torqued to 37 and 59

Does it have the Beam plates?

[VetteMed]

Lee, I had the same problem when I didn't completely clean the mating surfaces of the C-beam and of the transmission and differential. The bolts were torqued properly, but a few bits of the OEM adhesive were preventing flush fitment.

Of course, a worn or broken motor mount or batwing mount can do the same thing. But, if you've had the c-beam off recently, I'd want to check that there's no adhesive or debris preventing proper mating.

[scottfab]

Going to recheck the C-beam bolts, but under hard accel the shifter is moving up about 1/2" maybe more....any other possibilities? This is on the 90...pretty confident I torqued to 37 and 59

Yah, re-tighten bolts but check trans cross member and motor mounts too.

[Paul Workman]

Yah, re-tighten bolts but check trans cross member and motor mounts too.

No trans "cross member" on a ZR-1 (ZF) transmission. That leaves motor mounts, C-beam joints, and the "bat wing" bushings on the differential. Ya have ta go back to C3s to come across cross members for the trans.:cheers:

P.

[LGAFF]

Loos beam bolts.....surprised as my torque wrench was still set for them, and I used the 02 wrench to tighten...hopefully problem solved

did manage to take a nice 21MM deep socket to the eye

[rhipsher]

Lol! I took a Spicer Ujoint cap to the fore head while installing. I bled like a siv.

[scottfab]

No trans "cross member" on a ZR-1 (ZF) transmission. That leaves motor mounts, C-beam joints, and the "bat wing" bushings on the differential. Ya have ta go back to C3s to come across cross members for the trans.:cheers:

P.

Yup and my C3 had one. Brain fade. It's all that bike riding and fresh air. Well that and I haven't had to do anything under there since I rebuilt my ZF6.

[-=Jeff=-]

Loos beam bolts.....surprised as my torque wrench was still set for them, and I used the 02 wrench to tighten...hopefully problem solved

did manage to take a nice 21MM deep socket to the eye

you leave your torque wrench set? I always Zero it out after use..

but yeah not surprised the bolts were loose

[scottfab]

you leave your torque wrench set? I always Zero it out after use..

but yeah not surprised the bolts were loose

I loosen it also. Leaving it set is suppose to negatively effect the accuracy.

[-=Jeff=-]

I loosen it also. Leaving it set is suppose to negatively effect the accuracy.

Correct.. I learned that in my teens while working at an auto repair shop

[LGAFF]

Guess thats true:

The Wrench Should Always Be “Unloaded” Before Storage





http://image.circletrack.com/f/techarticles/ctrp_1111_torque_wrench_myths/33032657+pinline_medium/ctrp-1111-05-o+torque-wrench-myths+click-type-wrench.jpg (http://www.circletrack.com/techarticles/ctrp_1111_torque_wrench_myths/photo_03.html)
A click-type wrench is popular...

read full caption


http://image.circletrack.com/f/techarticles/ctrp_1111_torque_wrench_myths/33032657+w200/ctrp-1111-05-o+torque-wrench-myths+click-type-wrench.jpg (http://www.circletrack.com/techarticles/ctrp_1111_torque_wrench_myths/photo_03.html)
A click-type wrench is popular and dependable. You set the amount of torque you want by twisting the handle of the wrench. This compresses a spring in the handle which increases the amount of torque required before a steel ball will pop out of its detent inside the wrench, giving you the familiar “click” to let you know you’ve reached your desired torque setting.


If you’re using a mechanical click-type wrench, this one turns out to be absolutely true. A click-type torque wrench presses a ball into a detent that’s held in place by a spring. The wrench is normally adjusted by twisting the handle on the wrench. Twisting it in compresses the spring and requires more torque to pop the ball out of the detent. This is how it measures torque.

But if the spring is stored with the wrench “loaded” or set for a high torque rating, the pressure on the spring can cause it to weaken over time. To protect the wrench it should always be returned to the lowest setting before storing it back into your toolbox. For big wrenches (measuring in ft-lbs increments) the lowest setting is usually 20 ft-lbs. If, for some reason, you have a click-type torque wrench that goes all the way down to zero, leave the wrench set to 10 or 20 pounds. You always want to keep a minimum amount of pressure on the spring so that the ball can’t fall all the way out of the detent.



Read more: http://www.circletrack.com/techarticles/ctrp_1111_torque_wrench_myths/viewall.html#ixzz21PdMlrDt

[LGAFF]

No more issues with the shifter.....

[Paul Workman]

Interesting thread, Lee.

It reminds me of the time when I was installing those microwave antenna "dishes" you see on some radio towers - the bolts needing to be re-torqued, that is.

It was in the Andrews (antenna manufacturer) installation guide (I believe) where it mentioned "cold flow", a phenominon where under initial clamping force the "teeth" on the hardware that clamps to the galvanized tower legs would exert tons of "point contact" force in the small contact region to cause the metal - the relatively soft zinc galvanizing - to actually ooze out from underneath the contact points.

This would result in the relief of the clamping torque, and the hardware would then begin to loose grip on the tower legs and slip. And, here's the part that links back to our C-beams... Evidence of "cold flow" and the attendant loosening of the hardware was a ridge of metal that forms at the periphery of the clamp contact points and around the washers beneath the torqued bolts. After about a week, we'd have to remount the tower(s) and re-align the antennas and re-torque the clamping hardware. After the initial cold flow, the softer zinc galvanizing had migrated to the extent it would, leaving the much harder steel beneath it to arrest further flowing/loosening.

The first time I saw this ridge around the washers of the clamping bolts on the aluminum C-beam - was like "de ja vue all over again". It is what lead me to Bill B's Beam Plates in the first place! (Which, by the way, appear to dissipate the clamping force sufficient to avoid "cold flow" - worth every penny, IMO, not to mention the ease of removing and reinstalling the C-beam!)

Just some idle :blahblah:... I guess my point is, if you don't use Beam Plates, (torque wrench spring fatigue not withstanding) there is an opportunity for "cold flow" around the washers of the C-beam bolts, allowing the beam to start squirming, and one needs to keep an eye on the torque, especially after intial installation. I suppose GM thought the "glue" they used on the C-beam would prevent slipping...or at least until the warranty period was up!

P.