spinedoc

While at the track last week, two seperate maladies occured to the vette. One was the throwing of the alternator belt, the other was a vibration/noise coming from the shifter.

The fellow next to me said he used to throw belts on the 69 camaro he was running until he switched to what he called an 'L-88' alternator pulley. He showed me, it looked like a pulley with big built up sides, like washers to make it real deep. He said it worked great. Does anyone know where to get this?

The tranny now makes a vibration and noise when i get on it, I can't find the source. I have tightened all mounts, plates, etc. Everything SEEMS in order, but something is definitely wrong. I fear it is coming from inside the tranny, however, the tranny appears to work flawlessly. No grinding or missing shifts, very easy in and out of gears, etc. Any advice?

Thanks,

Eric

Matt Gruber

do you have a rev-limiter?

spinedoc

No rev limiter, but all shifts were conservatively made at 7000rpm. The motor should easily be good for 7600.

Wrencher

Kind of a wild guess, but check the drive shafts. I would expect a little vibration all the time, but way worse on accelleration if a U-joint, stub axle, or tailshaft bushing were the culprit. I'm guessing automatic, right?

On the pulley, you should be able to buy an aftermarket deep pulley. My BOSS 302 has the same thing from the factory, and they work great.

Hans


[Modified by Wrencher, 3:16 PM 7/8/2003]

Clink69

:confused: How is that motor set up to rev to 7600?? I keep mine under 6200.

Hobbes Blk '80

Must be on Warranty :lol: :lol: :D

Matt Gruber

that's a powerful engine and things happen fast.
Do you have a recording tach? That is the only way you can convince me ANY shifts were below 7600.
The reason i am so sure is the min. 1/2 second delay in the brain. And many tach's are dampened and can't keep up. in 1st my tach read 5500 and it was really 7000.( i now shift by a shift light only) I predict at least 1 shift was over 8000.(review the recording)
Any car this fast needs a rev-limiter.
Belts should stay on.
Check those u-joints too!
:cheers:


[Modified by Matt Gruber, 7:43 PM 7/8/2003]

dath

Also, check the obvious, did you maybe throw a balance weight from your driveshaft? How about wheel balance and tire health? Don't want to spend a bunch of time and effort on the tranny if it's something simple :)

Crash Dummy

Theoretically, set-ups like the March Underdrive pulleys should help in not throwing alternator belts... correct? Granted, if you don't have the pulleys aligned correctly then no matter what you are looking for problems at high RPM's.

I agree with Dath... check something simple like a weight coming off the drive shaft. That will definitely cause vibrations you never had before.

spinedoc

Thanks for the advice. I will check the driveshaft and u joints for trouble, I hope it is something that simple!

I will continue to look for that pulley, but still have not sen a source for it.

The motor is a high comp drag motor that was tore down, rebuilt with 10:1 for the street, the builders said you could shift at 8 grand without trouble. I will not test that theory though :eek:

updates to follow!

joe73vette

Did you try jegs or summit? I think Moroso sells deep groove pulleys. Joe

Budman68

Off the subject, 510hp from 383. :nonod: That's alot of ponies. Even 400 hp from a 383 is alot. Dyno that baby, because I need one if it's capable of that. What times did you run?

Turning 7000 rpms, things are going to start braking. My best guess is u-joint or bent half shaft. Good luck. :cheers:


[Modified by Budman78, 10:22 PM 7/9/2003]

spinedoc

Allright! Now we are getting somewhere. It seems the rear tires did lose their weights. I use hte stick on ones because VB states you cannot use bead weights on the inside as they may hit the suspension. I went back to the tire shop and had them put em back on. Got home and it still shakes even with the new weights. So on to the driveshaft.

It appears to have not lost any weights. There is a weight on it and no signs of an area where another weight may have flipped off.

I assume trying to detect twisted/bent half shafts by the naked eye is difficult, is hter a way to test this without removing them and taking them to a shop. and if they are bent, is there a sturdy replacement out there. The ones in the car are by VB, and I would hope are pretty good.

Thanks to all the help from the forum, i need you guys.

eric

As to the motor, i got it from our local race shop which seems to specialize in high hp, high revving small blocks. I believe it was dyno'd, or a companon motor was dyno'd at 485hp. Since then I have added aluminum heads and a high rise intake, which they stated should push around 510 horse. Unfortunately we don't have a chassis dyno in our area, as I would love to know what rear wheel hp is. :grouphug: :grouphug:

Budman68

What were the ET times. You can calculate HP by ET/MPH also.

theandies

:iagree: But don't forget the weight of the car :yesnod:
http://www.gordon-glasgow.org/hpcalc.html

Budman68

With a 13.9 at 106 in a 3600 car you have 375hp at the flywheel. Not shabby at all. :cheers:

8T1-7T9 BIONIC VETTE

Budman78......
What's my rear wheel HP if I have 11.9 ET???????

spinedoc

That's cool. What's that formula? How does it account for tire slippage, etc. My suspension is not tuned for the drags and my dry rot tires couldn't hold up. I took the slicks off my camaro and want to run them on the vette soon in hopes of better times.

Also, does anyone know how I can check those half shafts for wear/abuse to see if they are causing my vibration problem?

Matt Gruber

scribe or paint a thin line the length of the shafts. check them once in a while with a straight edge

Budman68

I think you would have to have a driveshaft place check them. Also, have someone follow you and see if there is any tire hop or strange tracking of the rear end.

The chalk trick is great. :yesnod:


[Modified by Budman78, 11:58 AM 7/11/2003]