1969 driveshafts

[69bigblock4speed]

1969 Camaro big block cars, and small block cars. Does anyone know for sure what driveshafts left Norwood in a BB camaro? Were the yokes lined up? Or were they off 32 degress?

[KurtS]

I assume you haven't seen this: http://www.camaros.org/driveshaft.shtml

[David K]

I have yet to see or work on any vehicle in 40 years that has an out of phase drive shaft.

[Jonesy]

Both my 69 Van Nuys small block manual trans cars were offset 32 degrees. Original driveshafts. Pretty normal on First gen Camaros.

[rich69rs]

Both my 69 Van Nuys small block manual trans cars were offset 32 degrees. Original driveshafts. Pretty normal on First gen Camaros.

I know we have beaten this to death in the past....the report referenced in the 1st reply details what Chevy did. 

From the perspective of this retired registered professional mechanical engineer and strictly from looking at how to properly set up a propeller (drive) shaft, the idea of offsetting the yokes makes no sense.  The whole idea of a propeller shaft, beside transmitting torque, is to keep the angular velocities the same (or relatively so) at both ends of the drive shaft to avoid torsional vibration issues.  This is accomplished by keeping the angle between the transmission output and the drive shaft and the drive shaft and rear end as nearly equal as possible at all times - including when the rear end is moving up and down goin over bumps, etc.  Offsetting the yokes 32 degrees works against this fundamental principle of keeping the operating angles, as well as the angular velocities, the same at both ends of the driveshaft. 

My guess is that Chevy discovered a vibration issue and the easy fix it was to offset the yokes which effectively stiffened the driveshaft and shifted the vibration to a higher frequency that was no longer excited by the drive train - as opposed to changing the design of the driveshaft itself which would have been a more costly endeavor. 

I put mine in line over 30 years ago.  But for those who want "factory correct"......

Richard

[David K]

Now I have to look at my drive shaft.

[Badshifter]

My x77 09C late Norwood car has the original offset driveshaft. Never been an issue.

[schlepcar]

Hmmm…
   Interesting because I have heard of this and have looked at all kinds of chassis diagrams on “ How to set up a chassis”. If the 32 degrees was used it was likely due to a dimensional diagram which they did have to redesign the driveshaft to compensate for the power of certain Camaros/novas. The ride height is one variable,the normal spinning at the normal height is another variable,and the third variable would change as the torque vs height changed,which also changes driveshaft angle depending on the amount of torque. We have to remember these are leaf spring cars with no panhard bar so the more torque the more “out of plane”.

[bcmiller]

If you guys have time, read the full report.

We researched this for over 10 years.

[rich69rs]

.

I agree - there could have been a vibration problem in the drive train.  Offsetting the yokes to “fix” a drivetrain vibration problem would have been an inexpensive course of action. 

If that was the case, then nothing was “fixed” - just band aided - with what was possibly a drivetrain vibration issue shifted to something else.  The drivetrain only had to survive long enough to finish a Trans Am race or last past the warranty period.

It would be insightful to know - over the years how may transmissions (aluminum cases) and rear ends have failed due to the induced stresses and torsional vibrations originating from offset propeller shaft yokes operating under heavy acceleration, load, and higher rpm’s.

Just because Chevy did it doesn’t make it golden.

If you guys have time, read the full report.

We researched this for over 10 years.

I have read the full report.  It is a very good report for documenting what Chevy did.  However, there is nothing in the report that states why, gives a reason, or an engineering explanation for why the SB driveshafts had the yokes clocked at 32 degrees.

And by the way, I have been researching mechanical engineering principles since 1971 (53 yrs) and have been a registered professional mechanical engineer since 1980.  I have more than a basic understanding of how a propeller shaft operates.

Richard

[69bigblock4speed]

OK Gentlemen,
Thank you for your input.  The statement below is copied right out of the CRG driveshaft page. It reads pretty clear except for the last sentance:

But in 69, the BB manual also used the SB driveshaft so it must not have been a major concern.

I have a 04C SS/RS with a 396/325 4 speed fully documented and origianl. I plan on being judged at the Camaro Nats in July. On page 59 in the LEGENDS judging maunal, it cleary says that all BB cars came with "IN LINE" trunnions or driveshafts. If we read the chapter about driveshafts in the CRG this differs from what the National Judges are saying is correct. Maybe they are wrong? I do not know, so I asked the question here on the forum.-
Did BB cars leaving Norwood have Inline of offset driveshafts? Does anyone have any further documentation than what the CRG has to offer?

This is stated righ out of the driveshaft section, from the CRG. It reads as follows:

Yoke offset
The 67-69 L6 and the small-block driveshafts had the yokes offset (or "clocked") by 32 degrees. The 67-69 big-block auto driveshafts have the yokes in-line with no offset. This may be to help limit vibration since the engine and transmission are not in direct line with the rear axle (due to the engine and transmission being offset toward the passenger side). But in 69, the BB manual also used the SB driveshaft so it must not have been a major concern.

[69bigblock4speed]

I should of ststed that my driveshaft in my 04C car if OFFSET with original spot welded weights on the tube of the driveshaft.

[bcmiller]

I should of ststed that my driveshaft in my 04C car if OFFSET with original spot welded weights on the tube of the driveshaft.

Post pics of your driveshaft and any stripes it may have have.

Who is listed as the head judge for Legends?  I may have to talk with Jerry M.

[bcmiller]

.

I agree - there could have been a vibration problem in the drive train.  Offsetting the yokes to “fix” a drivetrain vibration problem would have been an inexpensive course of action. 

If that was the case, then nothing was “fixed” - just band aided - with what was possibly a drivetrain vibration issue shifted to something else.  The drivetrain only had to survive long enough to finish a Trans Am race or last past the warranty period.

It would be insightful to know - over the years how may transmissions (aluminum cases) and rear ends have failed due to the induced stresses and torsional vibrations originating from offset propeller shaft yokes operating under heavy acceleration, load, and higher rpm’s.

Just because Chevy did it doesn’t make it golden.

If you guys have time, read the full report.

We researched this for over 10 years.

I have read the full report.  It is a very good report for documenting what Chevy did.  However, there is nothing in the report that states why, gives a reason, or an engineering explanation for why the SB driveshafts had the yokes clocked at 32 degrees.

And by the way, I have been researching mechanical engineering principles since 1971 (53 yrs) and have been a registered professional mechanical engineer since 1980.  I have more than a basic understanding of how a propeller shaft operates.

Richard

We have gone round and round with this. The horse was dead 10 years ago.

I have no way of getting into the minds of engineers that did this 50+ years ago.  If you have that capability, go ahead and find out.

[69bigblock4speed]

I am not trying to figure out why they were offset or inline, I am only trying to find out what is the correct driveshaft for a 396 4 speed 69 Camaro. I emailed Jerry M but he is in Scottsdale for 2 more weeks. He said he would reach out to me when he returns.
The LEGENDS book on pg 59 says all BB cars came with inline driveshafts weather it is a 4 speed or Auto 400. The colors according to LEGENDS do not match the CRG driveshaft chart either. I feel that the CRG offers more detailed info than 1 sentance on pg 59 from the Legends book.
Does anyone have proof in regards to offset vs inline?? Or is the section in the CRG under driveshafts all there is to offer?
If so what would you do, follow the CRG or listen to the LEGENDS book? I am stumped.