I posted before about driveshaft vibrations and some suggestions were driveshaft balance and to check the pinion angle. I got the driveshaft balanced and it took away most of the vibrations but it still peaks at 50-60mph. What is the correct pinion angle? Doesn't the angle change under load? Its a 70 camaro th350 if that has any affect on the angle. Im assuming pinion and is angle of shaft to rear. Thanks for any help.

I'm setting mine to 4 degrees down from level when the driveline is not under a load (not moving) i'm setting to 4 degrees becuase some of the other forum members recommended it.
It DOES change with a load, thats why you set it to say 4 degrees, becuase you want it to be 0 degrees under a load. The axles put a "twist" or "torque" on the rear when your moving and the pinion will rise a few degrees, the more it twists the more the pinion will rise.

To be exactly precise, the angle of the pinion should be relative to the angle of the output shaft of the transmission. A few degrees down will help to compensate for axle wrap up under load so that the pinion angle is equal to, or parallel to, the output shaft when it is under a load. As a general rule, the pinion angle shouldn't be set relative to the ground, or exact level, but to the output shaft of the transmission.

Check out Inland Empire Drivline at www.iedls.com (http://www.iedls.com)

http://www.iedls.com/gif/fig2.gif

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STEVE JACK
ConceptOne Pulleys and Brackets
Northern/Southern Rodder Magazine's "Jack'Stands" author and creator
Techical forum/links at www.inccn.net/techforum.htm (http://www.inccn.net/techforum.htm)

<BLOCKQUOTE>quote:</font><HR>Originally posted by CamaroNOTcamero:
I'm setting mine to 4 degrees down from level when the driveline is not under a load (not moving) i'm setting to 4 degrees becuase some of the other forum members recommended it.
<HR></BLOCKQUOTE>

Just to be clear CNC, when you say "not under load" you mean torque load don't you. You definately do want the vehicle weight load on the rear axle when making this adjustment. I think that is what you meant, but wanted to be sure.

hey guys, now i am installing a ford 9 in my 68 camaro, what is the best way to weld the perches on at the right angle??? i want to make it right and how do i do that?? do i set perches on leaf springs, the set rearend on perches in car,center axle,then measure pinion angle and then tack weld perches, then take out and weld solid&gt;??? also how can i make it like the vehucle weight is on it when the perches are not welded and i have to rotate the axle to get correct angle??? please give me a explanation, i would greatly appreciate it, thanks Jake

Yeah, torque load, not weight from the car.
I set it up using a GM diagram, so i'm willing to bet that i'm safe since thats the way the general did it.

Hey Guys,

Help me with this one!! The diagram shown above from Inland Empire Driveline looks to me like the pinion angle is set 3 or 4 degrees ABOVE level. I keep reading about people setting them BELOW level. Am I missing something here or just looking at this upside down??

Doug




[This message has been edited by GDV350SS (edited 08-14-2002).]

I agree the diagram is above level, is that what it is suppose to be? Right now mine is below level by probably a little more than four degrees, could that cause the vibration I described?

The GM diagram i got showed it down, not up like inline empire.
I dont understand why they would want it 3 degrees up, when under full throttlw it would have the potential to move to 7 degrees or more up, and i think that would cuase vibrations.
Steve jack, any reason why that diagram is like that?

It would depend on which direction you transmission is pointing. If it is pointing down like in the photo above, then your pinion should point up like in the photo, so that they are parallel. If your tranny points up, then your pinion should point down so that they will be parallel.

I think the tranny pointing up is more common, but sometimes it points down, like when you have a Tremec and can't push the rear of the tranny up anymore because it hits the trans tunnel.

The important thing is that the two center lines are parallel, and that the angle of them to the driveshaft isn't too large, 3 degress max according to the photo above.

Ray www.geocities.com/hrayhouston (http://www.geocities.com/hrayhouston)

It is my understanding (I read it on this sight and believe it was from someone knowledgeable but can’t remember who) that the standard configuration for a 1st gen Camaro using standard motor and transmission mounts puts the transmission at approximately 4 degrees down. If this is indeed correct, than the pinion needs to be up 4 degrees to be parallel. Any thoughts or more knowledge about this would be appreciated.

The more I learn the less I know!

Doug

It is my understanding (I read it on this sight and believe it was from someone knowledgeable but can’t remember who) that the standard configuration for a 1st gen Camaro using standard motor and transmission mounts puts the transmission at approximately 4 degrees down. If this is indeed correct, than the pinion needs to be up 4 degrees to be parallel. Any thoughts or more knowledge about this would be appreciated.

steve70: I hope that we get to figure this out because I beleive it may be the cause of your vibration as well as mine.

The more I learn the less I know!

Doug



[This message has been edited by GDV350SS (edited 08-15-2002).]

Guys. A couple of points here.

First, Steve70, if your angle does not look like the diagram.....Yes indeed the vibration is coming from mismatched angles. The center line of the crankshaft and transmission output shaft must be parallel to the center line of the pinion shaft as shown in the figure above. There are NO exceptions to this configuration unless you are a serious drag racer.

Camaronotcamaro....wrap up doesn't always happen if corrected for. And, you set the driveline for the most common mode of operation...cruising which the pinion is basically in a static mode. After initial wrap up deflection, the angle starts to decrease proportionately. If you are using the car just for drags then angles should be studied further for optimization and hopefully traction bars in place if you are worried about wrap up. Four bar links do not move at all. So, no need there.

68ssconvertible.....you are wisdomic in your post with one exception. "I think the tranny pointing up is more common, but sometimes it points down" This statement is incorrect. Most,if not ALL engine driveline designs are pointing the tranny down at the rear. There are several reasons for this. One is that it gives gravity a chance to work with the lubricant return mechanisims and cooling passages to natually expel air. All longitudinal mounted engines that I know of drain oil to the pan visa via gravity with oil flowing back and cooling systems (water jackets in the blocks and heads) to expell air with a planned downward plane in back. Also, note that most intake manifolds have built in corrective leveling angles of 3 to 4 degrees to allow the leveling of the carb. Some modern engines have as little as 2 degrees down in back.

GDV350SS....you are absolutely correct. Stock positoning of the Camaro should be found at 4 degrees down in back. Of course modifications that many throw in could alter this, but I have always found 3 to 4 degees down in back. This was the GM specification as well for all V8s longitudinally mounted to date except fuel injection cars which is 3 degrees. Your vibration is coming from mismatched angles for sure, I would bet on it.

Hope this helps!



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STEVE JACK
ConceptOne Pulleys and Brackets
Northern/Southern Rodder Magazine's "Jack'Stands" author and creator
Techical forum/links at www.inccn.net/techforum.htm (http://www.inccn.net/techforum.htm)


[This message has been edited by HOTRODSRJ (edited 08-16-2002).]

Steve, thanks for the explaination.
I'm setting mine up for street/strip, with more concern for streetablity, so i did mine to GM specs.
I'm going to be using leaf springs in there stock mounts. If i find traction to be a problem i will be using Cal-Tracks.

HOTRODSRJ (Steve Jack)

Great post! Thank you very much for taking the time to share your knowledge. I hope now that I can finally eliminate the vibration I picked up when I replaced my 8.2" open rear with the 8.5" posi rear last summer. I also checked out the link to the inccn.net site. Lots of great info there, especially in your "Jack Stands".

Your '57 and '69 look great also.

Thanks again!!

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'69 SS clone 350/M-20
'65 327/275 Corvette Coupe(previously)



[This message has been edited by GDV350SS (edited 08-15-2002).]

so guys, the sensus is have pinion on rear axle 3-4 degrees down??? getting ready to weld my new camaro spring perches on and would like to make sure i get them on right so i have no vibration, now do i level rearend pinion, then make it go 4 degrees downward and then weld my perches on??? please help, thanksalot
Jake

BB...unless you are specifically building a race car for drags, the consensus is to have the pinion pointed UP at the same angle your engine crank centerline is pointed down in back for optimum set up!



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STEVE JACK
ConceptOne Pulleys and Brackets
Northern/Southern Rodder Magazine's "Jack'Stands" author and creator
Techical forum/links at www.inccn.net/techforum.htm (http://www.inccn.net/techforum.htm)

Does anyone know wear I can buy some shims to use in re-adjusting the rear pinion angle. (I don't want to cut off the perches and re-weld) I've heard that they are available-but I don't know where to look for them. I could take the time and machine some I guess, but I'd rather just spend the money and get some ready to put into place.

Thanks

I have noticed a vibration in my drive line or the tail housing of the transmission (Muncie four speed) at speeds of around 80mph+. The noise starts when at a high RPM in third gear and continue on when I shift into fourth all the way up to 5500 RPM. At around 4500 RPM in fourth gear, the vibration smooths out, but doesn't go away. I was going to replace the output shaft bushing this weekend hoping to cure the problem. Could the vibration be due to mismatched pinion/output shaft angles? How do I check the angles?

GDV350SS, you can get the shims from Summit or Jegs.

HOTRODSRJ, thanks for the correction. I made the statement that most tranny's were pointed up because I read so many folks talking about pointing there pinion down for correct alignment. My tranny points down, so I thought I was an exception, not the rule. I'm glad to find out I'm normal http://www.camaros.net/forum/smile.gif.

HOTRODSRJ, also - is the diff. cover mounting surface on a 12 bolt perpendicular to the pinion? This would make for an easy way to measure the pinion angle (-90 degrees), like using the oil pan rail to measure the the tranny angle.

Ray

"HOTRODSRJ, also - is the diff. cover mounting surface on a 12 bolt perpendicular to the pinion? This would make for an easy way to measure the pinion angle (-90 degrees), like using the oil pan rail to measure the the tranny angle.

Yes.

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STEVE JACK
ConceptOne Pulleys and Brackets
Northern/Southern Rodder Magazine's "Jack'Stands" author and creator
Techical forum/links at www.inccn.net/techforum.htm (http://www.inccn.net/techforum.htm)

The factory position for the perches is with perches level, the pinion will point down four degrees, thirty minutes. Or four and a half degrees down on the pinion.

Don't assume the leaf springs are level to the ground when the car is running.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

David,

So - are you agreeing or disagreeing with the above 'consensus' that with the car on the ground one should have the pinion angle _up_ the same amount as the driveline angle is _down_ (assuming, of course, that for a camaro the driveline does point down, which, I think is true)? Thanks.

BTW - I measured the pinion angle in two places: the diff cover mounting surface and the pinion yoke flange. They are the same +/- 0.5 degrees.

Actually, I haven't seen the smoothness of drive to be very sensitive to this angle. Besides, the angle changes. But, by how much, I don't know.

I would be interested to know how much the pinion angle varies under load, cruise, decel, accel, empty car, with several hundred pounds of passengers (and a full tank of fuel), etc...

Who wants to hang under my car and measure while I drive?

Steve is absolutely correct. Even a drag car that is set up correctly shouldn't move the pinion angle much unless you have a wheel hop problem. Everything I ever built was set with the trans and pinion parallel.

I agree the pinion angle must pretty much parallel the trans angle, at least within three degrees of matching.
If the trans points down 4 degrees, the pinion should point up four degrees.

I have heard of stock first gen driveshafts being balanced and still not running smooth.
A poster here replaced his driveshaft with a complete aftermarket shaft and his vibration problem was solved...

Make sure the yoke is snug on the trans splines too.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

I have been doing pinion angle "101" to my car w/no improvements. I'm currently @ 3 down but have been down & up in 1/8" increments. I have a 700r4 & 9" Ford. Had shaft shortened & balanced. Running the TH350 yoke. Put all the way in & pulled out 3/4" for shaft measurements to shorten. Have checked rear end for slack/patern & pinion preload. Checked axles. All are new. Had tranny & torque convertor checked. Car starts vibration @ about 50 & increases w/speed being worst @ 65. Intensifies when you let off accel. slightly. Is present w/engine turned off @ speeds stated. Next I'm going to have a new driveshaft built. Getting real frustrating! Anything I'm missing? HELP!:confused:

Measure the yoke on the tranny. Whatever that measurement is, make the yoke on the differential the exact opposite. For example, if the tranny yoke is -2*, make the diff yoke +2*. I had this exact issue and until I got an angle finder and some pinion shims, I was wasting my time. I have mine set at 4* + and -.

My mistake was placing the shims behind the perches. Once I placed them in front of the perches, the vibration went away. I was like you, if I was at speed, whatever that may have been, I could place the tranny in neutral and cost and the vibration was still there. Which side of the perch do you have your shims?