Pinion Angle

[joe c]

Unfortunately there was two Joe’s with the same vibration, it can be confusing with the same name…Joe with the 63 had mods, trans and driveshaft etc.

I have a 65 with a 425 engine and no modifications. I’ve been through almost everything possible to figure out this vibration and now it’s comes down to balancing the engine. I’ve checked out the flywheel for correct alignment and it was in place with the 7th hole lined up with the crank. I just think it needed to be balanced… hopefully that’s all it is… 

Thanks Joe

[1965rivgs]

3 hours ago, joe c said:

Hey Guys, I'll touch on this topic again for an update on my vibration. I've decided to take the engine out for a balance and refresh, as some of you may have known from my aluminum rad posting...
The engine was completely rebuilt in 1986 but wasn't balanced. I probably have about 80,000 kms or about 50,000 miles, not much more kms if any... 

 

Anyway, with the engine apart and at the machine shop, the balancer, crank and flywheel on the balance machine is out 66 grams at the front and 117 grams at the rear. Hopefully this is my answer I've been looking for to solve this annoying vibration.

The transmission is going to the shop who rebuilt it in 2016 just for a once over too.

 

Before I took the engine out I removed the back half of the drive shaft to eliminate the rear end and ran the engine through the remaining drive train. Yes I still had the vibration. 

 

I'll keep this updated as I find out more info.

 

Thanks Joe

Joe, reference my reply to your first post on page 2 of this thread.....vibration diagnosis always starts with the vehicle standing still, engine operating through the RPM range, to take the driveline and other rotating assemblies out of the troubleshooting tree.

Tom Mooney

 

[joe c]

Tom, I had a few engine guys/ old school mechanics rev up the engine through different rpm’s with the car standing still and they all feel a vibration at different rpm’s but not consistently through all rpm’s. I changed my tranny mount and even had the car up to Toronto to a classic car transmission shop who balanced the torque converter and installed a new rear output shaft bearing. No change in the vibration or at least not better so I figured this is the next step pulling the engine to see what’s going on in there. 
 

thanks Joe 

[XframeFX]

On 3/8/2022 at 12:21 PM, joe c said:

Before I took the engine out I removed the back half of the drive shaft to eliminate the rear end and ran the engine through the remaining drive train. Yes I still had the vibration.

Transmission in Drive?😌

[joe c]

Hey Guys,

My engine is back in the car and running smooth at idle and down the highway...It's been a very long and frustrating ordeal and I'm glad it's over with.

My vibration problem was an out of balance engine 183 grams total. 

This engine was rebuilt in the mid 80's and was not balanced back then and it has been like that ever since...

 

 

Thanks, Joe

 

[Bloo]

Thanks for the update!

 

[XframeFX]

8 hours ago, joe c said:

My vibration problem was an out of balance engine 183 grams total.

Joe, details on what method was used to achieve your balance? An engine strip, crankshaft only, reciprocating masses only?

Just in case others have to go through the same ordeal.

Congrats!

[RockinRiviDad]

Nailheads require entire lower assembly to be balanced together (crank, pistons, connecting rods, end caps, bearings, H balancer & flex plate).

[EmTee]

18 hours ago, joe c said:

My vibration problem was an out of balance engine 183 grams total.

4/10 of a pound!  That should make a difference...

[joe c]

Guys,

Like David said the Nailhead engine requires the lower end to be balanced together and that's what I had done, which if that's all I did would have taken care of my vibration but

while the engine was torn down a complete rebuild took place. The crank was drilled and plugged with weights to balance everything evenly.

 

No more engine vibration feels like a new car for me!

 

Thanks, Joe

 

[joe c]

Here's a picture of what the engine compartment looks like now with the rebuild and a little work to the underside of the hood and inner fenders.

The rad fits better after some light modifications no interference from the rad cap to the hood. New front end components and rear control arm bushings and shock all around, new steering box and steering column bearing.

I'm done for this year... 

 

Joe

[EmTee]

Now the fun part - see how quickly you can get those new engine parts broken-in! 

[XframeFX]

On 6/23/2022 at 11:16 PM, RockinRiviDad said:

Nailheads require entire lower assembly to be balanced together (crank, pistons, connecting rods, end caps, bearings, H balancer & flex plate).

So a 2-prong balancing procedure. 1) The usual reciprocating masses and, 2) The rotating assembly with H-Balancer, Flexplate and Bobweights on the crankshaft.

So, where was the 183 grams out-of-balance found?

My Russ Martin flexplate for my 1963 crankshaft has a crude rectangular piece of sheet metal tack welded to it. Should all work. But, can't help to wonder how many grams that external mass is? A nailhead secret?

 

 

 

 

Edited June 28, 2022 by XframeFX (see edit history)

[RockinRiviDad]

Good Q. I don’t know the specifics on Joe’s 183 grams. Nor am I qualified in this area. I did mentioned to him that 183 grams sounded like a lot. But that was only comparing his outcome to the measly 10 (ten) grams my 401 was off by. 
 

I can tell u that at 10 grams I felt the vibration & hated it. Give me a couple more weeks & I’ll be posted my rebuild process 

[joe c]

After set up of all the rotating assembly and figuring where the out of balance was, turns out it was 66 grams on the front of the crankshaft and 117 grams at the rear of the crankshaft was needed, so they drilled in these predetermined locations, and welded in plug weights.

David if you were only out 10 grams and could feel it... mine at 183 grams wow!

Don't forget my engine was rebuild in the mid 80's and was not balanced then so this issue has been since then.

 

Joe

 

[joe c]

I was reading through some of these old posts on vibrations and came across something interesting that I'm curious about and maybe someone can answer.

There are shims between the hanger bearing and the frame...what thickness are these shims? mine have been gone forever, I don't remember ever having these shims. Just wondering how much of a difference these shims would make on the driveline?

I don't remember seeing any reference to these in the shop manual.

 

 

Thanks Joe

[fxrspjc]

What a great question.  I don't have any in mine either and it would be interesting to know what exactly they do.  Look forward to an educated answer from one of the guys that actually understand what their speaking about.  Thank God we have a few.

Best... 

Edited July 6, 2022 by fxrspjc (see edit history)

[joe c]

well... from what I've read and understand these shims would change the driveline angle and prevent vibration or at least keep the driveline true and help reduce vibration?

I'm going to check my driveline angles on the weekend when I can use my buddies hoist just for curiosity. should be 1 to 3 degrees.

My car runs good but I always wonder could it be better? 

[XframeFX]

5 hours ago, joe c said:

Just wondering how much of a difference these shims would make on the driveline?

Ray Morrison provided a link to a PDF explaining driveline angles here:

 

 

[joe c]

Hey Ray...this is what is was reading up on, which got me thinking of these shims. I was skipping through this post quickly for something to pop out at me, I'll go through it again a little slower.

Thanks, Joe

[BulldogDriver]

The shims are 1/16” or something close to that.
 

I did a lot of research on this.

 

Back in the day Buick had a kit to check the alignment of the drive shaft. I believe Tom T. has one or maybe Jim Cannon I can’t remember who had posted they had one. Anyway with the technology we have today, and the fact that an Alignment kit is not in everyone’s tool kit, the pdf that I linked to gives the theory and shows what you need to do for a proper alignment. Same theory back than so the only thing that’s different is how to check for alignment.

 

The digital gauge is very accurate and you have to be precise on making sure of the pinion flange being vertical and the car needs to be as it would be if ready to drive on the road. I used 4 tire ramps that were the same height.  Don’t forget to zero the gauge before taking your readings. I used the frame were the center carrier bearing is positioned. 

 

If someone is going to do this could they take readings before they change anything. As I did a transmission swap to a 4L60E, my readings wouldn’t be much good for a Dynaflow of ST300/400. 
 

Ray

[joe c]

I’ve been recently reading up on this because of all the frustration I’ve been through with my vibration. I’d like to keep current with anyone else whose going through the same process. Also I am not to pleased on the way the last shop balanced the driveshaft, so I’m curious if some new info is available. I’m considering trying the shim size you mention or maybe a different shop for a high speed balance. My car runs good but I think it could be a little better at 50 mph. All in all after the engine rebuild its 100% better than before maybe I should leave it alone. Humm
Thanks for the information  

joe c

[fxrspjc]

Just out of curiosity would anyone know if these shims would affect a vibration during Acceleration, Deacceleration or at

High speed say over 70mph?

[joe c]

My car runs smooth from 0-50mph and a little vibration at 50-60mph you can feel in the back of your seat then gone again. Nothing on deceleration unless your in this speed range. That's why I'd like to try the shims or maybe a high speed drive shaft balance from a reputable shop.

I can certainly live with that if nothing changes after this experiment.

 

Joe

[fxrspjc]

I have a slight vibration over 70mph.  I had so many problems with vibrations since I went to the 700R I'm afraid to touch anything at this point.  What I must say is that Ed and Tom were exactly right from the very beginning.  It all had to do with the phasing.  None of the drive shaft companies would believe me so I've been thrown out of every drive shaft shop in South West FL.  I really don't have anywhere else to go at this point, but like I said it so much better then it ever was I'm just trying to live with it.  Also I have been diagnosed with lung cancer so I really don't have the time or strength to deal with it right now.  Its just too much trying to put it up on stands and pull the shaft in and out.  I must have done that 50 times in the past.  Maybe some day if I can beat this I would like to pull the rear half of the shaft just to see if I could still feel it if I run it up over 70mph.  You know to determine if its the front shaft or the rear that's causing it.  Most of my driving back and forth to shows is on Rt 75 so if your not doing 70 to 80 you had better stay off the highway.  Also with the 373 Posi and the 700r4 if you not doing at least 70 your not turning at least 2K.

 

Best....

Edited July 7, 2022 by fxrspjc (see edit history)

[XframeFX]

1 hour ago, fxrspjc said:

if your not doing 70 to 80 you had better stay off the highway.

This indicates a resonant condition. So, a rotating mass that is not just the drive shaft. Two posts here concluded engine imbalance as the cause.

 

I'm sure your troubleshooting has included some of my suggestions. I am not an expert but it's good the have a round table of ideas.

The speed ranges you mentioned, the same in direct drive and OD? At the speed with most vibs, still there when coasting in neutral?

Aside from driveline angles (Ray M. mentioned to measure before a trans swap), the alignment of your TH700-R4 to the flange on the block and to the crankshaft pilot hole is important considering an adapter and custom trans mount is used.

 

I would find a competent shop in another area and bring your Riv there. There are resources out there. That is the case with chrome plating bumpers. Have to send away, the few local shops that remain do not want the job and they are not reputable anyways.

 

[BulldogDriver]

Try to find a service group that does commercial/industrial vehicles. Make sure they understand the driveshaft is for a special application and let them know the proper phasing. They know how to balance properly in my experience. 
 

Ray

[Zimm63]

I have the special tool for measuring and recently checked mine, as I still have a vibration at about 55 mph.  

 

Both the trans yoke and center bearing measurements were high by 3/16, while the pinion was dead on.  I took out 1/8 shims from under the trans mount and the center bearing.  It seems improved, but that may be a placebo effect.  I have not remeasured as of yet.  

 

Mine is a 63 with a dynaflow.  The vibration is more noticeable when the car is still a bit cold, and seems to improve when its fully warmed up.  I need to go through all the engine diagnostics to be sure its on spec.  Lots of little things can cause what I think I feel.  

 

If I circle back to the drive shaft, I am still thinking about building a frankenshaft using a 63 front and 65 back.  I have the necessary parts here.    There was a reason Buick changed the design early in the 64 run.  

 

 

 

 

[Bloo]

What you guys need is an real drivetrain engineer. As I recall there is one who is retired from GM who posts on 67-72chevrolettrucks.com. I believe he was from the truck division. Has anyone tried to sweet talk him into coming over here?

 

I haven't commented much because I don't know how to solve the problem. I do understand what the problem is though, and getting the pinion angle and phasing "correct" is only going to work if the car has the original transmission, or one exactly the same length. To get a grasp on this, lets forget Rivieras for just a moment and talk about regular cars.

 

A universal joint is not "constant velocity". In auto repair, a "constant velocity" joint usually means one with a bunch of balls in tracks, but that is not whats important. A cross-type universal joint is only "constant velocity" when it is running perfectly straight. If it is not running perfectly straight, and the input is running at a constant speed, the output is speeding up and slowing down as it turns. The more angle it runs at, the more wild the speed variations get.

 

If you only have one u joint, it must run perfectly straight or this speeding up and slowing down will manifest as a vibration. The trouble is that the sort of u-joints we commonly use are full of needle bearings, and they have to run with some angle or the needles will pound dents in their journals and destroy the joint quickly. The way around that is to run "plain bearings", also known as bushings. The catch is if you do, grease wont really hold up as lubricant. You have to run the joint in an oil bath. Buick has plenty of experience with this. They ran a single joint with plain bearings inside their torque tube for decades.

 

If you don't have a torque tube though, you have to run the joint at an angle and that makes vibration. The way to solve it is with a second u-joint. The second joint does exactly the opposite of that the first one does, and that eliminates the vibration. In order for that to happen the angles the two joints have to be exactly the same. The joints have to be phased perfectly (perfectly lined up in rotation) or the vibration will not cancel. This is what pinion angle adjustment is about in normal cars, getting the two joint angles exactly the same. Well... usually. There were cases in the musclecar era where more angle at the rear was specified. It was a compromise that sacrificed a little smoothness cruising in order that the cancellation would be perfect when the suspension was wound up hard under full acceleration. I'm not sure that was a great idea but it has been done. No matter. For perfect cancellation of the speed variations and thus the vibration, the angles must be perfectly equal.

 

Some trucks have 3 u-joints, and now we are officially beyond my pay grade. Somehow the speed variations of two of them must add, and cancel the the speed variations of the third. I don't even know how to begin to calculate this. Hang on, it gets worse.

 

That brings us back to the original RIviera. Apparently the 3-joint driveline was used to get the floor lower, or so I have been told. The joint angles are such that the speed variations do not cancel. Apparently some engineer figured out a way to introduce more speed variation to cancel whatever was speed variation was remaining by mis-phasing the driveline. Now we are way beyond my pay grade. There must be some particular angle that works. The splines would have to be arranged in such a way that a spline position exists that results in the correct angle.

 

The next version of the Riviera (1965?) has double-cardan joints for a couple of the joints. A double-cardan joint is a constant velocity joint. That removes them from any calcualtions, and we are back to one joint running at an angle that needs it's speed variations cancelled. If you run the single u-joint perfectly straight it will eat itself, so it must run at an angle. There is no second joint to do the speed variation cancelling. Pinion angle won't really help either because there is a constant velocity joint back there, and any factory specified angle probably has more to do with keeping that joint happy than vibration. Apparently Buick continued using creative mis-phasing to cancel that vibration. Not surprisingly, the mis-phasing angle is different than earlier cars.

 

If you change the length of the transmission, you change the angle of the front u joint. The amount of speed variation that needs cancelling will also change. If mis-phasing is what will cancel the speed variations, then the necessary angle of mis-phasing will also change. If you could calculate it, you might not even be able to get there with a stock driveline. No doubt Buick got that angle right for the number of degrees of mis-phase they were using. If you divide 360 by the number of splines in in the splined plunge joint, you will get the number of degrees change per spline. The probability of one of the splines landing on your newly calculated number of degrees is low. In that case the driveline would have to be cut apart and re-welded to your new specification.

 

I said it before and I'll say it again. You guys need an engineer.

 

[joe c]

That’s good reading, I’ll have to read it a few times to sink in. Speaking for my car it’s all original driveline with my engine just rebuilt and balanced and runs very smooth, just a little vibration around 50-60 mph. My driveshaft was rebuilt a couple years ago and phased at 67-1/2 degrees, I still have the pin on the splined shaft.  I’m not happy the way it was balanced…using vice grips to clamp the hanger?  then weights welded to the yoke… I don’t like that so I’ve contacted a driveline shop who will balance up to 2000 rpm and can balance two piece driveshafts. Next week I’ll be getting this done. 

joe c

[fxrspjc]

Joe Let us know how you make out.  Bloo I read your writing 3 times now.  I have a headache. But it sure was interesting.

[joe c]

hahaha... interesting is right! I need to read it a few times more.

I will definitely be back with results... 

 

Thanks, joe c

[drhach]

I'm working on a similar issue (not a Riviera). The discussion here has been very educational and helpful. I found this video on youtube that illustrates the issue and effects of pinion angle and phasing. Hopefully it embeds well. It doesn't go in to the math or the uniquenss of the Riviera phase question. But the effects are very clear. I had kind of a "Eureka!" moment after I watched it. 

 

 

 

Edited July 8, 2022 by drhach (see edit history)

[BulldogDriver]

This publication has all of the information on driveshaft design and reasons for setting the angles. Somewhere on the net I read what a vibration on acceleration and deceleration meant and how to adjust the angles to correct for the vibration. I’m on the road the next couple weeks and will try to post those posts but may not be till I return home.

 

https://www.waterousco.com/media/wysiwyg/pdfs/content/J3311-1-DSSP.pdf

 

If I remember correctly Buick was using CV joints in other models in 1963 and moved over to them in 64 Rivieras. I would think the shorter front driveshaft for ST 400 transmissions would be the deciding factor in this. 
 

I have a 64 shaft in case vibration was a problem on my application with a 4L60E transmission but has not been a problem as of yet. All of my u joints and bearings are new and the best quality available to us. I would think that making sure these parts are at the best condition possible is the most important thing to get the issuer resolved. Going to a repair shop that works on commercial and industrial vehicles is the answer to getting a driveshaft balanced properly today. Phasing is a key component also. 63 shafts are phased at 101* if I remember correctly.
 

If you make a hybrid shaft, I am not sure how you go about coming up with the correct phasing for application. Maybe the GM engineer mentioned earlier could shine some light on the subject and I would like to here what they have to say. 
 

Also I don’t remember if I mentioned that the 63 center carrier bearing housing on my installation had to cut down to the height that 64/65 carrier bearing is. That can be done without hurting the rubber on the housing if your careful when welding the base back on. 
 

Ray

[XframeFX]

2 hours ago, BulldogDriver said:

I would think the shorter front driveshaft for ST 400 transmissions would be the deciding factor in this.

Yes, my thoughts exactly why the switch in 1964 Rivs.

[telriv]

There were too many complaints about driveshaft vibration in '63 one of the reasons Buick decided to go with 2 CV Joints. Takes some of the problems out of the equations. 

 

Tom T. 

[joe c]

Thanks everyone for your input I’m going to check out the video in the earlier post, see if I can learn more about this issue. 

[joe c]

Guys,

this past weekend I swapped out my original driveshaft for one I bought a few years ago. I couldn't feel any play in this driveshaft and all the fittings took grease nicely, so it's worth a try to see what happens, and after the swap I took the car for a ride and the slight vibration I was getting between 45-65mph with my original dshaft was gone. If I had to say there was kind of a consistent feel throughout from 0-75mph, not a vibration but I think there's room for improvement with the second dshaft. I looked at my angles prior to removing my original dshft with a magnetic angle finder and seemed to be 1-2 degrees in either direction. Being an original car and drivetrain I wouldn't think this would be an issue.

I'm going to take my original dshaft to a shop for a once over and a high speed balance...I'll probably swap them out again...

 

Thanks, Joe

[XframeFX]

On 7/18/2022 at 2:41 PM, joe c said:

I'm going to take my original dshaft to a shop for a once over and a high speed balance...I'll probably swap them out again...

Gee, can you 'give me' your spare d-shaft after you have it swapped back? . . . . . LOL

[joe c]

Maybe…