alexandervdr

I am correcting the drive line angles on my rebuild 64 engine/gearbox/shaft/diff assembly. I have read many threads and theories so I understand (I think....) what and how to do.
I was wondering: anyone knows what the original driveline angles were on a 64 with a SBC327 and a muncy M20? Were the gearbox and differential parallel?

66jack

Why are you changing them?
Was your car HIT?

alexandervdr

I have a new 350 crate engine, a new (former Keisller) RS400 5speed gearbox, a new rear end and new rubber bushings&supports all around. So I need to align anyway.
My tunnel was raised to have more gearbox clearance, glad I did that...At the time I did not think about eventual alignment problems, just wanted some more room for heat&noise isolation.

DansYellow66

The transmission output lines up with the differential pinion shaft - but are offset to the passenger side. Several theories as to why this was done and if it was coincidental or intentional. So the engine, transmission and differential input should all be in a common line.

So up and down is the only alignment and phasing that needs to be looked at.

alexandervdr

I read many theories indeed

what do you mean by 'phasing'?

DansYellow66

Basically if you have a +2 degree angle down from centerline of transmission to centerline of driveshaft - you should have a -2 degree angle up between centerline of driveshaft to centerline of differential input. In other words the transmission alignment in the vertical plane should be the same as the differential alignment. And the driveshaft is at a different angle to take up the difference. This is basically in-phase.

Don't recall the exact numbers but in general an angle at the U-joints of 1-1/2 to 3 degrees is about what you should be shooting for. That keeps the needle bearings in the u-joints rotating and prevents their galling and freezing up.

JohnZ

No, you don't - just bolt it together and don't worry about it. When the car was built all that stuff was new too, and it was just bolted together. Don't over-think it - just put it together.

alexandervdr

The gearbox is longer than the original Muncy, the drive shaft is shorter, hence the angles are completely different from original. Dry fitting everything gives 4° gearbox end and 0° at the pinion. I did some angle simulation on a cad program and there is no way I could get the gearbox/pinion parallel AND the shaft at 3° or less both ends (which is what the theory says..) . I can get both ends at less than 3 degrees (raising the gearbox end 1/2"), but then I need to violate the "parallel" rule.
If you say so, that's what I'll do

Mr D.

Dan, your just a wealth of information these days. So in the process of all my clutch work I notice the drive shaft at the trans was offset to the passenger side and went hmmmm.

I was waiting for my Corvette bud to get his 65 back so I could look at his.

DansYellow66

It sounds like your RS400 transmission output yoke sits higher than a Muncie transmission if I understand your readings. If you really have 4 deg and 0 deg readings I think you will pick up a vibration. You can probably influence the angle of the differential by shims at the front snubber bushing but it really sounds like the tail of the transmission needs to also come down. You may need to post a separate thread asking other Keisller owners if they had the same results, if they had any problems and if they came up with any solutions.

zim64

this should help explain the difference in ujoint angles and phasing.

https://search.yahoo.com/yhs/search?...&hsimp=yhs-002

alexandervdr

It sits lower (my quoted 4° are actually -4°)
If I raise the yoke end of the gearbox about 3/8" I get the angles OK, but the gearbox centreline is not parallel to the differential centreline. That's the compromise that hopefully will be fine

alexandervdr

great link, I found this video very inspiring https://www.youtube.com/watch?v=gmV4qwLfOMY

plaidside

I have a vibration on my 64 at approx. 60 MPH.
Can the drive shaft angles be checked with the body on the car?
Joe

DansYellow66

Ohh - I assumed wrong. I think you can work with that through shimming the transmission mount and the differential pinion snubber mount. I don't think you have to come up with perfect results - I would think as long as you can get under 1% difference between the + and - figures it will probably be fine. No way car manufactuers attempt to dial them in perfectly with all the different suspension options, weighty accessories, etc.

DansYellow66

Yes, with some difficulty. It helps to be on a lift - although with a fixed differential it doesn't have to be a drive on lift. You need one of those inexpensive angle finders from a hardware store. Basically on the transmission you need to rotate the transmission so that the output yokes are top and bottom and use the angle finder to checke the angle on the yoke. Because the castings are a little rough I set a socket on the snap ring or a smaller one just inside the snap ring and set the angle finder on it. Then put the angle finder on the driveshaft tube and the difference is the angle for the forward end.

The rear is more difficult and my memory fails me on just how I checked the differential angle. I rotated the rear differential to get the input yokes straight up and down but there isn't room for an angle finder. I think I used a socket and straightedge to project forward and used the angle finder on the straightedge. But - if I remember correctly, the bottom, forward rib on the differential case is square with the pinion shaft alignment and you can verify your results by simply checking it against the u-joint cap results. I think they will be the same. Then subtract from the driveshaft angle for the difference.

Hopefully someone can fill in some more details on checking the rear angle for you.

alexandervdr

It is, I checked it.

If you have a smartphone, there are free apps to measure angles. I used Clinometer. Works great!

DansYellow66

Scarry isn't it. Don't worry, I'll probably venture in over my head here shortly. Who said "a man has to know his limitations."? Eastwood? Something always good to remember. That and having JohnZ around for backup and auto-correction.

DansYellow66

Wow - you have a lot nicer angle finder than the cheap plastic Home Depot one I have.

plaidside

Thanks Dan,
I do have a drive on lift and just installed a 'new' rear in my 64. the front angle is not too bad to check but the rear one is a whole other ball game.
I will try your suggestion.
Joe