Your post brings back memories when I worked as licensed technician in a Chrysler Dodge dealership. I did transmission and drive line. The factory driveline angle meter we used had a magnet on one end which stuck to the u-joint cup (still available from Comp Cams). 4 X 4's are very susceptible to driveline vibrations from many sources. I understand engineers are not perfect but wow!! I found them great to work with on problem child vehicles. The first thing that having different angles at either end of a drive shaft is trouble. ie 2 degrees at either end of the shaft not...... 2 degrees and 3 degrees at the other. This is not always possible but differences must be small. The driveshaft must be straight, concentric on the yokes and shafts, balanced and in phase.........you can balance an egg shape with enough mallory metal , but it will still turn like an egg. Today, technicians in dealerships have access to electronic vibration analysis equipment that a skilled tech can isolate vibrations by rotating speeds what area is causing problems. You still need to make sure physically components run true. In the world of mix and match with hotrods, basic engineering principles and rules of thumb still apply. A driveshaft doesn't care what it is connected too. Some of the older shop manual specs (60's) are great for hotrods and how to measure them.
Here is something that I found interesting. Friend has a 1967 Camaro. Takes the driveshaft to a shop and they end up deciding to make up a new one (larger tube/stronger joints etc ... he wanted a stronger driveshaft in case he decides to add slicks and take her down the track). The drivshaft from the Camaro is laying on the floor of the shop, a retired driveshaft shop owner enters the shop (he does not own this shop, he is there simply because he is training the owner of this shop as he is just getting into the driveshaft end of things, having focused on transmissions previously) glances down at the driveshaft on the floor and states "that is a genuine factory issue early Camaro driveshaft" ... he is correct but how could he tell? The U-joints were ... NOT in phase. Instead of the ends lining up, one was about 45 degree "out" from the other. I saw this driveshaft for myself (actually made a trip to the shop just so I could see it for myself). The retired shop owner had himself owned a 1969 Camaro drag car so not only was he familiar with driveshafts, he was also familiar with early Camaros too. With all the talk of "phasing" driveshafts I was pretty amazed to see a factory GM driveshaft that was clearly not in phase. I have no idea why GM did it that way? I know this doesn't exactly pertain to the original post regarding pinion angle ... but thought I would mention this due to someone mentioning the possibility of driveshaft phase being an issue. I am in agreement with some of the others that have posted here ... level the carb pad, this will make the trans output shaft point down ... if your measurement is 3 degrees down, then locate the rear so the pinion is pointing 3 degrees UP. I am also in agreement that it is not a bad thing to locate the pinion up to 2 degrees down FROM the 3 degrees up to account for suspension "wrap-up" when under load (think leaf springs).
I am talking street cars here, track and race cars are a different breed. Using a degree finder set crank shaft parallel to the pinion shaft. Than push the pinion down 1-2 degrees on 4-bar, or 2-3 degrees on leaf. I have never had any vibration using this method, in fact I cured the vibration at 60-65 on my 54 ford, we had changed the tire size. We have leaves so went to a frame shop and got some of those degreed shims. My 33 chevy has four bar no problems.
at ride under load. thats why you set the pinion down a bit, so under load it will pull up to parallel.
I agree with Kultulz, and post #8 (link) Carb base and crank centerline are not parallel either, so you can't just go off of the carb base.
Correct, If your setup is as per this pic and your UJ's are in phase it will work fine. 2-3 degrees down on diff is for race.
OK... How would one determine the amount of distance the pinion will (or needs to) raise and what torque conditions would you set it? The crank CL and Pinion shaft angles are set at a pre-determined setting as the pinion angle is going to vary under different fuel/braking loadings. WRONG- The crank CL is predetermined as to how the engine will sit in the cradle. The pinion angle must than be set off the resultant crank CL.
Correct... Not arguing here, but if one is setting down a carb engine in a chassis (OEM has already allowed for this), the manifold carb plenum must be @ or damn near horizontal for the carb to keep somewhat it's calibration. One then nails the eng/trans down and goes for the pinion angle.
Allow me to take it one step further. 1968 TBIRD 429. The engine /trans had to be set at an acute angle in the cradle for clearance (from FORD-MERC-LINC) and it threw the carb pad level off. Instead of casting a special intake for the BIRD/MARK, FORD used a wedged carb spacer to maintain carb calibration. While a carb must sit perfectly level for factory calibration, we all know the engine does not sit level at all times because of road conditions. In the same vein, pinion angle is not constant and is set for all variables. There are just too many variables to say just one way/setting is correct.
for what it's worth; the STOCK pinion angles on my 62, 3/4ton truck are approx 3 or 4º down at the trans and UP the same degree at the differential. after all of the brouhaha i finally putzed it to mark artis with texas outsiders and he crawled under the truck and immediately said: "your driveline angles are fine." ( THANKS AGAIN MARK! ) which is what i thought. just make certain that your vibes are caused by driveline angle issues. as previously stated, mine were NOT. it was the driveshaft! this thread reminds me of another. hey borntolose? refresh my memory, please.
And that is what most have been trying to get across. Both angles have to be the same. Exactly what are your settings? Is it three or four degrees? I didn't know FORD gave that much variance on specs. Did he take an angle finder with him or did he just eyeball it?
it's a 62, chevy, 3/4..... getting EXACT angles laying on the ground under your vehicle is almost impossible. i just measured both the best i could and they were equal and opposite. it has more angle (I THINK)because it's a tall truck. he just eyeballed it and he was right....
using the angle finder at the transmission output shaft and the the pinion yoke is the way i was shown years ago by a guy that built drivelines and his reasoning was the only thing between those 2 points is the driveline and when issues occur it point 99% of the time right at the culprit that being the driveline. i can say i have used carb base,pan rail before to get angle and has worked great.
The longer the shaft, the more difference you can get away with. Short wheelbase vehicles will be more sensitive to angle changes. Many 4wd trucks used a constant velocity joint on the front shaft because of the short length. Now that they use a solid mount differential with independent suspension, drive line angles don't change.
have drive shaft checked.is 60 where you are cruising with neither a positive or negative load on the drive line.does problem go away if you start accelerating or deccelarating.i had a new jeep do this in 1996 recalled it due to rearend internal problems.
My current '95 ZJ does the same thing. Howls between 55-65, and immediately disappears when the gas pedal is let off.
something that seems to have been lost in all this is U-joint operating angle. Yes, the crank centerline should be parallel to the pinion shaft centerline, but also, the operating angle; crank to shaft & shaft to pinion should be kept under 3* , matters not what the other angles are [within reason] , but operating angles should be kept in this range! dave
Do what you said here , then set your pinion parallel to the trans. tail shaft. If the body is off the frame estimate the weight that will be on the rear of the car and load the suspension before setting the pinion angle.
I have always leveled the carb weight on car.So i don,t know the angle of plane of engine,for the hills best be level.But say it was 4.5 degs.From ground to trans shaft is 13" and pinion is 10" and you have a 5' drive shaft.3 degs is about 3"that would be 3 degs a rearend and small movement at trans say 1.5 degs would be 3degs at both points.4x4 have a high angle but height of ground. Something like that.
Is the full weight of the vehicle on the suspension when you are setting these angles? Are you setting a trans angle or leveling the carb base and measuring your trans angle? Is your motor trans centre line parallel to the length of the frame? [sometimes motors get put in on an angle from side to side] If you shift into neutral at 65mph does the wur go away? Does it do it if you let off the gas?
What ever amount you raise the rear end up and put on jack stands raise the front of the car the same amount . It will now be at its ride height, at weight and just higher off the ground so you can get under it. You need a couple degrees at the pinion and the transmission weather they (output shaft and pinion) are parallel or intersect depends on the application as in post #18. In leaf spring cars the pinion will tend to wrap up under acceleration but regardless they (output shaft and pinion) need to be close to being in the same plane. I have a T-bucket the drive shaft is under 10" long, if I was to go from a quick change to a banjo rear end and keep my same pinion angle I would now have created a problem. If that didn't make sense get 3 kitchen knifes and make them your pinion, output shaft and drive shaft. And carbs work better when they are level but cars have been known to travel up and down different grades. All this has been said in different ways at different posts. Hi 2 old 2 fast Good Luck Joe
the definition of insanity,, doing the same thing over and over expecting a different response or reaction. 2-3 degrees down pinion angle has working everything I've tried it on. Lucky maybe,,,, but it would be insane for me to change tactics now based on an opinion of some random interweb Dude. sorry... as a side bar,, we should now and forever call this the Opinion angle, not pinion angle as it appears the opinion of how its done seems more important than the pinion angle itself.
Interesting quote... I have no idea what you are trying to convey but I suppose you have a reason. You mean like the one I am responding to now? I have no concern how you do it. I have even less concern that you continue going about it as you do. My only concern is that you are not a tech in a shop or build cars. The man asked a question and a field of opinions was given. I am sure that in all of those opinions one would be able to define the correct way to go about it. Have a nice day...
Wow Dude this was kinda tongue in cheek ho ho it is laugh stuff till you stuck your foot in your mouth. Not a tech in a shop or build cars,, thats pretty fucking funny fella. Been building cars as a pro for over 20 years, more than likely built more than you have, built them to go a lot faster than you, and not to kill you when things go astray. But what would I know....... I'm just another random interweb Dude.
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