Drive Line Placement
 

So I asked and got some answers on another thread on here, but I thought I was hijacking too much, so better start my own thread.

So when I mounted my engine, I'm pretty sure I screwed up.

At that time, I had my 4x4 S10 rear-end. Since, I've switched to an 8.8 Explorer rear, with coil-overs.

I initially thought in this picture that the stock S10 driveline was in at an angle: Off of the passenger's side at the front, angling back and meeting the center of the vehicle at the transmission tail shaft.

Thus, I mounted my LS that way.

I now realize this is not the case, and I may have driveline vibration.

But, with the 8.8 Output shaft 2" toward the passenger's side, should the engine be mounted the same?...2 inches toward the passenger's side?

I likely need to straighten everything out. Which will include cutting and rewelding motor mounts, and probably modifying trans-crossmember.

Or, do you think a few degrees of angle in the engine won't be a big deal?

Re: Drive Line Placement
 

Side2side angle is no different than up and down angle...as long as your engine/trans centerline is perpendicular to the rear axle.offset is not a big deal as long as it's 90deg.....what is important is that the engine angle match the diff angle .but are opposite...meaning diff up 3deg...engine down 3deg...

Re: Drive Line Placement
 

Ditto what Greg said. As long as the Engine/Trans is perpendicular to the rearend, it doesn't matter. The pumpkin 2" off to the side is no different than lifting or lowering the truck 2". Picture a framing square, hold it on it's 90 degree axis, then rotate it. the angles don't change as it rotates. If your tailshaft angle and yoke on the rearend are the same pitch you're in business.

Re: Drive Line Placement
 

NO you DO NOT mount the engine and trans so that they line up in a straight line with the pinion of the rear axle. I don't know why people come up with the nonsense that the driveshaft has to run in a straight line from the trans center line to the rear axle but I see it too often.

Ford has run that setup since 1957 with the offset pinion and they don't have any more U joint wear issues than GM or any other manufacture.

What it is, is that some guys are so anal about everything having to line up in a straight line and that the driveshaft cannot angle off slightly because it ruins the picture they have in their mind of how it should be while not affecting the function in the least.

I have seen guys who are so worried about the angle of the driveshaft that they cut one side of the Ford Rear shorter to center the pinion rather than center the pumpkin between the frame rails and that looks terrible in my estimation.

Re: Drive Line Placement
 

I am with whitedog on this. as long as the engine is at 90 degrees to the rear axle then the pumpkin being offset won't matter. the pinion up angle is the same-but opposite, as the engine and trans angle, you should be good to go.

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posted this link before somewhere but don't remember which thread. if you have seen it disregard

https://www.youtube.com/watch?v=Idk3BVDVHq4

Re: Drive Line Placement
 

Re: Drive Line Placement
 

https://www.waterousco.com/media/wys...311-1-DSSP.pdf

scroll down to installation tecniques and compound angles for a situation like yours with an offset pumkin. it also refers to maximum and minimum u joint operating angles. basically it says a min of 1 deg and a max of 3 deg for a trouble free, normal ujoint lifespan.
some good general info for anybody doing a driveline

Re: Drive Line Placement
 

the last link takes you to a publication from Dana/Spicer who make ujoints and related parts. they should be relied on for the correct info I would think. it's 23 pages long but some would be unrelated due to large truck or heavy equipment use. the theories are the same though.

Re: Drive Line Placement
 

basically it doesn't matter to the driveline where or how it is situated in the vehicle, offset to one side of the vehicle or whatever, it is all a geometry thing in how it relates to itself as a unit.

Re: Drive Line Placement
 

no you wont. at most you will need to slot the trans mount in the crossmember slightly to get it back square, the motor mounts will take even more misalignment than what you have.

I see guys shortening one side of a ford 8.8 is because its too wide for their application and shortening the longer side only requires one new axle, not from paranoia.


and DSraven, you forgot this, 4 times haha

http://67-72chevytrucks.com/vboard/a...1&d=1543611410

Re: Drive Line Placement
 

Well, Mr.48, I definitely like what you're saying.

(all these other guys telling me what I don't want to hear...)

But I think there may be some confusion on the question. I'm aware up/down of engine angle doesn't matter, as long as it's (roughly) canceled at the rear-end.

I think this diagram may help. What do you guys think?

Re: Drive Line Placement
 

I understood what you were saying. what I and everyone else is saying is, make the engine point straight back in the frame. the axle points straight forward in the frame. no matter the offset, as long as the motor points straight back and the axle points straight forward, the angles at the front and rear will CANCEL. no matter if the pinion output is offset an inch, two inches, five inches. same with the engine, as long as the trans output is parallel to the pinion, even if the engine/trans is offset an inch, two inches, five inches, the working angles of the driveshaft will cancel.

so slot your trans mount hole, move the engine trans so its pointing straight back in the frame (at most an inch, which is why others are saying it wont matter, that 1-3 degree thing) and leave the critical pinion angle setting to the up-down/y axis. if you think about your green line as looking sideways, instead of top down, you will see what you need to do.

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Well regardless wether you want to hear it or not the engine/trans needs to be 90deg to the rear axle..offset is irrelevant...

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I know to this is exaggerated but this is what you have now ...just sideways...with the engine and trans at a angle to the rear axle
https://m.youtube.com/watch?v=Idk3BVDVHq4

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It may be tough to explain why you're in trouble without pictures.

The front driveshaft angle at the trans can be thought of as two angles. The angle between the chassis centerline and crankshaft centerline, plus the angle between chassis centerline and driveshaft.

Because the rear pinion is parallel to the chassis centerline the angle at the rear u-joint is only one angle, which is the angle between the driveshaft and the rear axle.

In order to make the two angle front joint cancel with the single angle rear joint, you need to move the entire engine and trans assembly so the driveshaft is at a greater angle with the rear pinion.

The picture shows what you would have to do in order to keep the engine and trans angled and still have a cancelling angle at the rear.

The better answer is to do what everyone is telling you: Match the engine and trans centerline to the chassis centerline. This turns the front joint angle into a single angle, the rear joint angle stays a single angle, and they cancel automagically.

And yes, what is shown in the video above is exactly what will happen if you do not make the side-to-side angles cancel.

Re: Drive Line Placement
 

the angle of your green line needs to be the same viewed from the top, front and rear. just like the up and down angle would need to be the same, viewed from the side, front and rear. it's a different way of saying the same thing. ujoints don't care how they are situated in a frame or drive system, they just need to be paired with another ujoint with equal but opposite angle.front and rear angles need to match in order for the ujoints to cancel each others speed variations as they rotate. that is one reason why a lifted 4x4 will have more chance of having a driveline vibration if it has a 2 piece driveshaft. because the middle ujoint doesn't have a partner to be equal but opposite to. in the one link it will talk about this scenario and how it can be partially rectified by taking the one driveshaft out of phase (rotating the slip yoke).
if that doesn't confuse the crap outta you then you are just looking at the pics and not reading the dialogue, haha.

end of the day, use an angle finder to match the front ujoint with the rear ujoint from the side and top planes. equal but opposite angles. slot the mounts or whatever it takes

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you can use a plumb bob and mark the floor under the center of your crank pulley, trans output, pinion input and each axle. then connect the dots and use a protractor on the lines to get the angles for the top view. an angle finder on the trans output and pinion will give you the angles from the side view.
equal but opposite angles are what you want. eg 3 deg down on engine and 3 deg up on pinion will cancel and be vibration free (not factoring in spring flex under load changing the pinion angle with leaf spring suspension or having a recommended 1 deg variation in angles to counteract brinelling of the needle bearings on the joint's cross trunions etc).

Brinelling is when needle marks appear on the surface of the U-joint cross trunion

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you can also simply do the plumb bob marking routine on the floor, then, if you don't have a large protractor to accurately check the angles, match one of the angles onto a piece of cardboard as a pattern, then use the pattern to check the angle on the other end of the driveshaft. keep moving the trans over until the angles match. bolt it up at that point and then recheck to ensure they still match.

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joedoh, your pics didn't show up in post 11. maybe for my benefit, haha.

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Lateral alignment is no different than vertical alignment, but the engine and driveshaft angles must be the same on both planes.

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sure it did! its a picture of the edit button, confirming that you just dont see it haha :lol::lol::lol::lol:

just giving you grief, no one is counting posts.

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The center line of the trans out put shaft, usually down a 2-3 degrees and centered in the frame and the pinion shaft in the rear end must be very close to parallel, offset up or down left or right makes no difference until you exceed the maximum angle of the ujoint involved. A mistake made many times is the trans out put shaft is pointed down 2-3 degrees then the rear pinion shaft is pointed straight at the rear of the trans, this is wrong, it makes the front ujoint run at an angle and the rear ujoint run straight. If the difference is small maybe a degree or 2 it will run pretty good with no noticable vibration, if it gets out very much 4-5 degrees you will feel vibration, the further out the worse it gets. Have stretched many class 8 trucks and they dont vibrate and the joints last like they should. Just my 2cents on the subject.

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I agree with the first answer and I did not read much more.
But pinion angle with 500 horse power
with leaf springs
or with 4 bar
or with Ladder bars
or with 4 LINK are all different AT RIDE HEIGHT.
My drag car was Ladder bars and the pinion angle at the rear yoke was 2/3 degrees. @5000.00 RPM launch it was basically 0

https://www.hotrod.com/articles/91758/

Re: Drive Line Placement
 

YUPPERS plus the 1 to 3 degrees is highly desirable to stay within.

I understand the shortening one tube to use the opposite side short axle. that has been done for as long as I can remember. I can't remember the application or the axle used but it was a real common thing in the late 70's when guys started wanting the rear tires inside the fenders on full fendered street rods.

The driveline angle with the offset pinion is something that tends to freak guys out be it Chevy trucks or hot rods or street rods. Some guys have a real hard time dealing with that shaft not being perfectly straight and centered all the way back from the extension housing to the pinion. It's all about appearance and not function.