Featured Customs Do I offset the engine?

Building another frame, with a small block ford motor and an AOD trans for my 56 F100. The rear end I am using is offset 3” towards the right . A friend of mine said that I should also offset the motor that 3” to the right. Obviously the rear end at the U joint is lower than what the trans will be ….so he said you don’t want the driveshaft to both pitch down and because of the 3” side offset , also pitch to the right those 3”. I have not yet welded in any motor mounts yet and curious if I should do this?

 

Center the engine and you will be fine. The offset just makes the U joints work and not develop flat spots on the rollers.

 

Not a problem. I've done several swaps with offset pinions and never moved anything. Important thing is to make sure the pinion angle is correct for the engine angle.

 

Find another friend to get advice from

 

For the Win $)

 

Probably as many ideas here as can be posted, but I bought a truck where there was that kind of off set and the first highway drive resulted in the rear seal in the trans giving out and the resulting trans fluid spill had major smoke from the heat. Granted, the truck was low geared with considerable driveshaft speed. With no way to move the engine over I elected to use a double carden front joint from a ‘60s Lincoln suggested by the driveline shop, which worked out well.

Universals only like to accommodate one direction without problems. Adding another direction (sideways) only adds problems. I prefer to center the pinion to the output shaft by either offsetting the engine or modifying the rear axle.

 

Or just move him 3" away from the garage door... and then close it. Hahaha.

 

Good article

here:
https://www.hotrod.com/news/driveshaft-angles-angle

 

You should fill the engine bay….. 5.0 Coyote, early Cammer Ford, Chrysler hemi….

 

Millions....... no, wait......... probably BILLIONS of cars running around out there disagree with this statement.

 

As long as the engine is square in the ch***is and the rear end is also square, the angle at the rear end due to the offset pinion will be exactly the same as the angle at the back of the transmission. Since they are the same, they will cancel and not cause any vibration. Most rear wheel drive vehicle have the pinion off the center line of the vehicle. It does not cause any problem.

 

when I built my f1 pick up I used a 64 f100 9 inch which had 2 axles the same length setting it to the right. I set the engine to the right it made sense to clear the steering. When building the wife's 64 f100 I used a front frame section that had the motor centered with the same type 9 inch rear. from what I have read both work but you do not want to put the motor in at an angle to point it at the rear

 

Rotating 3D imaging will show only one angle, not two.

 

Where were the original engine and transmission positioned. ????
I'd ***ume that Ford had a good understanding of driveshaft geometry.
All earlier F100 - 9" rear ends had offset pinions because they used equal length axles on both sides. That positioned the pinion ~2" off center.

 

I put a zillion miles on drive shafts with more than one angle

 

@anthony myrick A ZILLION?

 

Lots of rods built with the center section “centered” for a uniform visual look.

Dang crooked drive shafts

 

There are millions of fords, car and trucks, that have been driven, used, abused, raced etc with offset pinions (9" uhm...) with no problems what so ever.

U-joints don't see up, down, right, left, level plane, 90° degree plane etc. They only see 1 angle, doesn't matter where the housing sets, its still 1 plane to the u-joint....

To you the housing nose may be 5° down, and offset 1" inch to the right, you see 2 planes, up/down-left/right but the u-joint doesn't. All it sees is 1 and that where the u-joint connects to the housing...


....

 

How to offset the engine?
Try installing it centered, it will be off one way or the other.

 

Universal joints only ever have one angle applied to them at any given time. The pinion might be horizontally offset and vertically offset from the transmission output shaft, but in reality it is only ever a single constantly varying angle that the joint operates at. It is called a "compound angle", and as long as it is within the maximum recommended operating parameters, all will be ok.......

 

You need to think 2 dimensionally.
The universals in what you describe are only accommodating one direction.

If it was pointing down [eg: 3" ] AND pointing sideways [eg: 3"] It is technically only one angle at 45° from vertical
[4.24" at 45°]

I've done more than that! I've done a "****load" of miles

 

A lot of Chrysler Corp. cars had their motors offset in the sixties and later.

 

C3 Corvettes as well
When they did RHD conversions on these, the firewall and tunnel was cut and shifted with the whole drivetrain to the left.

@ahshoe I have just done a swap of a Ford Explorer 8.8 rear end into a 55 Chevy
The 8.8 has the pinion offset 3.75" to the RH side [p***enger side] and there is Zero driveshaft issues.

 

You could move the frame over 3". Or better yet, move the frame 1 1/2" and the engine 1 1/2".

 

Just tilt your head 45 degrees to the side and you'll see the same thing the ujoint sees. Since it rotates, there is only one angle and it's measured in "X" degrees from straight.

Another way to visualize is to get 2 laser pointers, put one on the trans yoke and one on the pinion yoke, blow some baby powder or smoke in between to show the lines and observe the physical distance between the beams. That distance is where the angle comes from, not which line is left/right/higher/lower.

-rick

 

The offset will cause the ride to track crooked if you don’t change the thrust angle of the rear to compensate the offset.

dog leg like an old ford truck with frame damage.


(Sarcasm. This is BS)

 

Pinion offset, isn't the actual measure considered as ½ for offset purposes? I bought a lot of axles and narrowed a **** ton (a bit less than a **** load) of housings, and a distant echo is telling me this truck offset is actually referred to a 1½". Feel free to correct my recollection. GMs were ½, Mopars were ¾, Fords were either/or, some ½ and some ¾. Be gentle with me, that was more than 30yrs ago

 

As a mechanical engineer retired from the auto industry I just love these posts. If you're going to be wrong, be aggressively wrong. Kudos to people that can view things in 3D.

 

Is it this one? If it is, it has nothing to do with engine/pinion offset.