Engine Offset, Any Side Effects/Problems?

I was having some clearance issues with my balancer and decided to build new taller engine mounts. I intended to offset it to the drivers side 3/8" because the fuel pump was closer to the frame than I liked. Somewhere between drilling and measuring I got a little lost and the offset ended up being closer to 3/4". Other than resetting the pinion angle because of the extra height, is there anything I need to change because of the offset?

My main concern is that the transmission was bolted to the crossmember the whole time. Do I have to redrill the trans mount holes offset to the right, or is it ok to just let the trans pivot on the bolts at a slight angle? I hope that made sense...

before...



after...

 

when I built my rod, I centered the motor and rear in the frame, that is when I found out that gm had everything 3/4 to the right in the first place(my donor was a 77 pont. wagon) If your motor lines up with the rear now , i would redrill the tranny crossmember and straighten everything out.
The stock car guys run w/ everything a little to the right all the time.

 

If I recall correctly, the drivetrain is not straight to avoid harmonics. Every GM that I can remember is like this. The engine is actually in the bay at a slight angle. BUT, I don't think I have ever heard of anyone having an issue with it being in line.

 

Well hows that for dumb luck? That makes me feel better. I am curious about one thing, the 3rd member isn't totally symetrical. The pinion is a little offset to the passenger side. So this means that the driveshaft isn't just angled vertically, but because the engine is offset to the drivers side it also has a little bit of angle on the horizontal plane.

Even if the engine was centered, because the pinion is offset it would still have some horizontal angle. But I wonder if there is a maximum allowable angle on that plane just as there is on the vertical one.

 

While I cannot give a definitve answer on the maximum allowable angle...I don't think it is going to be an issue if you are keeping it as straight as you can.

 

With Mopar's, engines are offset aswell, and quite visible to the eye, but the rearaxle pinion is offset aswell, so everything is straight again.

 

Early Camaro BBs were offset from center.

 

Try this: www.rustynutscarclub.com and then click on the tech section about Drive Line Alignment

 

This is what I was talking about with the horizontal plane angle. thanks for the link -

 

I don't know what the max angle offset recommendations are, but you should be just fine under 5 degrees.

I have 47,000 miles on my 32 roadster and it's doing ok with a 1" engine/trans offset to the right.

Engine offsets are commonly done by the factories.

The engine/trans should be square in the chassis.

 

Here's more info: http://www.drivetrain.com/driveline_angle_problem.html

 

My first intuition was not what the later sketch showed. See diagram on the right, below.

 

More Driveline Alignment info: ( Various opinions?)
http://jniolon.clubfte.com/drivelinephasing/drivelinephasing.html and
http://www.drivetrain.com/driveline_angle_problem.html And then there's this: www.chra.org.au/tips/driveshaft.htm

 

Methinks I've got some new trans mount holes to drill.

This is the wrong way to do it, and although not anywhere as extreme as this picture, diagram (A) is the way I did it.

 

Yes, the figure on the right would allow the "non" CV behavior of a u-joint, to be canceled out by pair's proper phasing and equal angles. Each rotation thru an angle supposedly has a speed-up, slow-down aspect due to the geometry of four poles w/the needle brns around them. The angles are small, but clearances and wear can set up some interesting vibration "nodes" at certain velocities.

 

I would say Pic B is the way to do it.
You set up your engine/trans parallel to the pinion when you determine
your engine height.
So i would do the same if i set it to the side.
The u-joint wouldn't notice it .....
my 2 ct.
Michael

 

Chryslers are offset to the pass side over an inch...but the whole driveline is all offset. I wouldnt want the trans tailshaft to be mounted crooked to the bellhousing area...Id say move your trans mount the same amount you did your engine....then check out your rear axle and driveshaft location

 

Great info, this really helped answer my questions about the engine offset with my current project (albeit a 93 Mustang). I knew the HAMB would have the answer!

 

KCK, It looks like you LOST fuel pump clearance...
Yes, you need to move the tail over..
And, last but not least=== the factory offsets the engine to the passenger side a small amount due to the fact that most of the time the vehicle only has the driver onboard.
Us oval track guys set the engine over to the driver side for better left weight %..
Dave

 

Engine and tras. need to be like in the "b" diagram, since it can't be centered. If at an angle like in "a" their will be a bind in the joint while revolving/ vibrations. Looks to me like you could have notched the crossmember a bit for the balancer and built the strength back in.