Engine and transfer case positioning?

Let me start out by saying I don't usually like to ask for help....

I think I need help. I am soooo close to getting over what I find to be the most difficult part of my project so far- finding the best positioning for the engine/trans/t case. I'm stalled out again. One second I think I have it perfect and completely square in the chassis. The next second I'm second-guessing myself and not sure which way to move it. I've got the engine mounts C-clamped to the frame and the engine is sitting on those. I have a floor jack holding the crossmember onto the frame.

With the body (including new mount bushings) I have at least a finger's width between the tub and all other parts. The fit is tightest between the floor and transfer case- that's where I've got a finger's worth of clearance (maybe 1/2"?). Anyway, can anyone tell me how square the engine and t case have to be?

I measured the amount of offset of the front and rear pinions; they are different by about an inch (rear is about 8" from PS frame rail, front is just over 7" from PS frame rail), and the t case outputs- they are somewhere about 6-1/2" from the PS frame rail. Is this way off? I don't think there is any way they can match exactly. Am I being overly critical or should I just burn the engine mounts to the frame and start bolting it together? I wanted this part of the project to be 100% correct but I'm now wondering if that is even possible...


Idears????

 

i struggled with the same questions you have a fews back when sizing up my buick 215. i spent the good part of 2 weekends getting everything as perfect as i could. i took just about every measurement you can imagine and i even used one of those craftsman laser levels to help size things up. (i really recommend getting one if you don't have it already). the only aspect of my final fitament that i'm not happy with is that the engine slopes from the front to the rear. in other words, the front of the engine sits slightly higher than the rear. this in turn slants back the trans and tcase. the slight angle puts less stress on the u joint of the rear driveshaft, and the longer length of the front driveshaft will compensate for the increased angle, plus the front driveshaft is used only at slow speeds, if it all.

i had no choice but to settle with this tradeoff, but i don't imagine the slight slope will cause me any problems.

and whats the shame in asking for help??? thats what the board is for.

 

Thanks for the input linckeil. I've had the engine in and out, tub on and off so many times I really have no idea how many times I've done it. Luckily, I've got a lot of strong backs around here to help! The front to rear slope doesn't/wouldn't bother me. I'm just trying to preserve my sanity finding a way to run a steering shaft next to the engine while making sure the driveshafts aren't going to be at some funky angle or something.

This brings me to my next question, how far off (side to side) can the t case outputs be from the pinion shafts in the differentials without eating u joints or causing unwanted vibrations?

 

i shifted the engine/trans/tcase about 1 inch to the passenger side. i accomplished this by shifting the entire crossmember. this allows me to run the shaft for my saginaw steering with no interfernce and gives me plenty of room for my through the floor pedals. it also centers the v8 in the engine compartment. without the crossmember shift, the motor is offset to the driver side. the one inch shift isn't gonna hurt anything - i don't think. if it does, i'm gonna look to replace the driveshaft u joints with a cv joint.

my father put a volvo 4 cylinder in a cj5 20 years ago and shifted it all to the passenger side about 1 inch also. the jeep is still in use and there hasn't been any issues with the shift.

 

I’m hesitant to speak up here, cause I’ve got a GM engine not a Jeep or Willys, but a couple of things I’ve read on engine positioning.
First, you need a certain degree of back angle (slope). For a GM engines it’s around 4-6 Deg. tilted towards the back. This is measured simply by placing an angle finder on the intake manifold with the carb off.
Next, at least for a GM engine, the entire drive train should be 1” off center to the passenger side. I think this is partially to clear the steering shaft, don’t know why the need for back angle but theorize it’s for oil flow.
Finally, you can reference Advanced Adapters database. They may be able to confirm your work, or better yet keep you from making a regrettable mistake.
Hope this helps.

 

Most u-joints have a working angle of up to 15 Deg. but can work at angles greater than that if the “dog ears” are properly clearanced, if that helps any.

 

Oops, now that I think about it, I think you're right.

 

i hope i'm right, cus those motor mounts have been welded in there solid for a few weeks now!!!!!!

your input about the slight downward slope reassures me about what i did. advance adapters has a set of guidelines for this? where can i find this info?

 

Don't know if you have looked at this...
http://www.novak-adapt.com/knowledge/cj5_55-71_swap.htm

"These Jeeps actually have the original engine mounted offset towards the drivers side. The engine should be moved back towards the center of the frame about 1-1/4” for an engine swap. Note that this means back ”towards” center,but not ”on center”. This provides steering box to engine, and brake pedal to bellhousing clearance. The rear transmission mount on the cross member must be moved 1-1/4” also, so as to keep the drivetrain parallel."

 

After you mentioned it, I’m positive it’s to the passeng….I mean driver side.
JK, really it’s the driver side.
Also, I posted AA but meant Novak. Timgr posted the link.
Sorry, I’ve got a million things going on right now. Just ‘bout to close the deal on a power steering pump on Ebay to go along with the power steering gear box I just bought, thus beginning my next project. 8)

 

I've seen that though they seem to contradict themselves a little. The text says to move the engine back towards the center from the original offset to the driver's side. Below the text is a diagram stating that the engine should be offset toward the driver's side 1" to 1-1/4"

I'm confused by this.....

 

i've never read that link - i kinda wish i had before i secured my mounts, but i think what i did corresponds to what they are saying.

even after i shifted everything to the passenger side just over an inch, the motor is still slightly offset to the driverside. but not nearly as much as it would be if the shift was not made. i think that is what they are saying. that was the case with my mock-up at least......

 

Don't get overly concerned with where it "should" be. Whatever position that works for your situation is fine. There is no "right" position for engine swaps.

JB

 

So I thought I had my driveshaft and steering shaft issues behind me... I'm right at the point where I could burn the engine mounts into the frame but I thought I would test fit the mechanical fan and the stock A1 grille to see if they would work together. It turns out that the stock 4.3 fan hits the crossmember and I have virtually no clearance for a radiator or fan using the stock grille. I think I may have to replace the xmember with one made from tube steel which doesn't phase me but just means more work. I always thought that the stock grille and radiator could be left unmodified for a 4.3 swap. Can anyone confirm this? If so, it means my engine has to be moved back at least a couple inches, if not more. I was really hoping to keep the mechanical fan but I'd live with an electric one if I don't have to cut the grille all up...

Any idears???

 

Mike I'l send you some pics of how mine was set up. You also might wanna check out SSDutch. I know who ever did his 4.3 swap in the CJ6 was able to run the mechanical fan without having to cut into the firewall.

 

Mike here are some pics of when I did mine...

Heres where it ended up being mounted.


Heres how close it ended up being to the front of the engine. Its close but not quite as close as the pic makes it out to be. If I remeber right there was around 1" of space.



I had to notch the x-member so the radiator would sit low enough so the hood would close.



this was the begining of the the rad. support.

 

Thanks Jason! Those pics speak 1000 words! From the initial look, my engine is sitting too high. I also see that you had to modify the grille. I was hoping not to have to but you gotta do what you gotta do. I thought SS Dutch has an electrical fan...??? Boyink, are you out there?

I was hoping to use the following picture as a reference for how far forward/back to position my engine. I was looking at the upper engine mount (part that bolts to the block) in relation to the rivets in the Jeep's frame. I think the angle of the photo must be funky because I have my engine in a similar position to where I thought Boyink's is and yet, mine seems way off. I will get some pics tomorrow.

Boyink- any chance you can snap a picture of your crossmember?

I've far exceeded my question/favor limit for the time being. Gotta go!

Thanks everyone!

 

Heres some pics of the positioning Left to Right..

Pass Side.


Driver side


Before triming grille


Firewall Clearence. This was taken when I was mocking it all up. It ended up being roughly 2-3" from the FW.