• Welcome to For E Bodies Only !

    We are a community of Plymouth Cuda and Dodge Challenger owners. Join now! Its Free!

K FRAME

gf7cuda

gf7cuda

Well-Known Member
Joined
Mar 23, 2016
Messages
287
Reaction score
37
Hello Mopar friends, I was installing my engine this past weekend and had an issue with lining up my K frame bolts (3 ok \ 1 not ok). I built a jig and installed from the bottom with transmission attached. The main question is, with the weight of the engine/ trans already on the K frame, alter the bolt holes line up? This is a recent K frame I purchased and had it restored and had no damage to it. To take it one step further, the original one I had to put back in because my new purchased one wouldn't line up also gave me a hard time lining up until I took the weight off K frame with a screw jack. Has anyone experienced this problem?? Thanks in advance.
 
The factory K-Frame wasn't the most rigid piece! That's why people weld gussets into them and weld all the seams. So yes, your engine/trans weight could very well be distorting your K-Frame. You could try disconnecting the motor mounts and jacking the engine up with a floor jack a piece of plywood between the jack and oil pan. The removed weight may let you get all four K-Frame bolts in.
 
gf7cuda said:
Hello Mopar friends, I was installing my engine this past weekend and had an issue with lining up my K frame bolts (3 ok \ 1 not ok). I built a jig and installed from the bottom with transmission attached. The main question is, with the weight of the engine/ trans already on the K frame, alter the bolt holes line up? This is a recent K frame I purchased and had it restored and had no damage to it. To take it one step further, the original one I had to put back in because my new purchased one wouldn't line up also gave me a hard time lining up until I took the weight off K frame with a screw jack. Has anyone experienced this problem?? Thanks in advance.
Click to expand...
As a retired frame tech the first thing that comes to mind when I hear something like this is bent frame! Have you tried a diagonal measurement between the bolt holes? they should measure exactly the same. try this on the body and on your subframe. if you have a slight difference of 1/8 I wouldn't worry about it but because you have to divide that number by two leaving only 1/16 of a difference. But if you find a 1/4 or greater you could have a problem. also measure the length between the holes on each frame rail they should be the same if not ergo an issue!
 
Last edited:
The only time I've had issue with K-member to frame alignment, was when the K-member came from another car. In those cases, I may have been guilty of bolting just the K-member to the frame rails, and doing what I can to get them to align, such as loosen/remove fender, bumper, etc. Only AFTER it's bolted and torqued, will I add the motor-trans and suspension.

From the bottom, like the factory does with the motor-trans and suspension, I'm confident they have supports in place on the trans and wheel hubs to evade undue stress on the K-member.

If you're K-member came from this same car, it may not be that far out of whack.

Once your K-member-engine-suspension assembly is between the frame rails, lifting the engine-trans by carb plate (for example) may remove enough stress or "tweak" to get things aligned enough to bolt together.

While it's a PITA, as others suggest, see if you can find where the "tweak" is.

1. compare bolt hole cross measurements on the frame rails.
2. compare bolt hole cross measurements on the K-member.

If things are pretty straight, they should be within 1/4-inch more or less.
 
Rich Followell said:
As a retired frame tech the first thing that comes to mind when I hear something like this is bent frame! Have you tried a diagonal measurement between the bolt holes? they should measure exactly the same. try this on the body and on your subframe. if you have a slight difference of 1/8 I wouldn't worry about it but because you have to divide that number by two leaving only 1/16 of a difference. But if you find a 1/4 or greater you could have a problem. also measure the length between the holes on each frame rail they should be the same if not ergo an issue!
Click to expand...
Thank you for your advice. I will check this out. Appreciate it
 
gf7cuda said:
Thank you for your advice. I will check this out. Appreciate it
Click to expand...
It did come from a B body , but b/e body should be the same I believe, I could be wrong. Came from a 71 Roadrunner
 
gf7cuda said:
It did come from a B body , but b/e body should be the same I believe, I could be wrong. Came from a 71 Roadrunner
Click to expand...
B body k-frame will have a 2 degree angle difference in the steering gear to steering column alignment. It will also not support an e-body sway bar. Other than those items, it can be used on an e-body.
 
Xcudame said:
The factory K-Frame wasn't the most rigid piece! That's why people weld gussets into them and weld all the seams. So yes, your engine/trans weight could very well be distorting your K-Frame. You could try disconnecting the motor mounts and jacking the engine up with a floor jack a piece of plywood between the jack and oil pan. The removed weight may let you get all four K-Frame bolts in.
Click to expand...
I had to do that and it worked to get the old one back in. The jig I made supports the outer edges of k frame. So the middle under engine is open and not supported.
 
HooToTheCore said:
B body k-frame will have a 2 degree angle difference in the steering gear to steering column alignment. It will also not support an e-body sway bar. Other than those items, it can be used on an e-body.
Click to expand...
So they are different? My build sheet has 52 for frame and this K frame has a 52 coin on the front. I thought I seen somewhere 71 e/b body is same. I could be wrong...
 
This might help. Install K frame bolts that line up and check to see where it is out. Use a tape for these measurements. 38 1/8" and 54 3/8".
1724160581724.jpeg
 
HooToTheCore said:
B body k-frame will have a 2 degree angle difference in the steering gear to steering column alignment. It will also not support an e-body sway bar. Other than those items, it can be used on an e-body.
Click to expand...
This may be the case for '70 and earlier B-body k-frames. I know my '70 Challenger had a k-frame that should not have been on the car. I tried to add a sway bar and the k-frame required the bar to pass in front of the k cross member, not through the cross member. I swapped the k-frame for an e-body frame and the sway bar installed correctly.
 
Someone with more knowledge than me may know for certain, but I think 71 and 72 B bodies share a K-Frame that can interchange. 70 and prior, the B-Body had the different steering box attachment angle and sway bar mounted different as mentioned above. 73 and later B-Bodies had the weird biscuit rubber suspended front suspension that changed geometry again.
 
this how
i installed my drive train. Lowered the car to the k frame which was on a custom dolly, fit perfect. Originally a /6 now 340 6pak.

100-2156.jpg
 
You must log in or register to reply here.

Similar threads

Gumby
K-Frame 1972 vs. 1973
Replies
3
Views
719
Mr Cuda
Mr Cuda
L
Creative Fix for Spinning Frame Nut During Steering Gear Install
Replies
4
Views
856
Surfcuda
S
Gumby
K-Frame Identification
Replies
8
Views
1K
Gumby
Gumby
Gumby
Non-Hemi V8 K-Frame Part Number Differences
Replies
0
Views
546
Gumby
Gumby
K
K Frame number
Replies
8
Views
2K
Gumby
Gumby
Back
Top