As the title states, I am looking for the precise differences in the frames on a CJ-7 and a CJ-8. I know the 8 is longer in two places, just in front of the rear wheels in the flat part and at the back of the frame. I am wondering if anybody knows just how much you need to stretch in both places and where to add the new frame cross member as well as the new body mounts. My reasoning, fairly obvious as it may be is that I am contemplating stretching my 7 and starting with an 8 is definitely not an option. If anybody has pictures would be amazing and experience from somebody that has done this would also be fantastic. As always thanks in advance for the help guys.
Do a google image search on CJ frame specifications. There's a chart or two floating all over the internet that give the measurements for each, which originally came out of the factory service manuals.
Buddy bought a project Scrambler and it had BAD frame rot and more cracks than Ive seen in a frame ever. Instead of unsuccessfully trying to repair it, I made a spot on replacement using two CJ-7 frames. One was damaged in the front and the other in the rear. I cut each just past the halfway section in the center parallel rails so it would equal the extra length needed there. I did reuse the rearmost extensions from the old Scrambler as they were fine and different dimensions than any of the left over parts. A total of 4 tub mounts need to be moved. I used 2x4 3/16th thick square tubing running past the repair and welded to the thicker or outer rail as well. Here's some pictures that are self explanatory.
Started with these two sections:
What was KEY was that I had another GOOD bare Scrambler frame to take exact measurements from.
Thanks for the link but those were actually the pictures I was talking about. If you notice in those pictures the "H" dimension is the only one that changes. I know the frame is stretched in two separate places. Only in a Jeep CJ, Do you remember the amount you stretched it in both places? Thanks for the pictures they are helpful. Do you remember where you added the second brace at? Searching around the internet I did find the forum you posted in over at CJ-8.com and didn't see the specific measurements. I also tried to open the picture link that was supposed to have the measurements but I'm not a member there so it won't let me open the file. http://www.cj-8.com/forum/showthread...mensions/page2
This is the thread I was talking about.
A CJ7 has a 93.3" wheelbase. A scrambler has 103" wheelbase. So you need to add 9.7" to the straight section ahead of the rear spring hangers. As for the rear, add up dimensions G, H & S from the pic above for both a CJ7 (135.83") and a CJ8 (159.69"). The difference (less 9.7") should be what needs to be added to the rear of the frame (14.16"). not sure how accurate that is though. That pic shows that the distance between the front and rear spring hangers is the same for both models....which can't be true if the CJ8 wheelbase is 10" longer (unless scrambler rear springs are 10" longer?)
'84 CJ-7: Yota axles (spartan locked front, e-locked rear) 4" BDS, 1" Daystar & 3/8" shackle lifts, 35" X-Terrains on steelies, YJ Tub & family roll bar, heater blower upgrade, 4.2L w/MC2100 & Team Rush, Warn 8274. Rebuilt 4.2/4.0 hybrid, AX15 and twin sticks/clocking ring waiting to go in.
The advertised position for a topless, dirty jeep girl has been filled......by my wife. Thanks to all that applied.
<------------and yes, that is her. :-D
It was the middle of 2009, so I don't remember exact numbers and even if I did, just to tell you stretch it "X" inches here or there is only part of the solution. See the front 4 tub mounts are in the same spot, the next two, by the rear tire are moved from behind the rear main eye to in front of it. The rails on the Scrambler in original form are not CJ-7 parts with just an extension welded on but rather different longer pieces. So that said, the rearmost crossmember is the same on the 7 and 8. On the 7, the gas tank rear edge bolts to it, on the 8 it doesnt as the tank is in close to the axle as in the 7, so there is a second crossmember there (on the 8) that is the same piece, but with the outer parts cut off so it fits inside the frame rails. It is at this point where the next two tub mounts are mounted back a tad as to be different than the CJ7. For the rear rail extensions, I reused the old 8 parts and graphed them in before I welded in the two cross members. I did this to duplicate the way it is originally. I made my own rear crossmember out of a left over section of the tubing. I removed one side to make it a C channel and added the wings for the corner mount holes (not cut out yet in the pics).
If you need an exact number or need an exact picture, TELL ME NOW as I have a bare CJ8 frame and several CJ-7 frames in the back yard now about to go to the sandblaster and then to the galvanizer.
If you could measure the distances from each of the body mounts front to back and remember how much you stretched in both places would be fantastic. From there I believe i could figure it out and if you could share the pictures you do have of the bare scrambler frame would be great as well. Thanks a ton for all of your help so far.
Wikidpedia isn't exactly right on. The wheelbase difference is 10" to the dot. If it were mine I'd add 10" between the fixed spring hangers to the measurement in the chart above and the difference in measurement H in that same chart. I never noticed in those charts that they only give the one measurement difference and there are two.