Jontow 79 CJ7
From NNYOffroad
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1979 Jeep "CJ7"
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I bought this Jeep because I wanted to make a summer ride out of it. Didn't really intend on building
any kind of serious off-roader out of it, but I didn't want to eliminate the idea because, well.. why not?
It did look pretty good; passed the 50ft test but had an awful 3" hack of a body lift on it. I snapped a
few pictures from when I got it home. The guy I got it from didn't really know what it was other
than "a 1979 CJ7".. That said, it's a ~1990 YJ tub on a patched-up CJ7 frame. The shifter plate has '79'
cast into it, and the engine has been pieced together with a 1975 block and head, but what looks to be
the original 1979 intake & exhaust manifolds.. presumably someone put a rod through the original block?
Well.. started doing some serious inspection, teardown & cleanup.. got the body lift out, and found out that
the previous owner did a really nice cover-up of a couple nasty spots of rust. Guess I learned a few things.
The rebuild: attempt #1
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After some beer drinking and head scratching, I decided it had enough rust on it (top *and* bottom..) to take
the tub off it, and since the body lift had to come out anyway, I tore it off.. missing the pictures of that.
When the tub came off, some weak spots in the frame were exposed, and some of the frame-welded body mounts
were rusted through. I cut and welded some plates onto the body mounts, and also made some plates for the
rear passenger's side corner of the frame.
After all that, I got a bit discouraged about the tub and let it sit for a bit too long, as I had other things pending..
The replacement tub
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As it turns out, I had another tub that looked to be in better shape, so I started cleaning it up and found the
same rust (but worse in some spots) as the first tub.. at this point, I got a little annoyed and stopped to think about it.
The half-cab
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The black tub re-surfaced in my mind, and I had a few ideas and at this point just wanted a vehicle to use as a
buggy, with the possibility of using it as a driver later if the idea seemed reasonable.
So, it's a pretty strange experience standing in your garage with a Jeep tub and a sawzall, trying to decide how
it should work. It turns out, the best plan is just get out a paint marker, straight-edge/ruler, and a plum-bob,
and go crazy.
When you've got the measurements and markings done, nothing's more difficult than the first cut.. but after that one,
its apparently possible to cross-section a tub (twice) in one night, rough enough to "visualize it" with C-clamps.
Since that fateful (for the tub) night, I discovered a thing or two and made some decent progress. You can't use a
stock YJ tailgate with this conversion, because the lower hinge is in the way.. and drilling out those torx heads sucks.
I've got the fender openings marked and cut and the tailgate/hinges are off.
I even started re-assembling. I started welding in a piece of the floor patch, and started stitching things back together.
It took some creativity to make a brace for the center section, but it's in strong and seems to be holding up.
Starting to put it back together
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Started welding some patches into the rear corners (where the roll-cage mounts).. turned out pretty well (see pic at side).
Got some time and some help from Mark, so we dollied the rolling frame out front and started mocking things up; it looks good..
Actually turning out pretty solid and I'm happy with the work. Ran into a bit of a hang-up when setting it on the frame: the
rear crossmember and shock mounts came into contact with the finished edge below the tailgate... ... so I cut off the edge.
I did some drilling and mounted the cage in its permanent home to give the tub a bit of rigidity while I work on it, and so
the body mounts can be placed reasonably.
A bit more assembly
No welding, drilling, etc tonight.. a bit of cutting and a lot of bolting back together. Recycled some things to make bushings
for the grill (see photo), and put the steering column in. Bolted a seat down and found out the brake master cylinder is toast.
Brakes
I decided manual brakes were for the birds; so I dumped the original master cylinder and decided to go with some power brakes
out of a YJ, since I had a lot of the parts. I bolted up a spare booster (and found another toasted master cylinder.. then
replaced it) and got some crazy bullshit adapters at napa, bent the original lines all over the place and it still didn't
really work at all.. the unions leaked like crazy and I couldn't get a good seal..
So: what am I to do? I bought a 25ft spool of brake line at napa and a bunch of fittings, then proceeded to run all new lines
front to back. The PO was nice enough to replace the soft line in the back; I just need to do the front two. This job also
allowed me to toss the original CJ proportioning valve/junction block out the window and use the YJ one that was attached to
my spare booster. Win.. looks a lot cleaner now, and I can get to every fitting with relative ease.
Body Mounts
One thing still missing was some body mounts in the back of the tub.. they just never lined up; being a CJ frame / YJ tub,
so I cut them off the frame, modified them a little bit and moved them to the right location; then welded them back to the
frame and bolted it all down. The cage mounts could still use some reinforcement, and the ride quality is kinda garbage
with hockey pucks as body bushings.
Engine
With some playing around out back; I managed to get the thing running like crap.. I suspect it always did, but I hadn't run it
long enough yet to really notice. It runs great (at high RPMs and when cold) for a while.. once it heats up; it falls all over
itself and can't manage to stay idling at all.. timing is within spec, pulled the venturi assembly out of the carb and cleaned
it up really well, etc. Still no go: idles like garbage when warm. Compression tester doesn't have the right adapter.. oops.
Replaced coil and mechanical fuel pump: still nothing.
I spent some time decoding casting numbers and similar fun, found the
following:
Block: 3224098 (1975-1979 232/258), Cast 803A13 (March 13, 1975, 1bbl 258) Head: 3224490 (1972-1974 232/258) Intake: 2bbl, Cast April 26, 1979 Exhaust: Cast May 3, 1979
Anyway, leaks like a bastard at the mating surface on the head. None of the
bolts are properly torqued,
I pulled both manifolds and the valve cover (also leaking) and it currently
awaits reassembly.
Things left to do..
- Finish floor patches
- Get cage mounts back in place, strengthen them..
- Fix seat bracket mounts
