79 CJ5 Drivetrain concerns & Questions

[gadawg31]

Hey everyone, first time on here and it looks like there is a lot of knowledge. I have been out of the jeep world for about 15+yrs and I finally got my hands on my next jeep project. It is a 79 CJ5 and here are my concerns with the drivetrain. It has the straight six and (3) speed tranny. According to the previous owner, it ran, but now it doesn't. I have not been able to turn it over or attempt to crank and this is what I am concerned about. Let's say worst case scenario the motor is shot. With a small budget, what would you all think would be a suitable fix, rebuild existing 6 banger or maybe pick-up a used running v8? If I rebuild the 6 stock, what have you all been seeing these motors cost? I have a few machine shops in town, so I will start asking them next week, but wanted to get some opinions as to what you all would do if it were you. I hope to gets some pics up and let you all see it soon, but for now I wanted to see what you all thought of this issue first. THanks

JD

 

[Jimbos76cj]

Hey everyone, first time on here and it looks like there is a lot of knowledge.
Welcome..
I have been out of the jeep world for about 15+yrs and I finally got my hands on my next jeep project. It is a 79 CJ5 and here are my concerns with the drivetrain. It has the straight six and (3) speed tranny. According to the previous owner, it ran, but now it doesn't. I have not been able to turn it over or attempt to crank and this is what I am concerned about.
Define that it wont turn over or crank? How have you tried to turn it over or crank it? Heres a list of things I would do prior to trying to start it.
1) Pull all the plugs and inspect them looking for signs of water damage. If they are clean I would spray a bunch of PB blaster into each cylinder and let sit for a few hours.. then go back out and spray some more into the cylinders.. when I say spray I MEAN ALOT. Let it sit for awhile then try turning it over by hand. I think the crank boly is a 3/4" head. use a decent size breaker bar to try and move the crank back and forrth a little at a time. It normally turbns clock wise.. some times if you turn it counter clock wise it will loosen up the balancer bolt .. thats not a problem just turn it clock wise again to tighten it.

If its still stuck I would pull the head and see what the hold up is. Alot of times moisture will set in and stick the rings to the cylinder wall. If they break free I would continure to spray the cylinder with PB blaster and WD 4 and rotate it by hand. Oh loosening the accesories will also help turn the motor too. Once you have spun it by hand a bunch I would try replace the spark plugs, and try to start it. If it turns by hand but wont with the starter motor id look into your grounds, starter relay, cables.

Let's say worst case scenario the motor is shot. With a small budget, what would you all think would be a suitable fix, rebuild existing 6 banger or maybe pick-up a used running v8?

again define small budget.. Even if you were given a good running v-8 you have to look into motor mounts.. 200-400 dollars, trans adapter anotehr 200-400.. theres a good chance you will need to replace the drive shafts, new exhaust, radiator, etc, etc ,etc.. it all adds up. Look around for adapters and see how they price out. for a V-8 swap an AMC 304-360 will bolt to your trans with out an adapter but you will still need at least 1 motor mount and new exhaust.
If I rebuild the 6 stock, what have you all been seeing these motors cost? I have a few machine shops in town, so I will start asking them next week, but wanted to get some opinions as to what you all would do if it were you.

My local shop says it runs around $150 per cylinder for a basic rebuild plus anotehr $300 for the heads. then you have to ad in cost of parts.. will end up close to 2,000 when your done.
I hope to gets some pics up and let you all see it soon, but for now I wanted to see what you all thought of this issue first. THanks

JD

As for my thoughts... If I were to ever swap a motor I would have to go with a 5.3 or 5.7 LS motor with a 4l60e or GM Turbo 400 Transmission .. you will get plenty of power, good reliability, over drive and good gas milage.

I had a CJ with a locked up motor. water leaked down the carb into the rear 2 cylinders and rusted them up. When I pulled the plugs water ran out. I pulled the head, cleaned the water out, followed my steps I listed above and was able to get it moving. I used some 800 grit emory cloth to clean up the cylindr walls, cleaned and lapped the valves in the head, reinstalled every thing and fire her up.. ran great no smoke.

On a budget I would work with what you have first. beside the gasket set its pretty much free. If it doesnt work I would look at either rebuilding the motor you have now or finding a repalcement AMC 258 i6 / 4.2l .

then a v8 swap.

 

[thiswontbetooexpensive]

I did a complete rebuild on a 1980 I6 for roughly $1,300. New everything except the crank and head. I will let you know how it runs sooner than later I hope. Just food for thought.

 

[Hedgehog]

Before you do much of anything dump some penetrating oil in the cylinders, I love Marvel Mystery oil for this sort of thing. Let it sit, better yet put a little in everyday for a week. If water might be a problem start with WD-40. WD-40 will remove the water. Then put the oil to her.

 

[Saddle Tramp]

From your post I assume that you cannot make the motor turn over by hand with a nut and breaker bar on the crankshaft bolt that holds the balancer on. If this is the case Hedgehog has it right; start with the WD-40 and then Mystery Oil. This process can take a week or so. Should you be unable to break the motor free after giving the Mystery Oil a shot you may need to pull the head and see what you got. Sometimes a head gasket leak will rust up the cylinder walls if it sits too long.

If the motor is gone, I know Jimbo means well but stuffing a SBC into a CJ is not necessarily a cure all and requires a fair amount of hacking and whacking, not to mention expense. The good news is that with a 79 CJ you have options. As mentioned a full motor rebuild can be had for around $1300 give or take, with no fuss or muss; unbolt it, take to the shop then put it back in. Also you may be able to find a low mileage 258 (most likely it would have had a recent rebuild) and is basically the same swap as the rebuild. The other option is to swap in an AMC V8 (304, 360, 401). The passenger side motor mount needs to be relocated to mate up to the V8 mount location but the existing one can be reused if careful. Other than that everything else but the flywheel will swap in with the V8. (bell housing, clutch system, tranny, etc) The AMC V8s are esternaly balanced and each engine size has its own flywheel balance but the 360 is a plentiful engine and a good used one may be available too for cheap.

To step up on my soap box for a moment, there are fewer and fewer decent CJs left in the world and in my opinion as CJ owners it is our responsibility to preserve what is left. Gutting the drive train on a CJ just to drop in a SBC and GM tranny is far from preservation so to speak. Keep your Jeep, Jeep. Doing so is easier and less expensive anyway as no adaptors are needed due to the availability of OEM parts to do the job.

 

[Jimbos76cj]

Im a big fan of keeping a jeep a jeep also.. After my YJ the next jeep I build I expect to last me for many of years so Im gonna drop a sbc in it just for ease. I know it takes a little bit of hacking mostly wiring which I am very comfortable with. I know its pricey. I actually said that a AMC 304 -360 swap would be cheaper then any thing else. 360's are plentiful but its also getting more difficult to a) find em cheap and b) find em in good shape. I figured id get flamed for the LS swap idea but Im coming to a point in life where id much rather drive my jeep then mess with tuning it. The wiring harness Ive been looking at even has the poert for the reader so it becomes much easier to figure out why its running like .

 

[gadawg31]

Thanks all, I am definately going to try the recommended remedies. If I don't have to rebuild, but if push comes to shove, I will do what I have to do. I will try and get some pics up in a couple of weeks. Gotta get everything situated in the garage and buy the boss a couple of nice dinners after I pull it in the garage. I forgot to mention that I haven't told my wife yet, that I have bought another project. I am laughing now inside, but that will soon change. LOL! I think we have all been there, but the couch is only uncomforable the first night. Thanks.everyone.

JD

 

[Saddle Tramp]

Thanks all, I am definately going to try the recommended remedies. If I don't have to rebuild, but if push comes to shove, I will do what I have to do. I will try and get some pics up in a couple of weeks. Gotta get everything situated in the garage and buy the boss a couple of nice dinners after I pull it in the garage. I forgot to mention that I haven't told my wife yet, that I have bought another project. I am laughing now inside, but that will soon change. LOL! I think we have all been there, but the couch is only uncomforable the first night. Thanks.everyone.

JD

No, actually my wife is the one who has found a lot of the jeeps I’ve owned over the years. I’ve told the story here before but the short version is I pulled up in front of her parents’ house in my first CJ, a 1972 with a 304. Her dad was in the front yard and he asked me how I ever expected to get a girl to go out with her in that thing. Well, my then girlfriend, now wife came bounding out of the house, jumped in and away we went. She has been hooked on jeeps ever since. (I’m a lucky man!)

 

[johnnyreb]

atf fluid and acetone mixed make an excellent penetrating oil. As a side note; if you put as much oil in it has been mentioned. When you get it broke loose, I would try turning it over with the plugs out. It helps to get excess oil out and looses up the motor without fighting compression. Then put the plugs back in and try to start it.

 

[gadawg31]

Tramp, I think the big issue with my wife is the fact I have another project. My last couple of projects didn't go over very well with her, so now there is a stigma. Once I get it cleaned up and rolling, she will enjoy it just as much as I do. Just got to get past the project part. Thanks for all the advice.

JD