Eagle

I forgot about that. Yes, you will need to replace the speedometer drive gear. It is in the transmission tailshaft housing.

This is a common problem. The solution is to replace the lower control arms with LCAs from a Grand Cherokee WJ (1999-2004). They have a bend in them to provide tire clearance on turns. As a side benefit, they are also stronger.

Cool. So with that little toy you don't really need the degree scale on the harmonic damper. That's a new one on me.

Good luck. I pulled up the manual for that gun from the Harbor Fright web site. As usual, it was totally useless. Didn't make any mention of a dial feature. Try YooToob.

Timing should be set with the engine at warm idle speed -- which for that engine I think is around 700 RPM. If you set the timing when it's "idling" at 2000 RPM, the timing will probably be way out of spec..

Diagrams? Did someone say "diagrams"? '87 was mostly the same as '88. https://comancheclub.com/topic/55033-1987-comanche-electrical-troubleshooting-manual-full/

I didn't say the choke is normally open. I said if it has an electric choke, hook it up. Let's go back to basics. The old, mechanical chokes from the 50s and 60s had a bi-metallic coil spring that closed the choke flapper. There was a heat tube up from the exhaust manifold to the choke housing that fed heat from the exhaust up to the choke. As that heat warmed up the spring, it lost tension and allowed the flapper to open as the intake air flowed past it. I don't know specifically how the Weber electric choke works, but those I have seen simply substituted an electric current for the heat tube. The electric current flows through some kind of resistance coil, which generates heat, which then causes the choke flapper spring to lose tension and allow the flapper to open. So if you have an electric choke and you don't have power to it, more than likely the choke is always on (closed).

Which leaf is bent? Please post photos of both of your springs, at the front eyes and at the rear eyes. Stock springs in a SOA conversion should not produce 7 inches of lift. Should be closer to 5-1/2 inches.

Choke should only be on for initial, cold start. Immediately after start it should go to half choke, and then very quickly go to no choke. Some choke might be needed for warm restarts in cold weather. No choke should be needed for warm restarts in hot weather. If your carb has an electric choke -- hook it up.

Greyhound ...

What's the diameter of the harmonic balancer? Figuring out the offset from TDC for 10 degrees isn't difficult. Let's say the diameter is 6 inches. The circumference is Pi x diameter, or 3.1412 x 6. That's 18.8472". The full diameter occupies 360 degrees, so divide 18.8472 by 36 and you have 10 degrees occupying 0.5235 inches. Substitute the actual diameter where I used "6" and go from there.

Nothing here ...

With an automatic and stock size tires you won't have any issues. As DesertRat already mentioned, you'll feel some loss of acceleration, but it would be worse with a 5-speed. He's spot on about the driveshaft. Figure on getting it shortened by 1".

I've been pondering whether there's an easy way to correct this for years. Can't make up my mind if it's easy, or impossible. What happened is that Chrysler reversed the polarity of the sender. On the Renix models, the fuel gauge range was 0 ohms, for Empty and 88 ohms for full. The Chysler sender's range is (IIRC) 105 ohms for Empty to 5 ohms for full. I think what would work is cutting the traces on the cluster printed circuit and connecting the two leads from the wire bundle to the "wrong" terminals on the back of the gauge. But I'm not certain about that. I guess the way to test would be to pull the gauge out of the cluster and connect it to the appropriate two pins on the wire header corrector, see what the gauge reads, then reverse the two wires and see if the gauge reads in reverse. For this to be most useful, you would want to do it with the tank either 3/4 or more full, or 1/4 or less. If you're good with connectors, it might be possible to remove the two wires from the header that plugs into the cluster and switch their positions. I don't think switching the leads at the sender would have any effect. The resistance would still be the same.

The timing mark isn't on the pulley, it's on the harmonic balancer -- and you can;'t swap that from the 2.8L to the 3.4L because the two engines are balanced differently. What you can do is manually rotate your engine until the #1 cylinder is at TDC (top dead center) on the compression stroke. To find that, remove the #1 spark plug and probe inside the cylinder with something like a length of solid (not stranded) copper wire while a friend turns the engine with a wrench. (It'll turn easier with all the spark plugs removed.) Use a toothpick and some bright white or yellow paint to mark a line on the damper and on the block. Then calculate how far away from the first line you need to be to get 10 degrees, mark a second line on the damper, then wipe or scrape off the first line. Now replace the spark plugs, attach the timing light, fire it up and set the timing.

The GM 3.4L isn't a bad engine, and it's a MUCH easier swap in an '86 MJ. If I had to do one, I would do the 3.4L before I would even consider trying to convert to a 4.0L. What I want to know is why, if this truck is so pristine and rust-free, were the wheels and both bumpers replaced?

Nope. My house was built in 1950 by (for) my parents. It was a low budget house. All the doorknobs are brass (plated), except the bathroom door knobs are brass on the hallweay side and nickel (or some shiny, silver-ish color) on the bathroom side. mjben's answer seems like the best explanation.

It's been done ... by one of our members.

Flywheel won't be the same. 1990 is still Renix -- 1991 is Chrysler. He'll have to use the old flywheel or flex plate.

Ten years ago, when I worked for the building department in a small town up-state, our mail carrier made her rounds in a late model, right-hand drive Cherokee. I would have loved to buy it, but it wasn't for sale.

That's good to know. I thought only Redline had the friction modifier.

You will have to make a custom bracket. Where are you going to mount the license plate and light(s)?

Point of clarification: Your 4.0L engine does not have a PCV valve. PCV is an acronym for "Positive Crankcase Ventilation" -- the 2.5L engine has a PCV valve. The 4.0L system does not have any valve -- the flow is supposed to be controlled/regulated by the size of the rear (suction) tube. That's the one that gets clogged. There is no valve -- not in the front, not in the rear. In the old days, before emissions became a thing, engines just had an open tube out one side that turned down and vented to the atmosphere. That worked, but as the engines aged and developed more blowby, they pushed more and more oil out those tubes. Once we got into controlling emissions, the engineers decided to capture those oily fumes and recycle them through the engine to burn them. So -- no more dump tube in the side of the block. So now the inside of the engine was essentially sealed. But blowby still happens, so there has to be somewhere for those fumes to go. So they put a fresh air inlet in one end of the valve cover, and a suction tube in the other end. The suction tube led to the carburetor, throttle body, or direct to the intake manifold. Engine vacuum then pulled air out of the engine through the suction tube, and it was replaced by fresh air coming in through the inlet -- or by blowby. Unless an engine gets really bad, the system should suck out more than blowby puts in. The crankcase is under negative pressure. If the suction tube gets clogged -- which is what happens to the 4.0Ls -- there is no suction (or it's greatly reduced). When that happens, blowby pressurizes the crankcase. That pressure, which has oily fumes in it, has to go somewhere. I can't get through the skinny tube where it's supposed to go, so it goes out the other opening -- the opening that's supposed to be the inlet. That's when we get oil dripping into the air box. Rerouting the inlet hose to a catch can is essentially just reverting to the old, pre-emissions control system of leaving the crankcase open to the atmosphere. In theory (although it wouldn't be legal, but neither is the catch can) you could just put on a longer hose, run it down to the frame rail, and let it drip onto the ground while you drive.

True.

I think I remember someone in NAXJA doing a 3,1L swap "back in the day," but now? Why bother? The cost of a junkyard 3.1L is likely the same as a 3.4L so why get the smaller engine when you can get the bigger engine?