CJ3b....That is what the vin tag says.

[jonah]

Yeah, it should be fun, picking up 80-90hp is always good. Plus once set up in the ls family upgrades will be easy.

Not sure how the exhaust will fit, it is the same width as the v6 so it should fit. I just will have to find the riItght manifolds or headers. I am more concerned with the front, the front of the motor is really close to the radiator. We will see.

[jonah]

Been getting a bit of work done.

Transmission crossmember done. It got a little more convoluted than I had hoped but it was how it had to be to get everything above the frame rails, totally flat belly now, gained 3" of belly ground clearance!


At least I got one little section to look decent:

Finally had to break down and buy a decent hand drill after nearly smoking my 1/2" dewalt cordless. The dewalt does pretty well on normal stuff but drilling 1/2" plus sized holes all day was pushing it. This drill is the hole shooter!

[jonah]

I got the drivetrain in! The 4.8 is mated to the sm465 using a 2005 silverado flywheel and clutch inside the original chevy bellhousing for the sm465 (bigger front bearing retainer than other chevy 4 speeds). The sm465 goes to a dana 300 via a novak adapter. I did have some fitment issues with the novak adapter. It interfered with the retaining nut on the output of the sm465 but a little grinding on the adapter and it fit. I wasn't really happy to grind on a $500 adapter but it worked out.

Then I was on to driveshafts. I previously ran a np205 t-case with a 1350 cv yoke. The dana 300 I switched to was 1310 cv. A quick run to pick a part and I found two that would work for the rear. One was a front out of a Grand Cherokee and the other was a Dodge Durango. They were very similar, the Dodge had a thicker slip joint shaft so I decided to use that one. While re-tubing I messed up the measurement and cut it too short. So I ended up using the Cherokee one which I re-tubed correctly and got it in. On the front I had to lengthen it about an inch and a half. Luckily I had an different slip yoke that was an inch and a half longer so I just swapped the yokes and was good to go.

Next was wiring:

I had stripped down the stock harness using the info at lt1swap.com as my guide. It was a bit tedious but not too hard. The harness did have to be re-routed to put the ecu inside, so I did have to pull the harness apart and move things around as well as shorten some of of the wires.


Then I built this fuse panel to mount on the firewall inside the cab. It has all the relays for fuel, fans, lights, etc. It also has the TAC module which controls the communication between the gas pedal, throttle body and the ecu for the drive by wire. I ran 8 circuits. Four are keyed power and four are battery. I probably could have used two more slots but I think it will be fine the way I split it up. One thing I have to keep relearning is to leave plenty of wire in the runs to route everything nicely. I wired this panel on the trans tunnel thinking when I mounted it up on the firewall I would have plenty of wire to tuck it way up out of the way, but the way it worked the bundle ends up crossing right in front of the panel and it makes accessing the relays tougher without dropping the panel down. If I would have added 6 inches of length to each wire I could have run the bundle higher and out of the way. Oh well, next time...



I did take a minute to relocate my proportioning valve for easier access to the spark plugs on the drivers side. It used to block the middle of the motor and I couldn't get a straight shot at the plugs. So this should be better.


My friend Tomtom was generous enough to donate this fuel pump assembly to the cause. It came off his 2000 Chevy 1500 and it had a bad fuel level sender but the rest was good. I patched on a new sender, it was a bit of work since I had to change the direction of the sweep to work with my sunpro fuel gauge, rewiring on the variable resistor got it working. I built a retainer for the top of my fuel tank and bolted it in. Then all the plumbing I did with gm quick release connectors to attach to the fuel pump and fuel rails to normal rubber fuel line and ran normal steel line in between. A lot of people go to AN fittings, which are nice but all the connectors I used cost less than a couple of AN fittings, so I went the cheap route. I fired up the pump and it gave me 55 psi right away, perfect!

Next was exhaust. I ended up using the stock manifolds but I cut off the flanges and welded on v-band clamps. The flanges on those manifolds were huge and dumped right on top of the frame rails. So after a little cutting and welding it all fit nicely. Then with some mandrel bends from Summit, I made a the passenger side loop around the front of the oil pan and Y with the drivers side. Then a straight shot back to the Spintech muffler I was using before with the V6. It is all 2.5" which might be a bit on the small side, but didn't want to lose any torque from the 4.8 and most people say large pipes with the 4.8 will lose some low end.


So after a bunch of putting on wire loom and securing the wiring and I was ready for a test run. I hit the key and it cranked and cranked but no go...bummer. After poking around for a bit I realized I had spark, and the injectors were getting pulsed correctly and I had fuel pressure. But when I pulled the plugs they were bone dry, I concluded that the injectors must be clogged. Not to surprising since the fuel rails had some of the worst smelling gasoline I have ever encountered. I did some quick research and found GB Remanufacturing in Long Beach that sold the parts for rebuilding injectors. For $25 I got new filter baskets and o-rings for the injectors. I pulled the old baskets out using a #10 machine screw with a wing nut as a puller. Screw in the machine screw into the basket and tighten the wingnut against the injector housing to pull the filter out. I then used a friends ultrasonic cleaner with 50/50 simple green and water with two bottles of injector cleaner added, ran it at 120° F for 10 minutes and they came out as clean as new. I made a little injector pulsing rig with an arduino (fun little things) and I used a syringe to flow cleaning fluid through the injector. No scientific flow test but they all looked to operate the same. I popped them back together with new o-rings and pressed in the new filters using my drill press and an upside down drill bit of the correct diameter. Once reinstalled I hit the key and pow! the motor fired right up and started idling. Good oil pressure at 40 psi at idle, voltage good, came up to temp and the radiator fans kicked in. Time for a test drive.

Pulling out onto the main road, I gave it some throttle going around the corner and it started spinning the tires and the rear came around. I just about lost it but it didn't spin out. You just can't beat V8 power. Opy is pretty quick now, if it wasn't for the slow shifting sm465 it would pull decent 0-60 times. It will be interesting to see how it behaves on the dirt. I noticed that if i just let out the clutch from a stop without throttle the motor will lug down a bit then bring its own rpm up to get back to idle. That could be really nice for crawling without stalling. The only codes I am getting right now are knock sensor low signal codes (and you can feel it when it pulls timing because of this), the sensors and harness are new so I am hoping it is just a bad ground, I haven't put a ground strap from the block to the cassis yet, so that could be it. Otherwise it is running like a champ! We will see how the little axles hold up, lol....

[vwtipeii]

Amazing Jonah... awesome write up and update! I can't wait to go wheeling with you soon! Congrats on the 4th motor!

[jonah]

Thanks! Knock on wood, this might be the last motor for a while. Of course if a good 6.0 came my way...

Let's do a shakedown when yours is done. This week???

[aw12345]

How about next Tuesday?,
You are the ultimate tinkerer in my book Jonah

[jonah]

Thanks for the compliment!

I could do Tuesday. I have been driving Opy around town the past couple days and all is well except the pesky P0327 and P0332 knock sensor low signal codes. Reworking the grounds didn't help. I am getting two new AC Delco sensors to replace the cheapo knock off sensors that are in there now. It runs well but when the timing gets pulled and it loses a bit of power. I am sure I will get it solved eventually. This seems to be a pretty common problem with the Gen III's, some people turn down the sensitivity in the tune, but I am not ready to drop the cash for a tuner at this point.

[daniel_buck]

ah man, nice :-D can't wait to see it in action!

[jonah]

Soon, soon! Still fighting the knock sensors. I got the new AC Delco sensors that are recommended, but I need a few hours to pull the intake and swap them out.

[Tumbleweed13]

Awesome job Jonah. Impressive! With all that power, you gonna put coilovers on Opy, and hit the open desert at 60mph?

Seriously, great work. Way over my pay grade.

[jonah]

Thanks Joe! That would be the next logical step. The leaf springs have worked well in the rocks so far and Opy is pretty stable. But at speed in the dirt can do some serious kidney damage. Maybe when I need to upgrade the axles...

[daniel_buck]

yea watching you charge Opy through Hammer Down... I'd say those leafs work just fine You're gonna flip that thing in the flat areas though driving like a ralley driver hah!

[dirtman13]

Looks good Jonah. I had the exact same problem with the clogged injectors when I finished mine.

[jonah]

Today I finally had my first drive with no codes. I was getting knock sensor low signal on both of the knock sensors. Those were two cheap ebay sensors. I replaced them with two of the good AC Delco sensors and got down to one low signal code on the rear sensor. So I pulled the intake again and replaced the rear with another AC Delco and finally no code. It definitely helps the power, the computer pulls out 4 degrees of timing across the range when the knock sensors aren't working correctly. I didn't notice a huge difference at the top of the rpm range but you could really feel it in the low end. Now it is really pulling well.

My next project is getting all of the exhaust leaks fixed. I used v-band clamps at the manifolds and before the muffler. They were pretty tight before my Pumpkin Eater test run. But now they are leaking again. I am going to try flattening the mating surfaces with a file, then use some copper gasket spray to seal them up. I hope I can get them to stay tight, I had high hopes for this type of exhaust connection but so far I haven't been too impressed.

[jonah]

yea watching you charge Opy through Hammer Down... I'd say those leafs work just fine You're gonna flip that thing in the flat areas though driving like a ralley driver hah!

Still one of my favorite shots of Opy!