After successfully completing an AW4 swap, I realized the engine likely needs some bottom end work. After considering all the angles, a Gen 3 LS swap seems the best route. As many know, this is a well beaten path. That's good for me! I am disappointed though to get rid of the AW4/AMC 360 combo. It has been a good match.
Drivetrain and Theme
The drivetrain will be an LQ4, 4l80E, and a NP229. Snow traction is important and the NP229 really performs well in that regard. Also, this FSJ is used for vacations, joy rides, and other family occasions and not for off-road. The suspension is stock. The most weight it will see is a back full of camping gear. So, the theme for this build is reliability and good smooth performance.
So far, I have prepped the engine harness and figured out some of the wiring integration. Many thanks for LT1swap for the guide and wiring diagrams. Honestly, it was easier to prep the harness for the LS swap than figuring out the AW4 wiring. On the gauge cluster side, I feel like I cheated a bit as I splurged on a Dakota Digital gauge cluster last year. That also came with a digital speed sensor that goes into the NP229. The GM ECU can read that sensor, and from what I gather that's important. Also, the gauge cluster just needs to plug into the OBD port to get all the gauges to work (other than the gas level). That really simplifies things.
I have two lingering things about wiring....
1. 4-LO switch. As far as I know, there's no electrical signal for the LS ECU to see on the NP229. Has anybody added a sensor for this on the NP229?
2. AC signals. There's something about high and low pressure switches as well as AC request signal. I'm wondering if this could replace the AC module or if I'll have to piggy-back off it. I think I've read the HP-Tuners can modify the AC parameters.... eg only monitor low pressure switch ect? I need to look into that more. This swap will have AC.
I'm still undecided on whether to go electric fans or keep the mechanical. The GW has a newish 4 core unit in there now with BJ's aluminum shroud (Overkill? Yes!) so dumping another $500+ on an LS specific setup is hard to swallow, but so is a cobbled together radiator hose setup that could end up being unreliable.... unless there's a radiator hose combo that works well with the stocker?
Right now, my major focus is on freshening up the engine. I would like to take a stab at rebuilding this one. Currently, it's been taken apart in my garage. Like an idiot, I dropped a piston/rod on the floor and scuffed up the edges of the piston
. I just want to replace that set and not worry about gouging the cylinder walls.
---Can I just grab another LQ4 piston/rod from another engine and avoid a rebalance? I don't plan to take this engine past 5500 rpm ever.
Current thinking on the engine is to build for 93 octane, low-end grunt, on a stock-stall converter. I think that would work well with what I do with the Jeep. I was thinking of going with rebuilt 706 heads and a drop in cam from summit (8712). I am new to this engine building stuff, but I think that would land me around 9:1 dynamic compression, 10.5 static.
What do you guys think would be a good choice for smooth drivability on 93 octane and a stock stall? Should I go bigger on the cam?