An engine swap is way beyond anything I’ve attempted but I’m going to give it a shot. What could possibly go wrong? The stock 97 4.0 only has 155K and runs pretty well. It has a lifter tick but doesn’t burn oil and feels pretty smooth except occasional mild roughness at idle. Also, with the recent addition of 4.10 gears (vs stock 3.08), it’s less doggy around town. But everyone knows it’s not super powerful either. And it has developed low oil pressure at idle when warm (possibly suggesting excessive crank or cam bearing wear?). There is no rod knock. A new oil pressure sensor didn’t fix this. Neither did 20W50 oil and heat wrap around the exhaust by the oil pan (but they did help). A harbor freight mechanical gauge showed no less than 10-12psi at warm idle with over 40 psi while driving. So not entirely sure I’m having a real oil pressure problem or just a gauge problem. We will find out when the new motor goes in, I guess.
As to that, there are numerous people in my area who have V8 swapped Jeeps. Those Jeeps are very cool and I briefly considered an LS. But that would be a stretch too far for me both in skills and the mission of this Jeep so I decided a stroker was way to go. Mostly I just want to attempt the swap on my own and get some more power while maintaining the essence of what I consider to be a great original vehicle. The Golen crate 4.6L has a ‘92 block and 7120 casting head. According to Golen, this specific engine made 284HP at 5200 RPM and max torque was 323ft.lbs. (with over 300 from 3000-5200RPM) on their dyno. Stock 1997 4.0L numbers are about 180HP and 225ft.lbs. I’m going to try to get baseline dyno numbers on the stock 4.0L at the rear wheels before I pull it and then with the 4.6L once it’s in. I like data to back up my subjective impressions. I’ll post that info here.
Anyway, now I’m digging into preparation for the swap. I have a hoist and engine stand. Ordered some Brown Dog motor mounts, an OEM Luk clutch and flywheel with National throw out bearing (thanks to Jerry Bransford for the advice) and a new starter. The motor came with a stainless header, high flow water pump and 62mm throttle body as well as 24# injectors to replace the the stock 18# units (and necessary gaskets). Planning on straight swapping everything else except maybe the distributor.
This will may take a bit and I will probably more need advice from forum members along the way so thanks in advance.
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