Jack15379

Looking for exhaust header suggestions. Ive read mixed things about all of them so any input is appreciated.

I just got my block back from the machine shop and I found a hole right above the cam journals at the top of the timing cover area. Ive read that a lot of people have these holes and that it should be perfectly ok. Can anybody confirm this? IMG_0419.HEIC IMG_0420.HEIC

Block just went off to the machine shop! Most of my engine parts have arrived. I contacted Russ and he worked with me to put together a kit of everything I need and answered any questions I had. Phenomenal working with him and his prices are great as well. - Russ's custom RaceTech .060 over Edelbrock head specific forged aluminum pistons - Russ's custom Scat 6.125" floating pin rods - Russ's custom cam from Comp Cams - Hylift Johnson lifters - Edelbrock Head - Rollmaster double roller timing set - Hastings ring set - Russ's custom 1:6.5 Harland Sharp roller rockers Ill also be using 3/8 push rods over the stock 5/16. So stoked to get the block back and start assembling @ghetdjc320 You mentioned you've used Holley EFI. Can you elaborate on the process of converting to it and if there was anything you needed to change? Specifically will the OEM sensors work or is there a lot of conversion and finagling to be done. Did you go with a Terminator?

Which lifters did you use from them/do you have a part #. When I called them they said they didn't have any specifically built for the 4.0.

The old engine is out and dissembled! I found a surprise, my exhaust has a magnaflow cat and a flowmaster muffler lol. IMG_0251.HEICIMG_0247.HEIC The block is in good condition so ill be reusing it. All the rods looked good too so ill try and reuse those too. To those that have built strokers with the 258 crank: what piston compression height did you use? What compression ratio did you end up with? Any recommendations on pistons? If I can figure out what CR I should shoot for then I can find pistons to achieve that. After looking up articles I'm thinking I'm gonna go with a set of hypereutectics. I wanna keep it on 87 octane. Do you know if the 99+ engine management systems with the coil on plugs are as tunable? Gonna be trying to find a junkyard HO head that's in good shape. If I can't find one the Edlebrck it is.

Hi all! I wanted to start a build thread for the 4.0 stroker build that I've started to get input and advice as I'm going along. I'm learning as I go and it would make me feel a lot more comfortable if people with more experience looked through what I'm doin. My intended use for the truck is a dd, something with more power and just to make it really really cool. So getting into it.... Starting with a 1989 MJ with a tired 4.0 with a blown head gasket and high oil pressure. 5 speed to a ford 8.8 in back. The motor is completely ready to come out at the moment, gonna pull it in a few days. Right now I'm thinking ill do away with the whole old motor completely and get a HO head and an NVH block (plenty of XJs in nearby junkyards to look through). HO head over edlebrock because of the price. For the stroker part of it I'm gonna do the 4.2L crank and rod swap. I'm aware that ill need dished pistons with a different pin height for this setup. Probably gonna bore it to 30 or 40 over. Gonna need my engineering school friends to help me with compression ratio maths lol. Valvetrain/airflow: I'm gonna have my head ported and MAYBE do some LS valves to let it breathe, and a cam to make it breathe. I'm trying to learn as much as I can about cams but that sh*t is sooo confusing so any advise on resources to help pick a cam would be much appreciated. Ill do hydraulic lifters with the little oil hole in them and roller rockers. Port matched HO intake with a bigger throttle body and 1 inch spacer under the TB. 24# injectors. As for wiring and electrics I think I'm leaning towards replacing the whole Renix harness with the HO harness instead of getting my current wiring to work. If I'm gonna put this much into the performance of my motor I want the best wiring I can to use all its available potential. Something I am curious about is whether I should stick with the distributor or go with the coils from the early 2000s XJs, any input on this would be greatly appreciated. Other miscellaneous things: -high flow water pump with high flow thermostat and housing -high flow oil pump with a oil warmer/cooler box from Hesco Other things I'm thinking about: -could I get any more performance with a custom intake manifold or is the stock HO intake that's been port matched pretty optimal? -electric vacuum pump to tidy things up in the engine bay and not have to worry about low pressure at idle? -is a cold air intake a good idea or is that stupid? -oil catch can? Ill be posting more updates as I figure more stuff out and progress in the build. IMG_0239.HEIC IMG_0241.HEIC

I got an 89 4.0 that’s been missfiring and stalling. It started out missing and joulting when accelerating hard in first and second gear but the other day it sputtered and died right after I started it up. It will start smoothly cold but after a minute or two it begins to sputter and miss and stalls. It’s hard to start after that and if I do get it going it’s missing all over the place. Exhaust smells like gas and it backfires after a couple times restarting it. I’ve replaced plugs, distributor cap and rotor and wires and have a crank position sensor ordered. I believe it’s some electric ignition issue due to the rich misfiring but don’t really know where to go from there. If anyone has any of what the problem could be or how I can identify it I’m all ears.

1989 Comanche 4.0 w/ AX15 / Front Danna 30 / Rear Ford 8.8 Limmited Slip / Short Bed / RWD I think it's a Poineer Trim Package but haven't done any super deep digging on it Location: West Minneapolis Suburbs, Minnesota, Originally from Idaho Status: Right now its running strong as my daily driver. Eventually might want to make it 4wd but that's way in the future Notes: Ive lifted it 3" to get more of a 4x4 look and put 31s on. I also did the disk break conversion with the 8.8. It's painted white, interiors grey with the nice comfy bench seat This is in fact my first vehicle, grandpa has always been fascinated with MJs and that trickled down to me. Love having something different that everyone else, and I'm extremely greatful that I could buy this truck.

There hasn't been a lot of mentioning of just buying a kit and really if going from junk yard to junk yard is a little out of your league, a kit will do fine for a DD. I had the same idea about a year ago about getting a kit to fit 31s and I ended up going with the 3" add a leaf kit from Rusty's. http://www.rustysoffroad.com/rustys-mj-comanche-3-add-a-leaf-kit.html It comes with everything you need , although the add a leaf will not produce the advertised 3" on the rear. I've had no issues with this lift since I put it on. Making a kit yourself will get you better value and doing it now having more experience I would go that route but regular kits are nice when you don't know exactly what your doing.