jeep Girl 03 Posted January 24, 2023 Share Posted January 24, 2023 I have a 1987 jeep Comanche. Straight 6 stock engine. I would like to swap out the engine. Any suggestions on what motor would easily swap out! Link to comment Share on other sites More sharing options...
ghetdjc320 Posted January 24, 2023 Share Posted January 24, 2023 Another 4.0 or a stroker based on the 4.0 would be the most straight forward. Are you trying to get more power or just replace a bad engine? Link to comment Share on other sites More sharing options...
cruiser54 Posted January 24, 2023 Share Posted January 24, 2023 CRUISER'S MOSTLY RENIX TIPS HO INTO RENIX SWAP OCTOBER 31, 2015 SALAD 76 COMMENTS This swap is easier than some will lead you to believe. And generally Pooh-poohed by those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block. XJ Cherokee and ZJ Grand Cherokee 4.0L engine blocks interchange. 2000+ TJ Wrangler and WJ Grand Cherokee 4.0L engine blocks interchange. YJ and 1997-1999 4.0L TJ blocks will interchange in XJ/ZJ XJ/ZJ blocks, and the 2000+ TJ/WJ blocks do not interchange without significant modifications. TJ/WJ 4.0L Engine blocks underwent clean sheet design changes effective in the 1999 WJ Grand and 2000 TJ Wrangler. These blocks are not interchangeable with XJ/ZJ engine blocks. The reason is motor mount bolt holes and belt driven accessory mounting bolt holes are in different locations, or not present at all, TJ/WJ vs. XJ/ZJ. Now that we know which engines we can use, let’s get down to business. The HO and Renix have some differences but none that can’t be overcome very easily. One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from an HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head at the rear for the sender. You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use a new Renix gasket. Exhaust ports are identical. An alternative on exhaust manifolds: As far as exhaust, you can use the Renix exhaust manifold and be fine. If you want to use the HO exhaust manifold, you must go with an HO headpipe and screw your O2 sensor into that headpipe. Standard Renix harness is plenty long to do so. A bung can be welded into the HO manifold to accept the EGR tube. You will need to use your Renix distributor as it is different than the HO design. See Tips #12 – Setting Your 4.0 to #1 TDC and #13 – Distributor Indexing to be sure you get the distributor installed correctly. The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications. The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16” square drive or a modified 3/8” drive that has been ground down to fit. Do this before installing the engine. As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case. XJ: “Regular” (not Grand) Cherokees ’84-’01 ZJ: Grand Cherokee ’93-’98 (Gen1) WJ: Grand Cherokee ’99-’04 (Gen2) YJ: Wrangler ’87-’95 (Gen1) TJ: Wrangler ’97-’06 (Gen2) Link to comment Share on other sites More sharing options...
jeep Girl 03 Posted January 24, 2023 Author Share Posted January 24, 2023 9 hours ago, ghetdjc320 said: Another 4.0 or a stroker based on the 4.0 would be the most straight forward. Are you trying to get more power or just replace a bad engine? Link to comment Share on other sites More sharing options...
jeep Girl 03 Posted January 24, 2023 Author Share Posted January 24, 2023 I would like more power and a different engine then a straight 6. I was wondering if anyone out a different engine in. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted January 24, 2023 Share Posted January 24, 2023 I swapped in a 5.7 LS engine as have a couple others. There are a few who have also done diesel swaps. Look in the “Epic” build sections for builds by @Limeyjeeper and @70barracuda. There is one irrefutable fact for any of us who have done a V8 swap, they cost a lot more than it may seem. Those build threads will take you through the parts needed for the swap as well. Link to comment Share on other sites More sharing options...
Pete M Posted January 24, 2023 Share Posted January 24, 2023 What size tires do you have? Link to comment Share on other sites More sharing options...
Smokeyyank Posted January 24, 2023 Share Posted January 24, 2023 2 hours ago, jeep Girl 03 said: I would like more power and a different engine then a straight 6. I was wondering if anyone out a different engine in. How much money you willing to drop? If you're not comfortable doing a lot of fab work and spending 6-10k keep the 4.0. Do cruiser54 tips, regear it, drive. Link to comment Share on other sites More sharing options...
Eagle Posted January 25, 2023 Share Posted January 25, 2023 19 hours ago, jeep Girl 03 said: I would like more power and a different engine then a straight 6. I was wondering if anyone out a different engine in. Small block Chevy is a popular choice. EVERY single one I have seen has had cooling problems. The stroker version of the Jeep I-6 is, IMHO, the best option. It increases the displacement from 4.0 liters to 4/6 or 4.7 liters. Combined with a mild cam upgrade, you won't believe it's still a 6-cylinder engine. Link to comment Share on other sites More sharing options...
cruiser54 Posted January 25, 2023 Share Posted January 25, 2023 Post 1 says "easily". Link to comment Share on other sites More sharing options...
ghetdjc320 Posted January 25, 2023 Share Posted January 25, 2023 21 hours ago, Smokeyyank said: How much money you willing to drop? If you're not comfortable doing a lot of fab work and spending 6-10k keep the 4.0. Do cruiser54 tips, regear it, drive. 6-10K is extremely conservative Link to comment Share on other sites More sharing options...
Smokeyyank Posted January 25, 2023 Share Posted January 25, 2023 1 hour ago, ghetdjc320 said: 6-10K is extremely conservative ha ha, I can only imagine what the "true" cost is. Figured that was just pulling an engine and tossing it in. No rebuilding or a lot of the other things to be done right. Link to comment Share on other sites More sharing options...
75sv1 Posted January 26, 2023 Share Posted January 26, 2023 21 hours ago, Smokeyyank said: ha ha, I can only imagine what the "true" cost is. Figured that was just pulling an engine and tossing it in. No rebuilding or a lot of the other things to be done right. Just replacing a stock motor is going to be $1,000 on the cheap side for labor. So, then there is all the wiring, mounts, exhaust etc. etc. There was a really nice Yellow MJ on this board around 2004. It had a Ford 5.0 in it. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now