ocean Posted July 9, 2009 Share Posted July 9, 2009 Bolt size is 7/16. 89 Renix TBI 4cylinder. On the exhaust manifold is states the firing order and "XJ". There is an small metallic tag that looks like it is stamped that says '403'-. Any guesses as to what cylinder head I have? :huh???: I am asking because the exhaust valve is sticking in the #1 cylinder, we could hear the air escaping in the exhaust when we checked it) and while I have worked out a replacement engine I would like to know what the proper cylinder head is if I choose to replace it or have somone locally recondition it. I have not yet cracked the valve cover to check on the issue. The engine still runs, was getting 33 mpg, but when it gets warm it misfires under load. Thanks in advance! Link to comment Share on other sites More sharing options...
Oizarod115 Posted July 9, 2009 Share Posted July 9, 2009 i don't know that there is any major differences just try to get one off a similar TBI engine if you have to. the later stuff should still bolt up and work but it might have different bolt holes and such for sensors Link to comment Share on other sites More sharing options...
Eagle Posted July 9, 2009 Share Posted July 9, 2009 i don't know that there is any major differences just try to get one off a similar TBI engine if you have to. the later stuff should still bolt up and work but it might have different bolt holes and such for sensors No, the ports on the HO heads are higher up and shaped differently than those on the Renix 4.0L. It is possible to force-fit an HO head and still use the Renix manifolds, but it's not a bolt-on replacement. To keep it simple, the Renix years were 1987 through 1990. A head in that range should bolt right up. Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 9, 2009 Share Posted July 9, 2009 No, the ports on the HO heads are higher up and shaped differently than those on the Renix 4.0L. It is possible to force-fit an HO head and still use the Renix manifolds, but it's not a bolt-on replacement. To keep it simple, the Renix years were 1987 through 1990. A head in that range should bolt right up. He's asking about an 89 Renix TBI 4-banger. But a 4-banger head in that range should bolt right up too. Link to comment Share on other sites More sharing options...
Geonovast Posted July 9, 2009 Share Posted July 9, 2009 i don't know that there is any major differences just try to get one off a similar TBI engine if you have to. the later stuff should still bolt up and work but it might have different bolt holes and such for sensors No, the ports on the HO heads are higher up and shaped differently than those on the Renix 4.0L. It is possible to force-fit an HO head and still use the Renix manifolds, but it's not a bolt-on replacement. To keep it simple, the Renix years were 1987 through 1990. A head in that range should bolt right up. We're talking about a 4 cylinder. AFAIK, most of the heads of the 2.5s are interchangeable. It'd still be a good idea to get one from an 86-90 XJ/MJ/TJ, since those were the TBI years for the 2.5. 84-85 were carbed, and 91+ is MPFI. Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 9, 2009 Share Posted July 9, 2009 Hey Correy - beat you for once. :nanner: :cheers: Link to comment Share on other sites More sharing options...
Geonovast Posted July 9, 2009 Share Posted July 9, 2009 Indeed you have. :fs1: Link to comment Share on other sites More sharing options...
mnkyboy Posted July 9, 2009 Share Posted July 9, 2009 Car-part.com is showing 84-85 by themselves then interchanging 86-96 2.5L heads. Thats assuming their interchange is correct. I would still want to verify this before buying one. Link to comment Share on other sites More sharing options...
ocean Posted July 9, 2009 Author Share Posted July 9, 2009 Thanks for the information. I didn't know if anything changed during that year with the Chrysler buyout and the whole renix combo.. I just saw diffrent casting numbers and bolt sizes and thought there could be major differences. :thumbsup: Link to comment Share on other sites More sharing options...
Eagle Posted July 9, 2009 Share Posted July 9, 2009 Sorry -- I was tired and I missed the 4-cylinder part. So you lads are saying that the 1991 and newer 4-cylinder engines did NOT have redesigned ports and manifolds like the 4.lL did? Port height and shape is the same for the Renix 4-cyl and Chrysler 4-cyl engines? Link to comment Share on other sites More sharing options...
Geonovast Posted July 9, 2009 Share Posted July 9, 2009 Sorry -- I was tired and I missed the 4-cylinder part. So you lads are saying that the 1991 and newer 4-cylinder engines did NOT have redesigned ports and manifolds like the 4.lL did? Port height and shape is the same for the Renix 4-cyl and Chrysler 4-cyl engines? That's what I've been told. I have an 86 2.5 and 93 2.5 sitting out in the shed, but unfortunately the 86 is missing it's head, so I can't check that for sure. Link to comment Share on other sites More sharing options...
mnkyboy Posted July 9, 2009 Share Posted July 9, 2009 this would be good to know for sure. just because the heads will interchange doesnt always mean they are identical,so i would be curious to know of any differences between the TBI and MPFI heads. I'm getting a complete engine,wiring, and ECU from a 95 TJ and I'm going to convert my MJ to MPFI. Link to comment Share on other sites More sharing options...
mvusse Posted July 10, 2009 Share Posted July 10, 2009 I believe 84 and 85 might have been carburated. This may or may not make a difference. Then again, I could be wrong. Link to comment Share on other sites More sharing options...
Eagle Posted July 10, 2009 Share Posted July 10, 2009 I believe 84 and 85 might have been carburated. This may or may not make a difference. Then again, I could be wrong. 84 and 85 were carbureted, but there were no MJs in those years. 86 thru 90 were the Renix-based throttle body injection. 91 and newer were the Chrysler multi-port injection. It would really surprise me if the Chrysler engine have the same ports and manifoldsa as the Renix. The MPI engines produce a LOT more horsepower and torque than the TBI engines, and I can't make myself believe that some of the gains weren't from a head/manifold redesign. They did the development work for the 4.0L ... the two engines are essentially the same except for number of pistons, so why would they not port the improvments over to the 2.5L? Link to comment Share on other sites More sharing options...
mnkyboy Posted July 10, 2009 Share Posted July 10, 2009 Found these pages on the 2.5L they have alot of good info. http://www.offroaders.com/tech/jeep/gnu-engine-factory-150i4.htm http://www.allpar.com/mopar/amc-25.html Link to comment Share on other sites More sharing options...
ocean Posted July 11, 2009 Author Share Posted July 11, 2009 Thanks for the info on the 2.5. I am curious about the improvements to horsepower as they affect economy when it goes from TBI to the improved MPI. With TBI I was getting 33 MPG on the HWY. I like not going to gas stations... Link to comment Share on other sites More sharing options...
mnkyboy Posted July 11, 2009 Share Posted July 11, 2009 how are you pulling off 33mpg thats about 600 miles per tank. i get about 18-19mpg with the TBI 2.5L as does my brother in his 2.5L 5spd YJ with MPFI 33mpg hwy is about what i get in my 07 Focus with 2.0L duratec and 5spd. Link to comment Share on other sites More sharing options...
mvusse Posted July 11, 2009 Share Posted July 11, 2009 How are you getting 18-19 highway with a 2.5? I can get 22mpg highway out of my Renix 4.0 (60mph) and 21 out of my 4.0HO (75mph). Both I get 17-18mpg mixed driving. Or I did before I moved to 33" tires anyway. Link to comment Share on other sites More sharing options...
Geonovast Posted July 11, 2009 Share Posted July 11, 2009 My 2.5 averaged 16 the last few times I checked, but it's still running weird and I don't know why. XJ is getting 25 highway averaging 70mph and 89 octane. Seems to get better once I leave WI, since in Iowa and Missouri I can get gas without ethanol. Link to comment Share on other sites More sharing options...
mnkyboy Posted July 11, 2009 Share Posted July 11, 2009 I'm sure my 4spd doesnt help MPG on the hwy, but i still only get 16 maybe 17 out of my renix 4.0L. my city and hwy mpg really doesnt change much. here's the EPA fuel ratings comanche 2.5L EPA http://www.fueleconomy.gov/feg/calculatorCompareSideBySidePopUp.jsp?column=1&id=6098 Cherokee 4.0L EPA http://www.fueleconomy.gov/feg/calculatorCompareSideBySidePopUp.jsp?column=1&id=6316 Link to comment Share on other sites More sharing options...
Geonovast Posted July 11, 2009 Share Posted July 11, 2009 What gearing are you running? If you've got the stock 3.55s that came with the 4 speed, then that would definitely explain your mileage on 31" tires. Link to comment Share on other sites More sharing options...
mnkyboy Posted July 11, 2009 Share Posted July 11, 2009 ya I'm still running stock 3.55 gears for now. 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