Announcement Announcement Module
No announcement yet.
Help with new engine question Page Title Module
Move Remove Collapse
Conversation Detail Module
  • Filter
  • Time
  • Show
Clear All
new posts

  • Help with new engine question

    16 years ago I bought an 81 cj5 Renegade from a friend of my fathers and have enjoyed it ever since. It's never been 'upgraded' and I've been thinking about putting some money into it. I was just wondering if anyone could give me any info on what 6 cyl or 8 cyl engines I should be looking at and how hard/easy it's going to be to connect said new engine to existing transmission not to mention if I should upgrade that as well in my upgrade.
    I've got the stock gm 151 4cyl, the Sr4 transmission and the 300 transfer case. Any help would be appreciated. I'm thinking I might just look for a six cylinder considering gas prices these days.


  • #2
    6cyl isn't going to save you money over an 8cyl. my 8 get's better milage than the 6 did. especially now that it's broke and i cant drive it.

    how hard it is depends on your ability. it's done a lot so there's a lot of resources to draw upon.


    • #3
      If you could get your hands on a nice small block, say a 283 or something like that, it will be very good on gas. Put a small 2 barrel carb on it and you will still have plety of power on the trails. I figure in a Jeep, you would probably get 10 to 15 MPG. Which isnt bad consindering my 02 5.7 gets 17 MPG on a good day and usually 14-16. If you were willing to spend a few bucks, you could go TBI, your gas milage would only improve and so would your power. Depending on what you did, you would probably get 260-270 horse as a starting point and any mods you did to the engine would make the HP go up. I figure with a smaller cam, headers, TBI, and decent exhaust, you would probably have close to 300 horse which is plenty for an old CJ.
      I would ditch the Sr4 and go with a reman T350. Your not pushing a lot of weight so a 350 will be just fine and probably never give you a problem. I suggest the 350 for a few reasons.
      One, it will bolt directly to the small block.
      Two, their are an infinate number of t-cases that will bolt to it.
      Three, the tranny can take the mild HP that the 283 will push.
      Four, they are cheaper than say a 4L60, plus a 4L60 will be a bit harder to find that say a 4L60e but the 60e needs a computer to controll it, the 4L60 came in manual S-10s, not impossible to find but not as prevelent as the 60e but worth it in the long run, the only draw back of the T350 vs. the 4L60 is that the 60 is an over drive tranny, the T350 only has 3 gears so the gas milage will suffer a bit, but you could make up for that with say 3:73 gears, maybe even higher but it will make wheelen harder without the low gears. However, with the larger motor, the go pedal will make up for the lack of gearing.
      Now doing all this will cost a few bucks. Your going to need motor mounts, probably a new tranny cross member, an adapter for your T-case and probably new driveliness too (I am assuming that combo would push your t-case back a few inches). A wiring harness and their are always unforseeable odds and ends.
      You could do a stroker on your existing motor. That will give you plenty of power, will bolt right back into your CJ but it will cost you! The stroker in the long run would probably be cheaper than the V8 swap but comon, a V8 swap is just cool! Doing the V8 would be relativly painless. There is a plethora of info out there on doing it, you are not the first to do something like that and you will not be the last.
      Just my


      • #4
        the 4L60/700R4 (same trany different name) came in a lot of full size trucks untill about 91 or 92 as well as the s-10s. Since it has been more than 20 years since the TH350 was used in a production vehicle it may be tougher to find in a junk yard than one may think.

        If you change engines, the best advice is to find one that you like and don't compromise. it is your jeep and you are the only one who needs to be satisfied, don't go chevy because they are easy, or limit youself to jeep engines because the purists say so. Do what you think is best.

        That being said, I am partial to chevy motors, especially the 4.3 liter V6. At 170 HP and 230 lb-ft of torque for the stock TBI injected version (thats the same as a late 70's era 350!) and decent mileage (18-21 typical highway) it seems to be a nice motor.

        The only hard fast advice I can give you is to dump the SR4 trany. You are lucky it has held up to the 4 banger.


        • #5

          Thanks for that bit of info I will use that to my advantage also


          • #6
            makin' it better...

            Originally posted by setenney
            Thanks for that bit of info I will use that to my advantage also
            Setenney... read over Tracaym's post again as well and 'reflect'. Study up good. Best of luck with your choice of direction.


            • #7
              Thanks alot for all the info guys. Will put it all to good use in the future!!!