creekscout Posted November 27, 2009 Share Posted November 27, 2009 Since I can't get the search to help me find info I have to ask for info on swapping a 3.4 camaro into a '86 mj 2wd, auto, 2.8. I want to keep the swap as simple as possible so I would keep it carbuerated and use whatever parts I need to to avoid having to do much wiring hacking. I just bought the truck with a very good body but it has not been on the road for about 7yrs. because the pov said it had a blown head gasket. I am going to try to get it started but I don't have alot of hope. I have found a 3.4 motor out of a 94 firebird that I am thinking about buying to install. What is the bolt pattern of the bellhousing, gm or chrysler? Thanks for any help. Link to comment Share on other sites More sharing options...
Eagle Posted November 27, 2009 Share Posted November 27, 2009 The 2.8L is a GM engine that Jeep purchased from GM. The bell housing is the small GM bolt pattern, which is why the 3.4L GM engine swap is a slam dunk -- it's the same block. Use the manifolds and external brackets and such from the 2.8L and you should be good to go. The only thing to watch out for is the the 2.8L was not a well-designed engine (duh!). GM got it to balance by using an eccentric weight on the flywheel/flexplate to compensate for the fact that the engine was not balanced interbnally. By the time the 3.4L came out, they had figured that out and the 3.4L does not use the eccentric weight. So you'll need to have the flywheel or flex plate neutral balanced. Link to comment Share on other sites More sharing options...
Pete M Posted November 27, 2009 Share Posted November 27, 2009 and you'll need an electric fuel pump, since the 3.4 doesn't have the place for the mechanical. Doesn't have to be very powerful if you're keeping the carb. and speaking of carb, I highly recommend upgrading the stock carb. :thumbsup: Some may disagree, but I own a 2.8 and that stock carb could choke the life out of a lawnmower. :fs1: Link to comment Share on other sites More sharing options...
Eagle Posted November 27, 2009 Share Posted November 27, 2009 :agree: The stock carb on the 2.8L isn't even heavy enough to be useful as an anchor, and unless you spend more than it's worth in carb cleaner you can't use it as a paperweight. I don't know what it's good for. Link to comment Share on other sites More sharing options...
creekscout Posted November 27, 2009 Author Share Posted November 27, 2009 what replacement carbs will work. Also does the 3.4 have a distributor or coilpacks. Link to comment Share on other sites More sharing options...
glundblad Posted November 27, 2009 Share Posted November 27, 2009 And I assume he would still be able to use his existing gauges? Wouldnt his tach be inaccurate if he had one? Link to comment Share on other sites More sharing options...
Eagle Posted November 27, 2009 Share Posted November 27, 2009 what replacement carbs will work. Also does the 3.4 have a distributor or coilpacks. If you are using the accessories from the 2.8 rather than converting the electronics, you'll use the distributor from the 2.8L. Link to comment Share on other sites More sharing options...
Pete M Posted November 27, 2009 Share Posted November 27, 2009 And I assume he would still be able to use his existing gauges? Wouldnt his tach be inaccurate if he had one? Essentially all he'd be doing is replacing the old v6 block and heads with a matching (but better) set of new v6 block and heads. Tach should work fine. :thumbsup: Link to comment Share on other sites More sharing options...
JeepcoMJ Posted November 27, 2009 Share Posted November 27, 2009 edelbrock.com get a gm 60 degree intake manifold with a 4bbl adapter on it, and run a holley 390cfm 4bbl carb. well worth the money. the bell housing on a 2.8/3.4 is 60 degree. you need to swap your oil pan, exhaust manifolds, and valve covers. the timing is accurate for your setup. http://jeep.off-road.com/jeep/article/a ... ?id=277008 good write-up on tech, but no pics http://www.lunghd.com/Tech_Articles/Pro ... ect_XJ.htm EXCELLENT write-up on how to keep it carbeurated as well. this shows you everything you need to do to do the swap, with good pics. As stated above, DO NOT keep your stock carb or intake. they're half the problem with the 2.8. I did a similar swap, using a camaro buick 3800 v6...not nearly as "bolt-in" as a 3.4. you'll benefit ALOT by going to fuel injection, and you don't have to hack your wiring harness. it's simple when you get the complete camaro/firebird engine bay harness. just need some diagrams/pin connector views to delete what you don't need. then you piggyback the camaro/firebird harness to your factory harness, and use your jeep temp. sensor and oil pressure sensor, since the 3.4 ECU does not use the sensors to tell the motor what to do. the last thing you'll need to go fuel injection is a VATS (vehicle anti theft system) bypass module, which goes to pin #55 on the 3.4 ECU (blue wire) to bypass the injector cut-out. this cut-out is there in case someone tries to start the vehicle by bypassing the keys (which are coded). since you can't use the firebird steering column, this is necessary. follow this link, look for VATS bypass, it's only $25 for the module...cheaper than upgrading a carb. http://mysite.verizon.net/vze7erz1/id1.html if you do go carb'd and upgrade, I'd recommend using a late 80's ford fullsize v8 inline fuel pump...you can splice it right in your fuel line and mount it to the body, never having to worry about pulling the sender from the tank when it fails Link to comment Share on other sites More sharing options...
creekscout Posted November 27, 2009 Author Share Posted November 27, 2009 the main reason I do not want to mess with the wiring is that 23 year old wires look to be hard and brittle and I do not want to disturb it if I can help it. I would like to keep the fuel injection but I have to wait and see what the costs for the motor will be, I found one for $350 with 88x on it but it about a 3 hr drive to check it out. Thanks for all replies as I know I am going to need help with this alot. Link to comment Share on other sites More sharing options...
JeepcoMJ Posted November 27, 2009 Share Posted November 27, 2009 the main reason I do not want to mess with the wiring is that 23 year old wires look to be hard and brittle and I do not want to disturb it if I can help it. I would like to keep the fuel injection but I have to wait and see what the costs for the motor will be, I found one for $350 with 88x on it but it about a 3 hr drive to check it out. Thanks for all replies as I know I am going to need help with this alot. I understand that. thing is, there is only 1 wire that you'll have to splice in, and 2 wires you may need to extend. those are your tach, temp, and oil psi wires. everything else is "piggybacked". you'd ground the ECU near the battery (3 ground wires IIRC), have one constant power, and one ignition (constant ignition) wire, then a small seperate fuse block for those powers, and one relay for the fuel pump. the constant IGN is in your fuse box...just run a spade into it to the fuse block, then from there to the ECU. I was daunted by the 3800 swap, but it only took me 3 hours to have the wiring done. I used Alldata for the wiring diagrams...I'm sure I can get you the connector views, and layouts etc. using an edelbrock intake and holley 390cfm 4bbl carb will cost you more money than making the fuel injection work, and you'll be happier with the result in the long run. Link to comment Share on other sites More sharing options...
creekscout Posted November 27, 2009 Author Share Posted November 27, 2009 Well jeepcomj you do have me thinking maybe I will consider the fuel injection route if that is all that's involved, other than the fuel pump and fuel lines to be changed. I just got done taking the seats and carpet out and things don't look that bad there either. The only hole in the floor is about halfway up the trans. hump, drivers side, right under the heater duct. Where in the world would water come in from that high up? Thanks again for all your replies. Link to comment Share on other sites More sharing options...
Pete M Posted November 28, 2009 Share Posted November 28, 2009 water can come in through anywhere. it's almost magical. be sure to find and seal the leak before you put the carpet back. the baby powder trick works great. :thumbsup: Link to comment Share on other sites More sharing options...
mbigdawgcp Posted January 4, 2010 Share Posted January 4, 2010 :idea: so how did this swap turn out.... :thumbsup: Link to comment Share on other sites More sharing options...
-600JeepMJ Posted January 4, 2010 Share Posted January 4, 2010 when I did the swap in my 86 XJ , I found it to be a very easy swap. I rebuilt the 94 camero motor in my hotel room while was deployed to charleston SC. :cheers: (got to love the Air Force reserves) :eek: suprised the poor maid to walk into the room and find a motor had exploded in the room and all the parts had landed on my own towels speard all over the place. when I left the place 187 days later it was a lot cleaner then when i got there. and my $450 XJ was purring like a kitten with its new $200 junk yard motor. Link to comment Share on other sites More sharing options...
-600JeepMJ Posted January 4, 2010 Share Posted January 4, 2010 when I did the swap in my 86 XJ , I found it to be a very easy swap. I rebuilt the 94 camero motor in my hotel room while was deployed to charleston SC. :cheers: (got to love the Air Force reserves) :eek: suprised the poor maid to walk into the room and find a motor had exploded in the room and all the parts had landed on my own towels speard all over the place. when I left the place 187 days later it was a lot cleaner then when i got there. and my $450 XJ was purring like a kitten with its new $200 junk yard motor. Link to comment Share on other sites More sharing options...
Pete M Posted January 4, 2010 Share Posted January 4, 2010 no photos? :( Link to comment Share on other sites More sharing options...
freakjeep93 Posted January 5, 2010 Share Posted January 5, 2010 i waould love to see that Link to comment Share on other sites More sharing options...
knever3 Posted January 6, 2010 Share Posted January 6, 2010 This swap sounds like going fuel injection would be well worth it. That said you got the whole harness out of the firebird. If the motor is already pulled and you have to get another harness that would be a little difficult. Fuel injection is great, starts every time and runs great no matter what temp it is outside, rain or shine. I think you will be very happy about the swap and with all the support on this board you will get answers and pictures of any problem that you may run across. I would like to see some photos of the engine torn apart in a hotel though!! I am spoiled by having a 2 1/2 car heated attached garage... Link to comment Share on other sites More sharing options...
-600JeepMJ Posted January 6, 2010 Share Posted January 6, 2010 i wish i had some better pictures of the hotel rebuild but this is the only one i can find right now Link to comment Share on other sites More sharing options...
-600JeepMJ Posted January 6, 2010 Share Posted January 6, 2010 the motor now Link to comment Share on other sites More sharing options...
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