Well I'm starting a thread on my 79 CJ-7 that I have had for probably 3 years now. I have already tour it down to the frame. the tub was Swiss cheese so I scraped it and was able to get a 80 CJ-7 tub that was in better shape. Now it will need some work but not as bad as the original tub. I also got axles out of a 79 Blazer a D44 and GM12 bolt. Now the question I have is do I keep it as a leaf spring rig or do I go with a four link coil over? What do you guys think? pros and cons of both?
Originally I was going to use a chevy 350 four bolt main engine I have as the power plant. but I was able to get a hold of a 4.5BT Cummins engine my work was scraping it was brand new never used.so I'm going that way now.
Well I'm going to use a SM-465 that I already have. as far as the rear end goes I got the GM12 bolt I would prefer another axle but not sure what. would love to find a set of D60 but that's allot of $$. How would a Ford 9" be would that be a better axle? we had a few other engines but they where perkins this was the only Cummins.
Well I'm going to use a SM-465 that I already have. as far as the rear end goes I got the GM12 bolt I would prefer another axle but not sure what. would love to find a set of D60 but that's allot of $$. How would a Ford 9" be would that be a better axle? we had a few other engines but they where perkins this was the only Cummins.
14 bolt is hard to beat they are in so many different things easy to find. They can be bought from $50 to $100 around me. I got one for $25 once. Not that high to disc brake them either.
If you got that engine for free then......Congratulations!!!!!! you've just become my new most hated member on JF.....followed closely in 2nd by Scott21 and his barn find CJ7....
well the Hunt is on for either a 14B rear or a Dana 60 I called a few JK but they want over $350 for an axle. ugh so I'm going to keep looking. I found one on CL but he wants $200 for it and its 4:10 gears and the spiders have been welded. I found a D60 for $200 to but its also 4:10 gears. Not sure about the front if the D44 is good enough for now or if I should look for a set?
Since the 465 doesn't have O/D I'd just go with the more common 4.10's rather than waiting to find one with 4.56 gears in your price range. The 4.10's will help keep the rpm's down on the highway (especially since diesels are lower revving engines) and the cummins will have plenty of torque to get you moving. The 465 has the granny low 1st so the 4.10's won't be too high for crawling either.
Well I'm probably going to be running either 35s or 37s depends on what I can afford. Now I thought 4:10 wouldn't be a good gear to run because it increases the RPM. I'm currently running 4:10 in my YJ and after I installed them my RPM increased by at least 500 RPM or more. but I'm running 33 so maybe 35s or 37s might be a different story..
I'm building much the same rig (remember). Play with a RPM calculator to see what will make you happy. I'm going with 3.73s and 35"-37"s and I'm running the ZF with OD. You want your cruising RPM around 1800 highway. around town at lower speeds I'm looking for around 1500 (less wind resistance so less HP needed).
well I found a 14 Bolt on CL the guy want $200 for it. its complete drum to drum has 4:10 gears and the spiders where welded. so do you think its a good deal or should I keep looking?
If its going to be trail only sure. If not you'll need to regear as 35" tires, 1:1 final transmission, and 4.10 rear gears gives a 2362 RPM at 60. If you have to regear I'd keep looking for a better ratio axle. Gears, install kit, headaches are all going to add up quick. This is why I bought a 11.5" AAM, I wanted a 14 bolt or Dana 60 (plenty strong for a JEEP) but this one came along with 3.73s and disc brakes, and less than 50K miles with a G80 gov-lock. Since this axle is welded that could make street handling on a short wheel-base rig, I'd probably pass on this one. If the JY has a decent axle with the right ratio for you and possibly disc brakes for $350 I'd def. go that route before I'd try to save $150 and NOTHING be right except the housing.
If its going to be trail only sure. If not you'll need to regear as 35" tires, 1:1 final transmission, and 4.10 rear gears gives a 2362 RPM at 60. If you have to regear I'd keep looking for a better ratio axle. Gears, install kit, headaches are all going to add up quick. This is why I bought a 11.5" AAM, I wanted a 14 bolt or Dana 60 (plenty strong for a JEEP) but this one came along with 3.73s and disc brakes, and less than 50K miles with a G80 gov-lock. Since this axle is welded that could make street handling on a short wheel-base rig, I'd probably pass on this one. If the JY has a decent axle with the right ratio for you and possibly disc brakes for $350 I'd def. go that route before I'd try to save $150 and NOTHING be right except the housing.
Umm, NO that is wrong. 2600 is pretty much up against the governor on a stock 3.9-4.5 4BT. They like to be in the 1700-2000 RPM range. People will put higher spring kits to raise the governor speed but that is mainly to just give more RPM range while shifting or for racing applications. While not Detroit Diesel 71 series low rev engines neither are they Mercedes or yanmar "modern" automotive high speed diesels that like to rev. They are based off an industrial engine.
That's why I want to keep the 3:73 because I did a calculation last night and looks like if I'm running 35s my RPM will be in a good range. now I'm not afraid of Regearing because I have done it several times. So im going to pass on the welded one and keep looking.. I'm going to try calling more JK around here to see what they have..
Umm, NO that is wrong. 2600 is pretty much up against the governor on a stock 3.9-4.5 4BT. They like to be in the 1700-2000 RPM range. People will put higher spring kits to raise the governor speed but that is mainly to just give more RPM range while shifting or for racing applications. While not Detroit Diesel 71 series low rev engines neither are they Mercedes or yanmar "modern" automotive high speed diesels that like to rev. They are based off an industrial engine.
I apologize! You are correct. I'm used to the 3k springs in my 5.9. Sorry about that. Yeah these engines are made for serious power not rpm. Disregard that post!
Ben
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