Jeep 2.5 4 engine swap |
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Jeeps3,4
Member Joined: 14 Dec. 2017 Location: Louisiana Status: Offline Points: 21 |
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Posted: 23 June 2018 at 1:19am |
has anyone swapped in a 2.5 Jeep 4 cylinder, connected to original trans?
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New to old Jeeps
I drive 1998 Jeep TJ Wife 2015 Jeep JK |
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Ol' Unreliable
Member Joined: 25 Sep. 2016 Location: CO Springs CO Status: Offline Points: 4226 |
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You mean like with an AX-5 tranny? That's a pretty long setup. Plus, the centered rear diff issue comes up. I've wondered about that swap too.
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There's a reason it's called Ol' Unreliable
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Jeeps3,4
Member Joined: 14 Dec. 2017 Location: Louisiana Status: Offline Points: 21 |
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I want to adapt the engine to the original T90 and drive train. cant find an adapter. Would keep it Jeep!
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New to old Jeeps
I drive 1998 Jeep TJ Wife 2015 Jeep JK |
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Ol' Unreliable
Member Joined: 25 Sep. 2016 Location: CO Springs CO Status: Offline Points: 4226 |
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I would think that would be a more common swap than it apparently is. "Keep it Jeep" is an excellent idea.
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There's a reason it's called Ol' Unreliable
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nivrat
Member Joined: 27 May 2014 Location: Glendale, AZ. Status: Offline Points: 195 |
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Been down that road already. No one makes an adapter for the T90 to mate up to the 2.5. They dont see enough profitability in making an adapter for what they consider a throw away engine. I researched that very idea myself since I have a another flattie project and a free 2.5 laying around. The only way you could -possibly- do it ( I haven't tried it) is to find a bellhousing from an S10 or Camaro with the V6 and use that to bolt to the engine, and then find an old Chevy to T90 adapter and bolt it to the bell to mate the T90 to. Clutch/PP would have to be figured out, as well as clutch linkage. In the end you're still going to have a tranny with 2.79 first gear (unless you have a T90C) with way too much split between the gears for a 4cyl. to overcome. Don't let me rain on your parade though...just about anything is possible. I will be going a very different route with mine. Keep us posted... Mike |
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Jeeps3,4
Member Joined: 14 Dec. 2017 Location: Louisiana Status: Offline Points: 21 |
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I’m not really up for a science project right now - I will go a more established direction. Do the V6 swaps have the same ratio issue? How can you tell a T90 from a T90C? My parts Willys has a T90 adapted to a Ford straight 6, plate is between trans and bellhousing. Really don’t know what was done, need to pull it apart. Someone’s vision gone wrong.
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New to old Jeeps
I drive 1998 Jeep TJ Wife 2015 Jeep JK |
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64CJ5
Member Sponsor Member Joined: 15 Nov. 2013 Location: NE Wyoming Status: Offline Points: 941 |
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My 64 CJ 5 came with an F head engine and a T90C. The four cylinder over comes the split in the gears just fine. When I installed the 2.3 Pinto into our 52 M-38 I rebuilt the T90A into a T90C and here again the four cylinder overcomes the gear split with out difficulty. First gear is lower in the T90C, 2nd & 3rd are the same as the T90A. Novak built the bell housing to transmission adapter and new pilot bushing. When I had problems they were only a phone call away and ready to help. There are some really handy folks out there putting VW and Mercedes diesels into Jeeps. So any thing is possible with enough time and money. The Kobota diesel swap is more common. Just my 2 cents. |
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64CJ5 "Eeyore"
01TJ "Tigger" 52 M38 Severely demilitarized, "Popeye" The Coast Guard Jeep. 14 JK "Jake" To Trust Government Defys Both History and Reason. PUBLIC LAND Owner/User |
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Rick G
Member Joined: 17 May 2015 Location: Amarillo, TX Status: Offline Points: 1467 |
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Tom, actually 1st, 2nd, and Reverse are different between the T90A & T90C; 3rd is the same in both at 1. T90A T90C 1st 2.79 3.34 2nd. 1.55 1.85 3rd 1.00 1.00 Rev. 3.79. 4.53 Therein lies the issue with the T90C behind the L134 with stock axle ratios; much too big of a jump between 2nd and 3rd gear on the highway. Pretty much dictates the use of an overdrive unit, which is what I installed this past week to counter this issue😉. I had T90C gears installed in Gus this whole time and didn’t even realize it (or remember it if I ever knew).
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64CJ5
Member Sponsor Member Joined: 15 Nov. 2013 Location: NE Wyoming Status: Offline Points: 941 |
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With the Pinto engine I would like an overdrive to reduce the RPM's on the highway. However the overhead cam is not bothered by high RPM's, I am. But right now at 55 MPR and above there is a whole lot of shaking going on. 55 is plenty fast for the crowd I like to run with. This has gotten away from the question of putting a 2.5 Jeep engine into an older model. I would think it would be doable, with some machine shop creativity.
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64CJ5 "Eeyore"
01TJ "Tigger" 52 M38 Severely demilitarized, "Popeye" The Coast Guard Jeep. 14 JK "Jake" To Trust Government Defys Both History and Reason. PUBLIC LAND Owner/User |
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Ol' Unreliable
Member Joined: 25 Sep. 2016 Location: CO Springs CO Status: Offline Points: 4226 |
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I keep thinking that someone somewhere has done it but didn't bother to document it. Darn it! |
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There's a reason it's called Ol' Unreliable
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nivrat
Member Joined: 27 May 2014 Location: Glendale, AZ. Status: Offline Points: 195 |
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I'll be starting my project in the fall; I'll post some pics...
Mike
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Bill2A
Member Joined: 01 Mar. 2018 Location: Fort Worth, Tex Status: Offline Points: 516 |
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If the 2.5 uses a GM bell housing, then an SM 420 can bolt in behind it, but then you'd need an adapter to the TC.
They exist.
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1946 CJ2A 14098
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On Jeep About
Member Joined: 17 June 2018 Location: Mccall id Status: Offline Points: 35 |
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The jeep 2.5 use the GM front wheel drive housing. It’s not the standard small block. This was because Jeep was using Chevy engines for sometime. When they switched to there own 4 cylinder is was simpler to just keep the GM front drive pattern.
Good news is lots of engines used the pattern from GM in lots of applications. Even the late Buick v-6s used that pattern. I found a bell housing with front wheel drive pattern and standard GM tranny. There for can use t-90 with GM adapter. I did have to drill and tap for a clutch pivot that is the same as GM not a bad job with nothing more the a hand drill and carefull measurements. Sorry I don’t know what vehicle the bell housing came from. Nor have I finished the project so I haven’t sorted out the pilot bushing or clutch disc yet. I don’t except either of these problems to be much of a hurdle. I even found a 904 Chrysler auto tranny with the GM pattern that will end up a couple inches shorter then a turbo 350 if you wanted to go auto route. The back of the 904 is the same as all the ax trannies which advanced adapters make a t-18 adapter for. Anyway definitely a doable project. Have fun. On Jeep About. |
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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When I did my TDI - T90 swap there was no adapter. Dont let that stop you. Just get a plate of steel or aluminum and make one. Its not as hard as it seems. there are lots of write ups on how to do it. I just make the back of the block look just like the willys block then the t90 will bolt right up to it. I made mine out of aluminum but ive seen guys make them out of steel with an angle grinder and a cordless drill.
You just have to make the back of whatever new engine you plan on using look like this and the transmission wont know the difference. I made a plastic template and bolted the bellhousing to it then used the t-90 bearing retainer and an aluminum rod to locate the bellhousing. Adapter and crank spacer to keep the willys flywheel in the same location. Here is the adapter with the willys flywheel in there. The t90 doesnt know the difference. Here it is all together. TDI/T-90 no drivetrain mods needed. Stock trans mounts stock driveshafts. I would love you see you make an adapter and plop that 2.5 in there! Edited by Millennium falcon - 27 June 2018 at 10:50pm |
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02tj
Member Joined: 30 June 2015 Location: Culpepper va Status: Offline Points: 36 |
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Im doing a 2.5 yj engine, sm420, dana 300, dana 44 from a 76 cj5 and a dana 30 from a 80 cj in my 47 bubba willys. just got it running a few weeks ago.
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64CJ5
Member Sponsor Member Joined: 15 Nov. 2013 Location: NE Wyoming Status: Offline Points: 941 |
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02tj, Pictures and captions please. The stories and pictures that people posted helped me with my Pinto transplant. Novak helped me with hardware for the transplant and transmission rebuild.
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64CJ5 "Eeyore"
01TJ "Tigger" 52 M38 Severely demilitarized, "Popeye" The Coast Guard Jeep. 14 JK "Jake" To Trust Government Defys Both History and Reason. PUBLIC LAND Owner/User |
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unkwally
Member Joined: 16 Sep. 2020 Location: Washington,Pa Status: Offline Points: 5 |
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I'm working on such a swap now. I tried this with the jeep bell housing but no one makes an adapter. I'm using the 2.5 Iron Duke/ Pontiac engine/same as jeep 2.5 but with the GM bell housing. Then you buy a GM/Buick v6 adapter to the stock transmission, problem solved.
Unkwally
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