87 dakota 3.9L La to 318 La swap
#21
05-02-2017, 05:13 PM
If you search my username, I have several threads that will help, but the one Ralph linked is most helpful on the biggest issue you face. A 318/360 LA will not clear your radiator because of the long water pump snout. I actually put in a Magnum, but kept the LA water pump because my crate engine was carb'd and I prefer the V-belt look, so from a space requirement, it was the same as putting in an LA block.
Shelby solved the problem with its build by shoving the engine back against the firewall which means new motor mounts and driveshaft, and possibly tunnel work to make the bell of the transmission fit. I solved the issue by swapping a post-91 front end onto my truck. After 91, when Dodge started offering 5.2L options, they redesigned the radiator support and nose of the truck to give the extra room needed. The fenders stay the same, but to do the swap you need from a 91-96, a radiator core, hood, headlights, front bumper and bumper valence. You also need to move the radiator core support holes in the frame forward 3" (this is what gives you the extra room for the LA motor and puts the mounting holes in the right spot for the fenders). https://dodgeforum.com/forum/1st-gen...ert-build.html
The other option is to put a magnum 5.2 motor in there. The magnum with the serpentine belt setup uses a shorter water pump and it will just clear the radiator as is.
As for your other questions:
I have the overdrive version of the 904 (A500) in my setup. I did rebuild it with Ray Asbestos Clutches and Red Kolene Steels and other heavy duty parts to stand up to the 360 Magnum.
For electrical I mapped out everything and completely redid my wiring harness and removed the ECU (I went carb'd). I have a thread on that too and everything that can be removed, and what you need to add to eliminate the ECU. In general, the ECU in my 90 TBI controlled the fuel, spark, AC, transmission, cruise and emissions. I removed the AC to make room for the 360 plus mine is a drop top (don't need no AC). I went Carb'd, so all the fuel management went away...I kept the fuel tank electric pump and used it for the Carb. The Spark is easy...use an HEI GM style distributor. The transmission if you have OD and Lockup needs pressure switches and a vacuum switch to control. TCI makes a kit for that. I eliminated cruise. For Evap, I used a vacuum PCV setup and a vacuum switch to control the purge line to the evap canister as the fuel tank needs venting. https://dodgeforum.com/forum/1st-gen...onversion.html
Bottom line, it was a fun project for me, but if you're looking for a quick inexpensive swap, it's not going to be one. You're better off finding a junker 3.9L and rebuilding the engine.
Shelby solved the problem with its build by shoving the engine back against the firewall which means new motor mounts and driveshaft, and possibly tunnel work to make the bell of the transmission fit. I solved the issue by swapping a post-91 front end onto my truck. After 91, when Dodge started offering 5.2L options, they redesigned the radiator support and nose of the truck to give the extra room needed. The fenders stay the same, but to do the swap you need from a 91-96, a radiator core, hood, headlights, front bumper and bumper valence. You also need to move the radiator core support holes in the frame forward 3" (this is what gives you the extra room for the LA motor and puts the mounting holes in the right spot for the fenders). https://dodgeforum.com/forum/1st-gen...ert-build.html
The other option is to put a magnum 5.2 motor in there. The magnum with the serpentine belt setup uses a shorter water pump and it will just clear the radiator as is.
As for your other questions:
I have the overdrive version of the 904 (A500) in my setup. I did rebuild it with Ray Asbestos Clutches and Red Kolene Steels and other heavy duty parts to stand up to the 360 Magnum.
For electrical I mapped out everything and completely redid my wiring harness and removed the ECU (I went carb'd). I have a thread on that too and everything that can be removed, and what you need to add to eliminate the ECU. In general, the ECU in my 90 TBI controlled the fuel, spark, AC, transmission, cruise and emissions. I removed the AC to make room for the 360 plus mine is a drop top (don't need no AC). I went Carb'd, so all the fuel management went away...I kept the fuel tank electric pump and used it for the Carb. The Spark is easy...use an HEI GM style distributor. The transmission if you have OD and Lockup needs pressure switches and a vacuum switch to control. TCI makes a kit for that. I eliminated cruise. For Evap, I used a vacuum PCV setup and a vacuum switch to control the purge line to the evap canister as the fuel tank needs venting. https://dodgeforum.com/forum/1st-gen...onversion.html
Bottom line, it was a fun project for me, but if you're looking for a quick inexpensive swap, it's not going to be one. You're better off finding a junker 3.9L and rebuilding the engine.
I'm not sure if this applies to the years you are talking about but I just did a Magnum 5.2 into a 91 318LA and I just eliminated the flex fan setup and put in an electric fan. For $50 off ebay that seems to be the easiest thing you can do no matter what you are doing. I had MAJOR problems getting the serpentine belt setup working swapping some of the brackets from the LA 318 onto the Magnum... Plus from 6 rib to 7 rib pulley issues. I was damn glad to not have a fan in the way doing all of that. (I retained the original 91 R12 Air conditioning) Of course, I haven't exactly gotten to getting that working yet.... I might be converting it to r134. (It's got "some" gas in it, I haven't confirmed how much, but it does not come on so I'm assuming/hoping it low on R12)
I have not driven the vehicle long term yet, I suppose there could be a problem with cooling capacity so I'll keep you posted.
You sound like you have tried some pretty ambitious stuff, have you done much with putting a manual trans into this setup? 91 Dakota w/ 5.2 magnum? Right now its running off the 91 TBI setup/computer.
#22
05-03-2017, 07:07 AM
I'm not sure if this applies to the years you are talking about but I just did a Magnum 5.2 into a 91 318LA and I just eliminated the flex fan setup and put in an electric fan. For $50 off ebay that seems to be the easiest thing you can do no matter what you are doing. I had MAJOR problems getting the serpentine belt setup working swapping some of the brackets from the LA 318 onto the Magnum... Plus from 6 rib to 7 rib pulley issues. I was damn glad to not have a fan in the way doing all of that. (I retained the original 91 R12 Air conditioning) Of course, I haven't exactly gotten to getting that working yet.... I might be converting it to r134. (It's got "some" gas in it, I haven't confirmed how much, but it does not come on so I'm assuming/hoping it low on R12)
I have not driven the vehicle long term yet, I suppose there could be a problem with cooling capacity so I'll keep you posted.
You sound like you have tried some pretty ambitious stuff, have you done much with putting a manual trans into this setup? 91 Dakota w/ 5.2 magnum? Right now its running off the 91 TBI setup/computer.
I have not driven the vehicle long term yet, I suppose there could be a problem with cooling capacity so I'll keep you posted.
You sound like you have tried some pretty ambitious stuff, have you done much with putting a manual trans into this setup? 91 Dakota w/ 5.2 magnum? Right now its running off the 91 TBI setup/computer.
The 87-90 has the flat front end. In 91, they redesigned the radiator support, moving the radiator forward about 3 inches.
The way shelby got by on a 2wd truck was redesign the crossmember and move the motor back slightly, and then sandwiched 2 electric fans between the radiator and condenser.
On a 87-90, you can get by using a magnum engine with the serpentine accessories. They are slightly shorter then the v-belt accessories. This will barely clear the radiator in the 87-90 trucks.
But then you need to put fans in front of the radiator.
Again, anyone considering this swap, should take the time and go through the post of ragged89 and robertmee. They both have taken a lot of time, posting pictures and explaining what needs to be done.
The 87-96 dakota's may all be 1st gen. trucks, but there are a lot of differences in the various years and a lot does not directly interchange.
#23
05-03-2017, 07:24 AM
No, I kept my A500 Automatic and upgraded it with performance rebuild parts. Putting a manual in there shouldn't be difficult. In my setup, it would have eliminated the overdrive/lockup pressure switches and vacuum switch and I would have to bypass the neutral safety switch....probably wire it to a clutch pedal switch. That's about the only difference once I blew the CPU away.
#24
05-03-2017, 07:36 AM
I'm not sure if this applies to the years you are talking about but I just did a Magnum 5.2 into a 91 318LA and I just eliminated the flex fan setup and put in an electric fan. For $50 off ebay that seems to be the easiest thing you can do no matter what you are doing. I had MAJOR problems getting the serpentine belt setup working swapping some of the brackets from the LA 318 onto the Magnum... Plus from 6 rib to 7 rib pulley issues. I was damn glad to not have a fan in the way doing all of that. (I retained the original 91 R12 Air conditioning) Of course, I haven't exactly gotten to getting that working yet.... I might be converting it to r134. (It's got "some" gas in it, I haven't confirmed how much, but it does not come on so I'm assuming/hoping it low on R12)
#25
05-09-2017, 12:54 PM
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Motor I have is an 86 ram 318 La plan to use different mounts to fit elephant ear style, like y'all said probably swap for a 92 front, will have to beef up internals of trans and electric fans. Believe I have a 904 trans not sure tho y'all might be able to tell me. I have an 87 Dakota 4x4 3sp auto, longbed believe it says march 87 on the body tag. Also I plan to lift it at some point and do 33s or 35s so needs to be strong enough for the lift and bigger tires. I know engine will have more hp than 3.9 but also want it to be a strong puller also I don't plan on using ac or any of the smog stuff and also have no cat not sure if I need cat but if I do will put on a high flow.
Last edited by new_red87; 05-09-2017 at 01:01 PM.
#26
05-09-2017, 11:26 PM
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[QUOTE=new_red87;3343060]Motor I have is an 86 ram 318 La plan to use different mounts to fit elephant ear style, like y'all said probably swap for a 92 front, will have to beef up internals of trans and electric fans. Believe I have a 904 trans not sure tho y'all might be able to tell me. I have an 87 Dakota 4x4 3sp auto, longbed believe it says march 87 on the body tag. Also I plan to lift it at some point and do 33s or 35s so needs to be strong enough for the lift and bigger tires. I know engine will have more hp than 3.9 but also want it to be a strong puller also I don't plan on using ac or any of the smog pump stuff.
#27
05-10-2017, 06:54 AM
[QUOTE=new_red87;3343130]
If your going to run a 92+ front end, you probably can run a mechanical fan. At least the 318 magnums did.
Also, not trying to be smart, but how do you plan to beef up the suspension or raise the truck? I dont believe there is a lift kit available for these trucks other then a 2in. body lift.
If this is your plans, look at what crazy4x4 did. If I remember correctly, he used a dana 44 out of a jeep wagoneer and converted to a solid axle front end.
Did I mention, IMO, the 1st gen dakota's are the red headed step child of the truck aftermarket industry.
Motor I have is an 86 ram 318 La plan to use different mounts to fit elephant ear style, like y'all said probably swap for a 92 front, will have to beef up internals of trans and electric fans. Believe I have a 904 trans not sure tho y'all might be able to tell me. I have an 87 Dakota 4x4 3sp auto, longbed believe it says march 87 on the body tag. Also I plan to lift it at some point and do 33s or 35s so needs to be strong enough for the lift and bigger tires. I know engine will have more hp than 3.9 but also want it to be a strong puller also I don't plan on using ac or any of the smog pump stuff.
If your going to run a 92+ front end, you probably can run a mechanical fan. At least the 318 magnums did.
Also, not trying to be smart, but how do you plan to beef up the suspension or raise the truck? I dont believe there is a lift kit available for these trucks other then a 2in. body lift.
If this is your plans, look at what crazy4x4 did. If I remember correctly, he used a dana 44 out of a jeep wagoneer and converted to a solid axle front end.
Did I mention, IMO, the 1st gen dakota's are the red headed step child of the truck aftermarket industry.
#28
05-10-2017, 04:05 PM
[QUOTE=93 ragtop;3343162]
If your going to run a 92+ front end, you probably can run a mechanical fan. At least the 318 magnums did.
Also, not trying to be smart, but how do you plan to beef up the suspension or raise the truck? I dont believe there is a lift kit available for these trucks other then a 2in. body lift.
If this is your plans, look at what crazy4x4 did. If I remember correctly, he used a dana 44 out of a jeep wagoneer and converted to a solid axle front end.
Did I mention, IMO, the 1st gen dakota's are the red headed step child of the truck aftermarket industry.
If you run the LA water pump, you won't....least I didn't. I have about 1.75 inches from the nose of the LA water pump to the radiator. I don't think a clutch fan would fit in there. If you run a magnum water pump and serpentine pulley setup, then yeah, you'd have plenty of room.
1st gen Dakota's are also distant cousins within themselves...87's are different than 88 to 90s are different than 91s, are different than 92 to 95s and completely different from 96. Yet all are Gen 1. It's a fun adventure, cross referencing parts.
If your going to run a 92+ front end, you probably can run a mechanical fan. At least the 318 magnums did.
Also, not trying to be smart, but how do you plan to beef up the suspension or raise the truck? I dont believe there is a lift kit available for these trucks other then a 2in. body lift.
If this is your plans, look at what crazy4x4 did. If I remember correctly, he used a dana 44 out of a jeep wagoneer and converted to a solid axle front end.
Did I mention, IMO, the 1st gen dakota's are the red headed step child of the truck aftermarket industry.
1st gen Dakota's are also distant cousins within themselves...87's are different than 88 to 90s are different than 91s, are different than 92 to 95s and completely different from 96. Yet all are Gen 1. It's a fun adventure, cross referencing parts.
#29
05-11-2017, 12:05 PM
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