I bought a ‘94 Dakota pick-up as a shop truck.





After


I bought it knowing it had a blown head gasket. I should have done some research on this engine so I would have known how brittle the heads are. One of the cylinder walls were pitted from water sitting in it, one head was cracked, some cam lobes were trashed, and a piston was pretty messed up. Instead of doing a rebuild I figured a used engine was the cheapest route. I did a little research on upgrading to a 360. There is a lot of contradictory information out there so that’s why I’m doing my own write-up to give a first hand experience and hopefully clear up some misinformation out there.

The swap:
I scored a 360 engine on Craig’s list out of a ‘98 Dodge Ram for $450. I read that I need the harmonic balancer and the flywheel off the 360 because the 360 is externally balanced and the 318 is internally balanced. Fortunately for me the guy sold the engine with EVERYTHING attached, except for the transmission.

I used the engine, flywheel, and harmonic balancer off of the 360. The sensors I used off of the 318 because they had different plugs. I had to swap oil pans. I read that the 318 and 360 can not swap oil pans. Well I did. The Ram oil pan was too deep and wouldn’t clear my 2WD crossmember. I installed my ‘94 318 oil pan and it bolted up perfect. I did have to use the oil pump pick-up screen to match the pan. It screwed right into the 360 oil pump. I did have to remove the oil pan after I started the engine because one of the rods was hitting the dipstick trough in the pan. I notched the trough, bolted the pan back on and I was golden. I did use the ‘98 360 dipstick and tube because it had a nicer handle and an o-ring to seal it. I had to make new marks on it for the proper oil level. I also read that that you have to open up one of the holes in the flex plate because they don’t line up with the torque converter. I didn’t have to. The ‘98 360 flex plate lined up perfectly with my ‘94 46RH torque converter.



Mopar Performance heads installed on the 150 K engine at 130 K


Flexplates. 318 on the left, 360 on the right,


You can see on the dipstick trough where the rod was hitting it.


Intakes:
My ‘94 has an EGR and the ‘98 doesn’t. I tried to get through emissions without the EGR and failed NOX. So I had to swap out the non-EGR ‘98 intake for the EGR ‘94 intake. I barely passed NOX. That max was 3.00 and I passed with 2.99. It’s due to running too lean. More on that later. I also had to swap out the passenger side manifold because the ‘98 did have the EGR boss but didn’t have the holes drilled. The part numbers are the same for ‘94 318 to ‘98 360 exhaust manifolds, small and crappy.

Injectors:
So logic would dictate that the ‘98 360 would have bigger injectors than a ‘94 318. Wrong. I used the ‘98 injectors using that logic and the truck ran like poop. I did some research. In ‘94 the 318 and 360 used the same injectors and in ‘98 the 318 and 360 used the same injectors. The injectors for ‘98 are SMALLER that the injectors for the ‘94. Once I swapped in the ‘94 injectors to match my ‘94 computer the truck ran great.

Not enough fuel/running too lean:
I read that people have done this swap, used the 318 computer on the 360 and it ran good. Well what seems to run good and actually running good are two different things. For those that don’t have access to a scan tool I’m going to explain a few things. First off there is something the computer monitors called “Fuel Trim.” There is short term (what’s happening now) fuel trim and long term (what the PCM is trying to correct for) fuel trim. On OBD II vehicles long term fuel trim can go +9% (lean) or -9% (rich) before the computer sets a code. Well mine was 25%, almost the max the computer can register. I’ve seen 30% on some cars. The 318 computer can’t compensate for the 360 engine. It ran okay but I know what to look for. It’s running way too lean. Good for fuel economy but not good for cylinder temperature (NOX) and power. An old turbo-Mopar trick to running more boost to compensate for more air is to up the fuel pressure. Going lean under boost is VERY bad if you detonate (pre-ignition). In ‘94 Chrysler went to a returnless fuel system. The fuel pressure regulator is in the tank. You can’t modify that. So while perusing through the junkyard I found out that the 92-93 318’s had a return system with a fuel pressure regulator. Sweet! I grabbed the fuel rail, fuel lines, and the fitting on the fuel pump module that sends fuel out and allows it back in. The fuel pressure regulator in the 92-93 Dakota without vacuum applied, max is 40psi. The ‘94 regulator in tank only puts out 43 psi. Well the 96ish 3.3 Dodge Intrepid uses the same style regulator and max psi is 60. So now I have 60 psi, my fuel trims are close to zero, my O2 switches a lot better, and the lean misfire at idle (stumble) went away.

On the left is the '94 fuel filter/regulator. On the right, 92-93 fuel outlet/inlet. Get one and it fits the module perfect, just adapt it to the fuel pump.




Before


After


I didn't like how the compression fitting was cracking/cracked on the plastic/stainless fuel lines.


So I replaced them with high pressure fuel hose in wire loom for protection.


A.J.

 

nice job! I hope mine goes this well

 

I love having a 360 in my Dakota. Makes for the best of both worlds. Nice small truck but the power of a full size. I will recomend to re-do the rear suspension with a cal-trax like set up or it will end up dancing on you. Yes it will make the ride a bit stiffer but it will keep the *** end planted better.

I do have to say, I enjoy the strange looks I get at the local parts store when I need to replace something. LOL

 

I get almost the same response from people when I tell them I put a 360 in my Dakota as when I tell them I have a turbo-charged mini-van, eyes bug out and jaws drop. I don't like having what everyone else has. At least not under the hood.

A.J.

 

what transmission do you have? a500 or a518?
never mind, I reread it and saw the 46rh.....

I had a 95 with 5.2L and auto trans and 3.55 gears, it was a hot ride as it was.
Did you consider the 92-93 exhaust manifolds and Y pipe? they are larger than later years...

Dodge did away with EGR for the magnum engines in 96, they found that it wasn't needed.

I am putting a 5.9L and auto trans in an 89 short bed that started with 4 cylinder and manual trans....in Utah, tho. We don't have emissions testing in far north Utah....

 

Nice write up.

The oil pans do swap over like you found out, I believe the LA and Magnums are the same as well.

I did get something out of your post too. I have looked all over for a higher rate fuel regulator. I couldn't find any when digging around on napa's website. I don't know how I missed it, the Intrepid's fuel pressure regulator is perfect. I went to Napa and order one just now. I can't wait to see the improvement.

By the way Napa is doing up to 50% off on all items. Today and tomorrow only.

 

318 LA and 360 LA do not share the same oil pan....

 

I already did it. That's my next write-up. Lots of pics.

There must be something in the computer or a different cam because my '98 360 wouldn't pass NOX. But then again I was really lean which will make NOX go up.

I can't take all the credit. I got that tip from a guy on Turbo-Mopar who did this swap also. He was real helpful to me when doing my swap, but even he learned a few things that I found out doing mine. That's why I wanted to join a Dakota forum, to fill the void of information that I couldn't find but found out for myself.

A.J.

 

I made an adjustable fuel pressure regulator for my Dakota. I tapped threads in the vacuum port and installed a bolt to hold the diaphragm at the desired pressure. I used a #6-32 X 1 1/4" bolt. This only worked because I don't need the vacuum port on the regulator to change pressure. I also had to crimp down on the vacuum port with a pair of vice grips where the bolt goes in to tighten the bolt because it was loose and the vibration of the engine would have caused the bolt to move. Now you NEED a screwdriver to move it.







I don't know if you can tell in the video, but you can hear the engine idle better when you go from 43 psi to 60 psi. Running the higher pressure on a 360 engine with a 318 computer definitely helps things out. 60 psi seems to be the sweet spot. I've got some testing to do though.

http://youtu.be/N2qrkPET5Sk

A.J.

 

Cool modification. Where the screw touches on the diaphragm, is it metal or rubber in that spot?