2.4L Dohc Neon

This is not a "2.4L Swap How-to" but it will help you better understand what it is all about. If you have a question feel free to ask I'd be happy to help you in anyway I can. We no longer sale mount kits.

I've tried not to go into great detail on somethings. Just because they will make the swap seem difficult. This page is to give you an idea on how I did it. If you start on a 2.4L swap yourself this can give you some ideas but you will have to figure out some of the minor things yourself. If you have any mechanical experience you can probably handle this with no problem.

This is a picture before I did anything with it other than taking off all the acessories. But I did paint it before I put it in the car.

I removed the 2.0L and transmission as one part. This is after I removed them, looks like alot of space.

I had to cut a small hole in the hood to make it shut all the way. This isn't needed anymore it fits fine now.

You have to be very careful doing this because you can cut to much very easily. I didn't cut to much but a grinder will cut thru it like paper.

After installation.

The huge 2.4L intake manifold.

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If your interested in putting a 2.4L motor in your neon I'd suggest reading this info.

First off you have to decide weather or not you want to do it yourself or pay someone else to do it. ...

Performance Gains.

2.4L DOHC 150hp at 5,200RPM 167 lbs of Torque at 4,000RPM
2.0L DOHC 150hp at 6,800RPM 133 lbs *
2.0L SOHC 132hp at ?,???RPM 129 lbs *
The 2.4L DOHC will not produce as much torque as the above listing with the 2.0L intake manifold but may produce more than a 150hp. I really don't know. From what I've heard they make about 158 lbs of torque with the 2.0L intake, hp is unknown to me. I installed the 2.4L intake a few weeks ago and the torque increase is very noticable.
* I'm not sure that the torque numbers on the 2.0Ls I have are right. I always thought that the SOHC made more torque. I got the information from http://www.carforum.com/newcars/dodge/neon.html

When builing up this motor you have to remember that the 2.4L is a longer stroke torque motor compared to the shorter stroked high rev-high end power 2.0L motor. So many things that a very good for the 2.0L motor are not that great for the 2.4L.
The 2.4L's max HP and Torque levels are at very close and lower RMPs, only 1,200 RPM's between max torque and hp. The 2.0L is more than 2000 RMP's. I found that if you try to make the 2.4L into a high-end power maker like the 2.0L you will have a very hard time doing so. It is possible but not on a slim budget. It is much easier to optimize lower end power.

First off keep in mind that most of the 2.0L aftermarket mods only actually make a few hp difference and most of the time it is only a very high revs. So those mods that add 2-8hp at 6000 RPM will not help your 2.4L motor, that shouldn't be reved above 6,500, so that is a very short power range to be putting alot on time and money into it.
So adding a header that adds 5hp at 6,000-7,200 RMP is not going to help your 2.4L motor, a stock manifold will make more lower end torque than a header.

The 2.0L intake is also made for high-end power, the 2.4L intake will make more low-end torque. I know that many people think that the 2.0L intake is best on a 2.4L but that is not the case when trying to make good low-end torque.

Mods like the UDP and cold air intake also only make big differences at high RPMs so that won't make that much difference at the lower RPMs that you use on the 2.4L. NOTE:But I still recommend an ICEMAN INTAKE.

Higher rated valve springs will not help the 2.4L motor at all because your not going to run the 2.4L above 7000 RPM, unless you want it to fall apart.

Basically all the neon mods won't make as much difference on the 2.4L motor because most of the mods make a difference at high RPM's, but that doesn't mean that they are not at all worthwhile. Just think about how the mod makes that perf. gain and see if the same applies to the kind of power(Torque/HP) and RPM range that you are going to be running the motor at.

The 2.4L is harder to make a high reving, high-end powered motor. With it's longer stroke and limited air flow head. But with alittle work you can make a awesome amount of low-end power.

ALSO: When shifing think about where your power is at, it stops making good power at about 5,500-6,300. So running it up to 7,000 RPM is not best and when you finally get to the next gear your power band will be shorter, slowing you even more.

Intake and head porting may help with a few HP at higher revs without affecting low-end power. Keep in mind that the 2.4L and 2.0L's have the exact same head. So the 2.4L motor has to flow almost 25% more air thru the same ports. And the 2.0L makes good gains with some major head work so the 2.4L would probably make major gains also.

2.4L Info...




Bore .....3.445 inches




Stroke ...3.976 inches (2.4L engine) 




Stroke ...3.268 inches (2.0L engine) 




Compression Ratio: 




2.0L SOHC.9.8:1 




2.0L DOHC.9.6:1 




2.4L DOHC.9.4:1 




Displacement:




2.0L ....122 cin 




2.4L ....148 cin 




Firing Order: 




1-3-4-2 (Both)




Cam Lobe Lift:(Just because the 2.0L DOHC has more lift doesn't make it best) 




2.0L SOHC                  2.0L DOHC           2.4L DOHC




Intake   .307 inch         Intake   .327       Intake  .324




Exhaust  .277 inch         Exhaust  .30?       Exhaust .256




Fuel Pressure:




2.0L ....49 psi 




2.4L ....47-51 psi 




Rev Limiter is 6,500 RPM




Spd Limiter is 108 MPH 




When I shift(for performance) gears with the 2.4L PCM are as follows:




1st .... 30  mph 




2nd .... 50  mph 




3rd .... 80  mph 




4th .... 100 mph

* I have a perf. 5 spd tranny. Non perf tranny may perform better at different shift points.
Note: In the 96 yr production of the 2.4L engines there was some changes made. I honestly don't know all the changes made but the earlier model 2.4L had a mechanical timming belt tensioner, from that yr on all 2.4L motors have a hydraulic tensioner.

Is the 2.4L right for me?

As far as I know you can put a 2.4L in any neon DOHC, SOHC, manual, or auto. But they all take different setups to make them work. I don't know if the SOHC wiring harness will plug into a DOHC PCM if so you'd probably be ok.

If you have a DOHC motor with manual you have the most options on setting it up. You can use either the 2.4L DOHC PCM or the 2.0L DOHC PCM auto or manual. You can also swap in 2.0L's cams.

If you have a SOHC motor with manual you can only use a 2.4L DOHC or 2.0L DOHC PCM auto or maual, you can't use any SOHC PCM with this motor. So you'll have to buy a new PCM. You cann't swap 2.0L's cam.

The automatic motors are different. The 2.4L PCM's where made for a 4-speed auto, they will not shift your 3-speed properly. So you have to use a 2.0L DOHC auto PCM.

Note: When buying a PCM make absolutely sure you by a PCM of the same year as you Neon weather you buy a new 2.0L PCM or the 2.4L PCM. If you don't your cooling fans and tach may not work., it will run the motor but a tach and cooling fans are nice to have.

Also: I give the 2.4L PCM as an option only because I believe that you get proper fuel amounts when using this PCM even without raise fuel pressure. I noticed that when I had the 2.4L PCM installed it started better, idled better, and made more power. I think that the fuel pulses are longer to allow more fuel to get into motor.

Pros and Cons of each PCM:

2.0L Pros:

You will have a higher rev limiter (stay in gear longer)
You know that everything will work exactly the same as before(when I put my 2.4L PCM in my neon my radio would stay on after turning the key off for about 5 sec. ,it was ok but was different)
You can buy a Perf 2.0L PCM's like Mopar or AFX

2.0L Cons:

The high-rev limit is beyond what the motor orginally was made to run (more wear)
Must do re-wiring because the timming is different that 2.4L
You must get a more fuel to keep it from running lean

2.4L Pros:

You don't have to re-wire anything
You don't have to get more fuel (it seems to have longer fuel pulses that add proper fuel)
You don't over rev the motor

2.4L Cons:

You can't get a Perf PCM
You have to shift sooner
Some interior control may not work*

* I say this because I'm not 100% positive that everything like power windows, power sunroof, ect will work exactly the same. Like I said above when I use the 2.4L pcm my cooling fans and tach didn't work right. But everything else works fine on the car like fog lights, gas, temp, oil, and speed gauges all work fine. BUT I have a power nothing R/T, so I don't know for sure that all the power stuff will work.

Stuff you need:

2.4L DOHC motor (I'd get a low mileage 60,000 or less motor from a Salvage Yard) I got mine for only $400
Basic tools like 8mm, 10mm, 15mm, 18mm, ect. wrenches and sockets
You'll need a welder (I used a flux wire welder)
Hacksaw
Drill and Bits (to drill whole thru 1in, solid steal piece) I used a Lath
1 in. solid steal for the side mount extentions you'll have to make
Grinder
3-jaw pulley puller (I had to buy a 5ton puller to get my pulley off that 2.4L motor, the 2 ton broke)
Some bolts for the side mount because it will be longer and a bolt or to for the alternator (use 8 grade only)
Suggest a heavy-duty clutch
a UPD there isn't room for the 2.0L's pulley because of the oil pump
New 2.4L timming belt
New Alternator Belt, Oil, and filter

Possible Mods while you have your motor out:

I'd put a UDP on while you have it out of the car (you really do need this to make belts stay on)
Do all the sensor swapping before installing motor including the alternator
Do mount changes while motor is out (if possible, I didn't but that would probably be best)
a header would be good at this time
an iceman is also good
now would be a good time for a port and polish, and head work
Bored TB couldn't hurt (after all your pulling almost 25% more air thru the same stuff)
You can disable the counter balancing shafts (just cut the chain that links them to crank shaft) if you remove the whole asembly you will loss oil pressure if you don't block off the bolt holes. I just cut the chain and left the shafts in place.
switch to a non-modular clutch(if you have modular style) setup, they are cheaper, and get heavy-duty clutch
maybe even get an aluminum flywheel
swap 2.4L exhaust cam for the 2.0L's exhaust cam (I've found that if you do this the motor will make much more high-end power but it is at a loss of some of the low-end torque) don't swap the 2.0L's intake cam timming gets complex. You can do it, I did ,but you don't see much improvement and timming is a pain.

Now I'm going to try to write down everything that you have to modify,move, or exchange.
For the most part these motors are very similar. At first look they look exactly the same but there are minor differences. I'm not going to get into alot of detail, if you have a question use the e-mail below.

The transmission bolts right on
along with the intake and exhaust manifolds (if you have a DOHC 2.0L, SOHC intake and exhaust won't bolt on) .
You need to swap all sensor (if you have a SOHC you may have to cut wires and use the sensors that came with the 2.4L)on the motor so that they plug in right. You can use the sensors from the DOHC 2.0L and just bolt them into place onto the 2.4L motor.
You do have to cut the center brass out of the intake manifold, the manifold won't fit on without doing this, there is a sensor in the way. Or remove the knock sensor.
You have to swap the water pump pipe that comes straight out of the pump. The pipe is the wrong shape.
You can't use the 2.0l crank acessories pulley. The oil pump gets in the way. I tried to cut some of it off and did make it work but you still can't get the pulley all the way on. I had alot of trouble with the belts falling off and burning up. I put a UDP on and it works much better. If you have a UDP it would probably fit fine.
The crank pulley also sticks out about 1/2 in further than the 2.0L (it has counter balancers that require about a 1/2in more crank shaft for the gear and chain to the counter balancers) that means that the alternator belt will fall off if you don't shim the alternator out about 1/2 in futher from the side of the block. This is easy just buy new bolts and add a 5/8in nut behind the alternator bracket at the block and at the upper alt. bracket.
The power steering pump bracket doesn't fit on right. I got it to work but could only put on one bolt thru the bracket.
You must cut out alittle of the front motor mount to clear the oil pan.
You have to do alot of modifing of the side mount. You can use the 2.0L mount but you must make extentions to the bolt hole to clear the timing belt. And the bottom bolt is different so you have to drill a new hole for the third bolt. It won't hold without it, I tried and it kept breaking the mount bolts. But I finanlly got all three bolts in. I'll try to get some jpgtures up soon to show you exactly what I mean.

There are lots of ways to make a 2.4L mount kit. This is how we did it. Below is a picture of what we did. The bottom bolt hole will be off from the orginal hoole by only a .5" or less. Find a aluminum mount to do this work... it will be very hard work on the steal mount.

Below is a picture of how to lower the tranny mount. The pictures shows an automatic mount but the same would apply to a manual tranny mount. Notice that the mount isn't flat... so the 1" steal piece will need to be cut to follow the curves of the mount and then re-weld together. Make sure you weld it well and try to keep the rubber in the mount cool. It may burn alittle but just weld on piece at a time until it is all together.

Update: I guess at first I was doing it the hard way. Just take the rubber part out and hit it back in upside down. That will lower the tranny enough.

The lower alternator bracket doesn't mount the same you can just put a bolt thru it for support but will be slightly different.
You don't have to do anything with the transmission mount.
You have to cut a hole in the hood like above. You don't see it on the top of the hood you just cut away some bracing. This seemed to be the easiest way to fix the hood closing problem.
shorten the hose going from PVC valve to intake manifold
Bend the oil dip stick to fit around the 2.0L's intake manifold
And timming problem if you use the 2.0L PCM or if you swap cams

As far as timing this is where it gets difficult. At first I couldn't firgue out how-to make the 2.0l Pcm work on the new motor. If you get a 2.4L PCM it works fine, you must get a 2.4L computer of the same year as your neon. If you don't it your cooling fans and tach may not work. I tried a 2.4L PCM out of a 96 Status on my 98 Neon and the cooling fans and tach wouldn't work. But if you want to use the 2.0L Pcm you can do it. I will tell you that the timing on the 2.0l is different because the 2.0l intake cam is upside down to the 2.4L cam. So when you set the timing marks to the 2.4L settings the intake cam will be 90 degrees off. You can fix half the problem by swapping injectors as follows, swap 1 for 2, 2 for 3, 3 for 4, and 4 to 1. But that won't make it run. The other half of the problem. You have to swap the spark plug wires, spark plug 1 to 2, 2 to 1, 3 to 4, and 4 to 3. If you use the 2.4L PCM you don't have to do this swapping. You must also raise the fuel pressure or use larger injectors if you use the 2.0L Pcm.















This is what I do some of  the fabrication work on my little lathe, I also have a bigger lathe.

Updated:4-8-2004

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