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4.0 Cam Profiles

Super mud

NAXJA Forum User
Location
Bel Air Maryland
So I got a 96 motor getting new seals and junk to bolt to a 4x4 ax15 for the 4x4 swap in the mj. I'm thinking about getting an aftermarket cam since I've heard the stock one is overlapped for the non egr system. Also the 91 HO in the mj blows on the low end. Then I have a renix xj that rocks even though it runs like a tractor.

After looking at this chart http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm

The stock cam profiles aren't whats expected. 91-95 don't make peak torque till 4k but still have the renix cam that made it at 2.5k in those motors. The renix has an egr system so shouldn't the 91-95s have something different for emmisions? Also the renix cam is all around bigger but does not rev as well as the HOs, even the ones with the same cam. So whats the deal?

Also if anyone cares I'm looking for this motor to make good torque and be efficient as possible. I wouldn't mind if it ran more like a tractor but this jeep might be getting 4.10 axles with the 5 speed and stock tires. The renix cries at 2500 on the highway but that might just be my case.

And last I'm worried buying an aftermarket cam from all the failures I hear with multiple brands. Many of them are even a far narrower lobe measurement from the stockers, shown in this thread.
http://www.jeepsunlimited.com/forums/showthread.php?t=428969&highlight=cam+lobe+wear
 
Russ Pottenger gets a cam from Comp Cams that is slightly different than their stock 231-4 cam. It is specifically built for low end torque. You might try contacting Russ for some recommendations. I am running it in my 4.6 L stroker he built for me, and the power curve is insane for low end torque.

David Bricker / SYR
 
The stock cam profiles aren't whats expected. 91-95 don't make peak torque till 4k but still have the renix cam that made it at 2.5k in those motors.

The '91-'95 HO and the Renix cam are exactly the same and have the same profile. I think the only difference is that the cam was installed 8 degrees retarded in the HO (I believe it was 1-2 degrees advanced in the Renix) to reduce cylinder pressure at low rpm and prevent knock 'cause the HO came without a knock sensor. Although the factory quoted peak torque of 225lbft occurring at 3950rpm in the early HO, the torque curve was pretty flat and the engine produced almost the same amount of torque at 2500rpm as the Renix.
The '96+ cams shifted the HP/TQ peaks to lower rpm thus behaving more similarly to the Renix set-up so if low/medium rev torque is what you want, keep the '96+ cam and update the intake manifold to the later curved runner style.
 
Oh wow, learned something right there. Is the 91-95 cam cast differently up front to clock the timing gear? Also is the 96+ fairly advanced? Using the stock cam sounds great to me. Did you have a chance to notice the before and after with the 99 intake?
 
es: +1.9rwhp, +4.5rwtq, and +1mpg.

Well damn lol. Was that on the stroker or a 4.0?

Does the overlap/timing of the 96+, for the non egr, anything to worry about as far as potential for more power/efficiency? Also thanks for all the good info
 
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Well damn lol. Was that on the stroker or a 4.0?

Does the overlap/timing of the 96+, for the non egr, anything to worry about as far as potential for more power/efficiency? Also thanks for all the good info

Those gains were on my 4.6 stroker and those gains should be slightly greater on a 4.0.
The '96+ engine came without EGR and no knock sensor so using the cam won't be an issue.
 
Yea I just meant does the 96 cam still return/leave enough exhaust gases to reduce it's potential or is it not really enough to make a big difference. Also why would the horseshoe intake be better on a 4.0? Tighter runners or something?
 
Those gains were on my 4.6 stroker and those gains should be slightly greater on a 4.0.
The '96+ engine came without EGR and no knock sensor so using the cam won't be an issue.


Why would the gains be greater on a 4.0 compared to a 4.6 stroker from switching to the 99-06' style intake manifold? Would it actually be the opposite since the stroker uses up a larger volume of air, hence the larger need for better air flow?
 
Would it actually be the opposite since the stroker uses up a larger volume of air, hence the larger need for better air flow?

The stroker does need a larger volume of air but since the intake runners have a small cross-sectonal area, the engine is starved at higher rpm and that's the reason why most of the torque gains are at lower rpm.
 
I felt 0 improvement from the 99+ intake on my stock 4.0 with an APN header.

If anything, I lost some low end torque.
I agree with this to some extent.. You need the supporting mods larger TB/cai, better injectors, a free flowing exhause front to back and you might see some improvement, most of this inproment wont be something you feel but rather something that would have to be measure by dyno.
 
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