Is there a reason people dont put -95 cams in 96+ engines?

[seanyb505]

Ive been looking at a lot of cam specs over the last month or so as Im trying to decide which one I want in my stroker. I think Ive finally decided on just having the 95 cam reground because its a better place to start then the 96 and up cam. This got me thinking, if the 95 has better stock specs, why havent more people swapped the cam out of their 96+ engines for an older one? More duration, more lift, all seem like good things to me. I got this info from Dyno's page, so credit goes to him on this one Im just posting it for reference. Compare the first two columns, 87-95 and 96-06.
http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm

Any ideas?

[jeepinwi]

I can think of a couple reasons. First, the 96+ cam makes the same amount of torque at a lower rpm. The -95 cam makes its torque at 4000 rpm's and the 96+ cam makes its torque at 3000 rpm's. Second, replacing a cam takes a considerable amount of work, and it's hardly worth it to replace a stock cam with another stocker that is questionably better. Furthermore, I don't think many people do cam swaps in the 4.0 unless they are rebuilding the engine.

[gradon]

All the reasons he stated above(esp peak torque down 1K to 3Krpm). However, I still think my 94 with the same mods as my 96 was a little stronger(not now since I've regeared). I think that the Jet 2 for the OBD1 made more of a difference than the one for OBD2. So other than that, the two years have different injectors, fuel pressure, and cams as you've stated.

[seanyb505]

Thanks, I knew I had to be missing something. I didnt think I had come across this brilliant revelation that on one else smarter than me had thought about before. We'll see how a reground 95 cam works out in my stroker. I really think the specs can be changed to bring the torque curve down a bit and improve all around power. Even if there is no difference in power for the better, Ill be saving 150 by buying the rebuild kit which happens to include the 95 cam, so its not like Im going terribly out of my way to try this.

[Dr. Dyno]

I can think of a couple reasons. First, the 96+ cam makes the same amount of torque at a lower rpm. The -95 cam makes its torque at 4000 rpm's and the 96+ cam makes its torque at 3000 rpm's. Second, replacing a cam takes a considerable amount of work, and it's hardly worth it to replace a stock cam with another stocker that is questionably better. Furthermore, I don't think many people do cam swaps in the 4.0 unless they are rebuilding the engine.

Couldn't have put it better myself. :D
'96+ cam makes more torque at lower rpm, peak torque is same as for older cam but at lower rpm, peak HP is reduced and at lower rpm. If you already have one and want to use it in a stroker, you could get more valve lift out of it and a little more duration by bolting on a set of Yella Terra 1.7 roller rockers. These will give a bit more HP at higher rpm without losing torque lower down.

[seanyb505]

lol you keep trying to sell me on those rockers but I cant afford them right now! Are there any cheaper alternatives than the Yella Terras? Although what is another 400, really? Is there anywhere other than quadratec that sells them?

[Slo-Sho]

The 96+ cam also came with the 96+ emmisions friendlier cylinder head(s), a.k.a smaller ports and a new fuel pressure of 49 psi and larger fuel injectors vs. the 95 and older 39 psi and smaller injectors to make up for the hp #'s. I think that if you put a 95 and older cam/head with the newer hardware it would be the best of both worlds. I made a mistake when I swapped in my 97 shortblock into my renix and kept the 97 bumpstick b/c of what I read on the 'intranets' about how the 96+ cam was the sh!t. Having seen the actual cam #'s myself I am certain the 95 cam will make more power than the 96+ cam given the same motor.

[alex22]

I believe it is only the 0331 heads that have the smaller exhaust ports. The 91-98 heads are the same except for a coolent temp sensor location change in 96-98 heads.

~Alex

[Slo-Sho]

Nope.

[gradon]

I was under the same assumption alex, as it's been discussed here many times that the 0630 and 7120 heads are identical except the coolant temp sensor location. I have not personally compared the two side by side. I'm sure someone's gonna chime in soon. . .

[bill_j]

I just swapped a 98 engine in my 92 today because of an exhausted short block that had overheated and cracked the head. I was curious about any differences as well. had to resplice distributor wires to plug up my 98 distributor and I did use my 92 engine fuel rails and injectors. I am still using my 92 wiring and computer. I did notice the 92 had two temp sensors and assume one is used for the electric fan to kick on and possibly used by/through the computer for this purpose as well as letting it know then engine is warmed up, and maybe the second sensor is for the dummy light. The 98 engine only had one temp sensor and no provision for the other so that is a whole other issue I have to work out, maybe some sort of plumbers T-fitting to add both sensors to the one provision and just extend the wires from where the rear sensor was to reach the front of the head where the sensor resides on the 98 engine.

Back on topic though, I was wondering if there was a difference in injector size and cam specs. Would love to see some more information on this stuff since I am in the middle of working out any bugs and possible future problems, as well as maximizing performance. Engine runs now, just the small stuff left to do.

[Dr. Dyno]

I was under the same assumption alex, as it's been discussed here many times that the 0630 and 7120 heads are identical except the coolant temp sensor location. I have not personally compared the two side by side.

I have and the ports of both heads are indeed identical. The 0331 heads have smaller exhaust ports. It's all on this page of my site:

http://www.jeep4.0performance.4mg.com/tech_specs.html

[bill_j]

That is a very nice page Dr. Dyno. Very helpful and a real time saver for anyone needing those specs. Good to know that a good majority of us fall into having the better flowing of the factory heads.

[seanyb505]

To what is attributed the 95 higher torque curve? It has more duration and more lift, is it because it is single pattern or does it have something to do with the 95 having more overlap?

[Dr. Dyno]

The '87-'95 cam has more duration than the '96+ cam and a little more lift, and that's why the '91-'95 HO 4.0 produced peak torque near 4000rpm instead of 3000rpm for the '96+ 4.0.

[seanyb505]

I see....were there other factors which made up for the lack of duration and lift, or was less more for 96+ engines? I know the 95 didnt make more hp or torque than the 96, just higer in the rpm range, which is why im kinda confused.

[Dr. Dyno]

Apart from the cam, the '96-'98.5 engines were basically unchanged from the '91-'95 in terms of performance-changing mods.
It's interesting to note that European 4.0 models were rated at 184hp @ 4750 and 214lbft @ 3950 for the '93-'95, while the '96-'98.5 was rated at 176hp @ 4400 and 222lbft @ 3000. So you see, the later cam produced an 8lbft gain and an 8hp loss but torque was increased from idle to ~4500rpm, so you could indeed say less was more in this case.

[seanyb505]

So really it depends on what youre shooting for. The 95 did make more hp, albeit a little higher, but less toque, also higher. Its sounds like its just one of those things where you either get hp up high or torque down low. When it comes down to it I dont do any offroading, but I do take it to the drag strip often. I guess thatll dictate what I need..

[97babyXJ]

stumbled upon this thread while doing some research, i currently have a 97 motor sitting with a pre95 cam in it in my garage.
it is mid assembly, has anyone built a 97+ motor with the older style stock cam in it?
i only found out after i put the cam in that my machinist gave me the older style cam, due to the fact noone reproduces the newer style

[seanyb505]

I thought melling did. The reason I decided against it (the 95 cam in general) was because the 95 made the same power, just higher in the rpm range. If your engine will only see daily driving duties, I doubt you will really notice a difference.

[gradon]

You also might be able to advance the cam 4*, which will bring the power band down some rpms. You're gonna have to get some input from some gurus, to see if it is advisable. I love having the peak torque @ 3K(my 96) than 4K(88, 92, 94).

[Darky]

I love having all the torque this thing has, great for surprising little 4 bangers when they get uppity...Maybe within a year or two, I plan on rebuilding my engine and when I do, I see no reason not to do a stroker, probably 4.6, maybe 4.7. It'll be mostly a trail rig by then, but still driven on occasion and always driven to the trail. Is there any particular rule to increase torque down low without sacrificing hp? Or is this the proverbial golden egg? I know very little about the internal mods to be done to an engine. Basically I look at the cam profile and then read the companies description. They say it makes power, I say ok although I don't know why...:D

[Dr. Dyno]

Is there any particular rule to increase torque down low without sacrificing hp? Or is this the proverbial golden egg?

It IS possible to build more torque at lower revs without giving up HP but you'll need a combination of parts rather than individual parts that are installed singly.

[Darky]

See this is where I get torn...I want a stroker, but I also want more room at the front of the engine, like I'd get with a V8...But the stroker is so much easier to make work with my XJ since the engine is already there and designed to work with it...:)

[seanyb505]

What do you need more room for?

[Darky]

fan clutch to radiator, alternator to radiator, basically anything between the front of the engine and the radiator. Discovered a side effect of flex once when I started dripping anti-freeze after testing the flex on some new springs. Fan clutch hit the radiator and carved a nice half moon into it...:)

[seanyb505]

Efan solved that problem for me. Went through about 3 radiators before I got mine.