Comp cams

Hi guys, my engine had 2 dead cylinders after it overheated so I began tearing it down a week ago expecting the worst. Turns out that the short block is in perfect condition for having 165k miles. Great! Discovered that it has a blown head gasket and a few problematic valves. So I'm sending the head off the the machine shop to be built. With the engine out, I want to upgrade my camshaft while I have the engine accessible. The cam I am looking at is the 68-239-4 but Summit's site says in all caps "NOT FOR FUEL INJECTION". I've done a lot of research on it but can it find a definite answer. Half of the sites out there say that it can be run on fuel injected 4.0L's without any issues, and the other half say that it will cause the engine to not pull enough vacuum to run properly can would require me to install a vacuum reservoir for the brake booster to function properly. I've seen a few videos of xj's with the same cam in them but I can't find any additional information about them. So my question to you guys, is anyone here running the Comp Cams 68-239-4 cam with success? If so what was required to get it to function well if anything? If it helps my Jeep is a 1995 XJ with the AX-15.

Thanks,
-Mason

Looking at it's specs it's a long cam for fuel injection. Especially with the OBD II computer. Comp Cams web site makes these recommendations for the cam "Hydraulic-Good mid to upper torque, needs increased compression, headers and gears. Stock springs cannot be used. " It's power range is 1400 rpm -5700 rpm. I would look for a milder cam like their
68-200-4 252H cam or 68-201-4 260H cam, they are from their High Energy cams and give better low end torque, smooth idle and good vacuum signal. I haven't used these cams in a fuel injected motor so have no direct experience with them but their specs look to be much friendlier to computers.

That's a lot of cam.

Call Russ Pottenger at Bishop Buehl racing engines and talk Cam's with him. He's also a Comp dealer and can probably get you a deal.

He builds some of the best jeep strokers and race motors around, and has run every comp Jeep 6 option available, as well as had a lot of custom variations made.

Don't forget to talk valve springs. A cam that big won't work on stock valve springs (a lot of the aftermarket won't).


Russ Pottenger
Bishop-Buehl Racing Engines
531 N. Lyall Avenue
West Covina, California 91790
Work (626) 967-1000
Fax (626) 967-7836
Cell (626) 673-2203
Email [email protected]
__________________

All of these work with EFI keep in mind that you cant go over .450 lift with stock valve train,
http://www.angelfire.com/my/fan/Jeep4.0Camshafts.htm

Mason has responded to me directly through email, but to the benefit of others I'll give you my opinion.

The question was raised on Comp Cams 68-239-4 grind
It has a intake duration @.050 262 ex. 226 .493 .512 lift on a 111° lobe separation angle.
The problem with that camshaft along with most of the other shelf Cams is the 111 lobe separation angle. Comp grinds that cam for me on a 113° that I stock and sell.
The reason for the change is that it improves manifold vacuum.

Same go's for the 68-200 and 68-201. They both are on 110°
They are popular and used because they are under .450 lift and will work with the stock valve spring.

I have a custom that Comp has been making for me that is a much better choice than the shelf cam. It's 206 212 @.050 .435 .448 lift on a 113° lope separation angle.
It's a great choice for someone that is running a unported head with stock valve springs.
It's a vast improvement over the stock cam.

Anybody is welcome to contact me through email or a call if you have any questions or would like to purchase a cam, my custom Pistons, or any other products I have.

Russ

It's interesting that all of the Mopar Performance cams have a 108* lobe separation angle. I'm running the P4529230AB cam with 256* in&ex advertised duration and .45" lift in&ex with no problems on a '96 obd2 system.


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