Crane Cam 753941

uniteam · Mar 15, 2004

Hello,

Does anyone is using this cam on a 4.0L ???

I bougth this cam (ready to install), but I want to know more about the Fuel and MAP problems.

thanks

Dr. Dyno · Mar 15, 2004

That's a pretty wild cam (272/284 advertised duration) to use on a plain vanilla 4.0. I hope you're planning to build it for high revs. The stock 8.8:1 CR is low for this cam and you'll find that low rev response will be sluggish. The vacuum at idle and low rpm might just be low enough to cause the MAP sensor to read high and tell the PCM that the engine needs more fuel, thereby making it run rich.
If you're going for a high rev engine (6000+rpm) I suggest that you balance the reciprocating assembly, use a set of ARP rod bolts, upgrade the timing gear to a Cloyes dual system, and upgrade the oil pump.
There is a real possibility of low vacuum/rich running problems at idle and low rpm and if this is the case, the only proper solution is a custom PROM chip with a remapped fuel curve. At the moment, only ASE Performance can offer such a chip. E-mail [email protected] for more info.

uniteam · Mar 15, 2004

Dr. Dyno said:
That's a pretty wild cam (272/284 advertised duration) to use on a plain vanilla 4.0. I hope you're planning to build it for high revs. The stock 8.8:1 CR is low for this cam and you'll find that low rev response will be sluggish. The vacuum at idle and low rpm might just be low enough to cause the MAP sensor to read high and tell the PCM that the engine needs more fuel, thereby making it run rich.
If you're going for a high rev engine (6000+rpm) I suggest that you balance the reciprocating assembly, use a set of ARP rod bolts, upgrade the timing gear to a Cloyes dual system, and upgrade the oil pump.
There is a real possibility of low vacuum/rich running problems at idle and low rpm and if this is the case, the only proper solution is a custom PROM chip with a remapped fuel curve. At the moment, only ASE Performance can offer such a chip. E-mail [email protected] for more info.

thank you very much for the info.

About the CR, what is the best option for this cam ??
and what did you mean exactly with "I suggest that you balance the reciprocating assembly" ?? the list of parts that you metioned, or balance some engine part, like the Crankshaft...Sorry for my ignorance.

thanks

Dr. Dyno · Mar 16, 2004

The crank, rods, pistons, pins should be balanced if you're going to be revving the engine up to 6000rpm and beyond to ensure vibration-free operation.
You can raise the CR to 9.4-9.5 by simply shaving 0.010" from the head, 0.020" from the block (pistons will be only 0.002" below the deck at TDC), and using a Mopar Performance 4529242 head gasket. That'll restore some low rev response and help all round performance. You'll need to insert 0.030" thick shims under the rocker arm bridges to restore valvetrain geometry but that's no big deal.

uniteam · Mar 16, 2004

We are planning to use the crankshaft and Rods of a 4.2L to do 4.5 stroker owr 1994 4.0L HO. With this cam. What kind of ARP bolts do I need exactly, and what more do you suggest to this project ?

I will call to ASE to se the reprogramming details of the PCM, and I want to try find a local machine shop to do the milling job. What kind of head port do you suggest too? and what another part of 4.2L should I consider on this project.

Thank you very much for your patience and help

Dr. Dyno · Mar 16, 2004

I'm gathering parts for a 4.6 stroker myself and you can find more info. about the parts that you'll need on my stroker website http://www.angelfire.com/my/fan/stroker.html
The only parts that you'll need from the 4.2 are the crank and rods. The pistons will be from the 4.0. You'd better get the engine shop to check the bore dimensions to make sure the degree of taper and "out of round" are within factory spec. Otherwise plan for a mild rebore (0.020" will probably suffice) and new pistons. You'll need a new set of ARP rod bolts to replace the old ones.
You can follow my guide to porting the 4.0 head on this page http://www.jeep4.0performance.4mg.com/head.html
I'm going to port the spare '92 head that I'm going to use on my stroker in similar fashion. The only change will be to make the ports slightly bigger this time to take advantage of the bigger engine displacement.

Crane Cam 753941

uniteam

NAXJA Forum User

Dr. Dyno

NAXJA Forum User

uniteam

NAXJA Forum User

Dr. Dyno

NAXJA Forum User

uniteam

NAXJA Forum User

Dr. Dyno

NAXJA Forum User

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