Time for a new cam...

Bones

New member
I have a 4.6L stroker with about 70K on it and this will be the third cam since it was built. Jeep is lifted 7"/35's/AW4/4.56's/Borla/2"cat back with high flow cat/daily driver. Original cam was about 250/260 and the now trashed cam is a 260/270 give or take. I bought both of them from the now AWOL Accurate power and for the life of me I can't remember the part #'s. Both were Crane cams. The first cam was replaced due to a cam bearing failure in 2003, now I lost a lobe on #6cyl exhaust.

I really liked the power of the shorter duration cam but had some cold weather starting problems, not sure why but I've always wondered if I had the distrib a tooth off. It would flood out easily and occasionally try to start backwards or stop the starter from turning the motor over. The larger cam never gave me starting problems but seemed to lack power in the 1800-2700rpm range when compared with the shorter duration cam.

Can anyone remember the specific cams Mike sold? I will try and call him tomorrow. I hope he still has his machine shop. I have talked to him since Accurate Power's closing.

I'm not really excited about going back with the Crane brand. Anyone have any other cam recommendations. Summit seems limited on what they list on the site, and I'm not a big fan of Hesco.

As for what I want out of the XJ. It needs lower end power 1500-4500 RPM with peak torque around 2250 RPM for pulling a 2000lb boat and runs in the mountains pulling a Bantam pack trailer.

Any suggestions?

Bones :skull1:

 
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jeepinwi

New member
I'm very happy with the performance of my stroker with the Crane 753905 cam. I do believe, however, that it is a matter of time before I have a problem with the cam wearing out...and I only have 6k miles on the engine. Hesco makes a couple cams which may be worth looking at.
 

Flash

New member
I have been gaining Knowledge on these stoker so that i can build me on some day so any pit fall that i should avoid let me know!!! sending me a PM would probably be best so that i don't send your post in the wrong direction!:laugh3:


I have tested a lot of Cam's on my "Dyno Sim"(have no real world testing) and the best 3 cam i have found so fare, going form my favorite down is the comp 235,231(has a fue more pound of torque at 1500 rpm and a fue less HP on top) crane 753905 (lest torque them both comp cams at 1500 rpm but has a longer torque curve and peck HP is higher and further up the rpm scale.

All cams were tested with a stock 4.0 w/ a 258 crank!

Just my .02 worth

Flash.
 

old_man

NAXJA Member
NAXJA Member
Crap, I haven't seen you since ColoradoFest 2003? How's it going. Did you ever get the insurance to pay for a new rig?

You need to come to ColoradFest this year. It's back in the same locale.

Below is the info on the Crane Cam I am running in my Stroker. I couldn't be happier. It will pull stumps but does great on the highway as well. The power above 4000 rpms falls of pretty fast but that is about 90mph anyway.


Here's the cam specs on the Crane #753901 that I run

Lift Intake at cam is .2847 x 1.6 RR = .456
Lift Exhaust at cam is .3027 x 1.6 RR = .484

Cam timing @ .004 Intake Opens 19 BTDC Closes 61 ABDC Duration 260
Exhaust Opens 69 BBDC Closes 23 ATDC Duration 272

Cam Timing @ .050 Tappet Lift
Intake Open 5 ATDC Closes 29 ABDC Max Lift 107 ATDC 107 Duration 204
Exhaust Open 45 BBDC Closes 9 BTDC Max Lift 117 BTDC Duration 216

Recommended Springs #99833
 
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Dr. Dyno

New member
Given the rash of Crane 753905 cam failures in Jeep strokers including my own after 34000 miles, it's hard for me to recommend any aftermarket cam anymore given the risk of failure increases proportionately with valve lift and spring pressure. I went back to the stock cam in my 4.6 stroker and I'm very happy; 210rwhp @ 4900rpm and 250rwtq @ 3500-4000rpm is pretty good in my book. I have at least 90% of maximum torque from 1700-4900rpm and at least 95% of maximum torque from 2300-4550rpm. How's that for a flat torque curve?
 

Flash

New member
My "purple" camshaft out of my Cuda when thru 2 340 eng and 12 years of beating on it before it lost a lobe so.........ya I like mopar cams and bought the exact cam and put it back in!

flash
 

karter74

New member
It seems illogical to think that the cam is the reason for failure. Improper preload seems much more feasible. Think about it, if you get a valve job, you have just changed the position of the valve in the head, even by just a couple of .001" and it could be enough to slow eat away at the lobes/lifters. Since Cranes cams are probably just reground stock cams, I really doubt you can blame the company for producing a bad cam.
 

BlueCuda

New member
I also contribute it to the oil alot of people are running. Zinc is something thats good for flat tappet cams and alot of oils have a lower zinc level these days. Alot of people recomend Rotella 15/40 or some of the other Diesel Oils(Dello is another one) because they have a higher zinc content. They are recomended at break in especially. Me, I went kind of backwards as I didn't know any better. Mine got broke in on 10/30 valvoline and after the 2nd oil change has had Rotella. Its got 20K on it now with a 753901 cam from crane. I do worry a little bit after all these threads but I still beat the hell out of it :).
 

Flash

New member
BlueCuda said:
I also contribute it to the oil alot of people are running. Zinc is something thats good for flat tappet cams and alot of oils have a lower zinc level these days. Alot of people recomend Rotella 15/40 or some of the other Diesel Oils(Dello is another one) because they have a higher zinc content. They are recomended at break in especially. Me, I went kind of backwards as I didn't know any better. Mine got broke in on 10/30 valvoline and after the 2nd oil change has had Rotella. Its got 20K on it now with a 753901 cam from crane. I do worry a little bit after all these threads but I still beat the hell out of it :).
I 2nt it . I real thing it has to do with the new oil additve packages. There hands are forced by the EPA and what thay took out won't hernt a thing on a new (roler cam)car but i thing that we are going to see a lot more cam failers........only time will tell.:dunno:

I think that all of us should be adding to our oil or using those that the EPA hasn't gotten to!!!!!!!!!!!!!!!!


flash.
 

Bones

New member
karter74 said:
It seems illogical to think that the cam is the reason for failure. Improper preload seems much more feasible. Think about it, if you get a valve job, you have just changed the position of the valve in the head, even by just a couple of .001" and it could be enough to slow eat away at the lobes/lifters. Since Cranes cams are probably just reground stock cams, I really doubt you can blame the company for producing a bad cam.
Preload doesn't seem to be a problem with mine. I can actually turn the pushrods when lifter not up on the lobe (but there is no free play). The springs are Mopar 360 Magnum springs, not some wild overly stout ones, and the valves are stem height adjusted SS Mopar valves. Only aftermarket parts are the lifters, cam, and pushrods. The pushrods were bought after the head was reworked and installed

I figure the cam and/or oiling is to blame.

I run 10/30 Synthetic Oil in the winter (15/40 Summer) with Lucas Syn oil additive and the oil pressure never drops under 40 PSI warm above idle, so that leaves the cam as my #1 culprit...

Bones :skull1:

 

Flash

New member
Bones said:
Preload doesn't seem to be a problem with mine. I can actually turn the pushrods when lifter not up on the lobe (but there is no free play). The springs are Mopar 360 Magnum springs, not some wild overly stout ones, and the valves are stem height adjusted SS Mopar valves. Only aftermarket parts are the lifters, cam, and pushrods. The pushrods were bought after the head was reworked and installed

I figure the cam and/or oiling is to blame.

I run 10/30 Synthetic Oil in the winter (15/40 Summer) with Lucas Syn oil additive and the oil pressure never drops under 40 PSI warm above idle, so that leaves the cam as my #1 culprit...

Bones :skull1:

Cool pic by the way!

sense you have had several cams fail and your going to try again.

I encourage ya to replace the cam,brake the cam in just as the cam manufacture describes and run the GM supplement oil additive and see what happens.

if you have shaved you head or decked the block at all you really should check the preload of the lifters.

remember that the .010" to .020" of a Hydraulic lifter is useless(top and bottom) and then add machining tolerances into the mix and you could have one lifter that sets to hi in the lifter and anteater one that is to low(bottoming out in the lifter)

Maybe not.......... but its Worth a LOT of time,spent at this point!


Flash.
 

brent

New member
I had in the rvob cam from hesco for about 2 months, hated it, changed to the clifford love it, about 10k and counting on the stroker, starts up great down to -20, and runs smooth
 

Dr. Dyno

New member
karter74 said:
Improper preload seems much more feasible.
Not in my case. My cam lasted 34000 miles so that's far too long for it to be a preload issue. I had also checked the lifter preload when I assembled the stroker and it specced out at about 0.047" on all lifters (a 3/4 turn of the rocker arm bolts from the pushrod "free play" point to 19lbft of torque).
Was it the oil? I don't know. I used Castrol GTX 10W-30 for the first 3000 miles and then used Mobil 1 0W-40 full synthetic thereafter. Looking back, there was always one lifter that was a bit slow to pump up during start up from about 3000 miles, so I think I probably had one defective lifter in the first place.
 

jeepinwi

New member
Dino-
Did that lifter tick for a few seconds when the engine was started cold? How do you know it was slow to pump up with oil? I've had this situation since the engine had about 2000 miles.
 

Dr. Dyno

New member
Yes, if the engine had been switched off for a few hours and then I started it again, one lifter would tick for about 2-3 seconds before it stopped.
 

MudDawg

NAXJA Member #728
The cams are cut from new billets....it is very rare these days to find regrinds or weld-ups for any POPULAR engines....Jeep 4.0 included....(yes I am certain that some small custom cam shops do regrinds, etc...but the mainstream companies like Crane and Comp use new billets)...

Dino, it is odd that the ticking lifter syndrome seems to coincide with the change from mineral oil to synthetic....perhaps it began to have a problem with lifter rotation at that point.

Check this out: www.cranecams.com/pdf/548e.pdf interesting reading....is synthetic TOO slippery to keep the lifters rotating????
 
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Flash

New member
I have had reservation on syn. oil, just because i refuse to run oil as long as syn claimed to go, and sense i change my oil ever 3000, it would be a waste of $$$ for me. and now........even less interested in it!

I run it in my tow vehicle, but not in the eng, just in the boxes!:thumbup:

Makes me thing that i should be changing to diesel oil, cause of the additive pkg or maybe need to buy the GM additive and add a portion to the crank with every oil change:dunno: .

One of the cam manufactures.......... Hmmm hang on ........found it! the last time i had talk to LUNATI they were in the research and development of the a Hyd/ ROLLER cam for the chry small block/ big block!...........well it' a reality.:woohoo:

Sorry no Hyd/roller for the jeep 4.0.....yet! Just some food for thought. Hopefully will be developed for the 4.0 before i build my stroker!

http://holley.com/504A2LUN.asp :thumbup: :arrowl:


Flash.
 
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