Crane Cam Yes or No

[Narfxj]

I'm looking to do a stroker engine in the next month or two. But came across a new one from a project that some one never finished. So Im thinking I can save some money JOY!!! The only thing is it has a crane cam. I've heard and read alot of bad things about these cams. But never really why they failed. Are these bad cams and should I stay away from it.
This will be in a daily driver also.

 

[OCMI_Teddy]

if it's a DD, then you will want to stick to the stock 4.0 cam for reliability reasons.

 

[Dr. Dyno]

My Crane 753905 cam failed after 34k miles and others have failed much sooner, so it's hard to recommend it. I'm very happy with the stock cam in my stroker. Amazingly, it's more responsive at part throttle with the stock cam than it was with the Crane, and I often find myself having to slow down 'cause I get over the speed limits too easily.

 

[OCMI_Teddy]

I often find myself having to slow down 'cause I get over the speed limits too easily.

Now are these granny speed limits........

 

[Doublehead]

My Crane 753905 cam failed after 34k miles and others have failed much sooner, so it's hard to recommend it. I'm very happy with the stock cam in my stroker. Amazingly, it's more responsive at part throttle with the stock cam than it was with the Crane, and I often find myself having to slow down 'cause I get over the speed limits too easily.

I'll have to admit I'm a bit confused now - so the Crane cam isn't really an improvement in power compared to the stock or what? How is the '96+ cam compared to the stock '91-'95? :huh:

 

[TiRod]

IIRC, the specs on the '96 move the hp and torque up the rpm scale to take better advantage of the higher flow of the head and manifold.

I've read here some "stock" replacement RV cams here are a good value for the dollar as they have better specs for low end torque for the I6. Installing any cam is a particular operation, as new lifters, special lube, timing, and break in can all effect longevity, much more pushrod length, rocker ratio, and centered valve sweep. All the mechanical stuff has to be coordinated along with a good profile matched to the intake and exhaust, or you just don't get best power.

It's usually a guessing game based on best experiences, or a factory test program not to be taken as lightly as the average rodder treats it.

 

[j99xj]

Actually the older cams are the best for high rpm use.

The 96+ cams moved the power band DOWN about 1000 rpm.

 

[seanyb505]

Actually the older cams are the best for high rpm use.

The 96+ cams moved the power band DOWN about 1000 rpm.

Im not saying this is wrong, but can anyone verfiy this so I know what direction to go in when building my stroker?

 

[Flash]

Im not saying this is wrong, but can anyone verfiy this so I know what direction to go in when building my stroker?

Your Question is Crane Cam yes our no

If your looking for one of the bigger flat tappet (more power on the upper rpm range, and less torque on the bottom end) cams out there I wouldn't be afraid of the Crane cam.........or the big Comp. cam..........or even the biggest one, From MPP offers..........

Two thing that i would be worried about, ONE, would be how much spring pressure you put ON the cam(to much, cam has a short live, to little valve flow and could cause the keeper to fall out and drop a valve into the the piston)

TWO, todays modern oils, (ya right) if your not adding an additive with a "non modern oil" cam life could be vary short!

With a close to stock or stock cam the problems above are hardly something to worry about!

Sorry i was going to make it a short answer......but it just didn't come out that way!
:cheers:

Flash.

 

[Dr. Dyno]

I'll have to admit I'm a bit confused now - so the Crane cam isn't really an improvement in power compared to the stock or what?

Only at light throttle. At WOT, the Crane is definitely better than the stock cam but not hugely so. The difference is 11hp/12lbft at the wheels and 0.23secs to the 1/4 mile (14.55 Crane, 14.78 stock cam).

How is the '96+ cam compared to the stock '91-'95? :huh:

The '96+ cam moves the HP/TQ peaks down the rpm scale. The result is slightly more torque and slightly less HP.

Now are these granny speed limits........

Yeah. The highway speed limit is officially 75mph (unofficially it's 87) but I often find myself cruising at 95-100 in 5th gear between speed cameras and I'm barely touching the throttle.

 

[Doublehead]

One last question
Stock cam with 1.7:1 ratio roller rockers... how would that compare against the Crane? Reliability is a big concern for me and it is really keeping me away from the aftermarket cams... actually to be honest I think my choice is now between 1.6 or 1.7 roller rockers with the stock cam... I really don't like the idea of having such a weak link in my engine that might fail someday :S

Thanks!

 

[Dr. Dyno]

He he, now you know why I was prepared to give up some HP/TQ and go back to the stock cam. I always had a bit of valvetrain noise with the Crane cam/Mopar valve spring set-up but I don't have any with the stock cam/stock springs. My cam is the '87-'95 version and I'm using Yella Terra 1.6 ratio roller rockers (0.424" valve lift).
If you go for the '96+ cam, that has less valve lift with the stock 1.6 rockers (0.408/0.414) but you can increase valve lift to 0.433/0.440 by using the Yella Terra 1.7's. That's still low enough to allow stock springs, and that combo should make even better low/medium rpm torque than mine but with slightly less HP.

 

[seanyb505]

He he, now you know why I was prepared to give up some HP/TQ and go back to the stock cam. I always had a bit of valvetrain noise with the Crane cam/Mopar valve spring set-up but I don't have any with the stock cam/stock springs. My cam is the '87-'95 version and I'm using Yella Terra 1.6 ratio roller rockers (0.424" valve lift).
If you go for the '96+ cam, that has less valve lift with the stock 1.6 rockers (0.408/0.414) but you can increase valve lift to 0.433/0.440 by using the Yella Terra 1.7's. That's still low enough to allow stock springs, and that combo should make even better low/medium rpm torque than mine but with slightly less HP.

What about 87-95 style cam and 1.7s? Im just trying to exhaust every option so I know I can be confident in my choices.

 

[Doublehead]

What about 87-95 style cam and 1.7s? Im just trying to exhaust every option so I know I can be confident in my choices.

...if I understand correctly what I've been trying to read about camshafts, that might increase top-end horsepower on the cost of torque? Or is my brain just out to lunch?

 

[Flash]

Quote:
Originally Posted by seanyb505
What about 87-95 style cam and 1.7s? Im just trying to exhaust every option so I know I can be confident in my choices.

...if I understand correctly what I've been trying to read about camshafts, that might increase top-end horsepower on the cost of torque? Or is my brain just out to lunch?

------------------------------------------------------------------------

You guys real got me, a wondering, about this....... so i pulled out my 'Dyno Sim' and set out to answer this question.....was quit surprised by the results.

First off, I made two sim eng that were identical in every way. stock 4.0 bore, 258 crank eng,(3.875/3.895) 7120 HO head, stock 92-95 cam, 9.1:1 compression, 500 cfm induction, and Tune- Port injection. Both had the exactly same numbers.

now i added or changed the lift form 0.424 to 0.451 (1.6-1.7 rocker arm ratio) to sim 1 and keep #2 the same........

there was no HP or TQ change at 1500 rpm and this was the real shocker, TQ was up by only 1 and the HP was also up BY 1.

There is also variables such as ramp speed that is not being considered in "default' mode (I'm not smart enough to change this,and under stand what and why i should change it.....so i just let it do is thing.)

So the answer, the best that i can figure it, going form a 1.6 to a 1.7 will not hurt the bottom end at all......and will gain slight on top.

I went and look at the flow number and found some of the answer why

the CFM air flow between .400" lift and .500" lift was only 3 cfm more on the int. and 5 cfm more on the ext. side.

A ported head would help on these numbers.


Flash.

 

[Dr. Dyno]

What about 87-95 style cam and 1.7s? Im just trying to exhaust every option so I know I can be confident in my choices.

The valve lift would become 0.450" and that's just beyond the rating for the stock valve springs, yet not enough to make a performance difference. The 4.0 head doesn't flow significantly more air at 0.45" of lift than it does at 0.40" unless you port it and add oversize intake valves.

 

[JJacobs]

Only at light throttle. At WOT, the Crane is definitely better than the stock cam but not hugely so. The difference is 11hp/12lbft at the wheels and 0.23secs to the 1/4 mile (14.55 Crane, 14.78 stock cam).

Do you remember the 1/4 MPH difference between the two?

 

[MudDawg]

Whatever you decide for the cam...make damn sure the setup is correct...valve spring coil bind, retainer to guide interference, rocker bind are the three most common mechanical cam killers. Spring rate, seat pressure are critical as well as pressure over the nose...select a spring that meets criteria.

A dual pattern cam will help with flow, since the big cork is in the exhaust side...and there is no need for killer lift numbers...the head runs out of steam at about anything over .450 . Longer duration with more overlap will help in the higher rpm range, but will kill the bottom end (where most Jeeps need it).

The stock '91 - '95 ho cam is pretty good, as is the Renix cam. Personally, if it was my motor and I wasn't trying to build a high rpm buzzer...it would get a stock cam....If you are trying to build a lot of power....get a Hesco aluminum head....it will support flow numbers far better than an iron head and be far less likely to suffer detonation problems.

 

[Dr. Dyno]

Do you remember the 1/4 MPH difference between the two?

At WOT, the Crane is definitely better than the stock cam but not hugely so. The difference is 11hp/12lbft at the wheels and 0.23secs to the 1/4 mile (14.55 Crane, 14.78 stock cam).

[email protected] Crane cam
[email protected] Stock cam

 

[JJacobs]

So 1.5 mph difference. If you want to determine HP changes the track is the best dyno (obviously) but it's the MPH, not the ET that's talking.