another thread on cam selection.

Performance mods and Advanced Stroker discussion.
Post Reply
joshm
Where's the "any" key?
Where's the "any" key?
Posts: 21
Joined: February 2nd, 2017, 5:22 pm
Vehicle Year: 1984
Vehicle Make: jeep
Vehicle Model: cj8
Location: North Carolina

another thread on cam selection.

Post by joshm »

hi fellas, ill apologize in advance as this is asked a bit, ive got my head at the machine shop and im trying to nail down what cam i need to get. ill admit im not fluent in cam talk so.... Im wanting a good street cam. Motor is going in a cj8, its getting a 99+ intake machined for a 2 barrel carb (MC2100) 3.55 gears with 4 speed T176 tranny and 31" tires. highway cruising is around 2700-2900rpm. The gentleman doing the machine work said that my stock valves are good and that he will smooth out the intake and exhaust passages. He tested a couple of the springs and they are a little weak. so with all that said, what are my options? id like to have a fun/quick around town jeep with some extended highway driving. My guy said machining spring seats isnt a problem for whatever springs i need, and fuel injection problems are a non issue.
User avatar
DaemonForce
Making Progress
Making Progress
Posts: 99
Joined: November 15th, 2013, 7:18 am
Stroker Displacement: 4.7L Super
Vehicle Year: 1983
Vehicle Make: American
Vehicle Model: Eagle
Location: Olympia, WA
Contact:

Re: another thread on cam selection.

Post by DaemonForce »

Here's the thing about street cams and the stroker, they're not being shipped out with a VAM 282/stroker in mind. So whenever you see listings for the 232, 258 and 4.0L they are made to be a good tune for the bigger engines and GREAT for the smaller ones. There is also the factor of carb/EFI going on with these engines so whatever you choose, it's fine to go a bit wild with the stock EFI system but if you're planning on doing boost, watch out for erratic behavior.

When you see the amount of duration, lift and timing going on, you want to make a comparative list of these cams to figure out what all will make this work best for you. My stroker is already finished but I did a manual swap to a really fluid T-5 with a tall .76 ratio and I'm already on an outrageously tall 2.72 gears with my Dana 30IFS/35. I also have the rare carrier for these diffs to bolt up 2.35 gears at Bonneville. In other words this was built with a dual purpose of attempting LSR at the flats and swapping gears out for street cruise. Comparatively, your Jeep is intended to behave like a small truck that needs an additional margin of power than mine puts out just to get up to speed and hold. So while I cruise between 1700-1900, you're going to be somewhere around 2600-3000 comfortable but still hit peak power much further on. It's kind of a toy. Since you have a non-OD manual and much bigger tires, I suggest you keep your 3.55 gears or drop to 3.73 for future-proofing and stick with stock valve springs unless you want to go with a strong cam that goes over .480 lift or anything that requires machining. Each cam has a range where it comes alive and you want the cam floor to be just off idle at the worst or just under your projected cruise RPM at the highest. Since your cruise speed is going to be high anyway, you're pretty much open season for big cams. Cam ceiling should always be the redline.

I went with a really mild Crower 44243 hydraulic cam featuring 194/[email protected] duration and .437/.445 lift then retarded it 2º. At a glance, this is puny even compared to the stock 4.0L cam but I have my reasons for it. You will be in the market for BIGGER with mild overlap but will probably want a 2º retard setting like I did. There's a TON of available cams for these inline engines and I've had to contact so many people to get some cam details and still can't get them because all the data is so superfluous and clogged. Looking at what you have and what you're doing, I recommend any of these:

Crane Cams 753901:..............204/[email protected] duration, .456/.484 lift, 42º overlap, 1200-4800 RPM
Competition Cams 68-235-4:....210/[email protected] duration, .477/.493 lift, 36º overlap, 1000-5300 RPM
Crower Cams 44311:..............238/[email protected] duration, .480/.486 lift, 60.5º overlap, 1800-4500 RPM
Lunati Cams 63500:...............208/[email protected] duration, .484/.484 lift, 29º overlap, 1000-5200 RPM
Crane Cams 753941:..............216/[email protected] duration, .484/.512 lift, 54º overlap, 1800-5400 RPM
Howards Cams 330991-08:.......221/[email protected] duration, .501/.501 lift, unknown, 1800-5600 RPM
Crower Cams 44312:..............248/[email protected] duration, .499/.512 lift, 75º overlap, 2000-6000 RPM
Schneider Cams 10054:...........224/[email protected] duration, .496/.496 lift, unknown, 2600-6250 RPM
   ,__,_____,__,       ~A-M-C YA!
//___}/,_ll,_\__\,_____
,l_/¯\_l__ll__l__/¯\(¤≡¤)
   (o))o))        (o))o))
joshm
Where's the "any" key?
Where's the "any" key?
Posts: 21
Joined: February 2nd, 2017, 5:22 pm
Vehicle Year: 1984
Vehicle Make: jeep
Vehicle Model: cj8
Location: North Carolina

Re: another thread on cam selection.

Post by joshm »

wow, thanks for the detail in your response Daemon. The t176 complicates the jeep, I had 2.72 gears from the factory. It was great on the highway (20mpg) all day, but a dog around town with the taller 1st gear. I regeared it a few years ago to improve the city driving, but now i cring tacking it up to 2900 for extended periods of interstate driving. Add a worn wrist pin and piston knock= not fun to drive.
I like the lunati and the comp 235 cams as they come in sooner. Do you have any suggestions on for springs/retainers for those two cams. I guess the mopar performance would work if i could find the retainers. Ive read so many threads on combos that my head is spinning. Seems alot of the threads are older and some stuff isnt available anymore or has been discontinued $$$.

if anyone is curious my recipe so far is
91 block milled to 0 deck
KB421 .020 pistons hastings molly rings
4.0 rods
1982 crank
7120 head milled (.008) with stock valves
springs (TBD)
.044 quench
comp calculator is giving me 9.17:1 ratio (Lunati 63500 cam= 7.97:1) and (comp 235=7.92:1)
Russ Pottenger
Strong Poster
Strong Poster
Posts: 889
Joined: August 15th, 2009, 1:27 am
Stroker Displacement: 4.7
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: another thread on cam selection.

Post by Russ Pottenger »

A couple thoughts.

If you're willing to do a valve spring upgrade, I have on the shelf a Comp 68-235-4 cam on 114° lope separation angle. That will work much better than the 111° especially with your relatively low static compression ratio.

If you're looking to stick with the stock valve spring I have a modified 68-232-4 with the lifts reduced to .435 .448

You're welcome to shoot me a call or email if you'd like more information

Thanks,
Russ Pottenger
Bishop-Buehl Racing Engines
531 N. Lyall Avenue
West Covina, California 91790
Work (626) 967-1000
Cell (626) 673-2203
Email/PayPal: [email protected]
joshm
Where's the "any" key?
Where's the "any" key?
Posts: 21
Joined: February 2nd, 2017, 5:22 pm
Vehicle Year: 1984
Vehicle Make: jeep
Vehicle Model: cj8
Location: North Carolina

Re: another thread on cam selection.

Post by joshm »

That sounds good russ ill send you a email for a price. So less lobe separation will give me a little more "real" compression. starting to get this. After more searching it looks like the lunati 74814 springs and hemi retainers are a pretty good match. Another question for Russ (and posted in the Crower beehive thread) did you find a fix for the single groove keeper/locks and the hemi retainers?
Russ Pottenger
Strong Poster
Strong Poster
Posts: 889
Joined: August 15th, 2009, 1:27 am
Stroker Displacement: 4.7
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: another thread on cam selection.

Post by Russ Pottenger »

joshm wrote:That sounds good russ ill send you a email for a price. So less lobe separation will give me a little more "real" compression. starting to get this. After more searching it looks like the lunati 74814 springs and hemi retainers are a pretty good match. Another question for Russ (and posted in the Crower beehive thread) did you find a fix for the single groove keeper/locks and the hemi retainers?
Josh,

Got your email. I'll send more detailed information with prices and pictures.

As of now I haven't found a drop-in valve spring without some level of compromise.

95% of my builds utilize the Chevy LS1 valve upgrade.
That allows me to use a very high-quality PSI LS spring with matching lightweight small diameter chrome Molly retainers with molly locks for $195.00
It does require valve spring pocket machining, and of course, replacement valves.

Because so much of the power potential is in a good cylinder head and proper camshaft, I think the extra money spent will be well worth it.
joshm
Where's the "any" key?
Where's the "any" key?
Posts: 21
Joined: February 2nd, 2017, 5:22 pm
Vehicle Year: 1984
Vehicle Make: jeep
Vehicle Model: cj8
Location: North Carolina

Re: another thread on cam selection.

Post by joshm »

Thanks Russ, I found some mopar performance retainer locks spec 8mm 8* single groove. I'll let you know what they look like when I have them in my hand. I posted the part number in the beehive thread. I'm optimistic they will work.
User avatar
DaemonForce
Making Progress
Making Progress
Posts: 99
Joined: November 15th, 2013, 7:18 am
Stroker Displacement: 4.7L Super
Vehicle Year: 1983
Vehicle Make: American
Vehicle Model: Eagle
Location: Olympia, WA
Contact:

Re: another thread on cam selection.

Post by DaemonForce »

Russ Pottenger wrote:If you're willing to do a valve spring upgrade, I have on the shelf a Comp 68-235-4 cam on 114° lope separation angle. That will work much better than the 111° especially with your relatively low static compression ratio.
I've started to look into trying my own numbers and the data I see ranking the highest favors the 111º LSA. Here's an estimate of my radical grind:
214/240
.484/.496
-06, 40, 49, 11
Estimated 327HP@6000, 327LB-FT@4500

Thoughts on something that looks this ridiculous? I kind of want to see this at the track.
   ,__,_____,__,       ~A-M-C YA!
//___}/,_ll,_\__\,_____
,l_/¯\_l__ll__l__/¯\(¤≡¤)
   (o))o))        (o))o))
joshm
Where's the "any" key?
Where's the "any" key?
Posts: 21
Joined: February 2nd, 2017, 5:22 pm
Vehicle Year: 1984
Vehicle Make: jeep
Vehicle Model: cj8
Location: North Carolina

Re: another thread on cam selection.

Post by joshm »

That's nuts! I'd like to see that too. I've got a couple of spring combos on the way to try out. The hemi retainer and stock locks worked, but the retainer sits lower on the valve stem then the stock retainer. I ordered the mopar performance 8 degree locks to see what they do. Got a lunati 74814 Spring, a lunati 74818 spring and a 75761 keeper also have a pac R363 keeper on the way. I'll see what I can piece together.
Hey Russ, comp speced a 109# seat and 317# open spring pressure for the 235 cam. Does that seem high on the open pressure? What are you setting your Chevy valves up to?
User avatar
DaemonForce
Making Progress
Making Progress
Posts: 99
Joined: November 15th, 2013, 7:18 am
Stroker Displacement: 4.7L Super
Vehicle Year: 1983
Vehicle Make: American
Vehicle Model: Eagle
Location: Olympia, WA
Contact:

Re: another thread on cam selection.

Post by DaemonForce »

The way I'm starting to look at this lately, the spring load rating is just as important as the cam. Sure I can estimate how high this will go up through 10K but that doesn't mean it will even get halfway there. Physics like piston speed, spring load, valve float and all this other stuff comes into play. Looking back on some of my older notes, I had a few reasons for picking the Crower 44243 cam currently in my warm build and it's mostly to mimic the low grunty warhorse behavior of a built 258 over the peaky behavior of a 4.0L. Welp, I ended up with both. Guess that's what I get for using the stock short rods. :?

I remember an extremely technical detail about all of this that kept me within a safety margin for duration, valve lift and anything that didn't require aftermarket springs and machining. Looking back the low duration numbers looked stupid but I also spent several weeks porting and polishing that 7120 head only to skip excessive machining. I'm not sure what I was thinking back then but I must have had issues with consistency. I'm probably going to swap in a ready ported and polished head with bigger valves and deeper seats if and when I decide to get off the mild short lift cam. What was the main selling point of the beehive springs? Eliminating harmonic frequency?
   ,__,_____,__,       ~A-M-C YA!
//___}/,_ll,_\__\,_____
,l_/¯\_l__ll__l__/¯\(¤≡¤)
   (o))o))        (o))o))
Russ Pottenger
Strong Poster
Strong Poster
Posts: 889
Joined: August 15th, 2009, 1:27 am
Stroker Displacement: 4.7
Vehicle Year: 2000
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: another thread on cam selection.

Post by Russ Pottenger »

I've been putting the installed height on the Chevy valves at 1.700
That gives me approximately 110 on the seat and 285 lbs @ .500 lift. That seems to be working out pretty good on everything from the grandma stroker's to most of the KOH stuff.

Just to state the obvious, valve springs are there to control the valvetrain.
A significant change in camshaft lobe ramp speed, or valve seat hardness can put you in an entirely different spring that entail different spring pressures and spring rates

Conical and beehive spring designs help reduce some of the harmonics that occur in a single spring valve springs.
Post Reply

Who is online

Users browsing this forum: Ahrefs [Bot] and 14 guests