Camshafts and Mopars

[Ghoste]

This isn't really a question but more trying to open a discussion since I've already gone ahead and ordered a Crower grind for my car.  During some back and forth with Ron I had asked about Crower being a camshaft that takes advantage of the Mopar lifter diameter.  He didn't see it as a needed edge in my application and I trust his judgement.  I do find myself curious about it though and wondering how the other engine builders on here feel about it.  I realize that for years no one was utilizing the lifter diameter to get a Mopar specific profile but how necessary do some of you feel it is now that its there?  Is it mainly hype?  What of the ads and articles decrying the use of Chevy grinds and just what constitutes a "Chevy grind"?

[purple charger]

Which cam did you get?  I have the beast that only ran on the dyno I want to get rid of.

[Ghoste]

Crower HDP271 but it'll be a couple or three months before I can provide much feedback on it.
The "dyno beast" was an Engle correct?  What was it again that made you want to switch out and what are you going to instead?

[purple charger]

It made 471 Torque and 367 on HP I do not think the guy that installed it degreed it in right too. Specs on the cam are 32916 grind 256H  .474 intake .483 exhaust  center line of 108 degree's this hydrallic
Went to a Comp cams .502 intake .511 exhaust 110 degree  same pistons changed heads to Stealth it barks now as soon as I get some more cash I will let you know how much more it puts out
All i know right now it runs a lot better thn before

[Ghoste]

Is that one of the Comp grinds with the Mopar profile on the ramps?

[mauve66]

my understanding was that the larger the lifter diameter then the more surface area that the pressure of the springs would be spread out over therefor reduceing the chance of wiping the cam and allowing for higher spring pressures, to grind a "mopar" cam would make the lobes on the cam wider as opposed to the "chevy" grind that only needs a narrower lobe to cover the smaller diameter lifter

i'll try thse similarities but again this is only my understanding of the situation

mopar lifter to "chevy grind" cam = grapefruit sitting on top of an orange

mopar lifter to a "mopar grind" cam = grapefruit sitting on top of a grapefruit

see what i mean??.  its not that the mopar lifter is sticking out over the edges of the "chevy grind" but that the mopar lifter has more usable area for following the cam profile due to the diameter and the "chevy grind" lobes are a littler narrower than the mopar grind, this would also be true of the cam bearings, yes the "chevy grind easily fits on the bearing but with the mopar grind your using more of the bearing surface to distribute those spring pressure loads,  of course when you talking .001 (thousands) of an inch may not seem like alot but we know in an engine it is ALOT

again this is my understanding not camshaft science, so if you just using stock springs and a slightly hotter than stock cam you may not need the "extra" like they said but i think when you start to get really aggressive with a cam profile to the point where your choosing between a hydraulic or a solid and the associated required stiffer springs then it becomes a larger (pun intended) issue

anybody else on this discussion??

[Ghoste]

You're right but it also allows for a steeper ramp from the base circle to the lobe make for a lot more aggressive grinds on the Chryslers.  Or is that just cam maker hype?

[mauve66]

no your right, thats what i meant by the more aggressive profile

[purple charger]

One of the Cams Mancicni likes. Extreme mechanical.  An old hemi Drag racer like the profile for a 440 too

[maxwellwedge]

I have used Hughes in my last 5 or 6 motors and they make good power everywhere and have plenty of vacuum left for power brakes. Hype or not they have worked out good for me.

[Ghoste]

Was it not also true that Hughes cams were all rebadged Engles?

[maxwellwedge]

Was it not also true that Hughes cams were all rebadged Engles?

Could be - There is a lot of that stuff going on. I buy their timing sets as well (Hughes) which are some of the best I've seen. They are made by another company as well so maybe this Engle thing has some weight. Regardless, they are working well in 2 340-6 and 3 440's....1 6-Pack and 2 440-4's. On all of the above I picked "a notch" above the stock HP cams.

[firefighter3931]

Was it not also true that Hughes cams were all rebadged Engles?

Hughes used to use Engle to grind their cams but have since moved on to another supplier. The older Hughes (Engle) cam profiles were all ground on a 108* LSA unless otherwise specified/custom ordered. 


As for cam profiles of the flat tappet variety there are 3 basic families ;

.842 = chevy
.875 =  ford
.904 = Chrysler

The larger lifter bore diameter allows for steeper ramps w/o worries of wiping out the cam lobes. The larger the lifter bore, the faster you can move the valve off the lobe which means increased duration at incremental lift points. The increased duration results in increased torque and horsepower. The advantage with the larger lifter is less seat timing as compared to a slower grind for a given duration. In effect you could have 2 cams that make similar power but one will idle much better and be more streetable.

The fast rate hydraulics work well but there are pitfalls to consider. Increased spring pressure and high speed valvetrain stability are two that come to mind. Too much spring pressure will strain the valvetrain and collapse the lifters and higher engine speeds. Valve float becomes a reality in these types of builds not to mention the possibility of wiping the cam due to the increased spring loads required to keep everything stable....the classic "catch 22".

This brings us to the question of what works best in the typical Chrysler engine for street/strip use. 

My preference is for an agressive cam profile, but no so agressive that it's pushing the envelope.    A good compromise is an .875 lifter profile which strikes a good balance between power and reliability....especially in a street driven build that will see extensive low speed operation/idle time. Based on the seat and .050 duration numbers & lift the Crower Cams fit this criteria. So do the Engle Cams for that matter.

Inmo, the few hp a super fast .904 profile might make over a slightly milder cam is not worth the risk or potential downside. Having used a Crower cam before i can say without reservation it is an excellent choice for a mild build and that is why it was recommended to Shawn for his 383.  That particular 271HDP is sized "just right" for his combination of cylinder head flow/stall speed/gearing. The split pattern wide lobe profile works very well with stock unported heads.



Ron

[Ghoste]

And if its a solid lifter cam?

[maxwellwedge]

I believe this grind is the one I usually go with (I don't have my file here). This is generally a little higher lift and less duration than stock - In your opinion is this too aggressive on the lobe/lifter?

Flat Tappet Hydraulic / Three Bolt Timing Gear. Light car, mild street: medium to heavy towing or RV. Dual exhaust or headers, 4 bbl carb. Street gearing 3.00 to 3.55:1. 150psi suggested cylinder pressure. Good idle, resto/cruiser. Hot daily driver, mileage OK.

Camshaft Technical Details
Intake Valve Lift 1.5
Exhaust Valve Lift 1.5 .470"
.506"

Intake Valve Lift 1.6
Exhaust Valve Lift 1.6 .501"
.539"

Intake Duration at .050"
Exhaust Duration at .050" 215°
223°

Lobe Separation Angle 112º

Intake Opening at .050"
Exhaust Opening at .050" -1.5° BTC
46.5° BBC

Intake Closing at .050"
Exhaust Closing at .050" 36.5° ABC
-3.5° ATC

Min. Suggested Cylinder PSI 155

Sweet Spot RPM 1200 - 4800

[firefighter3931]

And if its a solid lifter cam?

The same rules apply....except that you don't need to worry about lifter collapse. The primary concern with solid lifter profiles becomes valvetrain stability at high rpm and the associated spring pressures to maintain that stability.

Fwiw, the custom Comp solid in my 446 is an .875 lifter profile with moderate spring pressures (130 seat/340 open) and it rpm'd to 6500 on the dyno with no hint of valvetrain float or wierd harmonics. The valvesprings are the stock Edelbrock RPM pieces....net lift is .565 at the valve (.585 before lash)


Ron

[firefighter3931]

I believe this grind is the one I usually go with (I don't have my file here). This is generally a little higher lift and less duration than stock - In your opinion is this too aggressive on the lobe/lifter?

Flat Tappet Hydraulic / Three Bolt Timing Gear. Light car, mild street: medium to heavy towing or RV. Dual exhaust or headers, 4 bbl carb. Street gearing 3.00 to 3.55:1. 150psi suggested cylinder pressure. Good idle, resto/cruiser. Hot daily driver, mileage OK.

Camshaft Technical Details
Intake Valve Lift 1.5
Exhaust Valve Lift 1.5 .470"
.506"

Intake Valve Lift 1.6
Exhaust Valve Lift 1.6 .501"
.539"

Intake Duration at .050"
Exhaust Duration at .050" 215°
223°

Lobe Separation Angle 112º

Intake Opening at .050"
Exhaust Opening at .050" -1.5° BTC
46.5° BBC

Intake Closing at .050"
Exhaust Closing at .050" 36.5° ABC
-3.5° ATC

Min. Suggested Cylinder PSI 155

Sweet Spot RPM 1200 - 4800

The specs on those cams look very similar to the Engle hydraulic cam profiles. Yours could very well be an Engle k54 intake/k56 exhaust custom grind on a 112* lsa. With a cam like that i would not run a 1.6 rocker arm because it is fairly agressive. Good oil with EP additives is essential to make it survive on the street. 



Ron

[Ghoste]

High rpm valvetrain stability and spring pressure are alaways a concern though, so is there a way to quantify what you're trying to say Ron?  And I'm not sure that I am asking the question properly.

[maxwellwedge]

I believe this grind is the one I usually go with (I don't have my file here). This is generally a little higher lift and less duration than stock - In your opinion is this too aggressive on the lobe/lifter?

Flat Tappet Hydraulic / Three Bolt Timing Gear. Light car, mild street: medium to heavy towing or RV. Dual exhaust or headers, 4 bbl carb. Street gearing 3.00 to 3.55:1. 150psi suggested cylinder pressure. Good idle, resto/cruiser. Hot daily driver, mileage OK.

Camshaft Technical Details
Intake Valve Lift 1.5
Exhaust Valve Lift 1.5 .470"
.506"

Intake Valve Lift 1.6
Exhaust Valve Lift 1.6 .501"
.539"

Intake Duration at .050"
Exhaust Duration at .050" 215°
223°

Lobe Separation Angle 112º

Intake Opening at .050"
Exhaust Opening at .050" -1.5° BTC
46.5° BBC

Intake Closing at .050"
Exhaust Closing at .050" 36.5° ABC
-3.5° ATC

Min. Suggested Cylinder PSI 155

Sweet Spot RPM 1200 - 4800

The specs on those cams look very similar to the Engle hydraulic cam profiles. Yours could very well be an Engle k54 intake/k56 exhaust custom grind on a 112* lsa. With a cam like that i would not run a 1.6 rocker arm because it is fairly agressive. Good oil with EP additives is essential to make it survive on the street. 



Ron

Just running 1.5 rockers, recommended springs etc. and I always use proper break-in oil and proper oil after. Most of my stuff is stock restored or survivor stuff - full factory exhaust etc. Internally - I like going with a modern cam profile, ss valves, ARP bolts, JE forged stock compression pistons in custom sizes for the minimal o/s if needed, deck plates, balance and all the good durability stuff. I always get the stock distributor re-curved - makes a huge difference. It is always cheaper to do it once! And if it makes a few more ponies - Good!

[firefighter3931]

Just running 1.5 rockers, recommended springs etc. and I always use proper break-in oil and proper oil after. Most of my stuff is stock restored or survivor stuff - full factory exhaust etc. Internally - I like going with a modern cam profile, ss valves, ARP bolts, JE forged stock compression pistons in custom sizes for the minimal o/s if needed, deck plates, balance and all the good durability stuff. I always get the stock distributor re-curved - makes a huge difference. It is always cheaper to do it once! And if it makes a few more ponies - Good!

That type of build should live forever with the 1.5 rockers. Good machinework, balancing and quality parts are allways woth the extra coin. 


Not sure what Oil you're using but most if not all newer formulations don't have enough EP additives to keep flat tappet cams happy. Just a heads up 


Ron

[firefighter3931]

High rpm valvetrain stability and spring pressure are alaways a concern though, so is there a way to quantify what you're trying to say Ron?  And I'm not sure that I am asking the question properly.

Not sure what you're asking Shawn ?  Are you looking for actual spring pressures needed for different cam/rocker combinations ?


Ron

[maxwellwedge]

Just running 1.5 rockers, recommended springs etc. and I always use proper break-in oil and proper oil after. Most of my stuff is stock restored or survivor stuff - full factory exhaust etc. Internally - I like going with a modern cam profile, ss valves, ARP bolts, JE forged stock compression pistons in custom sizes for the minimal o/s if needed, deck plates, balance and all the good durability stuff. I always get the stock distributor re-curved - makes a huge difference. It is always cheaper to do it once! And if it makes a few more ponies - Good!

That type of build should live forever with the 1.5 rockers. Good machinework, balancing and quality parts are allways woth the extra coin. 


Not sure what Oil you're using but most if not all newer formulations don't have enough EP additives to keep flat tappet cams happy. Just a heads up 


Ron

Thanks Ron,
I have been using Joe Gibbs Break-In oil and the Joe Gibbs Hot Rod oil after. Lots of the good stuff in there. Another engine builder friend has had a lot of success with Brad Penn but haven't found any up here. 

Jim

[Ghoste]

I gues thats kind of what I'm asking Ron, yes.  Generalizations more than specifics but as much as anything trying to ensure that someone completely new to this who may be following the thread understands that valvetrain stability is always an issue but its all relative.   That still isn't making sense is it?

[firefighter3931]

Just running 1.5 rockers, recommended springs etc. and I always use proper break-in oil and proper oil after. Most of my stuff is stock restored or survivor stuff - full factory exhaust etc. Internally - I like going with a modern cam profile, ss valves, ARP bolts, JE forged stock compression pistons in custom sizes for the minimal o/s if needed, deck plates, balance and all the good durability stuff. I always get the stock distributor re-curved - makes a huge difference. It is always cheaper to do it once! And if it makes a few more ponies - Good!

That type of build should live forever with the 1.5 rockers. Good machinework, balancing and quality parts are allways woth the extra coin. 


Not sure what Oil you're using but most if not all newer formulations don't have enough EP additives to keep flat tappet cams happy. Just a heads up 


Ron

Thanks Ron,
I have been using Joe Gibbs Break-In oil and the Joe Gibbs Hot Rod oil after. Lots of the good stuff in there. Another engine builder friend has had a lot of success with Brad Penn but haven't found any up here. 

Jim

Jim, i haven't seen any VOA data on the Gibbs oil but the latest batch of Brad Penn Racing 20/50 lube looks good. One of our members had a sample analyzed at the lab and the numbers look excellent. I've heard that BP is available locally (Ottawa, Ont.) but i haven't found the distributor just yet....still looking. 

Here's the BP Virgin Oil Analysis attatched below :



Ron

[firefighter3931]

I guess thats kind of what I'm asking Ron, yes.  Generalizations more than specifics but as much as anything trying to ensure that someone completely new to this who may be following the thread understands that valvetrain stability is always an issue but its all relative.   That still isn't making sense is it?

Ok, i think i understand what you're asking for. 

Hydraulic cams are limited by the lifter design ; they can hold only so much pressure before they collapse or pump up....neither case is desirable. The typical hydraulic lifter is safe to 6000 rpm but if you need more rpm than that to make peak power it's time to start looking at a solid lifter profile. The fast rate cams are allready agressive enough so adding a 1.6 rocker arm will only reduce the max rpm that the valvetrain can remain stable. Generally speaking, you will lose 300-500 rpm of power going to the higher rocker ratio. A few years back MM did a cam comparson using 2 identical spec cams but one was a flat tappet and the other was a solid lifter. Lift and duration were allmost identical between the two....and both would be considered fairly agressive. The flat tappet profile went into valve float and began to nose over at ~5700 rpm while the solid made power to ~6200. This happened because the valvetrain was becoming unstable at the higher engine speeds due to the limitations of the hydraulic lifter.


So, assuming you built an engine that has enough head flow/compression/carb/headers/intake manifold etc....to make power to 6200+ rpm then a hydraulic cam would be a poor choice assuming that you wanted to achieve maximum performance out of that build. Using a higher ratio rocker arm only reduces the potential power output by limiting engine speed when using the hyd lifter.

Moving on to a solid cam, the same principles apply with respect to valve control but you don't have the hydraulic lifter issues to contend with (lifter collapse/lifter pump-up) so the main focus becomes keeping the valve lifter on the cam to reduce valve bounce, spring surge and harmonics. Using a fast rate lift solid with 1.6 rockers requires increased spring pressures due to the fast valve action. The problem with that scenario is that the spring pressures required to keep the valvetrain stable will push you into the danger zone and risk wiping out the cam. The safe approach for a street driven build is a 1.5 rocker with any fast rate cam and possibly a 1.6 rocker on a "slower" grind that won't require excessive spring pressures.

It's important to remember that BB Chrysler engine valvetrains are "splash" lubed....oil from the rotating assembly is flung up onto the cam/lifters. There is no direct oiling to these areas. When the spring pressures increase (fast rate stuff) i prefer to keep the idle speed up (850+ rpm) to keep lots of oil going to the cam area. The new EDM style solid lifters help by pressure feeding the cam lobe with lube through the lifter bore. Comp Cams is also adressing this issue by special nitriding of their cams for an additional cost...added insurance for those who might be concerned.


That's the cliff-note version. 



Ron