Camshaft lobe experts opinions..
- Thread starter 360PLUS
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First opinion, it looks to be a hydraulic roller version of a ,let me call it, a Jumbo Mutha Thumpr! I'd rather not say what I think of the "Thumpr" offerings! It aint good!
There's no basis of "what to think" without an application and all other associated combo items. It's like goin to a whorehouse and pickin a gal without lookin at um. Need LOTS more info.
ok stroker 360 , rhs heads, bout 11.4 comp ratio, bigtor jr. holley hp 950 1 7/8 hedman w2 headers
yellow rose
Overnight Sensation
I don't care for the big split, but other than that, I like it.
What does the cam card call out for lash?
Also, if you have 1.6 rockers I'd use those. I like lift.
What does the cam card call out for lash?
Also, if you have 1.6 rockers I'd use those. I like lift.
its a hydraulic roller.
yellow rose
Overnight Sensation
Well...that crap canned my idea.
Still, I like the grind. Just not a big fan of that much duration split.
512Stroker
We are all here because we are not all there.
Save your money and aggravation and find a solid roller grind.
K.O. SWINGER
Meeting in the alley since 1976
That's a whole lot of duration for the lift compared to a modern cam, but pretty typical for the year of Cam that it was manufactured. I am by no means a guru on the subject but it seems like a lot of duration for a hydraulic roller especially for a small block even in a Stroker it would want to top 6800 RPMs or more, nothing wrong with. it I bet it would sound like a beast
DrEamer
I suffer from cars on the brain!
I had to go back to a 2010 Comp catalog to even find those lobe numbers. Someone had that custom ground (20-000-09 part number), and according to Comp's lobe description, for a race cams only. I have no opinion on the cam, but just wanted to offer some background on the lobe design.
I’m not a huge fan of these cam even though they seem to dyno well enough. I’m with YR on it. “I” also like a lot of lift in a head that can make use of it and the intake is OK fair enough, the exhaust, poor.
Also as YR mentioned, the 10* split. WOW! WTF?!?!
I know, I know, it’s a big mutha thumper right!
The split duration was designed for stock or just simply poor flowing exhaust. It does show some good even on ported heads though, the 8 or 10 degree split was for stock heads. Before that, 99% of all cams were a single pattern and rocked the power graph.
Are your heads ported?
Do you have flow rates for them?
Also as YR mentioned, the 10* split. WOW! WTF?!?!
I know, I know, it’s a big mutha thumper right!
The split duration was designed for stock or just simply poor flowing exhaust. It does show some good even on ported heads though, the 8 or 10 degree split was for stock heads. Before that, 99% of all cams were a single pattern and rocked the power graph.
Are your heads ported?
Do you have flow rates for them?
i'll never be able to look at a cam lobe in innocence again
K.O. SWINGER
Meeting in the alley since 1976
Oh how quickly the tide changes, just a couple years ago if you mentioned a single pattern camshaft everybody said they were obsolete, a lot of it was propaganda to help sell new cams
It’s build dependent I think. Extra exhaust helps. You do t need a dual pattern cam. If it should (key word) help.
K.O. SWINGER
Meeting in the alley since 1976
Yes I totally understand how in some or most stock applications it can help, but all of the modern heads Edelbrock trick flow ProCom whatever exhaust Port will outrun the intakes. So in my opinion I just find it strange that the so-called new modern cams are still catering to a restrictive exhaust side. And I'm also not saying that all cam Grinders buy into that, just an observation
yellow rose
Overnight Sensation
I agree. Until I started doing my own port work, I bought into some bad information about exhaust to intake flow ratio and junk like that.
When I bought my flow bench, it didn't take long to realize that shooting for a flow number, or porting the exhaust to get a certain percentage of exhaust flow relative to the intake flow.
That's why all that split bothers me. They usually add exhaust duration so they can get the power past peak to hang on. That way, they run less duration on the intake than what it really needs, and crutch it with extra exhaust to get the RPM where it should be.
As long as the exhaust port is quiet and relatively stable on the flow bench, the number is pretty much meaningless unless it's something really eye catching.
The amount of pressure in the cylinder at blowdown is incredible. The cylinder is essentially self emptying at that point in the cycle.
As the piston comes up on the exhaust stroke, it then is pushing out what's left over. So you done need a big valve or a ton of duration to get the work done.
DrEamer
I suffer from cars on the brain!
Sort of strange how the trends have come back around. Isky preached all you needed was single patterns, and it still is part of their website information. Then their site also sports some newer duel pattern grinds now, so who knows. I will say when I was asking for suggestions from various custom cam venders, most came up with a 4 degree duration split, or single pattern. Many of the older catalog cams still seem to be 6 degrees or more.
Wyrmrider
Well-Known Member
"square lobe" cheater lobes are for race only- hard on springs
agree on the split
which is the right duration - the exhaust with a short intake
or the intake with an extended exhaust
which in a perfect world would stretch the rpm range
Will need head flows to go any further plus all eh usage details
how much stroke, rod length, piston weight
That's a big cam and most likely an oldie but goodie grind as cheater grinds are not required much anymore
That said --- Mike Jones inverse profiles are the best you can get by far about 8 degrees
agree on the split
which is the right duration - the exhaust with a short intake
or the intake with an extended exhaust
which in a perfect world would stretch the rpm range
Will need head flows to go any further plus all eh usage details
how much stroke, rod length, piston weight
That's a big cam and most likely an oldie but goodie grind as cheater grinds are not required much anymore
That said --- Mike Jones inverse profiles are the best you can get by far about 8 degrees
dirty white boy
50 yr old Juvenal delinquent
cam card for comp's hyd roller mutha thumper cam! not the biggest thumper, the middle one!
nm9stheham
Well-Known Member
The duration matches up pretty well with the static CR for pump fuel. Definitely not a cam for cruising, or towing.
I wouldn't know but I've been told that is what bags are for ..... LOL
dano
Evil Handy Man
To those who know a hell of a lot more than I do looking at this, could this cam have been ground for an application like a turbo, roots or centrifugal blower, no2 or an alternate fuel like propane or nitro? Possibly a marine application?
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nm9stheham
Well-Known Member
Not anywhere close to typical for a turbo. Waaaay too much overlap.
Looks like the duration and lift got balanced a bit. More lift, less dur on intake; more duration less lift on exhaust.
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