Anyone using a Crower 52242 Compu Pro camshaft ..

Looking for some feedback on this or any other Crower Hydraulic camshaft for a 455 Buick to run mid to low 12,s with in a 3800# skylark. Iron heads flow 260/190 @ .550 valve lift , 10-1 cr , SP-1 intake & 1 7/8 headers. Trans is a TH400 with a TSP 9.5 converter stalls @ 2700 rpm ,rear gearing is 3.42 , MT 275 60 15 ET street radial.

Thanks ,

Mark

 

I would think with iron heads you would want a cam with more a split that favors the exhaust a bit more.

 

Mark

If you want to performance on the track use the Crower 52210.
The 108 lobe center will take advantage of the headers.

232/244 duration @.050"
.507/526 lift with 1.6 rockers
.491/.510 with 1.55 stock rockers
108 lobe center.

This cam comes on just after 2500 rpm so the 2700 rpm stall will be perfect.
You will love the midrange and upper end power.
The idle will be rough.

http://www.crower.com/camshafts/buick-400-455-hi-draulic-hauler-cam-296-hdp.html

Paul

 

I think people put way too much thought/stock into DCR calculators
Dont think they tell the whole story and actually can cause error in parts selection

 

Depends on where he is going to shift it,and if his converter really flashes to only 2700 then "I PERSONALLY THINK",its too much cam
Remember folks,there are 100% stock Stage 1 cars running mid 13s at 4000pds through exh manifolds,w mid 3series gears,and non ported heads/int manifolds
This combo with true 10-1 comp,heads that if done correctly flow 40 cfm better on both sides,a good manifold,headers(which alone is 25hp or better)isnt going to need much cam
I would venture to say,he could drop 5-8 degrees on the intake side,leave the exh where its at,and grind it on a 110l/s and i think it would be VERY happy
Look at mr Paul's cam idea-us weerdos think alike p
But hey,im just a hack from the sticks of Denver,all my stuffs slow :laugh:

 

Why does the 52210 with less intake duration (6*) & 108* LSA turn more rpm than the 52242 with more intake duration & a wider 112* LSA ? Is this due to lobe profile & lift rates ? I have looked @ the 52210 but would like a little more lift to take advantage of my iron heads flow @ .550 lift. The camshaft that I have in my car now is 226/240 @ .050 on a 113 LSA it pulls strong from 1800 - 5100 rpm & goes flat above 5100 . ( its a fast profile cam ). To stay in the duration range of 232* intake it might be tough to find a flat tappet cam with the .540 lift. I know I could get it done with a roller cam but I want to do this witha flat tappet camshaft , I must pull to 5500 rpm with strong power ! after that I don't need anything. I have asked about this before on the fourm & it ended with ....go with a roller cam. I have used the Hi Draulic Hauler grinds before in BBC with great results.

Thanks for the input folks

Mark

 

Mark

Crower will grind you anything you want.

Need to know a little more first.

What rocker arms are you using?

How much street driving versus racing will you be doing?

The cam with the 108 LSA takes advantage of scavenging from the tube headers. The scavenging effect helps pull the intake charge into the cylinder as the intake valve opens. The intake duration is effectively increased on the opening ramp.

The exhaust duration on the 52210 is a lot longer than the intake duration to help evacuate the extra exhaust volume.

As you noticed the 52242 is a big cam with the intake valve closing 7 degrees later than the 52210 cam. (.050" spec)
I don't believe there is a 1000 rpm difference in peak horsepower as listed in their cam specs.
The actual upper end power should be a lot closer.

As far as the fast ramp cam you have now, often times the reason they flatten out after 5000 rpm is because the hydraulic lifter pumps down.
The cure is to change to a solid flat tappet and find a way to set the valve clearance at .010".

Paul

 

For what it's worth, the 52242 was the first aftermarket camshaft I tried in my rebuilt 436 some time around 1987 which was in my '67 Electra weighing about 4600 lbs.

The rest of the combo looked like this if I remember right:

10.5:1 static compression ratio as measured w/TRW forged pistons
Port matched/bowl blended big port 430 heads with standard valves, surfaced to remove some cc's
Original '67 rockers and pushrods
Offenhauser 360 single plane intake
Holley 750 mechanical secondary carb, no spacer
Modified Kenne Bell 1-7/8" headers, 2.5" dual exhaust w/flowmaster mufflers
Cam installed 4 advanced
Stock variable pitch converter from a ST300
2.78:1 posi
P225 70R15 Eagle ST street radials

I remember poor traction through most of first gear but consistent 99 mph numbers at Milan Dragway in Michigan, which meant about 360 hp at the wheels. I also remember shifting out of 1st between 5500 and 6000 rpm (it was still pulling hard) and not needing third gear thanks to the rear gearing. I would think with a good setup a similar build with complimentary gearing and traction would be in the 12's in an A body without much trouble.

Idle was noticeable, power brakes worked fine. It was a fun learning experience.

Devon

 

I ran a 12.8 at 104 with stock 74 small valve heads stock intake quadrajet 219/226 cam and 9 to 1 compression with 2500 stall and 3.73s with your setup you should run low 12s easy. Shouldn't take much cam

 

what spring psi do you have ICk
what rockers are you running
what pushrod size
What lifter preload to you have
Are they a good Delphi lifter?
There are alot of good running BB's out there, with heavy valvetrains, running past 5000rpm
The BB Buick shouldnt be any different than those
I also may be stubborn on my thoughts,but unless those heads of yours have some decent cross section in them ,along with a intake that can keep up,i cant imagine that ting wanting to turn over or even 6000 rpm and still be making good power
I also think you need to nottake the cam catalogs min-max ropm range recommendations as gospel
Min crossection of the cylinder head/inlet tract will havea greater impact on rpm range than the cam will!!!!!!!!!!!!!!!!!!!!
depending on the other parts your working with,i believe those rpm ranges arent always close to what they say they should be
kind of like intake manifolds,where thy claim they work in this huge range
ive seen sngle plains make more torque down low thana dula plain,even though the rpm range should supposedly start 1500 rpm later
But hey,you never know
Good luck sir

 

The heads on my 462 are 1970 SF 455 castings that have been brought up to STG 1 specs & ported to level 3 specs by Greg Gessler . 260 / 190 @ .550 lift. True CR is 9.9-1 measured & engine has 200# cranking pressure. With that said there are (2) areas I want to address with a new camshaft grind.

1 I want the power band to be in a RPM range of 2500 - 5500 rpm (must pull strong to 5500)

2 I need the valve lift to be close to the .550 area with out causing lifter distress.

The camshaft I run now has great power from 1800 up to 5100 (flattens out) but has alot of lifter noise at idle & falls short on the lift area with .505 / .484 . with 1.55:1 rockers

Paul this car is just a toy & does not see 1000mi. a summer . The 52210 sounds good if I can get a little more lift ( I am running the stamped steel rockers (1.55:1) if the cam & valvetrain would be happy with a higher ratio that could be done.

I don't want to run solid lifters or have to adj my push rods for the proper lash , better to find the best grind for my use.

Thanks for all the input , sorry that this is a rehash but I did gain input on the 52242 & 52210 Crower cams.
Mark Campbell

"Lost in Cam Land" but not for long

---------- Post added at 09:34 AM ---------- Previous post was at 09:13 AM ----------

Nick I just saw your post, heres the specs you want , stock stamped steel 1.55:1 , 5/16 adj push rods , Preload is set @ 3/4 turn , have also tried less but no improvement. JW said to try 3/4 turn. Yes they are Delphi lifters. The valve springs spec out @ 115#@1.89 / 305# @1.39 coil bing 1.150

Nick , I don't take the cam co. specs as the gospel ... thats why I am asking for input on these & any cams that might fill my set ups needs , thanks for you help with this & eveyone else that has input on this post . this is the best group I have ever seen when it comes to preformance .

Mark

 

If it will fit, i recommend going to a 3/8" pushrod
The pushrods in these things are very long, and when you start tp get some deflection going on ,it does some weird things to the valvetrain
Theres no concern of weight on that side of the valve to a point
I also wonder if what you have coudnt use another 10-15 pds of psi
not so much seat,but open psi
if you have the room,shimming the springs would get you that pretty easily,and its a cheap fix
also ,depending on how far you are from coil bind,sometimes the more room you have the worse it is and the springs start to dance around
poss a good inside stepped spring locater would help as well
good luck buddy

 

Mark

The fast ramp cams tend to create problems with valvetrain stability. If you add more spring pressure to keep the lifters tracking on the cam
then the lifters strain to stay pumped up at high rpm.

The Crower cams you are looking are just the opposite. Notice the long advertised duration as compared to the .050" duration.
The ramps are long and have an easy ramp rate.
As a result the recommend spring setting is 92# @ 1.850 and 300# @ 1.350 which is lighter than your present setup.

I understand your wanting to take advantage of the level 3 port work and use valve lifts above .500. BTW great choice on head work!

The 52210 valve lift with the 1.55 ratio rockers is .491/.510
The 52242 valve lift with the 1.55 ratio rockers is .520/.519

Generally speaking the stock rocker arms become marginal at lifts over .500 with heavier spring rates but there should be no problem with the spring pressures you have and with low mileage driving.

If you wanted to use a cam that has a full .550 valve lift then roller rockers would be needed.

With a 73% intake to exhaust port flow ratio (which is a good figure for a Stage1 head) the 4 degree spread on the 52242 will work fine.

Both the 52210 and the 52242 will pull strong to 5500.

The 52210 will idle rougher than the 52242 and the power comes on more abrupt at 2500 rpm than the 52242

The 52242 will have better manifold vacuum for power brakes and with the Level 3 port work should make more power than the 52210 becuase of the higher lift.

Do you have the port flow rates for lifts between .100 and .500?

Paul

 

So Paul
Honest no alterior motive questions here?
why then if upping the spring psi causes lifter collapse issues
then why
a- do these cam companies advise running higher spring psi with their cams?
b-how do some engines run more rpm with these style cams and some wont
i mean an engine doesnt know the name on the valve cover?
c-is the lifter at fault
D-why does a comp xtreme energy faster ramp rate cam call for 100seat-295 open psi and a similar lunati piece wants 150-325 psi-both being hyd cams?
Does the higher rate beehive spring lose that much more mass over the valve ,they feel it not a issue
And if thats it the case,then is it a mass thing,and not a lobe issue
there are guys running hyd roller classes with a TON OF SPRING PSI turning 8500-9000 rpm with stock lifters
is it really all in the lobe design per say,or valvetrain weight issues?

 

one cam company told me the lifter collapse would be at idle or low rpm then they would pump back up at higher rpms, thats what they told me if its true or not i do not know.

 

Nick

The laws of physics are not only different for each engine brand but also for each cam company.
Just Kidding!

Very good questions and I don't know all the answers.

This is what I can tell you that is accurate and not Bull.
I'm leaving out friction and component flex.

There are many parts to a cam profile and each lobe section creates its own need to be matched by the valvetrain.

Example:
If the closing ramp is steep then the spring rates need to be high to keep the lifter on the lobe.
If the nose is sharp (open valve dwell time is short) then the open spring pressure needs to be high to keep the lifter on the nose of the cam.
When the difference between the .050" duration and the advertised duration is small, the valve is picked up off the seat abruptly and set back down on the seat abruptly. To keep the valve from bouncing on the seat as it closes the seat pressure needs to be higher.
Then there is the ramp angle of each section of the lobe versus the max rpm the engine will see.

So between Fast Ramps, Trying to get maximum area under the curve and asymmetrical profiles the combination of ramp angles as you go from seat to seat over a cam lobe can be all over the place needing a wide variety of different springs and valvetrain requirements.

To answer a question like "why does a comp xtreme energy faster ramp rate cam call for 100seat-295 open psi and a similar lunati piece wants 150-325 psi-both being hyd cams?" You would need to profile the cam lobes with a cam doctor or someway similar and compare the lobe angles from seat to seat. I don't know the difference and calling the cam companies tech dept doesn't always (I'm being nice here) get you the right answer either.

It is also curious to me why the BBB with a 1.55 ratio rocker seems to amplify the hydraulic lifter problem when going to a 1.6 ratio when the standard BBC rocker is a 1.7 ratio and seems to work fine with the same type of cam profiles. Again I don't know since I have not taken the time or money to investigate this strange phenomena.

There are lifters that do a better job at high loads so in some cases it can be the lifters fault but again this is a case by case situation and cannot be generalized

A beehive spring reduces the mass on the top half which is responsible for most the reciprocating mass but it is the large reduction in the size of the spring retainer that has a big contribution in mass reduction.
Every bit of mass reduction helps but again it may not be the single cause for the problem and each case may be different.

The folks running 9000 rpm have cams specifically designed with ramp angles that allow the hyd lifter to live at that rpm.
I would bet that the lifter is designed specifically for that application or they run the lifter plunger nearly at bottom or both.

I'm hoping there are others that can shed more light on the subject and make corrections on anything that is wrong here


Paul

 

Well geez Paul
I was wanting you to show me an epiphany or something? lol
All those comment you made were exactly waht i believed or thought to be true
Thats why i dont understand,and im glad you brought up the rocker ration with the BB chevy\i wonder if the reduced cam base circles on these bb buicks might be leading to some cam flex?
or the fact that you if have less cam base persay leads to a more intense lobe(less surface area to get the ramp in if that makes any sense?)
We have al seen examlples of faster rate cams working on heavy valvetrain engine to at least 6000 so what gives here?
Nick