Anyone using a Crower 52242 Compu Pro camshaft ..

Mark
Who grinds the EZ profile cams?
Thanks

 

Mark

Are the EZ followers the profiles that are a faster ramp or are all 4 profiles that you listed faster ramps?

Crower Cams

Paul

 

C. Rob , It seems high to me, what is your C.R. ? What are the timing specs of your camshaft ?

Might try another gauge to be sure .


Mark

 

NickEv ,pmuller9,

The EZ lobes are masters that have a shorter duration but retain the same lift ,all 4 of the lobes that were listed by Crower are the old trie & true profiles.

I think thats the end of the story at this time ....

ick

 

Mark

I'm good with a 232 duration intake and a 240 exhaust.

The reason why I suggested the EZ 232 intake was, it had a little more lift over the other 232 intake lobe.
How do you want to proceed?

Would you like for me to talk to Dave?

Paul

 

+1, but not so much cam flex. The smaller lobe size may be leading to some lobe/lifter dynamic instability, IMO.

---------- Post added at 04:16 PM ---------- Previous post was at 04:14 PM ----------

If that's psi then yes, way too much for any pump gas. There's a relation between DCR and cranking pressure, 8 DCR is roughly 185-190 psi, the limit for most pump gas,

---------- Post added at 04:22 PM ---------- Previous post was at 04:16 PM ----------

I would agree with their theory. The reason is that the lifter spends more time under spring pressure at idle than it does at rpm. In fact I don't believe lifter bleed down is an issue unless the lifters are severely worn out. With a normally functioning lifter, there is just not enough time at rpm for the plunger to bleed down while it is under valve spring pressure. Rather, the cause of the problem is more likely dynamic instability.

 

wow 3 great answers. thanks :TU: i learned something after all.

 

can someone explain why they call it ez lobes with a short duration and same lift. i would have guess that a ez lobe would have more duration and less or maybe the same lift.

 

I can't find that info but from the description here, it doesnt seem EZ on the valvetrain. Maybe EZ to grind...

If I decide to go with a hyd flat tappet, i had considered Crower's 288/234/.331" (adv/.050/lift) from their 288HDP (00244) and their 297/239/.334" from their 297HDP (60244) for stability reasons.

 

OK so I just talked with Guy at Crower

The EZ Lobe is where they grind the lobe with 4 degrees less duration at the early lift points which decreases the ramp rate.

A good indication of the ramp rate for a lobe is the difference between the advertised duration and the .050" duration
The Intake b1057 EZ lobe has a difference of 56*
The Exhaust b1058 EZ lobe has a difference of 56*
The regular b1058 has a difference of 54* which is still easy on the valve train while giving you additional exhaust duration for an extended power band.

So I still say go with the following on a 110 LSA

b.1057, lobe lift .326", adv. dur .288*, dur @.050 232* EZ follower
b.1058, lobe lift .333", adv. dur 294*, dur @.050 240*

Paul

 

thank you

 

Now we know the rest of the story ... I am still looking into several camshafts. Thanks for all the input.


Mark

 

Here are a couple of very good grinds used in are area 1400 above sea level .

My baseline 226/240 @.050 .505/.484 lift 113 Lsa. 1800 - 5100 power band

cam #1 233/249 @.050 .496/.496 lift 112 Lsa. 2800 - 5800 power band

cam #2 235/248 @.050 .524/.518 lift 112 Lsa 2800 - 5800 power band


cam #2 with 1.6 ratio rockers ,iron heads 260/190 @ .550 , 950 carb SP 1 intake & 1 7/8 headers this combo on the dyno built 535hp @5750 & 550 ft#'s @3700 rpm. 3900# Skylark with 3.42 gears , 3000 rpm stall runs 11.60's @ 118 mph. They are some what faster ramps but still have good dynamics @ higher rpms.

I will keep looking into the proven combo that are very close to what my set up is ...

Mark

 

theres 4 things that maybe someone could comment on to help Mark, my self and other board members pick a cam. 1- desk top dyno does not aways tells the whole story like when your useing advertise duration numbers among other things. 2- head flow, when your only picking up 5 cfm from 500-550 lift i dont think theres more then 3hp to be gain from 520-550 lift, am saying theres no need to worry about going to 550 lift. 3-exhaust duration do you really need that much spread with your intake to exhaust ratio, plus if your running headers and a free flowing exhaust, dont see a need for a big spread. 4- your old cam , what company is it from whats your advertise duration numbers how slow or fast a ramp is it really?. you say 1800 rpm-5100 rpm. do you mean tire smoking coming on at 1800. at 226-240 on a 113 LSA it seems it would come on a latter, also that cam should pull to 5500-5700 at the very least. was it degree in, guys will tell you they could be way off sometimes. wondering if the valve springs are still at the pressure you put them in at with the installed height. are your cam lobes rounded down at the tips. i would not run a cam with the oil out there and the higher spring pressure we need with a high performance cam, with out getting it nitrided its good insurance.

 

gsgtx, Thanks for your reply,I will do my best to answer your 4 points on picking a cam,

1 the horsepower & torque numbers posted are from a dyno not a software disc, I feel the et & mph figures support the dyno results. (235* / 248*) @ .050 - 112* Lsa .540 / .534 lift W/ 1.6 rockers will pull hard to 6100 if need be.

2 Joe I agree there is not enough HP gain @ .550 lift to spend the money for roller rockers, but in the case of the engine used as an example here ,they were on the engine already. also a well known head porter said to crowd .550 for max air flow.

3 Exhaust duration spread was left up to the camshaft Co. With the lobe profiles used these are the numbers they came up with & they seem to build good power.

4 The "old" camshaft is from Scott Brown,The adv duration is 270* / 290* (226* / 240*) @ .050 yielding a 44* spread on the in. & a 50* spread on the ex. I would think the intake is a faster profile than most, the spread between in. / ex.@ .050 is 14* As for the rpm range 1800 - 5100 pretty much sums it up for best shift point with my set up, the cam will turn 5500 plus but best shift point is @ 5100 rpm,the cam is installed on a 109 C/L as per card spec, total timing is 34* , I have not worked on jetting or any other area of tune up . Valve springs are @ 115@1.89 & 305@1.39 the porting & assembly was by Gessler Head Porting.
Mark

 

Mark

Somehow I was thinking that you had stock rockers.
You have the TA 1.6 roller rockers?

Paul

 

Paul I am running the 1.55 stock rockers. The engine combo that I have listed is very close to my air flow, intake ,headers ,gears, & stall converter . He runs a larger cam & 1.6 rockers. This combo pulls hard to 6100 rpm but the peak hp is @ 5750 on the dyno. I don't have the adv du. but I am sure it is a slower profile on the intake & exhust than my 226/240 "little cam" that has a degree differnce of 44* in. & 50* ex. The intake is a agressive lobe.

Mark

 

Mark, thanks for great and easy to follow reply. just a few more points, wondering if your running out of fuel, but if you have a 3/8 gas line and a hp pump? i wouldnt think so, the seat pressure is low it would be interesting to see just for the heck of it what a 15 thousand or so shim would do for your high rpm, could do that with the heads on, the reason i say that i had the same intake spread 44* and thats what i had to do. had about 110 seat to start with.. the only thing i would say about the new cam specs it will pull to 6100 and should be less noiser, but the bottom end will be softer and idle will be a lot rougher as to what you have now. sorry if am being a pain.

 

So the other fellows engine peaks at 5750 with a cam 10 degrees larger at 050' than yours,and yet you wonder why your's only seems to like a low 5000 rpm shift point
Probaby because it is all done by 5200 or so
Just my observation here,but i think BB buick folks expect way too much peak power rpm out of their combos
these engines are so cross sectionally limited ,that i dont know why folks insist on spinning them so high
being a long runnerdesign that they are,i would think in this case that they would run harder short shifting them ,than trying to get them to stay in gear longer hoping to "FALL BACK" ,sort to speak like a low torque,hi geared SB combo
Carry on

 

Doesnt make sense. Less duration with all else being equal means faster ramp rate.

That's what was termed "intensity" by Harvey Crane previously, then there's minor and major intensity, solids use .020 to .050 (if I remember correctly)