Pontiac Street Performance
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password

 All Forums
 Pontiac Performance
 Cams / Heads & Valve Train
 041cam and duplicates intake closing
 New Topic  Reply to Topic
 Printer Friendly
Author  Topic Next Topic  

Corncob2061
Two Feathers

USA
55 Posts

Posted - 04 Apr 2018 :  5:52:46 PM  Show Profile  Reply with Quote
I was curious where the intake closes at .006 lift on the 041 cam, specifically to calculate my dynamic compression. I am machining a dish in the piston on a 455 with 62 heads and i am shooting for 7 to 7.5 dcr. I specifically have the crower 60919 version and the card claims it has 112 centerline, and 109 intake centerline. I come up with 79 degrees. I have read that trying to measuring the crower comes way short of that. I have also read most of companies farm out the grinding of this cam and most of the regrinds are basically a copy of the 041? So do i go by comps 292, crowers 304, Pontiacs 308, lunati 308????? I saw someone say 87 on the 041...which sounds like 115 icl on a 308....i am confused...

Did a 041 melling a while back and it seemed more like comps 292 than 308....

I can try measuring but from past experience the margin of error is kinda big....

I will take a best guess..
Thanks
Jay

Edited by - Corncob2061 on 04 Apr 2018 5:54:55 PM

Steve C.
Crazy Horse

1739 Posts

Posted - 04 Apr 2018 :  7:43:00 PM  Show Profile  Reply with Quote
Cliff Ruggles has reported before that the Crower 60919 cam has a 113 lobe separation not 112 as indicated in the catalog. And if you search I think you will find he installed them at 109 intake centerline.

.

Edited by - Steve C. on 04 Apr 2018 7:46:17 PM
Go to Top of Page

Steve C.
Crazy Horse

1739 Posts

Posted - 04 Apr 2018 :  7:51:47 PM  Show Profile  Reply with Quote
Brand & part no.:Crower #60919 (RAIV "clone" cam)
Grind & lobe no.: 304H
Tappet type: Hydraulic Flat Tappet
Spec = intake/exhaust: (notes)
Adv.Duration. = 304 degrees/316 degrees (I/E split = 12 degrees)
Dur. @ .050" = 231 degrees/240 degrees (I/E split = 9 degrees)
Lobe lift = .313"/.313"
Lift @ 1.5 rr = .470"/.470"
LSA 113 degrees ICL = 109 ECL = 117 degrees

Seat events:
IO = 43 BTDC
IC = 81 ABDC
EO = 95 BBDC
EC = 41 ATDC
Total O/L = 84

.050" events:
IO = 7 BTDC
IC = 45 ABDC
EO = 57 BBDC
EC = 3 ATDC
O/L @ .050" = 10

Source:

http://forums.maxperformanceinc.com/forums/showthread.php?t=650118&highlight=60919

.

Edited by - Steve C. on 04 Apr 2018 7:56:06 PM
Go to Top of Page

Steve C.
Crazy Horse

1739 Posts

Posted - 04 Apr 2018 :  8:08:22 PM  Show Profile  Reply with Quote
And here is Bret P (screamingchief) info regarding the 041 cam in post #26

http://forums.maxperformanceinc.com/forums/showthread.php?t=787192&page=2


.
Go to Top of Page

Steve C.
Crazy Horse

1739 Posts

Posted - 04 Apr 2018 :  9:01:12 PM  Show Profile  Reply with Quote
When using a Dynamic Compression Ratio Calculator with a hydraulic cam you use seat timing for the closing events. One issue will be at what tappet lift the manufacture rates their cams at. Harvey Crane used .004" tappet lift, Comp uses .006" tappet lift and depending on who you talk to at Crower it might be .005" or .006" tappet lift. I have no clue as to what tappet lift the original factory 041 cam was rated at, but I'm pretty confident it was not .006" tappet lift.
Go to Top of Page

Steve C.
Crazy Horse

1739 Posts

Posted - 04 Apr 2018 :  9:21:06 PM  Show Profile  Reply with Quote

"Problem #1 is everyone has to be using the same valve event timing to accurately compute & compare DCR numbers."

"Honestly,IMO using DCR calculation as a precise tool is virtually useless. There are just too many variables it does'nt account for @ all.So it's really just more of a "loose guide" than an absolute truth."

And more.....
http://psp.aquacomp.net/topic.asp?TOPIC_ID=5984&SearchTerms=DCR
Go to Top of Page

Corncob2061
Two Feathers

USA
55 Posts

Posted - 04 Apr 2018 :  9:51:17 PM  Show Profile  Reply with Quote
Thanks....Interesting read. I know the calculators give ball park figures but for the 60919 closing at 82 degrees abdc at 1000 ft alt gives: 11.3 = 7.5 dcr, 10.5=7, 10.0=6.6....I can not picture it living long at 11.3 on pump gas..10.5 ??? Maybe ... according to that though maybe some have gotten by...I know I have had engines up in the 7.5 range...just not this combo...


Go to Top of Page

Corncob2061
Two Feathers

USA
55 Posts

Posted - 04 Apr 2018 :  10:11:10 PM  Show Profile  Reply with Quote
Defineltly not a precise tool, and probably useless, this cam being one of the worst for figuring this...plus port velocity and cylinder fill vary engine to engine... ..this engine is probably good at both...

Go to Top of Page

Steve C.
Crazy Horse

1739 Posts

Posted - 04 Apr 2018 :  10:40:55 PM  Show Profile  Reply with Quote
Cliff Ruggles stated he has run about 10:1 static compression with the 60919 cam with iron heads. It has a TON of seat timing in conjunction with a wide lobe separation that allowed it in that combination. But remember it is very combination specific. Others have tried similar and had issues.

.
Go to Top of Page

Blued and Painted
Chief PONTIAC

USA
3481 Posts

Posted - 05 Apr 2018 :  10:56:36 AM  Show Profile  Reply with Quote
Agree with Steve. DCR is a secondary tool to make sure your in the ball park.
U will need 9.6 to 1 CR on paper or better for good driving manors. This cam shines in the upper mid range to high rpm range. The factory combined this cam with a 3.73 or better rear gear to keep the engine close to the power range. These gears are not a lot of fun on an extended highway cruise without over drive.
Don't recall anyone complaining about spark knock or detination with the 041.

Lots of modern grinds out there. How will the vehicle be used and what are the power goals?


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
Go to Top of Page

Corncob2061
Two Feathers

USA
55 Posts

Posted - 05 Apr 2018 :  3:39:37 PM  Show Profile  Reply with Quote
I will have no problem keeping the compression above 9.7. I ccd everything right now it is at 11.4. I am a little surprised I saw that others reported #62 had 76 to 77 cc chambers, I measured 73cc. We are machining a dish so I can put compression about where ever it needs to be, probably looking at 10 ish like what Steve posted that Cliff r has ran. Cam and vmax Rhoads lifters were bought awhile back..may not be perfect but should work ok.

Car is not driven a lot, 1 to 2k a year at most, some drag strip time. 455 dual quads, mild port work, 17/8 headers, M22 4 speed, 3.5 gears, m&h 10x27 tire, 4000 lbs...450-470 hp would be ok..

What cam would you have used B&P?


Edited by - Corncob2061 on 05 Apr 2018 3:40:56 PM
Go to Top of Page
   Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
Pontiac Street Performance © 2006-2017 Go To Top Of Page
This page was generated in 0.12 seconds. This Site Sponsored By:
Powered By: Snitz Forums 2000 Version 3.4.05