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#1
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Calculating intake lobe centerline
Hi all,
I want to check the degree of my cam. I'm having issues trying to figure it out. Can someone explain it to me. Cam card pictured... Thanks, Jeff |
#2
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Looks like the numbers in the "max lift" column are the centerlines of intake and exhaust. Verified by cam calculator at Wallace Racing site.
Check using intake centerline method, with 113. I'll defer to others whether 113 is the best place to install it as opposed to 109, or 111, (4, or 2 degrees advanced)
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'65 Tempest 467 3650# 11.30@120.31 |
#3
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Thanks Scott,
That's where I'm at also....just a bit confused The card isn't saying if it's ground with advanced or retard. I installed it straight up,now I want to check if I should advance or retard and how much |
#4
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I would say it's ground with a 113, to be installed there. Hopefully you get some advise on whether to move it. I couldn't say, I've never used it.
ETA: If you can do a cranking compression check straight up and 4 advanced, that can offer clues.
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'65 Tempest 467 3650# 11.30@120.31 Last edited by Scott65; 05-09-2021 at 09:35 PM. Reason: Addition |
#5
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You need to call the cam manufacturer and ask. The RAIV cam used a 113.5 LSA (I think) so it looks like that that one is advanced 0.5 degrees for installation.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
#6
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That's the way I'm reading this card also.
So now I'm wondering if I should try advancing / retarding the cam, 2-4 degrees,checking piston to valve clearance and checking drivability.... Never had one that didn't say ILC... |
#7
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That appears to be an old Crane regrind of the 041. I don’t know if Crane even has customer support anymore, I think for that might be handled by compcams now.
Just like the others said, the ICL is position to be 113. Depends on the engine and car set up it is going in for where to install it. It can be a little soft on the bottom end if it is install as it is (113). Most install it on 109-111. |
#8
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Jay,
I'd say it's soft.... It makes power above 2500 rpm as advertised, But I want a bit more bottom end. The car is a 4 speed 2.59 1st gear with 3.31's It's a bit to get moving and has a hesitation under 1200 rpm, so I was thinking maybe advance 2-4degrees and see if it helps. |
#9
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"The card isn't saying if it's ground with advanced or retard"
THIS is where a lot of confusion lies when degreeing a cam. When you are physically degreeing in a cam, whatever they advertise as "4 degrees advanced ground in" or the like is moot. I believe cam manufacturers do this for those who are just going to install it "straight up, dot to dot" without actually putting a degree wheel on it. Once you put a degree wheel to it and verify where the intake centerline is, THAT is where it is, not 2 degrees retarded or 4 degrees advanced.
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Just a blind squirrel looking for a nut. |
#10
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If you want to move the power curve lower in the operating rpm range, degree it in at 111 or 109 intake centerline for either 2 or 4 degrees advance respectively.
Quote:
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Just a blind squirrel looking for a nut. |
#11
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Makes sense,. Thanks guy's
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#12
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LSA is 113.5 on this cam [(113+114)/2], but the intake centerline is 113. You have to ask yourself whether the cam company knows more about where they specify the intake centerline to be or if someone wants to gamble and pick another centerline out of thin air. More times than not advancing a cam 4° can loose horsepower across the curve. What you probably will end up with advancing the cam is moving the torque and horsepower peaks down around 200-250 RPM lower, but these peaks will probably have less power than the power generated at the cam company's specified centerline.
Now hitting the centerline is like horseshoes, and close is usually all you will get. Basically you might having to be satisfied being up to 2° advanced or 2° retarded even using the crank gear key slots or cam offset keys. In this case I would go for the slight advance since the chain will stretch some and slightly retard cam timing as you put on miles.
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Mick Batson 1967 original owner Tyro Blue/black top 4-speed HO GTO with all the original parts stored safely away -- 1965 2+2 survivor AC auto -- 1965 Catalina Safari Wagon in progress. |
#13
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I set my 041 at 2 degrees BTDC at .050 lift and let it go. The engine runs great
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1979 Trans Am WS-6 .030 455 zero decked flat pistons 96 heads with SS valves 041 cam with Rhoads lifters 1.65 rockers RPM rods 800 Cliffs Q Jet on Holley Street Dominator ST-10 4 speed (3.42 first) w 2.73 rear gear __________________________________________________ _______________________________ 469th TFS Korat Thailand 1968-69 F-4E Muzzle 2 |
#14
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In my years of reading here....109 or as close to it as possible seems like the preferred setting. Thinking Cliff, Jim Hand and many others preference...maybe...
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
#15
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love the 041 cam...I assume its in a 400? with 1.5 rockers you will not need to worry about PTV clearance unless your running some kind of DOME piston as there is so little lift at .469. 110 ICL is a great place on average. I know back when mine ran dialing it in much lower 106 really takes away the top end charge THIS cam gives. Also with that clutch and no gears you will want to avoid a single plane intake as it will KILL anything under the 2500 rpm which is where YOU are going to be trying to get that thing rolling.
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#16
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Quote:
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#17
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Bigger cams and stick shifts, = perfect place for Rhoads lifters especially if compression is conservative
2 degree advance on the cam and Rhoads lifters would significantly increase torque from idle to clutch engaging while not providing a total kill of top end charge Last edited by Formulas; 05-10-2021 at 12:38 PM. |
#18
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I'm building a 455 for someone and just installed one with an ICL of 109.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
#19
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Thanks Guys for all the great advice.
just an FYI... my combo.. 462 ci 10.2 CR KRE D ports poprted 290 CFM Crane 041 clone Rhoads V-max lifters HS 1.5 rockers Performer RPM manifold sniper EFI dual sync distributor M23W 4 speed 2.59 1 st gear 12 bolt rear 3.31 positrac engine runs real good, plenty of power, but i have a little off idle hesitation and being a 4 speed with the lower gear, hesitates a little, so I was thinking of degreeing the cam since I didn't. I was thinking 2-4 advance, looks like most like 2 degree advance, so I'll start there. Thanks Jeff |
#20
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My opinion, no more than 2 in a 455 it shouldn't need it. I believe you can tune your condition with the efi tuning manually.
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'65 Tempest 467 3650# 11.30@120.31 |
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