Couple of questions - degreeing my camshaft
#1449319
06/08/13 01:10 PM
06/08/13 01:10 PM
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Joined: Dec 2006
Posts: 507
Northern Indiana
capac
OP
mopar
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OP
mopar
Joined: Dec 2006
Posts: 507
Northern Indiana
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Let me start off by saying that this is the first time I've ever degreed a camshaft. Having said that, I feel like I have a really good understanding of what I'm doing and the proper procedures. Almost all of the specs on the cam card match the actual measuerments. The only variance (might not be the camshaft...) is the centerline. The cam card says 109, but my measurements come out to 114.5. My first question is: would this have the same effect as advancing the cam 5.5 degrees?
I bought a timing set that has 7 different adjustments (3R,2R,1R,0,1A,2A,3A), so I'm hoping to get this cam dialed in where it needs to be. The guy I bought the cam (and heads) from recommended 2 - 4 degrees of advance for my setup. What I'm not sure of, is did he account for the 3 degrees that are allready built into the cam. So addintionally, maybe you folks in the community can recommend what I should do. As always, let me know if I left out any crucial info (I usually do).
Car
- Street car with occasional trips to the strip.
- A body car, so 3200 - 3400lbs?
- Manual transmission
- Probably 3.91 gear
Engine
- 318 stroker (390)
- 9.877:1 static compression
- RHS heads ported, flow 288 @0.550/287 @0.600 lift
- Hughes 1.6 roller rockers
- Edelbrock RPM intake
- Quickfuel 750cfm
- Headers of some kind
Camshaft
- Hydrolic roller (Comp Cams)
- .586 Intake lift @.050 (1.6 ratio)
- .581 Exhaust lift @.050 (1.6 ratio)
- 242 Intake duration @.050
- 248 Exhaust duration @.050
- Intake centerline 109
- Lobe separation 112
- Intake open 12 degrees BTDC @.050
- Exhaust open 59 degrees BBDC @.050
- Intake close 50 degrees ABDC @.050
- Exhaust close 9 degrees ATDC @.050
'64 390 Valiant Signet Convertable (WIP...)
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Re: Couple of questions - degreeing my camshaft
[Re: RobX4406]
#1449326
06/08/13 03:29 PM
06/08/13 03:29 PM
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Joined: Dec 2006
Posts: 507
Northern Indiana
capac
OP
mopar
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OP
mopar
Joined: Dec 2006
Posts: 507
Northern Indiana
|
I made a piston stop that bolts directly to the deck. At first I just used a dial indicator on the piston itself, but quickly realized that there was about a 3 degree (guessing) period where the piston didn't move. So for best accuracy, I made the stop. I'm not sure exactly how far down in the hole the piston was stopping, but I know that it was hitting the stop 34 degrees on either side of TDC. Hopefully that made sense...
'64 390 Valiant Signet Convertable (WIP...)
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Re: Couple of questions - degreeing my camshaft
[Re: capac]
#1449327
06/08/13 04:25 PM
06/08/13 04:25 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
I made a piston stop that bolts directly to the deck. At first I just used a dial indicator on the piston itself, but quickly realized that there was about a 3 degree (guessing) period where the piston didn't move. So for best accuracy, I made the stop. I'm not sure exactly how far down in the hole the piston was stopping, but I know that it was hitting the stop 34 degrees on either side of TDC. Hopefully that made sense...
Doesnt matter how far in the hole it is... put the
damper on and roll it up till it hits and take a reading
on the damper.. roll it the other way till it hits
and take a reading.. split the 2 numbers.. thats zero
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Re: Couple of questions - degreeing my camshaft
[Re: capac]
#1449328
06/08/13 06:15 PM
06/08/13 06:15 PM
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Joined: Aug 2003
Posts: 43,213
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,213
Bend,OR USA
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Most SB Mopar cams ground on a 112 lobe seperation angle are ground that way for a power adder or for extremely high RPM drag racing like a stick shift drag cam with a lot of different motor specs than your motor has or a high RPM roundy rounder motor, some application where the motor never sees a load under 5500 RPM at the track  That being said you have the cam so try checking both lobes on the cam for lobe seperation angles at max lift. Check the intake first and then the exhuast, if you find the marks on the crank sprocket that actaully get the cam in with no advance or retard then the intake lobe max lift should be at 112 after top dead center and the exhaust lobe max lift should be at 112 before top dead center   Once you deteremine if it is ground on 112 then find the mark (by trying and degreeing until you get what you want) on the crankshaft sprocket that will get the intake lobe center(max lobe lift at)at 105,106 or 107 after top dead center. If you get 106 max lobe lift ATDC on the intake then check the exhaust lobe, it should be in at 117  The exhaust lobe has to follow the intake lobe centers, moving the max lift on the intake lobe closer to TDC advances both the intake and exhaust, moving the intake max lobe lift away from top dead center retards the cam. Advancing the cam normally will increase the power at the lower RPM, retarding the cam is suppose to increase top end power as well as kill bottom end, I have never had a N/A drag car, BB, Hemi or SB Mopars that like the cams retarded  IHTH BTW, I like to check the lobe seperation angles with the heads on with all the rocker gear with some light checking springs on both the valves so I can check piston to valve clearances while indexing the cam, I set the lash at zero and go from there BTW, you should do that checking with a solid roller lifter, not a hydrastic roller lifter That eliminates the chance of the lifter collapsing while checking the cam, which will skew the readings and clearances 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Couple of questions - degreeing my camshaft
[Re: capac]
#1449329
06/08/13 09:25 PM
06/08/13 09:25 PM
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Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
RobX4406
I Live Here
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I Live Here
Joined: Apr 2005
Posts: 12,271
Overpriced Housing Central
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Quote:
I made a piston stop that bolts directly to the deck. At first I just used a dial indicator on the piston itself, but quickly realized that there was about a 3 degree (guessing) period where the piston didn't move. So for best accuracy, I made the stop. I'm not sure exactly how far down in the hole the piston was stopping, but I know that it was hitting the stop 34 degrees on either side of TDC. Hopefully that made sense...
That why you set the indicator at your high point then go down in the hole a set amount, up stroke both direction, same technique as a piston stop. That 3-4 degrees of dwell time can play havoc.
Sounds like you have a good handle on it.
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Re: Couple of questions - degreeing my camshaft
[Re: Cab_Burge]
#1449330
06/08/13 10:02 PM
06/08/13 10:02 PM
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Joined: Dec 2006
Posts: 507
Northern Indiana
capac
OP
mopar
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OP
mopar
Joined: Dec 2006
Posts: 507
Northern Indiana
|
Quote:
Most SB Mopar cams ground on a 112 lobe seperation angle are ground that way for a power adder or for extremely high RPM drag racing like a stick shift drag cam with a lot of different motor specs than your motor has or a high RPM roundy rounder motor, some application where the motor never sees a load under 5500 RPM at the track That being said you have the cam so try checking both lobes on the cam for lobe seperation angles at max lift. Check the intake first and then the exhuast, if you find the marks on the crank sprocket that actaully get the cam in with no advance or retard then the intake lobe max lift should be at 112 after top dead center and the exhaust lobe max lift should be at 112 before top dead center Once you deteremine if it is ground on 112 then find the mark (by trying and degreeing until you get what you want) on the crankshaft sprocket that will get the intake lobe center(max lobe lift at)at 105,106 or 107 after top dead center. If you get 106 max lobe lift ATDC on the intake then check the exhaust lobe, it should be in at 117 The exhaust lobe has to follow the intake lobe centers, moving the max lift on the intake lobe closer to TDC advances both the intake and exhaust, moving the intake max lobe lift away from top dead center retards the cam. Advancing the cam normally will increase the power at the lower RPM, retarding the cam is suppose to increase top end power as well as kill bottom end, I have never had a N/A drag car, BB, Hemi or SB Mopars that like the cams retarded IHTH BTW, I like to check the lobe seperation angles with the heads on with all the rocker gear with some light checking springs on both the valves so I can check piston to valve clearances while indexing the cam, I set the lash at zero and go from there BTW, you should do that checking with a solid roller lifter, not a hydrastic roller lifter That eliminates the chance of the lifter collapsing while checking the cam, which will skew the readings and clearances
Thanks for all of the info Cab. I'll probably measure the lobe separation tomorrow to make sure it is correct. I didn't ask too many questions about the cam when I was purchasing it, I just told them what I wanted (Brian @ IMM). I feel pretty confident that his recommendation is good.
I didn't do any of this with the heads on because I don't have any pushrods, or a solid lifter(s). I have to measure the pushrod length once everything is assembled since the machine shop I used can't tell me how much material was removed when they zero decked it...  
'64 390 Valiant Signet Convertable (WIP...)
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