Inquiring minds want to know.
Comp Cam install
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Never degreed ft cams either back in the day. Larger rollers you bet
Only reason to really is some of the timing chain sets today you may find "off". Read about some random ones by Cloyes unfortunately over on speedtalk which have a real good reputation. Never seen it myself
More of a double checking thing than anything. Chances are youll be fine dot to dot.
Think many go nuts with prelubing/rotating motor and wash all the lube off. I do very little prelubing at all.
Only reason to really is some of the timing chain sets today you may find "off". Read about some random ones by Cloyes unfortunately over on speedtalk which have a real good reputation. Never seen it myself
More of a double checking thing than anything. Chances are youll be fine dot to dot.
Think many go nuts with prelubing/rotating motor and wash all the lube off. I do very little prelubing at all.
Had a 1976 L-82, 4-sp
Joined: Mar 2011
Posts: 5,338
Likes: 1,213
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
Degreed my cam using the ICL method recommended by Howard's. It was out by almost 2 degrees. Retarded the cam 2* to bring it into spec.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
I always degree the cam and I've never - ever - found anything out of spec. To be fair, I only use off-the-shelf cams from reputable vendors- almost exclusively CompCams - and nothing particularly extreme.
That said, being a good engine builder is all about learning to make precision measurements accurately and consistently. While you may not *need* to degree the cam, you certainly *can* - both as a check of the cam and installation as well as a check on your precision measuring skills.
The decision to advance or retard the cam to move the power peaks is made at the time the cam is purchased.
Use CAM LUBE from your cam vendor or another good one - nothing else.
That said, being a good engine builder is all about learning to make precision measurements accurately and consistently. While you may not *need* to degree the cam, you certainly *can* - both as a check of the cam and installation as well as a check on your precision measuring skills.
The decision to advance or retard the cam to move the power peaks is made at the time the cam is purchased.
Use CAM LUBE from your cam vendor or another good one - nothing else.
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
Ok.. thanks for all the help on this install. It really took longer than I expected. Got the cam installed and have had fits with the motor. I installed, new Comp Cam ( part 12-250-3) and lifters. Stayed with stock springs, new MSD Streetfire HEI, new 600 Holley. The problem is it idles fine, but has no power when you try to press on the pedal. All valves open and close so the cam is not flat. Strange setback. I was told maybe the cam was too big for the heads on it. Stock heads, but does have flat top pistons. No vacuum leaks anywhere. Compression in all cylinders. Any education would be appreciated.
284 duration and 507 lift.
284 duration and 507 lift.
Last edited by marz; Jan 26, 2014 at 10:28 AM.
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Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
Operating Range: 2300-6500 RPM
Duration Advertised: 284° Intake / 296° Exhaust
Duration @ .050'' Lift: 240° Intake / 246° Exhaust
Valve Lift w/1.5 Rockers: .507'' Intake / .510'' Exhaust
Lobe Separation Angle: 110°
I am thinking that the cam is too big for the heads, but I am not quite sure on this.
Thanks.
Duration Advertised: 284° Intake / 296° Exhaust
Duration @ .050'' Lift: 240° Intake / 246° Exhaust
Valve Lift w/1.5 Rockers: .507'' Intake / .510'' Exhaust
Lobe Separation Angle: 110°
I am thinking that the cam is too big for the heads, but I am not quite sure on this.
Thanks.
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
That's a lot of duration and with the lift stock springs is not a good idle. At the very least you need springs to match the cam specs. If the heads are 882's there not very good heads, not for sure but they might need cut down some to accommodate the lift . I would still think that the cam would add some but not knowing your compression or rear gears it might not make much torque until 2800 rpm. By doing nothing when you step on the peddle can you describe it more. This would be a good time to buy heads.
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
That's a lot of duration and with the lift stock springs is not a good idle. At the very least you need springs to match the cam specs. If the heads are 882's there not very good heads, not for sure but they might need cut down some to accommodate the lift . I would still think that the cam would add some but not knowing your compression or rear gears it might not make much torque until 2800 rpm. By doing nothing when you step on the peddle can you describe it more. This would be a good time to buy heads.
Thanks.
Le Mans Master
Joined: Oct 2010
Posts: 6,938
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
305 heads have small valves, that killed your flow. they probably have smaller chambers so compression may be good. a 600 holley with that cam isn't helping but those small valves will never work. my guess is to get some other heads. thats too bad , but with that much cam you need the stuff to go with it.
need a gear and convertor too
need a gear and convertor too
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
What the heck made you choose that cam? The info on the Comp Cams site says:
Street/strip Rough Idle
[2] Requires machining on cylinder heads.
[3] Standard weight and lightweight retainers
[7] Stock springs cannot be used.
[15] 50-State legal on ‘93 & earlier S.B. Chevrolet V8, 262-400 c.i., C.A.R.B. E.O. #D-279-4.
[52] Engines with self-aligning rocker arms must use part #1417-16 or 1317-16.
The carb, intake, heads, cam, valve train, and pistons all need to work together. It doesn’t matter how “big” the cam is, if you have heads that can’t flow any air, or an intake that won’t flow or the wrong size carb. You don’t necessarily have to change all those things when going to another cam, but you should make sure they can work together. It would seem you need to either work/swap your heads or go to another cam.
Street/strip Rough Idle
[2] Requires machining on cylinder heads.
[3] Standard weight and lightweight retainers
[7] Stock springs cannot be used.
[15] 50-State legal on ‘93 & earlier S.B. Chevrolet V8, 262-400 c.i., C.A.R.B. E.O. #D-279-4.
[52] Engines with self-aligning rocker arms must use part #1417-16 or 1317-16.
The carb, intake, heads, cam, valve train, and pistons all need to work together. It doesn’t matter how “big” the cam is, if you have heads that can’t flow any air, or an intake that won’t flow or the wrong size carb. You don’t necessarily have to change all those things when going to another cam, but you should make sure they can work together. It would seem you need to either work/swap your heads or go to another cam.
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
What the heck made you choose that cam? The info on the Comp Cams site says:
Street/strip Rough Idle
[2] Requires machining on cylinder heads.
[3] Standard weight and lightweight retainers
[7] Stock springs cannot be used.
[15] 50-State legal on ‘93 & earlier S.B. Chevrolet V8, 262-400 c.i., C.A.R.B. E.O. #D-279-4.
[52] Engines with self-aligning rocker arms must use part #1417-16 or 1317-16.
The carb, intake, heads, cam, valve train, and pistons all need to work together. It doesn’t matter how “big” the cam is, if you have heads that can’t flow any air, or an intake that won’t flow or the wrong size carb. You don’t necessarily have to change all those things when going to another cam, but you should make sure they can work together. It would seem you need to either work/swap your heads or go to another cam.
Street/strip Rough Idle
[2] Requires machining on cylinder heads.
[3] Standard weight and lightweight retainers
[7] Stock springs cannot be used.
[15] 50-State legal on ‘93 & earlier S.B. Chevrolet V8, 262-400 c.i., C.A.R.B. E.O. #D-279-4.
[52] Engines with self-aligning rocker arms must use part #1417-16 or 1317-16.
The carb, intake, heads, cam, valve train, and pistons all need to work together. It doesn’t matter how “big” the cam is, if you have heads that can’t flow any air, or an intake that won’t flow or the wrong size carb. You don’t necessarily have to change all those things when going to another cam, but you should make sure they can work together. It would seem you need to either work/swap your heads or go to another cam.
Thanks.
Last edited by marz; Jan 26, 2014 at 05:53 PM.
Burning Brakes
Joined: May 2008
Posts: 1,116
Likes: 5
From: Middleburg Florida
What can I say? I had a fit of stupidity. I thought they were larger heads than what are actually on it. The guy I got the motor from didn't give the truthful info on the motor, but in my heart I knew it was too much cam. That's kind of where I was leaning...getting a new set of heads. My mechanic friend can snag a set ( don't know the specs yet) , but said it would straighten it out. I am also getting new rockers, guides, pushrods. I figure I have too much invested in it now to abandon it. I just don't want to get the heads and other stuff and still not run. I also have a smaller cam and lifters that isn't quite as wild as that one.
Thanks.
Thanks.
Now you have an opportunity to improve! Make sure you’re new heads are set up for the cam you run with the right springs and such. As far as rocker are concerned, I just installed a set of Lunati VooDoo roller rockers in my engine, and though I don’t NEED to go full roller (I’m running a hydraulic flat tappet cam too), I swear they made the engine happy, happy, happy!! If you’re looking for rocker arms, I’d highly recommend them, got their push rods too, really, really nice stuff.Since you’re in this far, make sure you have the intake and carb you need too...
Thread Starter
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
Hey, happens to all of us! Now you have an opportunity to improve! Make sure you’re new heads are set up for the cam you run with the right springs and such. As far as rocker are concerned, I just installed a set of Lunati VooDoo roller rockers in my engine, and though I don’t NEED to go full roller (I’m running a hydraulic flat tappet cam too), I swear they made the engine happy, happy, happy!! If you’re looking for rocker arms, I’d highly recommend them, got their push rods too, really, really nice stuff.
Since you’re in this far, make sure you have the intake and carb you need too...
Now you have an opportunity to improve! Make sure you’re new heads are set up for the cam you run with the right springs and such. As far as rocker are concerned, I just installed a set of Lunati VooDoo roller rockers in my engine, and though I don’t NEED to go full roller (I’m running a hydraulic flat tappet cam too), I swear they made the engine happy, happy, happy!! If you’re looking for rocker arms, I’d highly recommend them, got their push rods too, really, really nice stuff.Since you’re in this far, make sure you have the intake and carb you need too...
Thanks.