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  1. #1
    Join Date
    Aug 2005
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    Pahrump NV.
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    5,534

    Default Cam Degreeing How Important?

    Let me start by saying I believe degreeing a cam to the cam grinders specs
    will undoubtedly help to achieve maximum power from that particular cam.
    But is there a lot of power lost by being off 2, 3, or 4 degrees off. I mean are you really going to feel the power difference in the seat of your pants, or is it going to take a time card to really know. Also is the power really lost or is it moved to a different rpm range. Advancing a cam increases bottom end and advancing increases the top end. It seems to me a few degrees would move the power to a different rpm range more than it would actually lose the power.
    I doubt that the factory degrees the cam in every engine that comes out of the factory but yet most of the comparably equipped cars seem to run about the same. How many degrees are lost to a worn or stretched timing chain?
    I'm thinking with a stock style timing chain there could be a 1/4 to a 1/2 a degree within the first 2 or 3 thousand miles. What got me going on this is I raced a lot of years and had some fast cars before I ever got into degreeing the cams until later on. It seems that some of the rhetoric about degreeing cams would almost discourage some from even attempting to build a warmed over stocker because they don't have the extra money or the knowledge to have their cams degreed. That being said, it is a good idea? Probably
    Is it a absolute must? I don't think so. IMHO

    Bob H.
    1953 Buick 455 TA Aluminum SE Stg2 Heads, B4B Intake, S/P Turbo 400, Gear Vendor, 3.42 Posi. A/C
    1970 GS Project Getting close.

  2. #2
    Join Date
    Feb 2002
    Location
    Flat Rock, MI
    Posts
    1,543

    Default Re: Cam Degreeing How Important?

    Quote Originally Posted by rmstg2 View Post
    Let me start by saying I believe degreeing a cam to the cam grinders specs
    will undoubtedly help to achieve maximum power from that particular cam.
    But is there a lot of power lost by being off 2, 3, or 4 degrees off. I mean are you really going to feel the power difference in the seat of your pants, or is it going to take a time card to really know. Also is the power really lost or is it moved to a different rpm range. Advancing a cam increases bottom end and advancing increases the top end. It seems to me a few degrees would move the power to a different rpm range more than it would actually lose the power.
    I doubt that the factory degrees the cam in every engine that comes out of the factory but yet most of the comparably equipped cars seem to run about the same. How many degrees are lost to a worn or stretched timing chain?
    I'm thinking with a stock style timing chain there could be a 1/4 to a 1/2 a degree within the first 2 or 3 thousand miles. What got me going on this is I raced a lot of years and had some fast cars before I ever got into degreeing the cams until later on. It seems that some of the rhetoric about degreeing cams would almost discourage some from even attempting to build a warmed over stocker because they don't have the extra money or the knowledge to have their cams degreed. That being said, it is a good idea? Probably
    Is it a absolute must? I don't think so. IMHO

    Bob H.
    My opinion is absolutely, see the other post about 8 off. Years ago we degreed 5 cams prior to our dyno testing, they varied 16 degrees (from best to worst) in order to match the cam card. Between variances in timing gears and cam flange threaded holes, who knows what you get.

    Years ago we installed a KB107 in Norm/Ken Dihle's Silver Mist GS in the parking lot of the Holidome (Bowling Green, KY). Looking back, I'd say we got lucky, the car won it's class but that doesn't mean the cam was installed optimum either.

    It's up to you, but I degree a cam everytime. Also, I've been off a tooth and caught during the degree process.
    Rob Ross
    rross455@comcast.net

  3. #3
    Join Date
    Sep 2002
    Location
    Michigan
    Posts
    391

    Default Re: Cam Degreeing How Important?

    Degreeing a cam is extremely important. Recently I've seen Buick combinations that were 5-9 degrees off. Part of the problem was the timing set and part was the cam.

    I've seen Chevy multiple key way double roller sets that were 13 degrees off. The owner had freshened the engine with the only change being the timing set. After correcting the cam timing the car picked up the 5 mph that it had lost.

  4. #4
    Join Date
    Aug 2005
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    Pahrump NV.
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    5,534

    Default Re: Cam Degreeing How Important?

    Quote Originally Posted by David Hemker View Post
    Degreeing a cam is extremely important. Recently I've seen Buick combinations that were 5-9 degrees off. Part of the problem was the timing set and part was the cam.

    I've seen Chevy multiple key way double roller sets that were 13 degrees off. The owner had freshened the engine with the only change being the timing set. After correcting the cam timing the car picked up the 5 mph that it had lost.
    How was the timing set a problem? There must be some real junk out there these days. I'm glad I'm out of the racing game.

    Bob H.
    1953 Buick 455 TA Aluminum SE Stg2 Heads, B4B Intake, S/P Turbo 400, Gear Vendor, 3.42 Posi. A/C
    1970 GS Project Getting close.

  5. #5
    Join Date
    Mar 2009
    Location
    Emporia, KS.
    Posts
    399

    Default Re: Cam Degreeing How Important?

    I have had a good friend that is actualy helping me with my 455 build tell me, he had a costomer bring him a fresh 383 sbc. The costomer couldn't get the engine to start or time.
    The problem was, The machining was wrong on the timing gears.
    Got a new set installed, problem solved! So, Always clock your cam!
    It could be the result of a valve train crash, wear or improper break in on the cam lobes, I think!?
    Junk!? maybe? thats what taiwanese stuff will get ya.
    Everything that I have ordered from T/A Has been U.S. or Austraian.
    John Whitaker

  6. #6
    Join Date
    Mar 2005
    Location
    Orlando Florida
    Posts
    6,272

    Default Re: Cam Degreeing How Important?

    OK so im just now starting to understand how machining tolerances can cause you to be out a few degrees... So how do you fix that?

    Do you jump a tooth on the timing so the marks are mismatched and repeat the test?
    Curtis
    ______________


    1970 GS 455 4-Speed
    1972 GS 350 Convertible (SOLD)

    My Blog http://72buickgs.blogspot.com/

    My Buick Facebook Page https://www.facebook.com/groups/BuickGSOwners/

    "Whether you think that you can, or that you can't, you are usually right"

  7. #7
    Join Date
    Sep 2004
    Location
    Michigan, USA
    Posts
    15,026

    Default Re: Cam Degreeing How Important?

    Quote Originally Posted by cstanley-gs View Post
    OK so im just now starting to understand how machining tolerances can cause you to be out a few degrees... So how do you fix that?

    Do you jump a tooth on the timing so the marks are mismatched and repeat the test?
    No, you don't need to make drastic changes like that, it's just a matter of using the appropriate offset keyways on the multi-keyed sets to get it where it needs to be. For instance, if the cam is ground six degrees advanced and you want to run only two degrees advanced, use the four degree retard keyways on the timing set and check to see what you end up with. If there's another issue with the way the timing set is machined and you're still seeing four degrees of advance for example, move the timing set to the six degree retard setting and measure again.

    Just think of the advance/retard increments as absolute numbers.

    Devon
    Fuel & Brake Systems Engineer
    "I can live with doubt and uncertainty and not knowing. I think it's much more interesting to live not knowing than to have answers which might be wrong." - Feynman
    "Good data is precious. The problem I have is when some damned fool fails to use it properly." - Slingerland

  8. #8
    Join Date
    Aug 2006
    Location
    Cincinnati
    Posts
    603

    Default Re: Cam Degreeing How Important?

    Quote Originally Posted by cstanley-gs View Post
    OK so im just now starting to understand how machining tolerances can cause you to be out a few degrees... So how do you fix that?

    Do you jump a tooth on the timing so the marks are mismatched and repeat the test?
    I have a TA timing chain set that has to be installed one tooth off. I assume the cam gear was mismarked. It's been used on a couple different cams and always the same result.

    I'd say it has to be checked for sure but if it comes up anywhere from 0-4 degrees advanced on a street motor your good to go.

  9. #9
    Join Date
    Sep 2002
    Location
    Michigan
    Posts
    391

    Default Re: Cam Degreeing How Important?

    I've seen the stock repalcement gear sets that were 5 or more degrees off. I corrected the cam timing by using a file to elongate the bolt holes in the cam gear and using JB Weld to fill in the gap if the cam needed to be advanced. If the cam needed to be retarded there was no need to use the JB Weld.

    On the Chevy I moved the cam gear 1 tooth and it was right on.

    DO NOT attempt to do this without using the proper tooling to find true top dead center for the piston and a good degree wheel.

    1 or 2 degrees will not be a problem in most cases but more than that can have a large affect depending on the combination.

  10. #10
    Join Date
    Mar 2004
    Location
    Edmonton Alberta
    Posts
    13,724

    Default Re: Cam Degreeing How Important?

    I agree with all of the above. The bottom line to me is: If you are building a race car then 100% degree the cam, experiment a bit if you want the most out of the combo... If building a street car then degree the cam just to be sure you are in the "window" of good performance.

    I read an article about this topic and the bottom line was surprising to me... I noticed that while the numbers changed a BIT they did not drop right off with a few degee change either way. A 500 hp engine will not be a 450 hp engine with a few degrees change in degree. Yes a few degrees advanced or retarded can slightly move and change the power curve. There was another article I read that is similar however it was easier to see the differences due to the dyno chart layout.

    http://www.carcraft.com/techarticles...hydraulic.html
    __________________________________________________ __________________________________
    My book called Small Block Buick Performance covering the V6, 215, 300, 340, and Buick 350 engines will be released soon.

    http://www.v8buick.com/forumdisplay....rformance-Book
    __________________________________________________ ____________________________
    1970 Buick Skylark Turbo 350 street/strip

  11. #11
    Join Date
    Feb 2010
    Location
    Florida
    Posts
    360

    Wink Re: Cam Degreeing How Important?

    My mechanic related a story while we were discussing my sbc with power problems. Had a customer with a sbc 350 with no power. After ignition and carb tune-ups he declined to pull the front and replaced the engine. Mechanic's employee bought the engine for a $100, timed the cam and had a healthy 350 for his work truck.

    My sbc 327 had power problems and low vaccum after tuneup similar so we pulled the front and degreed in the cam. He related that the cam was properly installed with marks in alignment. No jumped teeth. He started with offset keys and moved the cam where a compression check showed an increase over the original setting and ended up with a 4deg movment. The result was a noticable power gain, better vaccum production and also less exhaust noise.

    The compression check theory makes perfect sense unless you have a dyno.

    Chuck
    I NEED A REARVIEW MIRROR THAT DOESN'T SHOW RED!

  12. #12
    Join Date
    Aug 2005
    Location
    Pahrump NV.
    Posts
    5,534

    Default Re: Cam Degreeing How Important?

    OK Thanks for the rude awakening guys. My how things have changed in the last 20 years or better. I have been having my cams degreed since the mid 80s but I never used to do that. I did a little research and called a couple engine builders I know up in Washington and one in Arizona. They all said what I was suspecting after reading the posts on here. Accuracy in timing components is a thing of the past. They said the same thing that has been posted here you cant trust timing marks keyway locations and a lot of other things to be where they are supposed to be.It may have been true years ago that degreeing a cam was needed for optimum performance but now it is needed to prevent possible engine damage. So I will change my way of thinking here and be glad
    that I started having my cams dialed in when I did. Good posts guys.

    Bob H.
    1953 Buick 455 TA Aluminum SE Stg2 Heads, B4B Intake, S/P Turbo 400, Gear Vendor, 3.42 Posi. A/C
    1970 GS Project Getting close.

 

 

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