Register now to get rid of these ads!

Degree a cam question

Discussion in 'The Hokey Ass Message Board' started by Mike51Merc, Dec 22, 2012.

  1. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,834

    Mike51Merc
    Member

    Ok, so far as I understand, you degree a cam to see if it operates to specifications. I've read some articles and seen videos to learn the process, but I've never seen any that didn't degree to spec.

    Since most cams and gears are not adjustable, if you find it does not meet spec, do you send it back to the manufacturer for a refund or what?
     
  2. there are offset crank keys and bushings for the cam sprocket available
     
  3. TheMonkey
    Joined: May 11, 2008
    Posts: 312

    TheMonkey
    Member
    from MN

    Just did one that needed 2 degree adjustment and just twirled the crank sprocket to appropriate key.

    To be nuts on, cam grind, cam sprocket, crank sprocket, and crank need to be aligned. That's a lot of resolution to expect perfect out of the box, especially with any aftermarket parts.
     
  4. that's right...some timing sets come with crank sprockets that have more than one key way to advance or retard

    what engine were you thinking of?
     
    Register now to get rid of these ads!

  5. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,834

    Mike51Merc
    Member

    Just a general question, although a have a spare Flathead and a couple SBFs I may build up in the future.
     
  6. not sure what to do on a flathead....but the stuff i mentioned are easily available for common later engines like SBC , BBC , SBF etc
     
  7. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,254

    Rusty O'Toole
    Member

    Another old trick, from the instruction book of a well known cam company in the sixties:

    Do a compression test of 1 cylinder. Move the cam around and test again. Whatever setting gives the highest compression is the best for that engine. At least, will give the best idle and low speed performance which is the best overall for a street engine.
     
  8. richie rebel
    Joined: Oct 8, 2007
    Posts: 1,184

    richie rebel
    Member

    never heard that one..........
     
  9. Interesting approach. I wonder if you could do the same thing by monitoring the cranking vacuum? :confused: Of course I'd think that you'd want to make sure the throttle and any other potential vacuum leaks were completely sealed off.
     
  10. black 62
    Joined: Jul 12, 2012
    Posts: 1,895

    black 62
    Member
    from arkansas

    poor boy's degree wheel ---results will show up in your 60 fts---used many times since early sixties---even did it with the solid roller i am running now
     
  11. 29AVEE8
    Joined: Jun 28, 2008
    Posts: 1,384

    29AVEE8
    Member

    Anyone ever degree a cam after several thousand miles? Me either, always wondered if the cam would retard a half a degree or so after the chain/sprocket got a little wear in it.
     
  12. joel
    Joined: Oct 10, 2009
    Posts: 1,678

    joel
    ALLIANCE MEMBER

    The last one I did,sbc, the 3 keys in the crank sprocket were not all correct, so I couldn't get the cam correct. I called the manufacturer and after some convincing, they sent me a new crank sprocket and I still used an offset key. i will do it every time i install a cam.
     
  13. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,269

    Dan Timberlake
    Member

    I'm not all that comfortable assuming cam timing marks are correct. There is a tolerance on the location of the keyway locations on all the crank, cam, and timing components.
    And manufacturing mistakes happen. A friend has developed a good reputation building engines for race cars and specialty cars. A desperate owner brought him a land rover with inline engine was running weakly after being rebuilt with lots of new factory parts. The degree wheel quickly revealed the crank sprocket had the key generated in the wrong location. Re-timing it 6 times to the factor marks would not have fixed that.

    Assembly mistakes happen too.
    A mechanic of a friend of my daughter was recommended because "he works on Corvettes, and has a race bike." He changed the timing belt, and got the exhaust cam timing wrong by a tooth on her INTEGRA 3 times (and left the crank bolt just snug the last, and I do mean LAST time. The key and keyways were lighly battered after just a week or 2 in gentle service) .

    Often a decently useful valve timing can be made with the engine assembled.
     
  14. fossilfish
    Joined: Dec 16, 2010
    Posts: 320

    fossilfish
    Member
    from Texas

    I degree all my cams. I found one that was off 24 degrees and another I had a well known cam company(one with a long funny name) regrind a cam for a 6 cylinder and just for grins I degreed all the lobes. The front ones were close but things got worse as I went.
    I sent the cam back and they sent it back with a note saying they checked it and found nothing wrong but reground it anyway.
    I checked it again and it was spot on....go figure.
    I have friends who have never checked them and things are ok. Had a friend that made fun of me and told me he built engines for 25 years and never had a problem...a year or so later he bent a bunch of valves with a new cam and called me to borrow my degree wheel and help dialing in the cam it was off quit a bit.
    It only takes once to convince someone to do it.
    Advancing and retarding the cam will move your torque and horse power curve too.
    I will not build an engine without dialing in the cam.
    Your results may vary.
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.