Cam shaft choice small seal R90/6

Discussion in 'Airheads' started by chasbmw, Dec 5, 2012.

  1. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    I wrote that AFAIK the 344 was developed for the BMW 700.
    But not that BMW transfered it to the bike.
    Schleicher is not BMW.
    #41
  2. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    But didn't Schleicher do most all of BMW's cam development back then? At any rate, it really doesn't matter other than I remember a 'sport' cam AND a 'race' cam being available but I never looked into getting the 'race' cam kinda like I never looked into getting a 2.60 something rear end. I never needed one! At least we got past the need for specs with a check point!!!
    #42
  3. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    The man in charge for tuning the BMW 700 engines was Ludwig Apfelbeck.
    And AFAIK he made his own cams. I would have to check it but AFAIR he also did a conversion to roller cams at the very beginning. And the last evolution of the race engines had bevel driven overhead cams.
    #43
  4. chasbmw

    chasbmw Long timer

    Joined:
    Feb 19, 2006
    Oddometer:
    2,676
    Location:
    Bath Uk
    you can see on the racer No 4 in my photos above that it has the overhead cam engine.
    #44
  5. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    That was the RS54 race-bike. It was developed with that design.
    The BMW 700 car engines were OHV engines like our beemers.
    Apfelbeck converted them into bevel driven OHC engines.
    If I remember right the final tuning stage had 850ccm and 95PS.
    That was this engine here:
    [​IMG]

    In large:
    http://www.bmbikes.co.uk/photos/photophotos/BMW Apfelbeck (1).JPG
    #45
  6. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    Just a suggestion, as you are going to time the various cams to compare them:
    Additionally measuring duration at ~70% lift may be a better indicator of the profile and of filling than the duration at 1mm lift and max lift only.
    #46
  7. chasbmw

    chasbmw Long timer

    Joined:
    Feb 19, 2006
    Oddometer:
    2,676
    Location:
    Bath Uk
    I took the R90/6 to the Dyno today to get some baseline readings prior to changing the camshaft.

    Here is the Torque BHP curve, given i asked Jim to create a touring engine with good even torque, then i think that he fulfilled his remit.
    [​IMG]


    This chart shows BHP with the bottom line showing airfuel ratio, it all looks good to me. The lean condition spike at low revs may be due to the sniffer not reacting well or low revs, but also might reflect the surging I get at low revs
    and at slightly opened throttle. This may be rectified when I replace the throttle shaft O rings as I think this might be the cause.

    [​IMG]

    I will be changing the camshaft In January so I will redo the dyno runs after i have got a few miles on the modified engine. No other changes are planned.
    #47
  8. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    Most likely bigger needle jets are what you need. 266's up to 268's for instance. Or maybe 268's up to 270's? I would try bigger mains too. 140's to 145's for instance? A different cam might really change your off idle jetting. I needed to go from 268's or 270's (I don't remember right now) down to 262's when I put a 336 in my bike. A lot more reversion really richened it up there. It idled and blipped SO much better after doing that!
    #48
  9. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    Just to mention it: the 320° BMW cam has nothing to do with the 320° Schleicher cam (or HPN).
    The BMW cam AFAIK has been used for bikes that went to Switzerland and reason were not performance issues but exhaust emission.
    #49
  10. bmwrench

    bmwrench Long timer

    Joined:
    Nov 10, 2006
    Oddometer:
    3,444
    I have searched at length for the BMW 320 cam. I'm almost certain it used to be listed on their microfiche. Does anyone have part numbers?
    #50
  11. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    #51
  12. RGregor

    RGregor Been here awhile

    Joined:
    Oct 31, 2007
    Oddometer:
    549
    Location:
    Bavaria
    According to HD the 336 was the only sports/race-cam from BMW.
    #52
  13. Beemerboff

    Beemerboff Long timer

    Joined:
    May 23, 2005
    Oddometer:
    2,654
    Location:
    Adelaide, South Australia
    Norton gave their timing figures two ways, for their racers.

    The 339 degree inlet cam in the short stroke 500 40 M was either 74 / 85 at two thou valve clearance, or 0.280 lift at TDC, 0.315 lift at BDC, with the same 2 thou clearance.

    If Siebenrock did the same it would make Supershaft , and probably a few more of us , a lot happier.

    And if you read this , 983 Bob, any chance of giving us the lift figures at TDC / BDC with 2 thou clearance, on the cams you check?

    And a word of caution - if you intend using a 'Modern" cam which bashes the valves open and bangs them shut it is advisable to use modern valves, seats and springs which are up to the task, after all they are what make the use of "Modern" cams possible.

    Ritchie at Moorespeed has what you need.

    http://www.moorespeed.co.uk/moorespeed/bmw-engine
    #53
  14. chasbmw

    chasbmw Long timer

    Joined:
    Feb 19, 2006
    Oddometer:
    2,676
    Location:
    Bath Uk
    Ritchie provides absolutely no information about the 'sports cam' that he uses in some of the tuning schemes.

    My definition of a modern cam is one designed in the last 20 years, I don't mean a can that will give the valve train components a lifespan measured in nano seconds!

    Who can give me an idiots guide to setting up and timing a new cam on an airhead? I sort of think that if I am asking the question, then I should I be thinking of doing it?
    #54
  15. moorespeed

    moorespeed Adventurer

    Joined:
    Sep 23, 2010
    Oddometer:
    67
    The reason I do not give info on cams is because it would just go on and on, it is down to you to come to me with engine spec, what you want it to do and rpm limit. I have over 8 cams to pick from. they are all from the original chill cast blanks and run standard followers with no problems, even the race cams, the only thing is all my cams are the latest type.
    #55
  16. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    It seems we have moved past the notion that some cams are 'old fashioned' for being mild. I certainly hope so since mild cams and cams with ramps too steep and lift too high have been around for almost as long which is a long time! Asymmetrical timing seems to be a newer thing but a lot of strong performing race cams out there are still symmetrical. What does the 'latest type' mean? Other than slightly different timing that very well could have been tried years back?
    #56
  17. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    There are lots of books on it. I suggest reading at least a couple of them. It's what I call a lot of work and very tricky if rock solid, repeatable results are what you are after which I hope you are since a degree matters and that is very easy to fudge!
    #57
  18. moorespeed

    moorespeed Adventurer

    Joined:
    Sep 23, 2010
    Oddometer:
    67
    The latest type to me means a slot drive in the front for the ignitor.
    #58
  19. supershaft

    supershaft because I can

    Joined:
    Sep 9, 2010
    Oddometer:
    9,116
    Location:
    San Francisco Bay area
    Awesome! I always call them the 'later' type since they came out with that 33 (?) years ago but I thought we were talking about timing so . . . .
    #59
  20. Les_Garten

    Les_Garten Been here awhile

    Joined:
    Oct 6, 2011
    Oddometer:
    744
    Location:
    PSL, FL
    Chasbmw,


    Any update on how you like your 324 CAM
    #60