Cam shaft choice small seal R90/6

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

  1. supershaft

    supershaft because I can

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    What are you on RG? The goal of this fruitless discussion is to find some meaningful specs so that those of us that are interested in performance cams can compare the cams available without buying every one of them. I am very interested in performance cams for one. Motivation? Where do you guys get off? I know: WAY back.

    Some of us here have reported buying a number of these cams or even timing dozens of them. Surely someone has called for the cam's specs with a check point or has done enough cams to figure out a check point? The effort to report their findings here would be minimal indeed.

    Otherwise, get off my back for pointing out that those specs are just about useless for comparison or setup without a check point. I don't have very much cam experience but I do know enough to start at the beginning. And it's giving a bunch of you guys a headache? To the point of trying to make up why I am trying to find some meaningful cam specs other than finding some meaningful specs? :huh I have already emailed them and got the same stuff everyone has already seen. Call them? You are in the same country and already have some of their cams! But first you need to understand why and how specs with a check point are essential before you can meaningfully ask for them. That I have TRIED to explain and what do I get in return? This crap!
    #21
  2. RGregor

    RGregor Been here awhile

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    Sorry but, what you get back has something to do with the way you lead your discussions when it's about cams.
    I remember well the cam thread. I just was the messenger, that the 336 was not used over here and literary found myself in front of a cam-tribunal with you as the main inquisitor and the unvisible crowd (your words) in the back.

    And now I learn this was simply because you TRIED to explain the meaning and importance of a check point to me so that I could ask Schleicher for the missing information? Sorry man but, I must have missed that.

    Personally I did not get the impression that you are interested in performance cams as you already seem to have found one answer for all questions regarding cams.

    So if you're really interested, what do you suggest?
    #22
  3. supershaft

    supershaft because I can

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    Concerning cams? I just wrote that in my last thread.

    Otherwise, put me on your ignore list so you will quit bogging down this discussion with your psycho analysis of my motivations. After all, there are about five of us here who would love to get some usable specs without all the BS.
    #23
  4. RGregor

    RGregor Been here awhile

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    Just an idea to get comparable specs:
    The Schleicher data are theoretical data including the ramps, the BMW specs are given with respect to preload and additional lift, resulting in a measurable duration of 264° and the following timing.

    AO AS EO ES
    52 32 32 52

    The theoretical duration of the 336 is probably 336°.
    So if we add (336°-264°)/2 to the BMW spec we get

    AO AS EO ES
    88 68 68 88

    Very near the Schleicher 332 profile.
    Lobe center would be 100°. That would be reasonable.
    We know that valve lift with the 336 is 10.68mm, so cam lift is 7.79mm
    Lift at overlap probably is a bit higher than that of the 332 (3.7mm)
    For the later version of the 336 you'll have to shift it 3°.

    Comparing that with the Schleicher data it seems plausible.

    Still no check point to check the grind but probably comparable specs.

    Edit:
    AO: exhaust opens
    AS: exhaust closes
    EO: intake opens
    ES: intake closes
    #24
  5. 983Bob

    983Bob Adventurer

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    I've been following this thread and the cam thread for some time so I decided to do some research of my own. The motor I'm using as my street rod was built from the outset with the 336 BMW cam. At that time [1980] the only options were the Crane, Andrews and Erson regrinds which I stayed away from as I was worried about excessive acceleration rates and wear problems. When I had the heads flowed and ported the flow bench operator mentioned that the cam specs. that he measured were quite old fashioned and I could obtain better results with something newer. I let this slide until a few years ago, when I came across the Israel website. I substituted the 336 that I was using in the racer and noticed an improvement with the 344 that I installed. This is not a good street cam if you want low speed driveability but on the track, it was an improvement. Fast forward to last month when I started to install the 324 in the streeter. To check the cam specs., I built a dummy motor with post 81 clutch carrier and single row camchain. The results were 65/35,33/65.measured at 1.0MM lift. Once I've built this motor, I'll do the specs. on the 344, 330, Schleicher cams 336BMW and 320BMW cams. As an aside, the figures can be altered simply by adjusting the valves a bit looser or tighter than stock. Also, with heavy duty springs, there will be a certain amount of camshaft flexure as the lobes do not lie in opposing planes so the loading is cyclical. The pushrods flexing at high revs will also affect valve timing the only fix for this being to install chrome-moly rods which I have done. My results were from many repeats of the measurements including verification of true TDC mark on the flywheel which turned out to be correct. My use of the single chain and tensioner also meant that the 3Deg advance was included. My conclusion from all this is that this cam is ground with the later offset in mind as it can be installed without an offset key to achieve the symetrical timing these motors like. Darn, I had a set of keys made up in anticipation of needing them. I will post the figures for the other cams in the not too distant future. I hope this helps the discussion.
    Cheers
    Bob
    #25
  6. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    Ok, where is your website? Where are your specs? What information have you made available?

    Sheesh.

    --Bill
    #26
  7. RGregor

    RGregor Been here awhile

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    Hello Bob!

    The 344 and the 332 AFAIK are very old profiles from the early 60ies, developed for the car engines (BMW 700).
    The 344 is often mentioned as "the" race cam over here.
    A friend has one in his street bike and after a look at his torque curve I would share your opinion.
    A big boost above 5k but mid range suffers (although still in the 80+Nm range). Maybe good for open road, but not good for twisty roads like in the alps.
    The 324 and even more the 320 are popular cams for road use.

    Please keep us informed about your results with the 324.

    Regards,

    Rudi
    #27
  8. supershaft

    supershaft because I can

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    :clap:clap:clap NOW we are getting somewhere! For those of you that are trying to psycho analyse my motivations: This is why I am here!

    @Bill: I don't have any specs. That is why I am looking for some! I could pull some out of my ass that add to 360 but that would get us exactly where we were to start with. But some are happy with BS. Look at the idiotnet! :D

    @bob: I am pretty sure BMW had a 'race' cam and the 336 available at least in the seventies. Megacycle had one too in '80? Anyway, thanks SO much.

    Which cam is 65/35,33/65? AT 1mm!!! (Thanks again!)

    Sure just a few thousandths at a valve makes a big difference at the crank particularly on cams with long ramps. My advise is to forgo the entire setup. Check timing at the lifter. The engine is easier to turn and there is NO flex, NO ratios, and NO radii involved (they are ROCKER arms, not pistons!). Leave your test engine down to the crank and cam!

    I have always suspected BMW's TDC's were close because I almost never have a piston blow back during leak downs unlike many other brands. Timing cams? I would still find TDC with a piston stop and a degree wheel. We're timing cams. Just one degree matters!

    Despite all the crap on this forum, it can still rock! Thanks again so much Bob!
    #28
  9. chasbmw

    chasbmw Long timer

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    I have a feeling that the 336 was the early 70s BMW race cam"."................:rofl. Full circle guys!

    Bob, thanks for your input, it will be useful to get your results.
    #29
  10. supershaft

    supershaft because I can

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    No, it wasn't. The 336 has always been called the "sport" cam. I believe there was a "race" cam available too AT THE SAME TIME as the 336 was available from B+S and later BMWNA too if I remember right.

    Full circle? MI and Siebenrock cams with real, usable specs? It's a first as far as I know!
    #30
  11. tofgasp

    tofgasp Adventurer

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    If this can help :
    [​IMG]
    The "softer" cam is 336, the other is a special one made for a race bike, 5th place general, 1st of his class at the Bol d'Or Classic this year.
    Measurements at the valve, no play.
    #31
  12. chasbmw

    chasbmw Long timer

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    In the early 70s (pre90s) the only pukka BMW race bikes were the 500 and 750 sidecar racers for which the 336 cam was developed
    #32
  13. supershaft

    supershaft because I can

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    Whatever the 336 was developed for, it has always been called the 'Sport' cam ASFAIK. They also had a 'race' cam. Probably the one RG mentioned earlier. It all makes good sense since the 336 is not very racy but perfect for streetable sport. It was then and still is a mild cam. Old fashioned? Mild cams are not old fashioned, they are mild. Very often the smart way to go!

    But back to the subject of comparing cams: As soon as Bob times some more cams and posts the results, some of us need to time our cams and see if we can duplicate the results. After all, we not only need some specs but we need repeatable specs which is just about the whole point to start with. Since the manufacturers won't tell us how they are suppose to time, it will take a couple of samples in order to insure that how Bob cam's time are in fact how they are suppose to time.
    #33
  14. RGregor

    RGregor Been here awhile

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    Never heard of a BMW race cam other than the 336.
    Helmut Daehne raced the 336 and then (early 70ies) he was working in the test department.
    He probably had access to all parts available at BMW.
    I can ask him if that's of interest.

    BTW: I asked him about the 336 and he still is very fond of it. Used it even in his enduro "without disadvantages".
    #34
  15. RGregor

    RGregor Been here awhile

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    Man, you really seem to be interested in the matter. I thought this would be the start of another "praise the one and only cam" debate.
    Sorry.
    #35
  16. bmwrench

    bmwrench Long timer

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    I'd be interested in any memories he has from that time.
    #36
  17. chasbmw

    chasbmw Long timer

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    I saw him at the Goodwood revival races a couple of years ago, when BMW brought over some 1930s? Racers, the red leathers had stretched a bit!
    [​IMG]

    [​IMG]

    It would be interesting to know what the spec of the IOM TT R90/s that he rode in 1973 and 74. I was their in 73, riding my Norton Commando, BMWs were way out of my price range in those days. Even then it was amassing how fast those guys went on a 37 mile road circuit.
    #37
  18. supershaft

    supershaft because I can

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    That has been YOU the whole time. You really should try to refrain yourself and let me get on with discussing cams.
    #38
  19. supershaft

    supershaft because I can

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    Wasn't that you that said that BMW transferred the 344 profile from car to bike. Someone did. I suspect that is the cam I knew about as a kid. I know someone who would remember but he has enough idiots bothering him so I am not going to ask.
    #39
  20. Renner

    Renner combustophile

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    :thumb
    I suspect he's grateful.
    #40