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Degreeing my cams

  • Thread starter Thread starter Craig
  • Start date Start date
C

Craig

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I have a 83 GS 1100 ESD. I am putting in new cams - 0.348" lift, 257 degree duration @ .050". I am using adjustable cam sprockets. Any ideas as to a good staring point for both the cams? Thanks in advance for your help.

Craig
 
106 is a good place depending on what you want. if you want a combonation of low to midrange punch that is a good place to start. if you are looking for more high end power like in dragracing then you want to degree them a litlle higher like 110 degrees. I have g-4 cams and have run them at 106 and 110 degrees at 110 they make power about 1500 rpm higher then at 106
 
For the widest powerband and best compromise between top end HP and low/mid-range torque, 106 on both works well.
 
i once read on Cope racing websitesite. ((ask Greg) He liked 108 for street compromise. Lots of folks recomend 106. I like the combo skip recomends because of my particular riding preferences. now al i have to do is get a decent set of cams and some adjustable gears. :(
 
Degree Wheel

Degree Wheel

Thanks for the image of the degree wheel. Now...does anyone have the information on how to get the job done??

Thanks...Craig
 
There is one point in this thread which seems to have been completely overlooked. That is; what is the manufacturers recommended installation center? Every cam is different. XXX degrees of duration does not mean squat from one cam to another, if they have been designed with different lobe centers. So the starting point should be the manufacturers recommendation. Then you can advance or retard the cam if a different power band is desired, keeping in mind that changes of less than 4 degrees will be insignificant. You should also be aware that the cam in question will always make its Maximum Total HP at the centerline it was designed with. Just some food for thought.
 
Jeff - I think that's the one I was refering to. Jiggles does it again. :lol:
 
gearheadmn said:
There is one point in this thread which seems to have been completely overlooked. That is; what is the manufacturers recommended installation center? Every cam is different. XXX degrees of duration does not mean squat from one cam to another, if they have been designed with different lobe centers. So the starting point should be the manufacturers recommendation. Then you can advance or retard the cam if a different power band is desired, keeping in mind that changes of less than 4 degrees will be insignificant. You should also be aware that the cam in question will always make its Maximum Total HP at the centerline it was designed with. Just some food for thought.
Click to expand...
good point use the mfg recomendations as the starting point and then adjust.
 
skip[ said:
gearheadmn said:
There is one point in this thread which seems to have been completely overlooked. That is; what is the manufacturers recommended installation center? Every cam is different. XXX degrees of duration does not mean squat from one cam to another, if they have been designed with different lobe centers. So the starting point should be the manufacturers recommendation. Then you can advance or retard the cam if a different power band is desired, keeping in mind that changes of less than 4 degrees will be insignificant. You should also be aware that the cam in question will always make its Maximum Total HP at the centerline it was designed with. Just some food for thought.
Click to expand...
good point use the mfg recomendations as the starting point and then adjust.
Click to expand...
Cam timing, at least back in the '70/'80's, was a very difficult and expensive tolerance to hold for the manufacturers. Each engine has slight differences. The manufacturers did not set cam timing uniformly, they set it within a range. This goes for all Japanese bikes. The GS's could be set anywhere from 98-115 degrees. This was the main reason 2 identical bikes would differ in performance. The BEST cam timing very much depends on how you use your motor. But for the best compromise between top end HP and low/midrange torque AND the widest powerband, 106 degrees is good.
 
Does 106 go for all GS motors? My 400 hits the wall before red-line in 6th gear so I'd like to do this instead of changing drive sprockets. I should be able to get another 10km/h out of her which would be nice. :)

Steve
 
srivett said:
Does 106 go for all GS motors? My 400 hits the wall before red-line in 6th gear so I'd like to do this instead of changing drive sprockets. I should be able to get another 10km/h out of her which would be nice. :)

Steve
Click to expand...
This is what I've read. Combustion chamber configuration is important. The semi-hemispherical chambers of MOST older DOHC Japanese engines work well with a setting of 104-108 degrees.
If you are trying to increase the top end HP, you would want 108 degrees minimum and maybe 110. This will result in a narrower powerband and less low/mid-range power. On a small motor I would rather have the low/mid-range power the best it can be. Just my opinion.
 
Keith - while I believe your opinions on the effect of lobe centers on performance are valid, this topic started with Craig wanting to degree what I believe to be a set of Non-Factory cams, (though this has not yet been made completely clear). The manufacturers recommendations which I refer to are those of the cam manufacturer, not Suzuki. Somewhere on the face of this earth, somebody sat down and designed a non-stock cam with the profile he has selected. They ran it in an engine on a dyno and declared that "this is good, lets sell it". Before they came to this conclusion they spent many hours and dollars refining their camshaft to create good performance in a certain application. So my point is this: if this cam does not create the power band that Craig wants, he should probably look for different cams. Yes, minor shifts in the peak of the power band can be made by advancing or retarding the cam but, and I repeat myself, this cams ultimate total horsepower will be made in the "straight up" position designed by the manufacturer. The great value in degreeing the cams, as you have indicated, comes more from setting the cams accurately to the manufacturer's spec., than from shifting the power band up or down.
 
gearheadmn said:
There is one point in this thread which seems to have been completely overlooked. That is; what is the manufacturers recommended installation center?
Click to expand...

I'm going with G4 cams using the OEM sprockets and after a few runs down the track I'll install my adjustable sprockets at 110 degrees and see if there's a differance. Cam Motions recomends 110.

Jake
 
Jake - I like your thinking. Though much more labor intensive, your approach is the ultimate answer to questions such as this. Even a dyno sheet does not always give you a "perfect" answer as to how the bike will perform on the street or strip, (unless you already have a well established baseline of dyno and real world performance, which most of us don't). :)
 
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