cam degreing question

Hello all. 1st time poster here, but sure hoping you can help me. I too am trying to degree my cams on a 1000A with 1075 kit; Web 218 cams. I have reviewed the "how to" sheets from Cope Racing, and Web Cams, and I have to admit now that I am totally confused. First, The web cam degreeing procedure says to take the open value (@ 0.050")+closing value+180=duration @0.050". No matter how hard I try to set up my dial indicator, I CAN NOT get to the same duration of 242degrees as shown on my cam card. Is this normal ? I noticed in this article "cam degreeing for zombies" that his numbers for duration didn't equal the web cam spec sheet duration either. I also noticed that his degree wheel numbers @ 0.050" open and close didn't equal the cam card specs either??? The intake cam wasn't even close!

Second, both experts say that "tighter" lobe seperation angles give rougher idel, but make really good low end power, and that "wider" seperation angles give more high end power and better idel. The article referenced here seems to say just the opposite. Also, my cam spec sheet says use 105 degree lobe centers for both, and gives open and close specs just like show in the article. Cope says to set them up to 110 degrees each??? I would greatly appreciate some help here as I am totally stuck. I have paid close attention to valve clearance, and all seems in order, but the bike won't start / run unles I'm half thottle.

Lastly, I also have the Dyna elect ignition. I installed this several years ago, and its been great, but I always wondered why my timing adjustment wasn't centered with the crank - it was always at max retard as far as I can go. In the pic in this article the unit's timing adjustment is about in the center. What would cause such variation ? Is that the same part working for both 900 and 1000's ?

Any info would be GREATLY appreciated.
thanks
Jeff B

jab wrote:

Hello all. 1st time poster here, but sure hoping you can help me. I too am trying to degree my cams on a 1000A with 1075 kit; Web 218 cams. I have reviewed the "how to" sheets from Cope Racing, and Web Cams, and I have to admit now that I am totally confused. First, The web cam degreeing procedure says to take the open value (@ 0.050")+closing value+180=duration @0.050". No matter how hard I try to set up my dial indicator, I CAN NOT get to the same duration of 242degrees as shown on my cam card. Is this normal ? I noticed in this article "cam degreeing for zombies" that his numbers for duration didn't equal the web cam spec sheet duration either. I also noticed that his degree wheel numbers @ 0.050" open and close didn't equal the cam card specs either??? The intake cam wasn't even close!

Second, both experts say that "tighter" lobe seperation angles give rougher idel, but make really good low end power, and that "wider" seperation angles give more high end power and better idel. The article referenced here seems to say just the opposite. Also, my cam spec sheet says use 105 degree lobe centers for both, and gives open and close specs just like show in the article. Cope says to set them up to 110 degrees each??? I would greatly appreciate some help here as I am totally stuck. I have paid close attention to valve clearance, and all seems in order, but the bike won't start / run unles I'm half thottle.

Lastly, I also have the Dyna elect ignition. I installed this several years ago, and its been great, but I always wondered why my timing adjustment wasn't centered with the crank - it was always at max retard as far as I can go. In the pic in this article the unit's timing adjustment is about in the center. What would cause such variation ? Is that the same part working for both 900 and 1000's ?

Any info would be GREATLY appreciated.
thanks
Jeff B

a] not uncommon to find the duration numbers don't match the card spec. Reasons for this are grinding operation imprecise, indicator not following true valve motion, lash not equal to zero.

b] it doesn't matter if you have zero or running lash when you do the operation. Main thing is find true
TDC and the dial indicator tip must follow the valve precisely and repeat the numbers you get at the check lift each time. If that's not happening, sort out the cause. Very skinny indicator tip helps. Align indicator position to valve angle so the tip runs straight, doesn't drag on the tappet bore or cam and isn't bumped by lobe. THAT IS THE REAL TRICK.

Math shortcut to lobe center value:

[big number - small number] + 180 / 2

O/C values example

55/23 Intake
23/55 Exhaust

[55-23]=32
32+180=212
212/2=106 lobe center

Doesn't matter what the cam card says to get lobe center set. Lash and grinding imperfections can cause numbers at check lift to be different. Whatever you have at .050 check lift should be somewhere around what the cam card says but doesn't have to be dead nuts match.

Use what you get as long as the number repeats.

IMPORTANT - make sure the dial indicator does not run out of travel on you before valve reaches max lift or that can cause errors.

After you've got them to what you believe is correct, if you position the crank at TDC for #4 cylinder at beginning of intake stroke and take a good clear picture of the lobes looking across the edge of the valve cover surface, I can tell you if the timing looks to be way off.

lewisj wrote:

kzz1p,
I am looking at three different set of instructions and trying to figure out which is best. i have the instructions from Pit-Stop-Performance, they are a little vague at points throughout. I have the Web Cams instruction and I have the Cam Degreeing for Zombies. I am just getting eberything set up for the process. Degree wheel, TDC tool,Dial indicator, etc.
Do you have a perferred method?
Jim

Jim

Let me see if I can give you some information. I am not trying to overwhelm you, just inform. Once you know whats out there, it's easier to research. Hang in there, take your time and learn all you can.

With the (DOHC) motor we are lucky. There are two basic styles of cams. The single pattern cams(the intake & exhaust lobes are the same size) and the Dual pattern cams(the intake & exhaust lobes are different sizes)

Note- Single pattern cams generally have better low end/mid range power. The Dual pattern cams have better Mid range/top end power.

You will hear people talking about checking cams at .050". That was the industry standard that was formed by Isky cams in 1958. The cam is open enough so that small errors on the dial indicator (.002") would only equal about 1 degree on the crankshaft. The second thing is that at .050" you are starting to have a good air flow standard.

Currently there are two popular methods for degreeing
a cam: the centerline method, and the duration at
.050” lift method. I believe it is far better to degree
the camshaft with either method than not to degree
the cam at all; but of the two methods, the duration at
.050” lift is much more accurate.

The main problem with the centerline method is it has
you finding the theoretical centerline of the intake and/
or exhaust lobe and lining up on it. It makes the basic
assumption that the lobe you are checking is symmetrical,
with its opening side being the exact same shape
and size as the closing side of the lobe.

The truth is that most modern lobes are asymmetrical, with the opening side of the lobe being much more aggressive and the closing side being more gentle. Therefore, when you attempt to locate the middle (or centerline) of the asymmetrical lobe there is an automatic error factor.

It could be as little as 2° off or as much as 6°, depending on the exact lobe shape and the procedure you use during the degreeing operation.

Neither does it verify that the camshaft has been properly ground with the correct duration lobes, which can drastically affect your performance.

Since the duration at .050” lift method is not affected by the asymmetrical lobe design, I believe it is the more accurate way to degree.

Now that you know the two most common methods of degreeing. You will need to decide witch method of cam adjusting you will use after finding your cams position. There is the split centerline or the split overlap.

Keep asking questions, we are all learning!

Thanks for the info. I assumed not getting the correct duration was measurement error, so I just assumed the opening number was correct since there is very little dial movement when you first start out, and I assumed the closing number was wrong. From there, I set it close to the cam card spec. It said 16 BTDC, but since I thought a 105 lc was too tight, I set it to 13 BTDC. I simply assumed the closing number was correct for a 242 degree lobe, and did the math that way. So, for the intake cam I measured open=13 close=46, which lc=106.5, but with my assumptions that the duration MUST be correct, it should have a closing number of 49 degrees, which gives lc=108. Perfect, or so I thought. I did this the same way for the exahaust cam and ended up with a measured lc=110.5, but assuming the duration must be accurate, I again assumed my closing number was off. I measured 48 and 7, but assumed it must be 48 and 14 to equal 242 degrees duration. SO my lc measured was 110.5 but I assumed it must be 107, so I quit. My measured duration for intake was much closer to the cam card then the exhaust cam was. In=239 dgrees duration measured, while the exhaust was 235 degrees measured.
thanks again - I'll keep at it
Jeff B

jab wrote:

Thanks for the info. I assumed not getting the correct duration was measurement error, so I just assumed the opening number was correct since there is very little dial movement when you first start out, and I assumed the closing number was wrong. From there, I set it close to the cam card spec. It said 16 BTDC, but since I thought a 105 lc was too tight, I set it to 13 BTDC. I simply assumed the closing number was correct for a 242 degree lobe, and did the math that way. So, for the intake cam I measured open=13 close=46, which lc=106.5, but with my assumptions that the duration MUST be correct, it should have a closing number of 49 degrees, which gives lc=108. Perfect, or so I thought. I did this the same way for the exahaust cam and ended up with a measured lc=110.5, but assuming the duration must be accurate, I again assumed my closing number was off. I measured 48 and 7, but assumed it must be 48 and 14 to equal 242 degrees duration. SO my lc measured was 110.5 but I assumed it must be 107, so I quit. My measured duration for intake was much closer to the cam card then the exhaust cam was. In=239 dgrees duration measured, while the exhaust was 235 degrees measured.
thanks again - I'll keep at it
Jeff B

Jeff

Please bare in mind! The cam grinders give us the lobe centers for a reason. They are saying this is what works best for the app

If you need to change the lobe centers very much to gain performance, then you have the wrong cams.

Please don't believe that adjusting the cams a few degrees will produce magic. Adjusting the lobe centers is a "fine tuning aid" and should be treated as such.

Adjusting your lobe centers is a "tool" for moving the power band up or down. Sometimes you need to know what power you have, before you know where to move it.

My personal suggestion with a new motor is, advance both cams three degrees. This will compensate for stretch in your new cam chain. The worth thing that can happen is as the cam chain breaks in, your cams will be in the straight up position.

Good Luck! Don't give up until you got it.

jab wrote:

Thanks for the info. I assumed not getting the correct duration was measurement error, so I just assumed the opening number was correct since there is very little dial movement when you first start out, and I assumed the closing number was wrong. From there, I set it close to the cam card spec. It said 16 BTDC, but since I thought a 105 lc was too tight, I set it to 13 BTDC. I simply assumed the closing number was correct for a 242 degree lobe, and did the math that way. So, for the intake cam I measured open=13 close=46, which lc=106.5, but with my assumptions that the duration MUST be correct, it should have a closing number of 49 degrees, which gives lc=108. Perfect, or so I thought. I did this the same way for the exahaust cam and ended up with a measured lc=110.5, but assuming the duration must be accurate, I again assumed my closing number was off. I measured 48 and 7, but assumed it must be 48 and 14 to equal 242 degrees duration. SO my lc measured was 110.5 but I assumed it must be 107, so I quit. My measured duration for intake was much closer to the cam card then the exhaust cam was. In=239 dgrees duration measured, while the exhaust was 235 degrees measured.
thanks again - I'll keep at it
Jeff B

Don't assume anything. You could get slightly different numbers if you used a different lobe.

Thanks for the tips. I wasn't really looking for magic power, just trying avoid having the engine "ping" if the timing was too tight. Just trying to be conservative. I thought lc=105 spec was tight for optimum racing performance, which I don't need. I just want a strong, solid, dependable running street machine. I know I'm close. One more time and I'll have it.

Thanks Larry and 10-4 on avoiding assumptions. I first started using the #1 cylinder, then noticed that the cams are shorter on the #4 side and gave more room for the dial indicator. So, if I understand you correclty, use the measured numbers. Accuracy comes from the inidcator being in constant contact with the bucket. I did purchase a set of dial indicator tips, as this was giving me trouble. I think I'm really close. I'
ll try again.

jab wrote:

Thanks Larry and 10-4 on avoiding assumptions. I first started using the #1 cylinder, then noticed that the cams are shorter on the #4 side and gave more room for the dial indicator. So, if I understand you correclty, use the measured numbers. Accuracy comes from the inidcator being in constant contact with the bucket. I did purchase a set of dial indicator tips, as this was giving me trouble. I think I'm really close. I'
ll try again.

When I order cams, I have the end ground flush on #4 cylinder lobes. They don't charge extra for that and it makes the job easier.

Also I took long dial indicator tip and ground it down very thin.

This is the setup I use.

ok guys, now I'm completely stuck. I have redo the cams, and I have the same basically the result. The bike will start fine with the choke on. Then idles down nicely when I turn the choke off. It will run smooth and nice - for about 15 seconds, then grayish smoke starts to come out the exahaust, it begins to bog down, and stalls. The plugs are oil fouled, and the oil in the sight glass on the clutch cover is all foamy. There is no blow-by coming out the vent, or the oil fill hole. At first I thought I had the cam timing off and was pulling too much acuum and sucking oil thru the valve guides or something. I have move cam timing slightly each way, and I get the same result. I suspected it wasn't cam timing because it started and idled so good for a short time. I am totaly lost as to what would cause this. Any ideas before my frustration lands this bike on Craig's list would be greatly appreciated.
thanks - JAB

yep, looks pretty similar to what I did, only I put the degree wheel on the stator so I could continually referece the ignition timing marks - just to make sure nothing moved on me. The first time I did this, I put the wheel as you have it, but it would move on me. I suspect it was on those occasions when I would rotate a little too far and would back-turn it. Please see my lastest post a few minutes ago. I am totally stumped as to what is going on.
thanks for the continue help.