Retarded will move the powerband up. Advancing moves it down.
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| Cam degreeing https://slantsix.org/forum/viewtopic.php?t=36317 |
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| Author: | kesteb [ Thu Jul 16, 2009 9:51 pm ] |
| Post subject: | Cam degreeing |
Anybody in the Seattle area have the cam degreeing setup they wouldn't mind loaning out for a few days? Thanks |
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| Author: | emsvitil [ Thu Jul 16, 2009 11:40 pm ] |
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Just emailed you a degree wheel.......... |
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| Author: | emsvitil [ Thu Jul 16, 2009 11:43 pm ] |
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Well, I thought I sent it to you............ some sort of delivery problem PM me your email and I'll resend. |
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| Author: | kesteb [ Fri Aug 07, 2009 9:19 pm ] |
| Post subject: | |
OK in need of a sanity check. I picked up the Summit cam degreeing kit and I am in the process of trying to degree in the cam. The cam is an Erson TQ20m. Using the "center line method" the intake starts to open at 22* at .050 lift and closes at 161* at .050 lift. Doing the math (161 + 22) / 2 = 91. So the intake center line is at 91*. The cam card says 107*. I have done this multiple times, adjusted the dial indicator, tried again, rechecked TDC, tried again, same results. JP timing chain is at 0*, timing chain marks are lined up correctly. So, the cam is really off, or the JP timing chain is really off, or the crank shaft is really off, or Erson sent me the wrong cam, or I am just flat out doing something wrong. Can anybody verify these figures for this cam? Thanks |
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| Author: | emsvitil [ Fri Aug 07, 2009 11:25 pm ] |
| Post subject: | |
Sounds like you're a tooth off somewhere.......... |
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| Author: | DusterIdiot [ Sat Aug 08, 2009 1:33 pm ] |
| Post subject: | Don't use the timing chain marks... |
Like Ed says you're off a tooth...I don't trust the timing gear marks...rarely are they spot on.... Reset to your calcs and try again...check the lobe lift per the card and see if you get all the numbers they list. My Erson was right on, except they gave me 2 degrees more on the foot of the lobe for some reason so the closing event was off just a smidge... runs fine, so I won't complain... good luck, -D.Idiot |
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| Author: | slantzilla [ Sat Aug 08, 2009 2:12 pm ] |
| Post subject: | |
What are you using for a TDC stop? I tried using the universal one in the Comp kit and it had so much play in it you could not trust any readings you got with it. |
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| Author: | kesteb [ Sun Aug 09, 2009 7:06 am ] |
| Post subject: | |
Intertestingly enough a Comp cams one. Seems sturdy enough.All well, I guess I will tear down the timing chain and try again. I am glad I am testing this now, instead of later... |
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| Author: | kesteb [ Sun Aug 09, 2009 9:12 am ] |
| Post subject: | |
Hmm, that didn't take long. Moved the everything back a notch. Now the readings are starting to match the cam card. Centerline is now 78* Intake opening is 7* Intake closing is 42* It is 4* retarded, if I am reading this correctly. If so, according to Summit stuff this means the power band will go down about 200 rpm. So instead of 2000 to 5000 it would be 1800 to 4800. Which would be closer to what I want. I just may leave this as is. Unless I am mis-interperting stuff again. |
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| Author: | slantzilla [ Sun Aug 09, 2009 9:50 am ] |
| Post subject: | |
Retarded will move the powerband up. Advancing moves it down.
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| Author: | Charrlie_S [ Sun Aug 09, 2009 5:34 pm ] |
| Post subject: | |
None of the numbers make any sense to me. The intake should open (x) before TDC, and close (x) after BDC. Are you saying the intake is opening 22* before TDC or after TDC. What about the exhaust. I always find the high point of the lobe, then turn the engine backwards past .050 lifter drop. Turn the engine forwards slowly till you get to the .050 lifter less then max lift, and read the degree wheel. Continue to rotate engine past lobe high point till .050 drop on the down side, and read the degree wheel again. Now do the math to figure centerline. |
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| Author: | kesteb [ Mon Aug 10, 2009 5:55 am ] |
| Post subject: | |
The Summit degree wheel has two sets of numbers. One set is a full 360*. The other is split into two 180* segments. The first set of numbers were taken from the 360*, the second is from the 180* segment, just because it was closer to the cam card. Which has the intake opening at 4* and closing art 37* with a center line of 107*. Charlie, the numbers were taken as you describe. I think I am still off by a tooth. Damn bi-focals just can't see the little markings like I used too. I will try again. |
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| Author: | kesteb [ Tue Aug 11, 2009 10:30 pm ] |
| Post subject: | |
Damn, I think I finally got it. I moved the lower sprocket to the -4 slot. Which makes for an interesting time lining up the timing marks. The readings are now: (34 + 172) / 2 = 103 Center line: 103 Intake open: 8 Intake close: 34 Cam card has this: Center line: 107 Intake open: 3 Intake close: 37 I believe I am 4* advanced now. Right where I wanted to be, |
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| Author: | Dart270 [ Wed Aug 12, 2009 5:50 am ] |
| Post subject: | |
Most Slant cams I've tried like 99-103 centerline, so 103 will work well and lean a little toward higher end power. I've never seen a cam company that really put this into their cams. They always give you a V8 centerline or close to it. Lou |
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