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Degree a cam

Posted By: 426runner

Degree a cam - 07/03/16 10:58 PM

Hey. Can't I degree in the cam using any cylinders intake tappet? Does it have to be #1? I cannot get my dial indicator in position at the #1 tappet due to space in the valley. Any reason why I can't use #3 or #5 with the same procedure?
Posted By: SportF

Re: Degree a cam - 07/03/16 11:51 PM

What a great question! After thinking about it, seems perfectly fine to me!
Posted By: elmor353

Re: Degree a cam - 07/04/16 12:21 AM

I'm not sure if you can do that, because the specs given are for #1 intake and exhaust lobes.
Posted By: 426runner

Re: Degree a cam - 07/04/16 01:41 AM

So with that thinking, intakes 2 thru 8 are different than 1? Seems we would need specs on every cylinder and check the CL of every cam lobe. Now that I think about it, since manufacturing error is one of the possible problems you're looking for when checking the centerline, why is not recommended to check EVERY intake CL? I take it that we are really only checking lobe geometry to the chain sprocket mounting and take for granted that the cam lobes themselves were machined correctly in relation to each other.
Posted By: pittsburghracer

Re: Degree a cam - 07/04/16 01:44 AM

Buy one of these and you will love yourself forever.


https://www.summitracing.com/parts/cca-4926
Posted By: ek3

Re: Degree a cam - 07/04/16 01:49 AM

you can check any intake lobe . with cnc machine apps if the first lobe is off the rest will be off just like them. the degree process is used to bring the index of all parts to the same "designed location"
Posted By: RapidRobert

Re: Degree a cam - 07/04/16 03:21 AM

426, VG thinking as you never hear to check all of em since (for some reason) it is assumed that if one is good then all of em are (might be the CNC repeatability precision I would assume). Yes you can do any cyl & the reason doing #1 is common is the wheel shows TDC when the (#1) piston is at TDC (makes for easier math). On any of em just find true TDC of that particular piston (a # on the wheel) then see how far away from that point that the lobe peaks at such as 102 ATDC. Try #6, get its piston on TDC compression then find exact lobe peak & note how many degrees that that is past piston TDC, this is the bottom line including crank keyways/sprocket keyways & for example 102 degrees lobe peak is closer to the piston TDC (more advanced) than 106 is cuz if you are 102 ft away from your door in a rainstorm you are closer than if you were 106 ft away. EDIT been awhile you might want to be on overlap
Posted By: E-Ticket

Re: Degree a cam - 07/04/16 03:56 AM

Originally Posted By RapidRobert
426, VG thinking as you never hear to check all of em since (for some reason) it is assumed that if one is good then all of em are (might be the CNC repeatability precision I would assume). Yes you can do any cyl & the reason doing #1 is common is the wheel shows TDC when the (#1) piston is at TDC (makes for easier math). On any of em just find true TDC of that particular piston (a # on the wheel) then see how far away from that point that the lobe peaks at such as 102 ATDC. Try #6, get its piston on TDC compression then find exact lobe peak & note how many degrees that that is past piston TDC, this is the bottom line including crank keyways/sprocket keyways & for example 102 degrees lobe peak is closer to the piston TDC (more advanced) than 106 is cuz if you are 102 ft away from your door in a rainstorm you are closer than if you were 106 ft away.


#6 is what I had in mind also.... I love the "rain storm" theory... up
Posted By: Cab_Burge

Re: Degree a cam - 07/04/16 04:39 AM

I'm assuming your working on a 426 hemi motor so if so try degreeing the #6 intake and exhaust, they will be 360 crankshaft degrees different , same numbers, as cylinder #1 scopeBoth pistons are at TDC on both strokes, intake compared to compression, power and exhaust shruggy
A freind and fellow NHRA SS racer and engine builder, now deceased whiney, always plotted every lobe in five degree increments to make sure every lobe was exactly the same, he sent many cams back work IHTHs
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