Having trouble degreeing my cam on 460. Gears are installed straight up. From TDC I'm rotating clockwise to max lift. Zero dial. Turn to .050. Record number (45). Back up past max lift to .050. Record number (141). Divide by 2. This gives me 93. Numbers are way off. Should be 108. What am I doing wrong ?


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What you are doing is starting at the top of the mountain, and going down .050". thats bass ackwards.

zero the heel of the cam. Then fwd to .050". log degrees (A).

then Fwd rotation, over the top (.320" Cam Lobe lift), all the way to .050". log that degree (B).

Then (B)-(A)= intake lobe centerline in relation to the crank. Adjust ISL from there.

If the valve is adjusted already, It needs to be done with rocker removed. Ideally off the rim of the lifter.

Dan'l

What you are doing is starting at the top of the mountain, and going down .050". thats bass ackwards.

zero the heel of the cam. Then fwd to .050". log degrees (A).

then Fwd rotation, over the top (.320" Cam Lobe lift), all the way to .050". log that degree (B).

Then (B)-(A)= intake lobe centerline in relation to the crank. Adjust ISL from there.

If the valve is adjusted already, It needs to be done with rocker removed. Ideally off the rim of the lifter.

Dan'l

I have the heads off. I found TDC with a piston stop and recorded numbers going both ways. Found the middle and zeroed the degree wheel. This was done with the gears installed straight up initially. When trying to find intake centerline, it's starting at the bottom of the lobe with the dial indicator on the edge of the lifter. Very frustrating.


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If you're doing it the centerline method... then as long as the lobe is symmetrical, then the way you were doing it will work... if it is not, then peak lift may not be the centerline of the lobe... though I'd zero off the base circle of the cam, then just measure .050" down either side of peak lift... gives you smaller numbers to deal with. No matter whether you go .050 from zero, or .050 from peak... or hell .127 from either direction... as long as you zero off the base circle, and go the same measurement on both sides of the lobe, you'll get there. You can always verify if you are way out in left field, or somewhat close, by checking the intake opening @.050" (zeroed off base circle) to see if the the numbers jive.... if you're doing it right, and your cam grinder is worth a damn... both sets of numbers should jive together.

The biggest reason I have seen people be off, is not finding true TDC. I had a customer pissed that the cam I had ground for him was junk and ground wrong... turns out... his trusty stock tin timing tag and stock 30+ year old balancer (complete with blown out rubber)... was 12 degrees off from true TDC when checked with a degree wheel and indicator.


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Thanks James. Yes i am trying the intake centerline method. I will give it another try after work today and start from scratch.
It's my first attempt degreeing a camshaft so I'm pretty sure it's me and not the cam. It's a clay smith so I'm assuming it's been made correctly.


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Yep, the cam from Clay Smith should be right.

However, when you degree in a cam, you are also checking several other things:
...Crank key way position.
...Crank gear key way position.
...Cam gear dowel position.
...Cam face dowel position.

If each of these were off by 1*, there is a 4* 'outa-whack', or 'stacking tolerances'.

Dan'l

What timing set are you using?

GT

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It's a clay smith true roller with the 9 way crank gear. I have it set at zero with the woodruff key pointed up. the dowel and timing mark on the cam gear pointed down towards the crank.


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You should be in the ballpark then... BUT... it never hurts to check, since sometimes, people can make mistakes. Seen a really nice timing set by a well known mfg be off half a tooth... and had a cam by a very large popular cam company actually not only degree in off to the dowl pin, but come up 6 degrees short @.050... but correct duration @ .006. No matter how good a quality of a part and company that produces said part... ultimately they are made by people... and occasionally, rven the best can make a mistake... so best rule is to check everything twice... then check again.


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Couldn't agree more. Not to mention the time and money invested only to slap it all together in good faith.


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Well I checked. Double checked. And checked again. And I'm still getting the same number. 93. I measured from the top of lift an from the bottom of the circle. Same result.
Does this mean the cam is jacked up? Or do I need to retard or advance the crank gear to a different key slot??? Seems really far off.


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Not to sound stupid, but what lifter are you reading?

GT

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Not to sound stupid, but what lifter are you reading?

GT

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Have a better picture of the timing set?

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Just for shits n giggles... what do you get at .050" lift intake opening?


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On the degree wheel I'm getting 46 before max lift and 142 after at .050


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Is it possible the cam is pinned wrong or am I retarded?


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What does the other side of the crank gear look like? Thinking out loud, sure feels like the gear is backwards. Grasping at straws.

GT

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