Degreeing a Cam vs. Lining Up the Dots

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clifftt

clifftt

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This is my first time degreeing a cam. I'm putting a solid lifter cam in a 273. I've verified TDC with a dial indicator at least ten times to make sure I'm not going crazy. Then I put on the sprockets and chain, and lined up the dots straight, cam dot at the bottom, crank dot at the top. I started with the #1 exhaust, which is supposed to open at 62.5 BBDC, but it's opening at 50 BBDC.
Well, OK, I shift the cam sprocket one tooth, and now I'm getting my 62.5. But when I sit back and look at the dots on the sprocket, they don't line up, looks like I'm a tooth off. Same thing happens when I measure the intake.
Cam manufacturer is closed until Jan 6. I'm assuming I'm supposed to take these measurements at .050" lift.
Do I discount/ignore the position of the dots and rely on my numbers, or does it sound like I'm doing something wrong? Does this ever happen to you seasoned guys?
 
Usually...Yes, you ignore the dots if you are sure you are at the correct position. I just did this on mine. I had to run the crank gear 4 degrees advanced to line up at 53 ABDC. This is why you degree the camshaft because the dots are not always correct.
 
I don't know.

"Not knowing" nor "not seeing" what you know and see, all we do is guess

My advice

There is simply TONS of "how to" on the internet. Most of the major cam makers have downloadable "how to's" on degreeing a cam, and there are vids on YouTube and other sites

It might be possible the cam is ground wrong. It might be possible the cam sprockets are mis-marked

It might be possible there are cumulative errors in both the cam drive and the cam

AND........

It might be possible you are making a mistake somehow.
 
Those possibilities have run thru my tiny little brain. The timing set is a Cloyes double roller set. If I have doubts come Monday, I might return the cam and have the manufacturer recheck it for index.
 
Usually you degree the cam on #1 intake centerline. Turning only the way the engine runs. You measure, using a dial indicator on a dummy lifter, some number in degrees, .060", from max lift then same number. 060", in degrees on the other side of max lift. Add the two degree numbers together and divide by 2 to get installed number. Most cam lobes are not symmetric. TDC you turn the crank both ways and the degree number should be the same, some number, .060" from TDC.
 
I always install at recommended cam centerline. If you are unsure there are several videos on YouTube explaining how.
 
Hows about a pic of the cam card so we know
what manufacturer/specs your working with.
If done right your card should be specific to your cam
Many vids on youtube to explain degreeing..
 
I've had one mopar cam that was 18 degrees retarded with dots lined up ,and another one dead on .So you must degree the cam to be safe, it makes a big difference in the way it will run
 
Dial indicator and mag base, about 25 bucks at harbor freight and it will pay for itself the first time you realize your eyeballs are wrong. Degree wheel from tavia.com, print 2 out and glue to cardboard or LP record. Mount on crank and cam use Piston stop (bolt welded in old spark plug) only turn crank in clockwise direction to keep timing chain taught when looking at cam wheel values. Use coat hanger piece under bolt for marker. Loads of fun. Bushings are available to advance retard came a few degrees. Or use 3 values on lower cog from cloyes or more from better chain maker.
 
Dial indicator, piston stop, degree template & coat hanger as mentioned above. No better feeling than knowing it's right.

attachment.php
 
longarm said:
Hows about a pic of the cam card so we know
what manufacturer/specs your working with.
If done right your card should be specific to your cam
Many vids on youtube to explain degreeing..
Click to expand...

The cam card provides minimal info. I'm at work now, will post a pic when I get home.
 
My x bro in law installed a Mopar performance .508 in a 340 dot to dot. Biggest dog you ever did see. Ended up being close to 16 degrees retarded. After everyone messed w it i straightened it out. I knew something was up when it only had 110 psi in ea cylinder
 
clifftt said:
This is my first time degreeing a cam. I'm putting a solid lifter cam in a 273. I've verified TDC with a dial indicator at least ten times to make sure I'm not going crazy. Then I put on the sprockets and chain, and lined up the dots straight, cam dot at the bottom, crank dot at the top. I started with the #1 exhaust, which is supposed to open at 62.5 BBDC, but it's opening at 50 BBDC.
Well, OK, I shift the cam sprocket one tooth, and now I'm getting my 62.5. But when I sit back and look at the dots on the sprocket, they don't line up, looks like I'm a tooth off. Same thing happens when I measure the intake.
Cam manufacturer is closed until Jan 6. I'm assuming I'm supposed to take these measurements at .050" lift.
Do I discount/ignore the position of the dots and rely on my numbers, or does it sound like I'm doing something wrong? Does this ever happen to you seasoned guys?
Click to expand...



I hope your not moving the cam sprocket one hole tooth! i hope its a degree key way for the cam or a crank sprocket that has several key ways cut into it.


OK now, if you do not have the dial indicator perficly straight with the push rod, it will be off.

When i was messing with my cam, and checking the intake/ exh open and close, mine was not right either! when i got real picky with dial indicator plain and the push rod plan. The ## all cam in to spec.
 
william said:
I've had one mopar cam that was 18 degrees retarded with dots lined up ,and another one dead on .So you must degree the cam to be safe, it makes a big difference in the way it will run
Click to expand...

swinger340 said:
My x bro in law installed a Mopar performance .508 in a 340 dot to dot. Biggest dog you ever did see. Ended up being close to 16 degrees retarded. After everyone messed w it i straightened it out. I knew something was up when it only had 110 psi in ea cylinder
Click to expand...

That's disturbing.
 
Cudafever said:
I hope your not moving the cam sprocket one hole tooth! i hope its a degree key way for the cam or a crank sprocket that has several key ways cut into it.


OK now, if you do not have the dial indicator perficly straight with the push rod, it will be off.

When i was messing with my cam, and checking the intake/ exh open and close, mine was not right either! when i got real picky with dial indicator plain and the push rod plan. The ## all cam in to spec.
Click to expand...

Yes, I rotated the cam sprocket one tooth, not a big deal on the engine stand. I'm taking the measurement from the top of the edge of the lifter, heads are off. The Cloyes sprocket can advance or retard two degrees either way.
 
if you have to move it one full tooth, there is something Wrong!

Go back and double check every thing.
 
longarm said:
Hows about a pic of the cam card so we know
what manufacturer/specs your working with.
If done right your card should be specific to your cam
Many vids on youtube to explain degreeing..
Click to expand...

Ok, here you go:
 

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There is something that I'm not getting here.

0 overlap :scratch:
 
longarm said:
Hows about a pic of the cam card so we know
what manufacturer/specs your working with.
If done right your card should be specific to your cam
Many vids on youtube to explain degreeing..
Click to expand...

What I meant to say was each cam will be ground a little different
and it should have a card specific to that cam.
That's not how I've found it to be unless a custom grind.
If you get her zero'd in it will pay in spades.
I'd also check the balancer and housing pointer for TDC, mark the hub and ring
on the balancer, dizzy height and run a bronze gear on the
diz shaft if you can.

Sorry I was typing as you were posting.
 
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