Those cam card #'s are assuming "perfect world" circumstances. Machining tolerances in all the components involved are in play, and thats why we check how the actual cam events correspond to the manufacturers data. It could have just as easily have been 3 degrees retarded, but without checking would not have been discovered, and it wouldn't have been installed to a more optimum setting. The fact is you checked it and verified an absolute setting of 3-3.25 degrees advanced using several different methods as a backup. So I would say good job and let it stay there and have fun cruising with it!

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There's no such thing as too much cam....only not enough engine!

I prefer the intake centerline method as I feel it's it's more accurate than the valve opening and closing points. You got 213.5° duration at .050" tappet rise on a cam that is rated at 212°. Nothing is perfect. Not the cam nor your degree wheel. The intake centerline is perfectly acceptable. If the opening and closing events aren't too far off then you're fine. Run it.

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Joshua

so everybody agrees that my 2.75 of advance is a good amount? run it with no shim? just curious what would be optimum?

The different measurements you are getting are due to "measurement error." I would not trust anyone who tells me they can get better than +/-0.5 degrees repeatability on a conventional cam degreeing measurement. If you do this over again 10 times, I bet you will get 3 deg advanced +/- 1 deg. That's what I and others get, typically. It looks like you did a great job of degreeing this cam to me.

We could all discuss what is optimal for this cam, but it will really depend on your other components and personal taste. 103 deg centerline will work very well, and is what I would call an optimal number (for my taste). Very few people can tell the difference in running between a cam at, say, 103 and one at 105 or 101.

I would run it and not touch it.

Happy motoring!

Lou

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Home of Slant6-powered fun machines since 1988

This is for anyone who wants who wants a clearer picture, and my final measurements, if mods want to do something with it be my guest. This cam is Oregon Cam Grindings #125

First off, I set it up with a lifter, and a pushrod. I set the pushrod and guage perfectly straight, and made sure everything was clean of course.


TDC


Now this is the "Centerline Method"

Roll motor over clockwise untill you get to the higest point of lift, and set gauge to 0


Now roll motor over counter-clockwise .050, and check your degree wheel. I came up with 58°


Now roll the motor clockwise back to max lift, and back down to .050 (on the oposite side of the lobe), and again check your wheel. I came up with about 148.5°


58° @ .050 from Peak Lift
148.5° @ .050 from Peak Lift

148.5+58=206.5, 206.5÷2=103.25°
Cam Card States 106°
106-103.25=2.75° of Advance

And now the "Open/Close Method"

TDC


Turn motor over untill you reach the "heel" of the cam, and set your dial to 0


Now turn motor over till you see your gauge hit .050 of the opening side. Check your degree wheel. I came up with 3° BTDC


Now roll motor over untill you see your max lift # if you wish, this cam has .277 of lift


Now roll the motor over past max lift, and stop at .050 before it completely closes, check your wheel once more. I came up with 30.5° ABDC


3° @ .050 OPEN BTDC. 30.5° @ .050 CLOSE ABDC
Cam Card states 0° BTDC 32° ABDC

Now you can "split the difference" of these numbers.

Since its 3° off from opening, and 1.5° from closing, we can add these
3+1.5=4.5 and now divide to split. 4.5÷2=2.25

This is not too far off from my number of the centerline method of 2.75. I suppose we can allow some leeway for "measurement error" nothings always perfect.

NOW ITS TIME FOR A BEER!

(note: when ever moving in a counterclock wise rotation, you should over shoot your destination, and return back to it in a clockwise rotation. this is to account for any slop and play in chain and other components.)

As I mentioned earlier, anytime you reverse the direction of rotation while degreeing the cam you are introducing error into the equation. That is likely the cause of your numbers not being the same as the "correct" centerline method I asked you to try. So I would consider the first method you tried the least accurate and more error prone, not only because you reversed the rotation, but also because you are starting midway thru the process and not from the beginning with the cam lobe @zero lift as you should.

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There's no such thing as too much cam....only not enough engine!

well i guess i should have mentioned, when ever i went in a counterclock wise rotation, i would purposely over shoot the .050, and crank the motor back over clockwise to correct any slop, no mater what i did, i did not see any noticeable difference because of slop. and i tried this with the bigger wheel, and the fine pointer.

Ok, you got this one obstacle resolved, what's next. Got any pics of the car your putting this engine into.

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There's no such thing as too much cam....only not enough engine!

65 plymouth valiant, and as for whats next... i guess putting the rest of the motor together. i also want to rebuild the trans myself, although ive never done one, but heard the 904 is pretty damn easy asside from needing 1 or 2 special tools

As for the cam degree, look to ISKY cams for the stop bolt method they have in their literature but for the 904, you could get away with a flat nose snap ring plier and a trip to the local builder to compress the clutch springs when they're ready to be reassembled, that with regular pin type snap ring pliers and standard hand tools.

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Advise should be taken as ongoing, that way, when you get to realizing what you are doing you can include yourself.