degreeing a cam / Intake Centerline

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360duster

360duster

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Hi Guys, i´m a newbie regarding cam degreeing, the ones i did before went in without checking. With my new engine i want to do it right the first time and try to degree the cam to confirm the Intake center line.

I got a comp XR286HR cam, the specs say 106° Intake center line. Build a positive stop, bought a degree wheel / dial indicator and did some testing. Set the degree wheel to TDC.

The instructions say to rotate the engine normal direction until it reaches max. Lift, set the dial to zero. Then move engine backwards until indicator reads .100". Turn engine forward til indicator reads .05" before max. lift - Record the wheel reading (62° in my case).

Then go on rotating the engine until indicator reads .05" on the closing side of max. lift - Record the wheel reading (150° in my case).

Then add these numbers and divide by 2: = centerline. 62+150=212/2=106°

Seems very good so far, exactly what it should be.

But since i have no pushrods for the engine i took the measurements directly from the lifter. My question is: is something wrong with my procedure or is it the same when you put the dial indicator at the lifter instead of the valve retainer?

Thanks for any input!

Michael
 
I have never heard of it done that way not saying that it's not right but, when i degreed my cam i went to UTUBE and watched videos on how degree it, i learn alot more by watching it done then reading, hope this helps
 
Nope, That's the right outcome I do it that way too... there are other ways. I clear everything and do it twice. If it repeats, move on. If it doesn't, do it again and go with the reading that repeats.
 
That is a good way of doing it by measuring right off the lifter.
Set your cam so the lifter is on the base circle, zero the gauge, rotate and record the highest lift off the liter, multiply by the rocker ratio and that will give the valve lift.
Probably unlikely that you will get the advertised valve lift as the SB geometry is very poor.
When degreeing the cam you want to read off the lifter. Check the cam card specs and compare to what you get. This will tell you if the cam is ground correctly. Then you can advance or retard the cam if you wish.
You are doing good so far.

onig
 
Sounds nice! so it seems i did it right. Will double check my readings and if it´s the same i can go on - fine!

Thank you for your help!

Michael
 
The only thing I like doin different is usin the Mopar degree wheel. It reads directly so you don't have to divide by 2 at the end. Not a big deal, but it's nice to just look at the wheel and there's your answer. lol
 
Taking the reading off the lifter is correct way, not off the retainer. The only thing I do differently is look at the opening and closing events listed on the cam card, Match the intake closing event to the card as that is where compression starts to build and is the most important event, not necessarily the centerline.
 
For what it's worth, I've always flipped the lifter upside down when degreeing with flat tappets. Gives you a lot more room.
 
isn't degreeing a cam all in all is to tell you if the cam is ground correct and i have a question how many of you found cams to be out ? and if it is out and you buy a multi timing chain it advances it or you can retard it. it other words more bottom end or more top end . right.?
 
It's for all of the above and then some. Not only to make sure the camshaft is ground correctly, but to assure it is in the engine where it is supposed to be in relation to everything else. Also, there's absolutely no gaurantee that the timing chain and gear set is machined exactly right. No gaurantee the crankshaft key is in exactly the right place. Beyond the mere physicalities of it, a lot of engine builders like to experiment around with putting the camshaft in the engine in different places in relation to crankshaft rotation. So, to do that you need to know where the camshaft is in the engine and the only way to do that is with a degree wheel.
 
there was a test done before i forgot who did it but they tested alot of timing chains and most where out on the marks....when i did my cam before it had to buy the offset keys ...
 
You can find TDC with a piston stop. You can make one or buy one from Summit. Then you bring the piston to close to TDC on compression. Install the stop, and turn the engine clockwise until the piston contacts the stop (slowly for a light touch...) Place a mark on the balancer. Then turn the engine counter clockwise until the piston comes back up and touches the stop again. Make a second mark on the balancer. Remove the stop. Measure the long distance between the marks. The midpoint of that distance is exact TDC.
 
i made a stop out of a old plug and some treaded rod......
 
66fs said:
How did you find TDC?
Click to expand...

made a stop from an old spark plug and a long screw and did it like moper said.

Another question: the timing @ .050" - is this also measured at the lifter or at the valve? i´m a bit worried :toothy10:

I think it must be at the lifter since the rocker ratio will have a big influence.

Thanks a lot

Michael
 
360duster said:
made a stop from an old spark plug and a long screw and did it like moper said.

Another question: the timing @ .050" - is this also measured at the lifter or at the valve? i´m a bit worried :toothy10:

I think it must be at the lifter since the rocker ratio will have a big influence.

Thanks a lot

Michael
Click to expand...

Yes, measured at the lifter.
 
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