Cam Degreeing Confusion

-
T56MaxTorq

T56MaxTorq

Well-Known Member
Joined
Dec 21, 2010
Messages
1,023
Reaction score
376
Location
CO
Installing a MP .528 solid flat tappet into a 360 and I'm having problems degreeing the darn thing. I'm getting some funny numbers while finding the intake centerline. Following the directions that came with the cam on how to degree it I should be installed at 112 ICL. I made a degree wheel from a template online and glued it onto some cardboard, then made a piston stop from an old spark plug, bolt, and nut. I have the dial indicator set on the horizontal plane of an upside down lifter on the #1 intake lobe.

I rolled the motor over til it hit the stop, set the wheel at 0, rolled it the other way and it was 26 degrees. Rolled the motor back to 13 degrees, and the #1 intake lobe is just about to open. Set the wheel to 0. Rolled it over and found max lift of the lobe. Set the the dial to 0. Rolled it counter-clockwise til the indicator was past .1, then rolled it clockwise til the indicator was .025 from max lift. I think this is the part that is confusing me. Recorded the degrees as 76.5, rolled it clockwise past max lift - past null of the gauge and down .025 and recorded 103 degrees. The degrees were based off the outer most numbers on the wheel, the inner numbers were 103.5 and 73, respectively.

No combination of those numbers make near 112, where it's supposed to be set. The best I could get would be 103ish. I don't think it could really be off 9 degrees could it?

Confused on what I'm doing wrong but it must be that I'm on the wrong stroke (I placed the wheel at 0 degrees TDC where it's just about to go into the intake stroke) And the #1 piston looks like it's actually at TDC. Or I'm reading these numbers all wrong. The timing chain is nulled to 0, no advance or retard. Thanks guys!
 
The lifter may be running on the edge of the cam lobe, which may not be uniform. I would place the lifter in the bore with proper orientation and get the gauge on the top edge of your lifter.

I don't usually degree using that method. Can you try using the old at .050 method? The numbers you have are something in the 88 range for ICL which is not close.

Re-check you tdc setting. Don't move anything, install the stop and make sure the wheel stop equi-distance both sides of TDC.

That cam usually has a recommended installed CL of 110 IIRC. I put mine in at 107.
 
only thing I can think of is that your timing gear is off by one tooth - count the number of teeth on your cam timing gear and divide that number into 360 -- think each tooth is
around 8 degrees.
 
I agree with crackedback. On the intake centerline method take a reading at .050" before and .050" after and do the math. More accurate.
 
It very well can be off that far. MP quality control sucks. If you get repeat results, I'd believe it. The last MP cam I ever used was 8° off. But, is there a chance the wheel you printed got changed in size/scale when you printed it? The measurements are only good if the wheel is exactly the same size as the one that was originally scanned for posting. I dont think I'd ever trust a downloaded degree wheel.
 
I tried to degree the motor with the heads on and it was a *****, I also tried to do it with the motor in the car. Not fun. I will be degreeing the motor with the heads off now and out of the car and hopefully I will get better results.
 
moper said:
It very well can be off that far. MP quality control sucks. If you get repeat results, I'd believe it. The last MP cam I ever used was 8° off. But, is there a chance the wheel you printed got changed in size/scale when you printed it? The measurements are only good if the wheel is exactly the same size as the one that was originally scanned for posting. I dont think I'd ever trust a downloaded degree wheel.
Click to expand...

C'mon, the scale of a degree wheel still shows 118 no matter how big or small it is. Its a polar reference, scale of the wheel is unaffected. measure the radial lines that bisect the points on a pentagram, they all measure 72 degrees no matter if the protractor is 2 inches or 20 inches in diameter. Tavia has an online degree wheel. try and print it at its finest resolution to reduce blurring
free_degree_wheel.jpg
 
The dots are lined up perfectly..as close as theyll get. The wheel is perfectly round so that's not a problem

I'll flip the lifter which I agree with crackedback and it may not be uniform..I thought I was being smart by flipping it over and having all that surface area to position the needle on the dial cause it took me forever to find a way to clamp it to the block and read lifter height.

And I'll use the same method I am using but instead use .05 instead of .025?

I'll also double check tdc and my chain config

Thanks again guys!
 
Don't turn the cam/crank backwards. The slack in the timing chain will throw you off.
 
I do it off the base circle and find .050 up. Bigger numbers and the math is not as easy...

Yes you don't want to take any readings turning it counter-clockwise. I turn them backwards all the time, Always start to turning back proper rotation, getting rid of slack, before taking any readings.

If you want to do the max lift thing. Find max lift and wind the engine counter so the lifter will be coming up, then track it back clockwise, get the number at .050 before max, and roll over nose and get number on backside at .050 down. When you get to max lift look at where the pointer is. It should be REALLY close to actual C/L.

I'd re-verify TDC before starting anything.

I've had timing chains that were manufactured HORRIBLY... so that's another possible issue.

Have fun with it.
 
crackedback absolutely knows what he's talking about, but don't mess with "max lift." You can NOT with much accuracy measure anything looking for max, because it "rounds off" at the top and there is some "dwell rotation." Much, much easier to get down on the slope and equalize the readings --which is why you pick a number like .050, because this gets you down on a "rapid rate of change" slope.

The same deal happens finding TDC on a piston. You can SEE this happen on a short block. You wrench it around, and as the piston comes up to the top, it slows down as it goes "up and over."
 
pishta said:
C'mon, the scale of a degree wheel still shows 118 no matter how big or small it is. try and print it at its finest resolution to reduce blurring
Click to expand...

I have several scanners, faxes, and printers here. I can print it on all three and get different skewing of the image. I agree geometrically that yes, diameter doesnt matter. But software will change the dimensions of small areas to make it fit a standard page. I'm sure there's a way to address that but I don't know how. I just bought a wheel years ago.
 
Ok thanks guys for all the help! Flipped the lifter and found TDC again. Feeling confident in TDC, I get the same numbers every time. Read an ICL of 113 using the max lift technique. I tried .05 lifter lift method and came up with some numbers but what is the math formula for them? And what is the answer supposed to be?

Called MP for the intake open/close angles and they said the numbers are for when the lifter is up on the intake lobe just a bit, like .008 for example, but he didn't know exactly how much. I came up with some pretty close numbers this way. They also mentioned the ICL is actually supposed to be 110 degrees, and that 112 is really the lobe seperation.

So I retarded the cam 3 degrees to get a 110 ICL and will find some numbers when I can work on it next, which is only an hour or so a day.

Should I just leave it at 113 ICL? What would be best for my motor?

360 .030 over w/ flat tops
lightly ported x heads
Headers and duals
LD340 and 600 cfm carb, may go back to a 750
3000 stall 3.55 gears
5900-7000 ft. elevation
 
Formula

(IO + IC + 180) = total

total /2 - IO = ICL

So if you have an IO of 9 btdc
AN ic of 53
you would have
9+53+180= 242
242/2 = 121 -9= 112CL

If the IO number is after BDC, it would be a negative number in the first spot and you would ad it to the total # divided by 2

That cam should have a .050 number right around 241-242. The IO should be around 8-10, IC should be around 52-54. IIRC
 
just a side note...there is a .528 cam with a 106 LSA...make sure you got the right part number for your cam.
 
70aarcuda said:
just a side note...there is a .528 cam with a 106 LSA...make sure you got the right part number for your cam.
Click to expand...

Isn't that the oval track cam?

Might be smart to do the exhaust lobe as well to find it's CL and average the two. That will give you the separation angle of the lobes.
 
yes..it is the oval track cam ....and you usually find it for sale cheap....

bought one just for the lifters....cause it was cheap...
 
If you got a 113 ICL, then yes advance it 3* to get a 110. Even if you went to 107-108 it's not a bad thing.

I like this cam. It runs really good.
 
No kiddin! I could probably use the compression. My cranking pressures are 120's
 
Ok guys it's set at 107ish ICL which is a 69 IVC ABDC and gives me high 130's cranking pressure at altitude. The old cam (same grind) was set straight up and was probably a little retarded in actuality.

I did feel the motor needed a little lower power band. It liked 3-6k. I'm thinking more low end torq would help get me going a lot quicker. I do have an unconfirmed 3000 stall which feels about right. Moderate highway speed and I'm never usually lower than 3k. I do have 3.55 gearing..
 
You must log in or register to reply here.
-

Back
Top