4.6 4v Cam Degreeing

[Yardracer]

I am attempting to degree a set of COMP cams in a 4.6 DOHC Ford Mod motor and had a couple questions. I am getting correct degree measurements on both intake cams that are within range of what is indicated on the cam card. However, on the exhaust cams I am not coming up anywhere near what I am expecting to see. I have never degreed a DOHC motor before so perhaps I'm missing something here? Or is the measurement indicated on the exhaust cam card based on the intake centerline perhaps? I either am factoring the exhaust numbers incorrectly or I need the actual exhaust lobe centerline numbers for cylinders #1 and #6. Any help I could get with this would be greatly appreciated. Part numbers follow.

106-064-9RI
106-062-9LI
106-061-9LE
106-063-9RE

Thank You

[iwannagofaster]

The centerline on the card is for the exhaust centerline, but the numbers do read a little different. It is almost flipped because you are reading exhaust, but it should come out close. What numbers are you getting?

[Yardracer]

Just re-checked the Right side Exhaust cam and got 242.

[iwannagofaster]

Is that the open and close readings added together? If so, and you are using stock gears, that is probably as close as you are going to get without adjustable gears. 3 degrees (230/2=115) is not bad for stock gears. You can always account for a couple degrees in the loooong chain, and factory tolerances in the gears.

[Yardracer]

That is the opening and closing averaged (added and divided by two). Via centerline method. I can't help but to feel like I'm just missing some basic element of how this works on the exhaust side. I have been able to get readings that reflected near to cam card measurements in both intake cams, but exhaust seems to be nearly twice what it should. Is there perhaps some consideration of cumbustion cycle that I'm not factoring in here? I do also have a set of COMP adjustable gears on the primary chains so once I figure out what I'm doing wrong I have a large range of adjustment. I have also already triple checked that the cams are installed in the correct orientation as per the COMP tech phone line's info. Just a little lost here and trying to figure out how to get it right.

[iwannagofaster]

I completely understand that. Are there two sets of numbers on your degree wheel? You are actually reading ATDC when the Numbers on the wheel are BTDC, so if there are two sets of numbers, it may have the exhaust numbers factored in. If there are two sets of numbers, use the smaller of the two and see if that comes out close and let me know.

[Yardracer]

It does have two different sets of numbers, one counts clockwise from TDC, the other counterclockwise from TDC. Is that what that is? Having only checked intake centerline on SOHC or OHV engines, I never ran into this problem until now. It's driving me nuts!

[Yardracer]

In that case, 242 clockwise and 118 counterclockwise would line up, which would give me a much more acceptable reading. Hmmm....

[iwannagofaster]

I believe we have stumbled on to a logical explanation, or found the missing link, however you want to look at it. Let me know if you need anything else.

[Yardracer]

Thank you so much for your help. I knew it had to be something simple. I had always assumed that the second set of numbers was for an engine that rotated counter-clockwise. And I suppose it would work for that as well. But now it would seem that my haywire numbers I was getting are the complement of 360 from the numbers I was expecting. Simple math prevails somehow. Maybe when I have the time I'll sit down and devise the methodology for this so I can get it straight in my brain. Thank you again.