need help camshaft degreeing question

[rcodecj]

My cam is 5.5 degrees retarded when installed with the crank sprocket at 0 degrees advance/retard.
My Cloyes timing has three keyways, 0, +4, and -4.
It says in the instructions that this is crankshaft degrees so camshaft movement would be half. Makes sense.
Problem is +2 cam advance will only get me to 3.5 degrees retarded.

Now the question. My timing gear has 48 teeth on the cam sprocket and of course 24 teeth on the crank sprocket.
Am I correct to say 360/48 = 7.5 degrees?

So.... If I move the top timing gear 1 tooth (7.5), and move the bottom sprocket to the advance keyway (2), I should be at 4 degrees advanced.
In other words, cam LSA is 110. Right now I have 115.5 degrees intake centerline, 115.5-7.5=108,   108-2=106  which is 4 degrees advanced on my 110 LSA cam.

2nd question:
How would this affect my distributor rotor phasing?

[jayb]

It sounds like you are using the intake lobe centerline method to degree the cam, in which case you probably have a degree wheel on the crank, and are reading the numbers off that.  The 110 degree intake lobe centerline that you are shooting for is in crank degrees, not in cam degrees.  This also should be what you read off the degree wheel when you degreed the cam; you are at 115.5 crank degrees ATDC, not cam degrees.

So, if you put the crank sprocket at the +4 degree position, your cam will be degreed at 111.5 degrees ATDC, not 113.5.  Everything is crank degrees.

If you skip a tooth on the cam sprocket, you are rotating the cam 7.5 degrees as you stated.  This corresponds to 15 degrees of crank rotation.  So, at the zero position on the crank gear, moving the cam sprocket one tooth would make your intake lobe centerline 100.5 degrees ATDC.  So, to get closest to 110 you would be best off leaving the chain and sprocket relationship where it is designed to be, and just move the crank gear to the +4 position.

Hope that helps - Jay

[rcodecj]

I am using the instructions in the Comp cams book. I have always used this and never had a cam so retarded. After finding true TDC, the instructions say to find maximum lift, back up .100, then rotate normal direction .050. That number on mine is 159. Continute to rotate the engine in normal rotation until the indicator goes past zero to .050 on the closing side of max lift. That number is 72. Add the two number together is 159+72 = 231.  Divide by two is 231/2= 115.5. Comp cam says that is the intake centerline for the camshaft.

So no, I am not reading 115.5 degrees off the degree wheel, that number is derived from the 159 and 72 number readings. I think that is what you meant though, (derived) you just said it differently.

So you are saying moving the crank sprocket would move the intake lobe centerline 15 degrees?
That would make sense to me because 7.5 cam degrees would be 15 crank degrees.

So 115.5 is my actual derived intake centerline. If I use the +4 crank sprocket keyway, I would be at 111.5.
The cam is 110 lobe separation angle, and calls for a 106 intake centerline.
So if I move the cam gear one tooth I am at 100.5. If I then use the -4 crank sprocket key, I would be at 104.5. Correct? Whew!

[rcodecj]

After looking at my readings and realizing that I should not be getting the big number first, I went down to the shop and looked and found out I was measured off the exhaust valve. I am going to redo my measurements.

Funny thing is I have a LARGE note written to myself stating:  (Not so funny I guess)
Double check that the indicator is on the INTAKE VALVE!

If I still find it retarded is what I wrote/asked in the last post correct?
Thanks.

Also I am using a Moroso 11" degree wheel. I see Summit has a Moroso 18" degree wheel for $46.
Should I get it for more accuracy?
I can only move 4 degrees at a time with the crank sprocket anyway so it's always a bit of a compromise.
For my 460 I ended up buying the Ford timing set to get more settings.

http://www.summitracing.com/parts/MOR-62191/?rtype=10

[rcodecj]

My new numbers when measuring off the intake lobe are:
62 and 148.5, 62+148.5=210.5   210.5/2=105.25

I measured twice and got the same numbers.
It now makes sense to me that when measuring off the exhaust lobe it would be a larger number in step with and in the opposite direction as when measuring off the intake. a 110 lsa cam that is 5 degrees advanced will measure 105 intake centerline, and will measure 115 on the exhaust centerline.
Thanks Jay for the help.

edit to change = to a +, to make post more readable, no data was changed

[jayb]

Glad you got it sorted out.  Measuring off the exhaust valve is an easy mistake to make...

[rockhouse66]

I think you have this figured out, but all of these numbers get confusing, so just to be sure....

Your last measured intake value of 105.25 is the measured intake centerline versus a spec of 106 intake centerline.  Your cam is only off spec .75 degree.  I would probably advance it 2 degrees to anticipate chain stretch and pick up a little bottom end, but you could run it "as is" IMO.

BTW, I am a rookie at this stuff myself, so I hope the experts here will correct me if I am wrong.

[rcodecj]

I think you have this figured out, but all of these numbers get confusing, so just to be sure....

Your last measured intake value of 105.25 is the measured intake centerline versus a spec of 106 intake centerline.  Your cam is only off spec .75 degree.  I would probably advance it 2 degrees to anticipate chain stretch and pick up a little bottom end, but you could run it "as is" IMO.

BTW, I am a rookie at this stuff myself, so I hope the experts here will correct me if I am wrong.

The Cloyes timing set only goes 4 degrees at a time, so I will leave it. At least it's off in the direction I would like.
This engine has 150 miles or so on it so the timing chain has done its initial stretch and will be more stable on out.
At least that's what I have found in previous builds where I have redegreed after previously running the engine some miles.
The cam was degreed in the first time, but I had it apart for other reasons, including low vacuum so I thought I would check it.

The Cloyes tru-roller is supposed to be a really good timing set, it had better be for the price.
I typically use the Ford 9 way timing sets with no issues, but I have read that the Cloyes is top notch.