Replacing the cam....

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Aug 17, 2008 | 08:37 AM

#21

jsup

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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan

Quote:

Originally Posted by Kubs

What do you mean by 12 and 6 or 12 and 12? I have 3 different keyways on the crank gear. The first is for 0 degrees, and the other two are for 4 degrees advance or 4 degrees retarded. I think I said 8 before but I was wrong. Which keyway does the key on the crank go into? Once I have it set to one of those how do I set the rest of the timing?

I'm sorry this is my first aftermarket cam swap and with a roller cam. Some of these parts Im not used to.

Set it up for 0 degrees. Set the timing marks as I said above. IMO, don't screw with the cam timing. It will move the torque curve up and down the rpm range in a way that may conflict with your intended build.

Aug 17, 2008 | 08:57 AM

#22

Pete K

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I always degree a cam as per the manufacturers recommendation.
I use the multi-keyway sprocket to achieve this, due to stacking tolerence differences.
If you are not degreeing the cam, use the zero setting.

Aug 18, 2008 | 06:55 AM

#23

Kubs

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From: Akron Ohio

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I am doing nothing else to the motor for now so I am just going to set it at zero.

Jsup..

The numbers 12 and 6 you were talking about, where do they come from? Does that have something to do with the distributer when I reinstall it?

Aug 18, 2008 | 08:13 AM

#24

jsup

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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan

Quote:

Originally Posted by Kubs

The cam gears have markings on it. Typically people set the marks together the small gear at the top, and the large gear the mark on the bottom. Hence, the 12 and 6 reference. If you do this, this is TDC for CYL 6.

If you want TDC for CYL 1, set the markings to 12 o'clock on the big gear, and 12 o'clock on the small gear. Both markings at the top.

People find it easier to line up when the big gear is at 6 and the small gear is at 12.

Remember, the cam makes one rotation for every two rotations of the motor. So if you move it 180* from 6 to 12 the only difference is which cyl is at TDC.

Just be aware of where the marks are when you set the distributor.

Aug 18, 2008 | 09:45 AM

#25

Kubs

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From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

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2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

Oh ok. That makes sense. I did align the two dots on the gears so the cam gear is at 6 and the crank gear at 12. So now when I put the distributer back in it should be ready to fire at cyl 6. right?

Also, how should I time the distributer? I normally do about 35-38 degrees advanced at 2500 RPM for a carb engine. Is a computer controlled engine different?