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Degree Wheel or Dot to Dot?

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Old Yesterday | 05:00 PM
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Lght Spd's Avatar
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Default Degree Wheel or Dot to Dot?

About to tear my C6 down to do heads and cam. I want to do this right and don't want any issues in the future if I can help it. The guy helping me is blowing off the degree wheel and says, "I do all the LS cam swaps dot to dot, and I've never had a problem."

I've watched videos on YouTube and even on Brian Tooleys channel, and they do the degree wheel.

Trick flow is telling me I need to do piston-to-valve clearance with their heads. So, isn't it in my best interest to do the degree wheel?
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Old Yesterday | 08:23 PM
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I've never used a degree wheel on any of the cam swaps I've done. Every cam I've ever bought has been meant to run dot to dot. I guess it all depends how particular you want to get, but deciding to advance or retard it a couple degrees isn't going to make a difference that you can even feel. Unless every dyno comparison that I've ever seen is wrong.

You don't need one for piston to valve clearance, just get some valvetrain checker springs and some modeling clay to check for clearance.

Chances are that you're not running a big enough cam to even have to worry about piston to valve clearance anyway. Is this an LS7? Just guessing based off the picture in your signature.

I ran a 238/254 114+4 cam with 12:1 compression one a stock bottom end and I had plenty of room. I later upsized to a 245/256 112+4 camshaft with the same compression ratio and still had plenty of room, although that was with forged pistons. A lot of people are running a bigger cams than I am with stock pistons and 12:1+ compression with ported factory LS7 heads.
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Old Today | 06:32 AM
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The degree wheel can be useful to know that the cam was ground similar to what the cam card says. If its off you can advance or retard based on what you measure, but more often than not the cams come out within a degree of what they should be anyway. Its nice information to know, but dot to dot will results will be the same.
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Old Today | 08:01 AM
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since you have to check PTV, may as well use the degree wheel to get it done right.
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Old Today | 09:14 AM
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All you're accomplishing using a degree wheel in a cam swap is, you're doing the cam mfr's quality control for them.

Don't bother. Dot to dot is fine, as long as you trust the cam mfr. Like most people who would ask this sort of question on an Internet forum, as opposed to experienced professionals, the indications from a degree wheel would be more confusing than they would be useful.

PTV clearance measurement needs will depend on the cam more than anything else. "Max lift" type specs are USELESS for predicting it, because the pistons come closest to the valves near the instance of TDC opposite the firing one, while "max lift" occurs when the piston is about halfway down the bore. Big durations, which will have the valves open significantly when the piston is up near TDC and the valves are "changing over" (exh closing and int opening), are what causes problems. A cam generally has to be pretty "big" before it causes problems with that, and particularly, "big" duration, although lift and duration generally go more or less hand-in-hand in the matter of "big"ness.

Note also that "dot to dot" is #6 firing, not #1. #1 is on the other instance of TDC at that time. "Both dots 12:00" is #1 firing; i.e. exactly 1 full crank revolution from "dot to dot". However, we build em "dot to dot" because it's easier to see accurately.
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