Degree Wheel or Dot to Dot?
Thread Starter
Staging Lane
Joined: Jan 2022
Posts: 59
Likes: 4
From: Azusa, California
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?
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?
TECH Enthusiast
Joined: Feb 2018
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From: Michigan
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.
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.
On The Tree
Joined: Sep 2009
Posts: 113
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From: Akron, OH
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.
TECH Addict
Joined: Dec 2017
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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.
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.
Thread Starter
Staging Lane
Joined: Jan 2022
Posts: 59
Likes: 4
From: Azusa, California
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.
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.
Trick Flow Heads. 225 cc Runner / 62cc Chamber. Inconel Exhaust Valves. (Boosted Application)
Cometic Gasket, 4.040" x .066" thickness.
Also, have the new PRW Shaft Mounted Rockers.
BTR .660" Springs.
BTR Titainium Retainers.
TECH Addict
Joined: Dec 2017
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Not a horribly "big" cam then. Seriously unlikely to be a problem. However, you can "solidify" a pair of lifters by filling w TransGel or Vaseline, slather some modeling clay on the head of a piston, bolt on a head w some sort of shim the same thickness as a gasket, install the prepared lifters w correctly chosen length push rods (VERY important if you don't want to end up in GIGO), turn the crank 5 or 10 full turns, pop the head back off, and see how thick the clay is at its thinnest, if you want. No check springs or other "special" prep needed besides the lifters.
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Thread Starter
Staging Lane
Joined: Jan 2022
Posts: 59
Likes: 4
From: Azusa, California
Not a horribly "big" cam then. Seriously unlikely to be a problem. However, you can "solidify" a pair of lifters by filling w TransGel or Vaseline, slather some modeling clay on the head of a piston, bolt on a head w some sort of shim the same thickness as a gasket, install the prepared lifters w correctly chosen length push rods (VERY important if you don't want to end up in GIGO), turn the crank 5 or 10 full turns, pop the head back off, and see how thick the clay is at its thinnest, if you want. No check springs or other "special" prep needed besides the lifters.
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A degree wheel is generally used to verify valve events, check P-V and to verify the camshaft matches the cam card. Installing dot-dot is the standard but what if the camshaft was ground incorrectly? You would have no way of knowing because well you didn't measure.
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what if the camshaft was ground incorrectly?
As said, other than replacing it, there's NOTHING you can do about it anyway even if you find that it's "wrong" (and again, the indications you can get from a degree wheel can be VERY confusing, especially if the lobes are asymmetrical, which most are nowadays), unless you have an "adjustable" or at least "selectable" timing set.
You don't need a degree wheel to check P-V clearance.
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Did I say you needed a degree wheel?
I degree every cam in every engine I send out the door here. Super simple. Takes 10 minutes. I’m simply verifying ICL and what to expect performance wise, according to which way it’s out. 90% of cams are off somewhat, and it’s data I need to give to the customer. You can’t see tenths of a degree with a coat hanger on the wheel…takes a precision pointer, but it’s worth it 100% to me to know what’s what. I give the customer a long list of clearances and numbers. I’m a data nerd.
To RB’s point here, the average guy throwing a cam in, doesn’t need to know where the ICL is and doesn’t care.
To RB’s point here, the average guy throwing a cam in, doesn’t need to know where the ICL is and doesn’t care.
The "right" way is definitely to degree it although you're limited on what you can do if there is actually an issue given some parts you may or may not have. With that said probably 90% of LS cam's are installed dot to do and don't have an issue. I've done several myself and have not had an issue.
A less laborious way (in my .02) to check P-V clearance is to use checking springs and solidify (one way or another) 2 intake and exhaust lifters. Do this on an easy to access cylinder, like #1 or #2, if checking with the engine in the car. Install the 2 lifters and 2 checking springs all on that cylinder. Turning the engine over by hand, as the piston is approaching TDC, simply push the valves down until they contact the piston. Then record minimum clearance. I've used an indicator in the past to record actual distance if it looks like a questionable distance. This saves installing, then removing, then reinstalling the head. I agree with the other guys here that this cam isn't aggressive enough to cause P-V interference. I've found that a tighter LSA reduces P-V, all other things being equal. Hope this helps!
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a tighter LSA reduces P-V, all other things being equal.