Importance of Degreeing in your Camshaft

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BBO Omega
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Importance of Degreeing in your Camshaft

Post by BBO Omega »

Before I expound upon the importance of Degreeing your Camshaft, I have to admit to simply lining up the dots or picking the appropriate advance setting garnered from the latest issue of Car Craft on many engines I have assembled earlier in life. Ever since I purchased my handy dandy Summit Racing Degree Wheel, value priced Dial Indicator and Magnetic Base, and fabricated a Piston Stop, the gross inaccuracies of available Timing Sets and even Factory components has opened my eyes. I have tried 3 different timing sets on the same short block and seen a difference of 4+ degrees on the same timing marks. These were obvious reboxed units from some of your favorite Cam Manufacturers (gears had the same casting marks). The really nice set from Pro-Gear has the Advance and Retard settings reversed. And on my latest 468 BBO, the Factory keyway in my 45 year old N crank is several degrees retarded (8degrees). Using the .050” lift method that most Cam Manufacturers recommend (vs the ICL method) is very simple and should not challenge anyone with basic mechanical skills.
73 Omega, 468 BBO, 4.185 ICON Pistons,RR/Wenzler Heads with HS 1.7 rockers and PAC 1220X Springs,J&S 5-main Halo with Billet Caps, .590I .580E 242I 256E HR Cam, 1000hp Carb,2" x 3 1/2" headers,Coan 2900rpm Conv.,TH400,3.73 12 bolt,11.32/118
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Re: Importance of Degreeing in your Camshaft

Post by Walter R. Malik »

You THINK you know where it should be installed but, it is simply a guess. So, just make sure it is not way-off from where you wanted it.
The real need for degreeing-in a camshaft is for if or when you want to make a change, you'll know exactly where it was installed.
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Re: Importance of Degreeing in your Camshaft

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Walter R. Malik wrote: Sat Jul 07, 2018 10:57 pm You THINK you know where it should be installed but, it is simply a guess. So, just make sure it is not way-off from where you wanted it.
The real need for degreeing-in a camshaft is for if or when you want to make a change, you'll know exactly where it was installed.

I asked my Cam Grinder Mike Jones where he thought the cam should be installed, and I followed his advise. I’m sure he knows more than both of us combined.
73 Omega, 468 BBO, 4.185 ICON Pistons,RR/Wenzler Heads with HS 1.7 rockers and PAC 1220X Springs,J&S 5-main Halo with Billet Caps, .590I .580E 242I 256E HR Cam, 1000hp Carb,2" x 3 1/2" headers,Coan 2900rpm Conv.,TH400,3.73 12 bolt,11.32/118
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Re: Importance of Degreeing in your Camshaft

Post by Geoff2 »

If you want to know where to install the cam for best HP, pick a ICL, dyno the engine. Then change the ICL in 2* increments, re-dyno the engine, until you find best HP....
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Re: Importance of Degreeing in your Camshaft

Post by user-23911 »

I've spent hours and hours and hours degreeing cams on my own engines.
Quad cams,

The thing is though........measure everything on no 1...........is it the same on all the other cylinders?
There's only 2 options.
Where did you make the measurement errors?

How would you know?
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Re: Importance of Degreeing in your Camshaft

Post by BigBlockMopar »

I've found the same issues as BBO Omega in the past. You can't/shouldn't trust anything/any part with an index pin or dot.
Cams, cranks, and especially timing gears can be all over the place. I've degreed 3 timing sets once in an engine too and all three were off by a good noticable amount. Was able to mix and match parts to come up with a number that was close enough to the number wanted.
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Re: Importance of Degreeing in your Camshaft

Post by Walter R. Malik »

BBO Omega wrote: Sat Jul 07, 2018 11:23 pm
Walter R. Malik wrote: Sat Jul 07, 2018 10:57 pm You THINK you know where it should be installed but, it is simply a guess. So, just make sure it is not way-off from where you wanted it.
The real need for degreeing-in a camshaft is for if or when you want to make a change, you'll know exactly where it was installed.

I asked my Cam Grinder Mike Jones where he thought the cam should be installed, and I followed his advise. I’m sure he knows more than both of us combined.
You can ask whoever and as many people as you want ... it is still a GUESS, (possibly NEAR correct), until the engine has been run and valve timing tested in different places.

NOBODY is infallible.
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Re: Importance of Degreeing in your Camshaft

Post by pamotorman »

I replaced a cam with the identical cam and checked the intake timing. the customer drag raced the engine and tagged all the exhaust valves because the cam company had ground the them 10 degrees off of spec. the cam company paid for the repairs. always check both intake and exhaust clearance. people make mistakes they made one and I made one by not checking.
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Re: Importance of Degreeing in your Camshaft

Post by plovett »

I've only degreed a few cams. All of them were off from where I wanted them when installed dot to dot. I had one that I had to advance 8 degrees to get it close to where I wanted it! I think it's important to check.....even though it is true I am just guessing at the best installed location.

JMO,
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Re: Importance of Degreeing in your Camshaft

Post by Walter R. Malik »

plovett wrote: Sun Jul 08, 2018 11:27 am I've only degreed a few cams. All of them were off from where I wanted them when installed dot to dot. I had one that I had to advance 8 degrees to get it close to where I wanted it! I think it's important to check.....even though it is true I am just guessing at the best installed location.

JMO,
paulie
Checking where the camshaft is timed is important to know, especially with all the tolerance stack-ups which are there.
One reason is because it may not be NEAR where you would like it to be; (whether right or wrong) you know where it is.
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Re: Importance of Degreeing in your Camshaft

Post by CGT »

BBO Omega wrote: Sat Jul 07, 2018 11:23 pm
Walter R. Malik wrote: Sat Jul 07, 2018 10:57 pm You THINK you know where it should be installed but, it is simply a guess. So, just make sure it is not way-off from where you wanted it.
The real need for degreeing-in a camshaft is for if or when you want to make a change, you'll know exactly where it was installed.

I asked my Cam Grinder Mike Jones where he thought the cam should be installed, and I followed his advise. I’m sure he knows more than both of us combined.
So he knows the perfect position? Ive dyno'd a few of his cams and that wasnt my experience, and thats been my experience with most all cams ive tested.
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Re: Importance of Degreeing in your Camshaft

Post by MadBill »

True, just bolting a cam in dot-to-dot is a bit of a crap shoot, but absent a quick change cam indexing set up (for a probably one-off use), a lot of guys just can't afford hundreds of dollars of additional dyno and tear down costs to perfect the cam setting. For a garden variety hot street SBC, putting it in at either the cam company's suggested spec or a default 4° A. isn't going to turn a great combo into a dog.

A high-dollar race engine for a heads-up class is a different story..

PS: Be very interested to know how far off a Jones index recommendation has been for you CGT, and the specific effects of optimizing it. A friend that builds big inch Hemis reported that retarding the cam from LSM's 3° A. recommendation to straight up was good for 24 HP in a thousand plus HP 572", with no loss anywhere in the tested range.
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Re: Importance of Degreeing in your Camshaft

Post by rustbucket79 »

Did the multiple timing changes on the dyno, at the end it was a trade off, 4 degrees retarded traded 4 lb ft for 1.5 hp.
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Re: Importance of Degreeing in your Camshaft

Post by CGT »

MadBill wrote: Sun Jul 08, 2018 1:10 pm Be very interested to know how far off a Jones index recommendation has been for you CGT, and the specific effects of optimizing it.
The most drastic of mine was a i believe 231 234 108 roller in a 383 chevy. Recommend icl 104. It ran good there, and if you never tested any other position you wouldnt have known there was 30+hp moving back to 108. It interestingly enough, lost a bunch of power retarding it back even further to 112.
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Re: Importance of Degreeing in your Camshaft

Post by BBO Omega »

Mike’s Cam mathched my last Cam (Strange Majik by Andy Miller ground by Crane) exact as far as the recommended.050” Intake tappet opening and closing events. Both were exactly 1 degree retarded with the same timing set (2 degree R position on the backwards Pro-Race timing set). This was as close as I can get with the two timing sets I have to work with. I asked Mike and he recommended staying with that vs. going with a 3deg Advance, which was my next closest option. We will see how it runs.
New cam .050” open is 12deg BTDC. Cam card says 13deg BTDC
Old Cam .050” open is 8.5deg BTDC. Cam card says 9.5deg BTDC
73 Omega, 468 BBO, 4.185 ICON Pistons,RR/Wenzler Heads with HS 1.7 rockers and PAC 1220X Springs,J&S 5-main Halo with Billet Caps, .590I .580E 242I 256E HR Cam, 1000hp Carb,2" x 3 1/2" headers,Coan 2900rpm Conv.,TH400,3.73 12 bolt,11.32/118
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