Cam timing 4 deg. or ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

buckola · 06-04-2004, 09:37 PM

I'm about to install a new Cloyes timing and gears. Should I set the gear to 4 deg. advance? Whats the advantage and disadvantages

bigjimzlll · 06-04-2004, 10:08 PM

Thats a loaded question. You can get in piston to valve clearance problems when advancing the cam. What are the specs on the engine and drive train? Basically advancing 4º will increase the DCR and lower peak torque about 400 rpm..while lowering the peak HP by the same. If the cam is too big..then adv. will make it think its a little smaller

67shortie · 06-05-2004, 12:16 PM

Jim is right, advancing the cam will close the exhaust valve quicker on the compression stroke and trap slightly more ar resulting in a better acting engine low speeds if the thing is slightly overcammed or one is in need of more lower end power curve.

My Ultradyne solid in the 427 is advanced 4* on the keyway, degreed in nice, and I have no problems whatsoever with valve to piston clearance. Every application should be checked though, do the tried and trusted clay on piston method just to be sure.

robertwb · 06-06-2004, 11:21 PM

many cams have the 4 deg ground in already-make sure before you go 4 more

06-04-2004, 09:37 PM	#1
buckola 1 Wrench / 10 Knuckles Join Date: Sep 2002 Location: Burlington Ontario Posts: 179	Cam timing 4 deg. or ? I'm about to install a new Cloyes timing and gears. Should I set the gear to 4 deg. advance? Whats the advantage and disadvantages __________________ 1970 GMC Custom Vortec Heads, Edelbrock Performer Intake, Crane 272 Energizer, Hedman Full Length HTC Headers 2006 Dodge Charger SRT8. 1/4 mile 13.3 1973 Z1 900 Kawasaki ( all original)

06-04-2004, 10:08 PM	#2
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	Thats a loaded question. You can get in piston to valve clearance problems when advancing the cam. What are the specs on the engine and drive train? Basically advancing 4º will increase the DCR and lower peak torque about 400 rpm..while lowering the peak HP by the same. If the cam is too big..then adv. will make it think its a little smaller __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

06-05-2004, 12:16 PM	#3
67shortie Green club Join Date: May 2002 Location: Central CA Posts: 1,059	Jim is right, advancing the cam will close the exhaust valve quicker on the compression stroke and trap slightly more ar resulting in a better acting engine low speeds if the thing is slightly overcammed or one is in need of more lower end power curve. My Ultradyne solid in the 427 is advanced 4* on the keyway, degreed in nice, and I have no problems whatsoever with valve to piston clearance. Every application should be checked though, do the tried and trusted clay on piston method just to be sure. __________________ 71 short/fleet ECE 4/6 drop, LQ4/700r4/3.42 gears 70 SS396 Chevelle 427/200-4R/3.73posi 61 Lincoln Continental, black on black Son you are going to drive me to drinkin if you don't stop drivin that hot rod lincoln

06-06-2004, 11:21 PM	#4
robertwb Registered User Join Date: May 2003 Location: brooksville-fla Posts: 77	many cams have the 4 deg ground in already-make sure before you go 4 more __________________ 1972 LWB 4x4 1970 LWB 2wd 1971 chevelle 1972 datsun PL-521/nissan

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