440 timing question
03-06-2014, 03:23 PM
#1
440 timing question
I have been looking around on the web for a few days now for info on timing my 440. Some people say rev the engine between 2 and 3k rpms then set the timing between 34-38 degrees. Others say anything from 2-15 degrees at idle.... So which way should i go what is the best way to time my motor?
edelbrock aluminum intake
holley 770 street avenger carb
comp cams extreme energy cam .488/.491
hooker super comp headers with 3 inch duals
Also this car is a 4 speed. Originally an auto but i swapped it over to manual. What should my idle be set at? Does it being manual affect timing? If i time it according to the 34-38 degree idea should i mark say 36 on my balancer then time it according to the 0 degree mark on the timing chain cover? Any help is greatly appreciated. Thanks!
edelbrock aluminum intake
holley 770 street avenger carb
comp cams extreme energy cam .488/.491
hooker super comp headers with 3 inch duals
Also this car is a 4 speed. Originally an auto but i swapped it over to manual. What should my idle be set at? Does it being manual affect timing? If i time it according to the 34-38 degree idea should i mark say 36 on my balancer then time it according to the 0 degree mark on the timing chain cover? Any help is greatly appreciated. Thanks!
03-06-2014, 04:37 PM
#2
You need to do both. Read this article
http://www.moparmusclemagazine.com/t...m/viewall.html
There are a number of things you need to realize..........
Modern fuel (alcohol) and depending on your "build" IE compression, chamber design, and cam / cam timing are all going to affect what timing the engine "wants" and can tolerate
Also, how heavy and high geared is the vehicle, IE little Dart, or big motorhome?
ALSO most of the distributors you are likely to encounter are going to have TOO MUCH distributor advance (in degrees) but VERY SLOW (advance per RPM) that is very strong springs.
Your choice is to either buy a performance aftermarket unit, or have yours recurved.
What you HAVE is INITIAL, what you have at idle, added to MECHANICAL (centrifugal) which is the weights and springs in the distributor, and this will be in effect at RPM.
VACUUM is added to the two above, ONLY at "light throttle." Vacuum is usually hooked to "ported" vacuum which means "it ain't there" at idle, is ONLY there at med to high speed at LIGHT throttle, and drops off again at wide open throttle.
WHAT YOU WANT "in general"
LOTS of initial. Best way to set this is to disconnect the vacuum advance, get the engine to idle down as low as it will go, and set for highest vacuum on a gauge, or highest RPM on a tach. Then start a few times when GOOD and WARM to be sure the starter won't "kick back."
NOW CHECK with vacuum disconnected at high RPM and see how far it advances. "Blip" the throttle good to be sure it's all in. If you are "scared" of the fan (I AM!!!!) do this when engine is lukewarm and disconnect the fan belt.
TOTAL at high RPM will again, depend on what the engine can tolerate. If you have a mid 70's "smog" distributor, it very likely will be OVER advanced!!!.
Some engines make max power at only 32 degrees. I'm told the new gen 3 hemis use way less than that down in the 20's!!!! Older engines with "back then" fuel could tolerate 36-38 degrees, sometimes a little more. Listen for pinging!!! under load READ the plugs!!!!
VACUUM is last. It is added on to the total and typically when the vacuum is "in" timing will go up into 50-55 degrees or so.
GOOGLE this. "recurve distributor" etc
https://www.google.com/search?q=recu...h=611&dpr=1.09
https://www.google.com/search?q=recu...h=611#imgdii=_
http://www.moparmusclemagazine.com/t...m/viewall.html
There are a number of things you need to realize..........
Modern fuel (alcohol) and depending on your "build" IE compression, chamber design, and cam / cam timing are all going to affect what timing the engine "wants" and can tolerate
Also, how heavy and high geared is the vehicle, IE little Dart, or big motorhome?
ALSO most of the distributors you are likely to encounter are going to have TOO MUCH distributor advance (in degrees) but VERY SLOW (advance per RPM) that is very strong springs.
Your choice is to either buy a performance aftermarket unit, or have yours recurved.
What you HAVE is INITIAL, what you have at idle, added to MECHANICAL (centrifugal) which is the weights and springs in the distributor, and this will be in effect at RPM.
VACUUM is added to the two above, ONLY at "light throttle." Vacuum is usually hooked to "ported" vacuum which means "it ain't there" at idle, is ONLY there at med to high speed at LIGHT throttle, and drops off again at wide open throttle.
WHAT YOU WANT "in general"
LOTS of initial. Best way to set this is to disconnect the vacuum advance, get the engine to idle down as low as it will go, and set for highest vacuum on a gauge, or highest RPM on a tach. Then start a few times when GOOD and WARM to be sure the starter won't "kick back."
NOW CHECK with vacuum disconnected at high RPM and see how far it advances. "Blip" the throttle good to be sure it's all in. If you are "scared" of the fan (I AM!!!!) do this when engine is lukewarm and disconnect the fan belt.
TOTAL at high RPM will again, depend on what the engine can tolerate. If you have a mid 70's "smog" distributor, it very likely will be OVER advanced!!!.
Some engines make max power at only 32 degrees. I'm told the new gen 3 hemis use way less than that down in the 20's!!!! Older engines with "back then" fuel could tolerate 36-38 degrees, sometimes a little more. Listen for pinging!!! under load READ the plugs!!!!
VACUUM is last. It is added on to the total and typically when the vacuum is "in" timing will go up into 50-55 degrees or so.
GOOGLE this. "recurve distributor" etc
https://www.google.com/search?q=recu...h=611&dpr=1.09
https://www.google.com/search?q=recu...h=611#imgdii=_
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