TIMING MOVING
07-29-2009, 03:17 PM
#3
Senior Member
DYNO OPERATOR
Join Date: Apr 2008
Posts: 504
If it is only retarding two deg or less with RPM change, it is likely your cam end play moving forward and rearward changing the gear mesh and backlash of your helical cut dist gear altering your timing setting. Less end play settings give less timing change at your dist. A crank trigger pick up eliminates this issue that most all distributor triggered igns that are rotated by the cam have due to necessary cam end play. The retard can be virtually near zero to 1/2 degree with minimum recommend cam end play settings.and proper gear backlash set ups.
Bruce
Bruce
07-29-2009, 03:34 PM
#4
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RACING JUNKIE
Join Date: Sep 2007
Location: Belleville, IL
Posts: 658
You shouldn't be setting the timing at idle anyhow.
Always rev the motor and watch the timing during RPM climbing.
The valve train has to be loaded to properly set the timing.
It can't be done right at idle, or at a constant RPM because there will always be slack in the chain.
As was said prior, make sure the cam isn't walking either.
Always rev the motor and watch the timing during RPM climbing.
The valve train has to be loaded to properly set the timing.
It can't be done right at idle, or at a constant RPM because there will always be slack in the chain.
As was said prior, make sure the cam isn't walking either.
07-29-2009, 04:01 PM
#5
Senior Member
DYNO OPERATOR
Thread Starter
Join Date: Apr 2008
Posts: 496
Originally Posted by OneBadGMC
You shouldn't be setting the timing at idle anyhow.
Always rev the motor and watch the timing during RPM climbing.
The valve train has to be loaded to properly set the timing.
It can't be done right at idle, or at a constant RPM because there will always be slack in the chain.
As was said prior, make sure the cam isn't walking either.
Always rev the motor and watch the timing during RPM climbing.
The valve train has to be loaded to properly set the timing.
It can't be done right at idle, or at a constant RPM because there will always be slack in the chain.
As was said prior, make sure the cam isn't walking either.
07-29-2009, 05:38 PM
#6
Member
JUNIOR BUILDER
Join Date: Nov 2008
Posts: 87
If ya got vacuum advance remove the hose from the distributor pot and plug it,get an adjustable knob type timing lite,have someone sit in the car and watch the tach, lets say ya want 35 degrees total as an example, set the light at 35 and give the car some rpm until the balancer mark stops moving, I like fully advanced in a race only car around idle or by 1200 rpm,on a street racer say 2000 rpm, with the engine fully advanced set the timing to 35 degrees,now do it again, note the rpm that it takes until the engines fully advanced, what you want is the engine fully advanced by 1200 rpm to 35 degrees,thats total advance and it also tells you your advance curve. This will give ya a lot more spark advance and the engine will respond. If ya run an msd dist and you arent advancing fully at 1200 rpm change the springs and or the button. This is generally speaking, works for me....
07-29-2009, 05:47 PM
#7
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Join Date: Mar 2008
Location: New Orleans,La
Posts: 515
Originally Posted by mopar1962
If ya got vacuum advance remove the hose from the distributor pot and plug it,get an adjustable knob type timing lite,have someone sit in the car and watch the tach, lets say ya want 35 degrees total as an example, set the light at 35 and give the car some rpm until the balancer mark stops moving, I like fully advanced in a race only car around idle or by 1200 rpm,on a street racer say 2000 rpm, with the engine fully advanced set the timing to 35 degrees,now do it again, note the rpm that it takes until the engines fully advanced, what you want is the engine fully advanced by 1200 rpm to 35 degrees,thats total advance and it also tells you your advance curve. This will give ya a lot more spark advance and the engine will respond. If ya run an msd dist and you arent advancing fully at 1200 rpm change the springs and or the button. This is generally speaking, works for me....
