Checking Distributor Advance

[cgrooves]

For starters: Mercruiser 898 (305) engine with mallory distributor. New points, condensor, rotor, cap, etc. this year.

My timing light does not check total advance like some apparently do. On a couple of occassions recently, I've heard some odd sounds (low volume popping type sounds) that I'm afraid is pre-ignition. I know how pre-ignition 'pinging' sounds on air cooled engines, but I haven't messed around with the Chevy V8's much. My base timing is set to factory spec (8 degrees advance).
What does pre-ignition sound like on these engines? Is there another way to check total advance other than buying a timing light with an advance checking feature (i.e. attempting to make a mark on the pulley at approx. 28 degrees)? Can improper dwell cause pre-ignition? Also, if I find the distributor is advancing too much, will a new spring on the advance plate probably be the cure?

Sorry for the '20 questions'.

 

[mkast]

Re: Checking Distributor Advance

Just increase engine rpm to 2500-3000 while the light is on the damper.

 

[bomar76]

Re: Checking Distributor Advance

To check total advance:
Just buy the correct timing tape for your size damper.....you can get them just about anywhere, Summit would be a good online seller.
http://store.summitracing.com/egnsearch.asp?Ntt=timing+tape&N=700+115+4294908216&Ntk=KeywordSearch
Tape it on to a clean balancer, make certain the 0 mark on tape is on the line on damper, hook up your timing light and fire it up.

 

[MikDee]

Re: Checking Distributor Advance

Pre ignition is a "pinging" sound like ping pong balls, not a "low volume popping sound". If your distributor weights, & springs in the base (under the breaker plate) are working propperly, and you set the correct dwell, Then the timing afterward, the noise is not from that, but do as either of the previous posters said, if you want to ease your mind.

By the way, the advance mechaism can only advance so far, there's a stop on it, you set the initial advance manually by turning the Dizzy. Stay with the factory stock springs, unless you are into "supertuning".