Mercruiser 470 Delco Distributor weights & springs

stonyloam

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IMHO the best way to check the advance weights and springs is to take the distributor to your local auto- electric shop and have them run a advance curve to check your timing advance. That is what I did, and they put in springs that gave the correct advance curve. They also replaced the bushings. Costs a little more, but all of my timing " bounce" has been eliminated. Should be good for many years.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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the last shop that I knew that had a distributor machine went out of business in the mid 90's

Also, the spring kit shown is for the Delco HEI automotive distributor. my experience to date on marine distributors is they are not the same.
 
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Mar 27, 2010
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There is also Mr. Gasket 928G. spring kit without the weights. I think I would re use the original weights. General Motors use to like to make the same part work for several model cars, easier to produce... I bet the springs are no different.



You could check your advance timing with an advanced timing light before you buy anything....

You only use the Zero mark on the timing tab. Turn the dial on the timing light until the timing mark is at Zero, then look at where the dial it pointing at....that is your timing.

You can use it for initial timing and advanced. You would have to experiment with those weights to see how they work compared to the factory timing chart.

Here is my old Craftsman Advanced Light:


timing marks on light.jpg
 
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stonyloam

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You can map your own advance curve. Just need a timing degree tape that fits the diameter of your rotor a timing light and accurate tachometer. Just shine the light on the tape, note the RPM and advance and plot it on a graph. Match it to the advance curve in the manual. You can change the curve by changing springs. Here is an interesting read: http://www.britishv8.org/articles/mechanical-ign-advance.htm
 

blkzoe

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Jan 16, 2013
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Got off my butt, tore down distributor, cleaned parts with carb cleaner and an ultrasound bath lubed and reassembled. Found 25 plus years of goo that inhibited spark advance weights. Springs even look much better. Started 470, much smoother acceleration. Still would like to replace bushing and find a Sun machine. Have contacted some MGB addicts to see what they do. Several sources on internet. Prefer local (MD).

nice curve plot. source?
 

achris

More fish than mountain goat
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May 19, 2004
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...nice curve plot. source?

Mercury Marine service bulletin. (I use to be a dealer) :D
Also available in the service manual (a proper one, not a seloc or clymer :puke:)
 
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