Reply With QuoteDecide which bushing to limit your total timing,take an allen wrench and spring kit with you,start off conservative and switch springs while on the water,I assume the distributor is easy to access. What's the top rpm the motor will pull?
I am installing a MSD distributor and need advice how to set up the advance curve. The engine is a LS7 454 with a tunnel ram and twin 600 Holley's running avgas....Any ideas out there???? Thanks.....
Decide which bushing to limit your total timing,take an allen wrench and spring kit with you,start off conservative and switch springs while on the water,I assume the distributor is easy to access. What's the top rpm the motor will pull?
Oh yeah,I bought the full MSD marine setup 2 years ago,and it sure was rusty when I de-witerized it last week.It did clean up O.K.,but I'm going to leave it apart and dry this year.
Originally posted by Mike Lindberg:
Decide which bushing to limit your total timing,take an allen wrench and spring kit with you,start off conservative and switch springs while on the water,I assume the distributor is easy to access. What's the top rpm the motor will pull?
The engine will pull 7000 rpm and access is easy. How do you figure out which bushing to use?
If you have the box the distibutor came in,the bushings are color coded.Mine's out in my shop,I'll dig it up tomorrow if you can't find the info. Anyway,you should probably use the bushing one step down from max. total advance.Start with 10 deg. base timing at idle,and 2 steps down from the slowest advance curve.Make a pass,listen for ping or detonation.I doubt there will be yet. Then bring the advance in one step at time by going to the smaller and smaller spring combinations. You won't believe the power difference! Just don't go too far advanced. I take one of those T-handle allen wrenches that are long to make it easy to pull the cap on and off.
I dug it up in case you need it now.The red bushing is smallest.It will allow 28 deg.advance plus your base timing-total 38 deg. Then its silver(a good place to start)which allows 25 deg. Next is blue then black which are 21 and 18 deg. You may be able to run the red one if you use 10 deg. base. Or you could try the silver one and 12-14 deg base. Good luck,have fun.
The more initial timing you can get into the engine (and still start it) the better it will idle, and the quicker it will respond. This is why most race engines have there timing locked no curve. With a tunnel ram increasing the timing at idle will get you much better low end, and response.
rr is right lock down the MSD and set it at about 33 to 35 and check plugs after each hard pass. you should be able to run 36 to 38 degrees timing with no problem and good gas. I beleive the stock LS7 had 11.5:1 or 12:1. I hope your not running the stock ls7 cam. It will float befor 7000. your probably running low gears ie... 9-15 in the box to get that rpm unless the motor is just an LS7 foundation with good stuff shoved in it.
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