MSD ignition timing question

dave89iroc

dave89iroc

Club Member
chevy 355, 13.5:1 compression
ported Dart Pro-One 230 heads
forged pistons, h-beam rods
solid roller(not sure on specs, somewhere around .630 lift)
harland sharper roller rockers, crane stud girdles
holley 850cfm carb, race version
MSD Pro-Billet mag pickup distributor
MSD 7AL-3
MSD Pro-Tower coil
MSD 8.5 mm superconductor swires

cold start, it starts great, once its warm, it starts hard, cranks a long time

I am thinking it may be how we have the timing advance set up

the centrifigal advance in the distributor is working, I will check the curve tomorrow(will get stop cam and springs in it)

what timing curve/advance amount should we use to help us out? present total is about 35 degrees

or I have the option of locking out the advance in the dist, and using the start retard feature of the 7AL-3 box to pull 25 degrees when cranking?
 
Sounds like it might not have enough timing, take what ever you have base at idle and subtract 25 degrees whatever you get it is what it has cranking.


If its crank for along period of time but not igntion lugging or slowing down its prob to retarded.
 
igotaneed4speed said:
sounds like it might not have enough timing. take what ever you have base at idle and subtract 25 degrees whatever you it is what its trying to start with.


If its crank for along period of time but not igntion lugging or slowing down its prob to retarded.
Click to expand...

yeah, it just cranks for a while, no lugging

thanks, I will also check the timing amount tomorrow at the track if we head out there, I will add timing a degree or two at a time to see if it helps
 
If this is primarly a race set-up and you have a convertor thats pretty loose there is not much\if any gain in running mechanical advance. Just lock it out so you dont have headackes from it later.

Easy way to check put a light on it, rev it up until the advancing stops, note the rpm. If its lower or within a few hundred rpm of your LAUNCH stall rate then forget it and lock it out.
 
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yeah, race only, and a 5500 rpm stall Vigilantie would count as loose, right?

and yeah, it stops advancing lower then the launch stall
 
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