Setting MSD timing

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fnaramore

fnaramore

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So just got a MSD pro billet distributor and blaster 2 coil and am trying to think where to put my initial and total timing. 1973 dodge dart 318. Currently the engine has a XE256H camshaft (1000-5200 rpm range), 600 cfm carb and weiand stealth manifold. Timing is 11-12* BTDC. In about 3 months Im putting in a XE262H (1300-5600 rpm range) comp cam and eddy performer rpm heads. Engine should have around 8.5:1 8.6:1 compression. Anybody have any suggestions on where my initial and total timing should be set? And if you have an MSD dizzy, which springs you prefer? Right now am looking at two light blues or a heavy silver and light silver. Thanks for the help guys.
 
You will have to experiment 12 to 15 initial should work since cam is not to big, around 34 total. Spring I go on the light side get it all in around 2200 rpm, I have a set of the MSD bushings for sale if your initial will be at 20 or more they allow you to run hi initial but still keep your total low, I don't think you would end up needing them to be honest since the cam is smaller in your case.
 
Okay cool! Yeah I was guessing around 34 total and 12 initial, just wanted to hear what others had to say, always like getting opinions. The blue bushing that comes stock in the dizzy puts it about 22*. so 12* initial+ 22* centrifugal = 34* if I am not mistaken. Looking at the charts they sent, it looks like when it comes to the springs, I would be choosing whether the centrifugal hits its high point at either 3500 or 3000. Unless I go even lighter with them. This may be a stupid question, but I do run both the centrifugal and vacuum advance at the same time? or does one HAVE to be locked out?
 
The vacuum should be hooked to "ported" vacuum, that is, no vacuum at idle. Vacuum only comes into play at light throttle / cruise, when you give it more and more throttle, the vacuum goes away, so at WOT you only have initial + mechanical

Someone on here was selling special bushings for MSD with less curve in them. Sorry I don't use MSD and don't remember who.

For most perfornances stuff nowadays 12-34 would be considered a fairly long curve. I run more like 15--35, so 20 in the dist, and I may shorten that.
 
I run 15/35 all in by 3500. No vac advance. Initial timing is key. I don't like bringing it all in real fast on a street car. YOu mentioned 3000rpm for total. I think that would be ok. I wouldn't venture too far under that.

EDit: I may bump my initial up a bit more but will not touch the total or the cureve. However I run a 3500 convertor so when I mat it it has full timing upon convertor flash.
 
Alright, I got you guys. So in that case, I should have 12-15* initial, 20* mechanical and have it all in at 3500 rpm. And as I understand it, I am good to run the vacuum advance and the mechanical at the same time.
 
I hear you, guess I'll have to play around with it a bit to see what I feel works best for when to bring it all in. Thanks guys!
 
With my setup is there not a chance of spark knock if I have it all in that early? or since 2500 is in the power band of the camshaft, it is getting me the most power?
 
Frankly, a matter of "playing" with it. some factors are cam, intake, head design, compression ration, fuel octane, and even engine temp as well as load (IE heavy, high geard, trailer pulling) etc.

Heck there's even guys experimenting with connecting knock sensors to headphones so they can better detect knock!!!
 
67Dart273 said:
Frankly, a matter of "playing" with it. some factors are cam, intake, head design, compression ration, fuel octane, and even engine temp as well as load (IE heavy, high geard, trailer pulling) etc.

Heck there's even guys experimenting with connecting knock sensors to headphones so they can better detect knock!!!
Click to expand...

I hear you, thanks again man! haha
 
I guess I'll start with 12* BTDC, 22* mechanical and it all in at 3000 (two light blue springs)
 
fnaramore said:
I guess I'll start with 12* BTDC, 22* mechanical and it all in at 3000 (two light blue springs)
Click to expand...

That sounds like a reasonable starting place.

I would NOT run vacuum advance... unless you are dead certain how much advance it provides and when and how. I like straight timing because I know what it will do, every time, and that my engine runs properly under those conditions.
 
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