[Eric Jacobs]

Can someone please tell me what to do when setting the timming with a MSD distributer, i do not know where the book for the distributer is...

Eric

[ August 25, 2002, 10:05 PM: Message edited by: Eric 427 Shelby ]

 

[Aaron Silidker]

Umm, loosen the clamp use the timing light and set it, easy as that, nothing special. Just disconnect the advance if you have one.

 

[Eric Jacobs]

there is no vacum advance on my distributer, so do i have to do anythign special? What RPM should the timming be set at?

Eric

 

[Wade Chamberlain]

Eric - you should set your total timing at about 3500-4000 rpm. You should have all the advance in by then. With the blower, you won't be able to run as much advance as a NA car. I run about 24° total advance with 6-7# boost. If I were you, I'd start about 22° total (under boost), and get it to a dyno for further tuning. Listen for detonation if you're hammering it.

Do you have boost timing retard? If not, your MSD distributor may need to be re-curved, or you'll have very little base timing (or even retarded).

 

[6T5 Cbra]

If you're looking to reset your timing curves, MSD makes a kit (springs and cams) to do this. You can pick one up and almost any good autoparts store for ~ $15.

Here's a good article that explains the how's and why's about setting the timing. Not sure it addresses a Supercharged engine, but it might help you out.

Ignition Timing for Modified Engines

Good Luck,

Gene

 

[Aaron Silidker]

Eric, as I said online, maybe a vacume advance is in order. From what I understand it will advance less under load which is perfect for your supercharger.

 

[andy dunn]

here are the MSD charts if you need them
http://www.cobralads.com/gear/msd2.gif

 

[Eric Jacobs]

So hear me out....if i need total timming to be 22 degrees, i can put the 18 degree spring in my distributer, then set my timming to 4 BTC. Does that sound right? Or am i way off on this understanding?

thanks
Eric

 

[billk]

Eric,
It's not the springs, but the advance stop bushing that sets the advance. The weight of the springs determines at what rpm the advance begins and how quickly you arrive at total advance.My MSD distributor came with a kit containing extra springs of various weights and different bushings along with complete instructions. Call MSD tech.They were very helpful to me.
Good Luck.

billk

 

[6T5 Cbra]

Not way off. Change one word in your reply and you have it correct.

So hear me out....if i need total timming to be 22 degrees, i can put the 18 degree bushing in my distributer, then set my timming to 4 BTC. Does that sound right? Or am i way off on this understanding?

After installing the desired bushing, you need to choose the timing ramp you want to use. See the link above for the choices. These different ramps are set by using different combination of springs.

Gene

 

[Eric Jacobs]

what "ramp" do i want to see?

Eric

 

[andy dunn]

When I've called MSD tech in the past, they state that you want the steepest ramp you can get, without causing detonation. From the factory, they install the slowest ramp (two heavy springs)
http://www.cobralads.com/gear/msd1.gif

You might ask some other supercharger users which springs they like, or a quick call to MSD tech to give you a starting point.

Andy

[ August 26, 2002, 02:32 AM: Message edited by: andy dunn ]

 

[6T5 Cbra]

The timing ramp (or curve) will be different from engine to engine. There are many factors that need to be taken into consideration. I actually set mine by trial and error. After reading various articles and posts on the subject, I figured I needed about 36-38° total advance. I also read that it should be 'all-in' by ~ 3000 rpm. After some experimenting with the different ramps, I ended up using ramp "C" on the MSD instructions. My initial is now at 16°, total at 37° and using a 21° bushing. This seemed to give the best performance throughout the rpm range with no pinging that I could detect. Remember, your's will be different (I'm running a 390 FE).

If you want to get real technical, here's a quote taken from an article I read a while ago.

"Optimally, the timing curve should be set so most of the fuel/air mix will have burned by the time the piston is 12 to 14 degrees after top dead center (ATDC); this will allow the most amount of useful work to be applied to the crankshaft, hence to the wheels."

I'm sure there is a better way to determine the curve than just guessing but it worked for me (no expert at this stuff by any means). Eventually I want to put it on a dyno and try to dial it in even better.

Hope this helped.

Gene