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DRR Sportsman
Picture of chasracer
posted
Recently I had the chance to do some work on a dyno engine. My primary job was setting up the Fast II system for the injection system.

What caught my eye was watching what happens to the spark as it jumps from the rotor tip to the cap tip. I know that a MSD system stops firing multiple sparks in the 2500-3000 rpm range but what was interesting was watching the spread of those sparks across the width of the rotor tip. To me it proves that while most of us check rotor phasing when using a crank trigger system and the distributor is locked out, I am not so sure we are phasing it "correctly". Of course I am basing this off of one instance but if you are setting your phasing to be in the middle of the rotor, while it will work I am not so sure it couldn't be better. The rotor was turning clockwise and what I saw was the multiple sparks jump starting at the left edge of the rotor viewing it from the top, then as rpm increased, the sparks started to diminish in number until about 3000 it was down to one spark jumping between the very end (right side) of the rotor to the cap tip. I didn't get to play with moving the cap or rotor tip but I have since wondered if "leading" the rotor tip to the cap tip might not pay some dividends in reduced mis-fire at higher rpms.


www.rutherfordms.com - tips and tricks, project builds and how-to's
 
Posts: 897 | Location: The problem is not the problem. The problem is your attitude about the problem. Savvy?” ~~ Captain Jack Sparrow ~~ | Registered: August 21, 2000Reply With QuoteReport This Post
DRR Sportsman
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I would expect that what you see in the rotor to distributor phasing when the multiple spark stops at 3000 rpm would be the exact same at 9000 rpm. Easy way to check. Point the timing light at the crank trigger pickup. At 9000 rpm you should see the magnet on the wheel at the same place as at 3000 rpm… which should be very close to directly over the pickup center.
 
Posts: 688 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Sportsman
Picture of chasracer
posted Hide Post
I don't disagree with your point at all. I am just wondering if it would help to pull that line back a touch in as far as having ample contact area between the rotor tip and cap tip.


www.rutherfordms.com - tips and tricks, project builds and how-to's
 
Posts: 897 | Location: The problem is not the problem. The problem is your attitude about the problem. Savvy?” ~~ Captain Jack Sparrow ~~ | Registered: August 21, 2000Reply With QuoteReport This Post
DRR All Star
posted Hide Post
Is it missing now?


Does your party represent personal responsibility?
Bill of non rights: http://www.crossroad.to/Quotes/law/non-rights.htm
 
Posts: 3064 | Location: Illinois | Registered: July 08, 2004Reply With QuoteReport This Post
DRR Sportsman
posted Hide Post
quote:
Originally posted by chasracer:
I don't disagree with your point at all. I am just wondering if it would help to pull that line back a touch in as far as having ample contact area between the rotor tip and cap tip.


Ok. I understand now what you’re referring to how setting and agree on within contact of the plug tower. If one is running retard during the run maybe it’d be best to check with retard and without to possibly center ??
 
Posts: 688 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Sportsman
Picture of chasracer
posted Hide Post
Exactly. I am keep thinking about pulling out some timing at different places in the run but most people claim in a 1/8 it doesn't make much difference.

Bucky - this is actually just bench racing an idea due to that dyno run. That engine is going to find a nice home in one of those Factory 5 hot rods.


www.rutherfordms.com - tips and tricks, project builds and how-to's
 
Posts: 897 | Location: The problem is not the problem. The problem is your attitude about the problem. Savvy?” ~~ Captain Jack Sparrow ~~ | Registered: August 21, 2000Reply With QuoteReport This Post
DRR Sportsman
Picture of Quick Dawg
posted Hide Post
I did play with rotor phasing when I first got my Grid. Before I was pulling timing out with the Grid I use to phase my dizzy with the leading edge of the rotor at the leading edge of the cap. I found that if I pulled 10 out with the Grid I would sometimes get a miss fire. I now phase the rotor closer to the middle of the cap lug.
 
Posts: 108 | Location: Salt Lake City | Registered: January 16, 2012Reply With QuoteReport This Post
DRR S/Pro
Picture of XPS fan
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Similar here....... max timing is usually 28 and I've pulled as much as 20 out for track conditions, so I phase in the center of the lug while at 18 degrees.



.


NHRA Pro Stock..........now on a no CARB diet.
 
Posts: 3115 | Location: ohio | Registered: February 21, 2006Reply With QuoteReport This Post
DRR Sportsman
posted Hide Post
quote:
Originally posted by chasracer:
I am keep thinking about pulling out some timing at different places in the run but most people claim in a 1/8 it doesn't make much difference.


Removing timing (early) will slow a car more than you think even in the 1/8. My 6.10 car will run 6.45 and still mph within 1.5 mph. I always run with a timing retard map as I want a 6.2x et even on a good track.
 
Posts: 688 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Pro
posted Hide Post
easy way to check rotor phasing with fix'd and pulling timing is......motor not running, rotate motor to timing mark (example) to 30 degrees, then pull dist cap and see the relationship of rotor to #1, then rotate engine to 20 timing mark (example for 10 degree retard), see were rotor is nor. That way you phase is for fix'd and retard. Hope that makes sense.....


Fellow racer and servant of the Lord of Lords
John 14:6
"Creekside Racing Ministry"
MFI system, ProCharger Non-intercooled [6.02 @ 229 or 3.91/660' soft tune and killing power above 6K rpm]
Ron Clevenger
 
Posts: 1000 | Location: Visalia, Calif. 93292 | Registered: November 23, 2000Reply With QuoteReport This Post



DRR All Star
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I have a test cap with a 1" hole in it for checking phasing. Not real easy to see, but you can see it.


Does your party represent personal responsibility?
Bill of non rights: http://www.crossroad.to/Quotes/law/non-rights.htm
 
Posts: 3064 | Location: Illinois | Registered: July 08, 2004Reply With QuoteReport This Post
DRR Sportsman
Picture of 329L
posted Hide Post
quote:
Originally posted by Ron C.:
easy way to check rotor phasing with fix'd and pulling timing is......motor not running, rotate motor to timing mark (example) to 30 degrees, then pull dist cap and see the relationship of rotor to #1, then rotate engine to 20 timing mark (example for 10 degree retard), see were rotor is nor. That way you phase is for fix'd and retard. Hope that makes sense.....



^^^This


Jeremiah Hall
 
Posts: 177 | Location: Evansville, IN | Registered: February 24, 2010Reply With QuoteReport This Post
DRR Trophy
posted Hide Post
quote:
Originally posted by markemark:

Removing timing (early) will slow a car more than you think even in the 1/8. My 6.10 car will run 6.45 and still mph within 1.5 mph. I always run with a timing retard map as I want a 6.2x et even on a good track.


When coming off a launch retard, do you ramp timing back in or do you put it all in at once?
For example..say launch retard is -10 for 1.5 seconds- after 1.5 seconds from launch do you ramp 10 degrees in over time, or put it all back at once?
I've done it both ways (usually ramp it back to 0 at the end of my launch retard curve) just curious how everyone else does it.
 
Posts: 124 | Location: South MS | Registered: September 07, 2015Reply With QuoteReport This Post
DRR Sportsman
posted Hide Post
quote:
Originally posted by XPS fan:
Similar here....... max timing is usually 28 and I've pulled as much as 20 out for track conditions, so I phase in the center of the lug while at 18 degrees.


I like this method best for a running engine.
 
Posts: 688 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Sportsman
posted Hide Post
quote:
Originally posted by Iforgot:
When coming off a launch retard, do you ramp timing back in or do you put it all in at once?
For example..say launch retard is -10 for 1.5 seconds- after 1.5 seconds from launch do you ramp 10 degrees in over time, or put it all back at once?
I've done it both ways (usually ramp it back to 0 at the end of my launch retard curve) just curious how everyone else does it.


For me it’s 0.10 ramp to full retard and 0.50 ramp to no retard.
 
Posts: 688 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
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