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DRR Pro
Picture of 00 DEAD ON
posted
Has anyone had this happen to them
Dragster runs mid 4.40’s with a MSD distributor NO crank trigger with 34* of timing. Now I install a crank trigger, set timing at 34* then phase it
Go to the track and it only runs back to back 4.58’s. Baffled so I disconnect the crank trigger and plugged the MSD distributor back in and set timing to 34* and it runs 4.46. What in the world would cause this. IDK guess I have a killer MSD distributor worth .012 lol.
Thanks in advance


Brian Mollison
2013 American Dragster
2020 Sumerduck Dragway VA Top ET Champion
2017 Sumerduck Top ET & SSS Track Champion
2017 MAC Top ET Track Champion
2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion
2008 IHRA Division 1 Top ET Bracket Final Runner-up
2007 Colonial Beach Dragway Top ET Track Champion
 
Posts: 1032 | Location: Stafford, Virginia | Registered: October 03, 2006Reply With QuoteReport This Post
DRR S/Pro
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quote:
Originally posted by 00 DEAD ON:
Has anyone had this happen to them
Dragster runs mid 4.40’s with a MSD distributor NO crank trigger with 34* of timing. Now I install a crank trigger, set timing at 34* then phase it
Go to the track and it only runs back to back 4.58’s. Baffled so I disconnect the crank trigger and plugged the MSD distributor back in and set timing to 34* and it runs 4.46. What in the world would cause this. IDK guess I have a killer MSD distributor worth .012 lol.
Thanks in advance


As with any newly installed crank trigger, check the two wire going to it, green and purple, make sure they are reversed.

Next would be to get the crank trigger wires as far away from the coil wires.

Does the motor run clean??? Simple test, try a new crank trigger pick up.
 
Posts: 2163 | Location: Tewksbury, MA,USA | Registered: November 03, 2000Reply With QuoteReport This Post
DRR Pro
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The phasing of the crank trigger will depend on the type of ignition you have analog or digital.

With analog ignition you want the trigger to produce the least amount of timing when phased.

With digital, you want the trigger to produce the maximum amount of timing.

By phasing is meant , when the wires from the crank trigger are inter-changed going to the ignition box.
 
Posts: 2681 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR S/Pro
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quote:
Originally posted by markemark:
The phasing of the crank trigger will depend on the type of ignition you have analog or digital.

With analog ignition you want the trigger to produce the least amount of timing when phased.

With digital, you want the trigger to produce the maximum amount of timing.

By phasing is meant , when the wires from the crank trigger are inter-changed going to the ignition box.


That should be taken care of at the ignition box by the +/- labels on it. Purple/Violet (+) and Green (-).

If he has an MSD crank trigger sensor it has the same color layout, other may or may not but it should have a plus minus label shown in the paper work.

When all else fails switch the wires
 
Posts: 2163 | Location: Tewksbury, MA,USA | Registered: November 03, 2000Reply With QuoteReport This Post
DRR Pro
Picture of 00 DEAD ON
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The ignition box is a 7al3 box. The wires from the MSD and the distributor are the same color and the crank trigger wires are also the same color and the connector can only be hooked up one way. IDK


Brian Mollison
2013 American Dragster
2020 Sumerduck Dragway VA Top ET Champion
2017 Sumerduck Top ET & SSS Track Champion
2017 MAC Top ET Track Champion
2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion
2008 IHRA Division 1 Top ET Bracket Final Runner-up
2007 Colonial Beach Dragway Top ET Track Champion
 
Posts: 1032 | Location: Stafford, Virginia | Registered: October 03, 2006Reply With QuoteReport This Post
DRR Sportsman
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The easiest way to check the crank trigger polarity is with a timing light. When it's correct the magnet is directly under the pickup. When they are reversed they won't be lined up.


Denis LeBlanc

 
Posts: 504 | Location: Manchester, NH | Registered: February 03, 2006Reply With QuoteReport This Post
DRR Pro
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You have analog ignition so you would want the most retarded timing when switching polarity.

To switch polarity of the trigger just reverse the M+ and M- wires on the 7al3 terminal strip. When switched if the timing is now more retarded then this way is correct. If the timing becomes more advanced then this way is incorrect.

What Action said about shinning the timing light at the pick up also works as he said. The magnet should be almost directly over the pickup.
 
Posts: 2681 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post



DRR Top Comp
Picture of Curly1
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But if both the timing was 34* with distributor and 34* with crank trigger why performance difference? The net timing was still 34*?

That is a pretty significant difference in performance from 4.40's to 4.58.


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Posts: 4284 | Location: United States of Texas | Registered: April 02, 2011Reply With QuoteReport This Post
DRR Trophy
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The 7AL-3 will retard your actual timing setting by 4 degrees in operation. If you phased in your timing at 34 your actual timing will be 30 when checked with a light on a crank trigger ignition. So you need to phase in your initial timing at 38 to get 34 in actual operation used with a crank trigger. I use my MSD billet distributor totally locked out. I lost over .06 in et eighth mile when using the distributor only and bringing in full timing well under low side launch rpm.
 
Posts: 8 | Location: LIMESTONE, TN | Registered: December 13, 2014Reply With QuoteReport This Post
DRR Sportsman
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Just went thru this with a 7AL-3.. Changed motors and put crank trigger back on, set timing to 34 degrees, went to track and car sounded terrible and would hardly run under power.
Brought it home, checked everything, timing was still on 34, but it was at idle, I just happened to reach up and give it a little gas and timing took off to 40 something degrees. Switched wires and timing rock solid.
 
Posts: 268 | Location: Irving, Texas | Registered: March 24, 2005Reply With QuoteReport This Post
DRR Pro
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Here’s a patch cable that I made that will quickly reverse the wire polarity of the pickup when installed between the pickup and cable. The pin extractor in the pic is a Blue Point GA 500A. Use this if needed to permanently change the polarity of the pickup plug in.

 
Posts: 2681 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR Sportsman
Picture of sr4440
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if the wires are reversed then your going to lose a he11 of lot more then .12.LOL
I willing to bet you run a timing chain combined with the twisting of the camshaft @RPM. your timing is retarded a little at race RPM.
Easy way to tell, set crank trigger @32 and see if it picks up,if it does take a little more until you get back your ET.

Joe


Without data, you’re just another guy with an opinion.
 
Posts: 1313 | Location: TEXAS | Registered: February 07, 2003Reply With QuoteReport This Post
DRR Pro
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It has a belt drive not a chain. I will do some checking


Brian Mollison
2013 American Dragster
2020 Sumerduck Dragway VA Top ET Champion
2017 Sumerduck Top ET & SSS Track Champion
2017 MAC Top ET Track Champion
2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion
2008 IHRA Division 1 Top ET Bracket Final Runner-up
2007 Colonial Beach Dragway Top ET Track Champion
 
Posts: 1032 | Location: Stafford, Virginia | Registered: October 03, 2006Reply With QuoteReport This Post
DRR Pro
Picture of 00 DEAD ON
posted Hide Post
quote:
Originally posted by Curly1:
But if both the timing was 34* with distributor and 34* with crank trigger why performance difference? The net timing was still 34*?

That is a pretty significant difference in performance from 4.40's to 4.58.


Oh I agree 100%. Didn’t make since at the track. Have to find time and check it out again.
Thx everyone’s suggestions


Brian Mollison
2013 American Dragster
2020 Sumerduck Dragway VA Top ET Champion
2017 Sumerduck Top ET & SSS Track Champion
2017 MAC Top ET Track Champion
2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion
2008 IHRA Division 1 Top ET Bracket Final Runner-up
2007 Colonial Beach Dragway Top ET Track Champion
 
Posts: 1032 | Location: Stafford, Virginia | Registered: October 03, 2006Reply With QuoteReport This Post



DRR Sportsman
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My first thought would be is the distributor you are using with the crank trigger a mechanical advance and is it completely locked out. Just wondering whether the distributor could be advancing and going out of phase with the crank trigger.


B.J. Masiello
 
Posts: 250 | Location: Connecticut | Registered: November 27, 2007Reply With QuoteReport This Post
DRR Trophy
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be sure the wheel is on correctly. It is directional and can be put on backwards...
 
Posts: 46 | Location: stonypoint,nc | Registered: October 11, 2010Reply With QuoteReport This Post
DRR S/Pro
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Your transducer is junk, most likely.

It's why you will never see an msd wheel or transducer on any of my engines.


strangemagicperformance.com
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WD dealer for just about all your performance needs.
 
Posts: 1604 | Location: Suffern, NY | Registered: November 03, 2001Reply With QuoteReport This Post
DRR Top Comp
posted Hide Post
quote:
Originally posted by markemark:
You have analog ignition so you would want the most retarded timing when switching polarity.

To switch polarity of the trigger just reverse the M+ and M- wires on the 7al3 terminal strip. When switched if the timing is now more retarded then this way is correct. If the timing becomes more advanced then this way is incorrect.

What Action said about shinning the timing light at the pick up also works as he said. The magnet should be almost directly over the pickup.


Good call.

OP check the polarity on the crank trigger wheel, too.
 
Posts: 9398 | Location: Madeira Beach Fl. | Registered: June 12, 2018Reply With QuoteReport This Post
DRR Pro
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quote:
Originally posted by Strange Magic:
Your transducer is junk, most likely.

It's why you will never see an msd wheel or transducer on any of my engines.


What brand is better iyo? Or do you just use a distributor trigger?
 
Posts: 2681 | Location: 53056 | Registered: December 30, 2009Reply With QuoteReport This Post
DRR S/Pro
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I use Moroso. Never had a failure yet. I've experienced over 20 bad msds, most of the time it's the transducer. 2 of the times it was the wheel.


strangemagicperformance.com
oldsperformanceproducts.com




WD dealer for just about all your performance needs.
 
Posts: 1604 | Location: Suffern, NY | Registered: November 03, 2001Reply With QuoteReport This Post
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