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  #1  
Old 08-19-2006, 06:11 AM
crashly crashly is offline
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Default msd 10...

Orginally we had problems with 6al not having enough spark to burn fuel mixture. Now purchased msd 10. What spark plug gap change would i use.
sbc twin turbo, methanol fuel , 7.5 comp static, 24-26 psi boost., 3.2 to 3.5 gpm fuel going into engine
thanks

Last edited by crashly; 09-01-2006 at 06:30 PM. Reason: correction of figures
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  #2  
Old 08-19-2006, 03:50 PM
bill jones bill jones is offline
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-I would like to say that I have tested one of the MSD10's many years ago and that thing took a ton of battery power---lots of amperage.
-It would drain a battery so fast it's just about incomprehensible.
-It seems to me like it used something on the order of 30amps at high rpm.
-----------------------------------------------
-I see where the MSD catalog says the MSD10-plus only takes 6 amps at 8000 rpm.
-So maybe MSD has changed something to significantly reduce battery amperage requirement but I would suggest that you might think about spin testing the distributor to the equivelant of about 8000rpm and check the amperage draw.
---------------------------------------------
-I can also tell you that the MSD10 box I tested was scary as hell and I'd suggest that you realize this thing can very likely do you serious harm if you get bit by the secondary spark.
------------------------------------------
-If I was going to use one today with your engine I'd start with the plug gaps at about .022" to .025" and change up or down about .002" at a time if you aren't happy with what happens at .022" to .025".
------------------------------------------
-I have seen many people grab ahold of the distributor cap to rotate the distributor to adjust the timing while the engine is running and I believe that would be asking for trouble.
-Personally I would shut the engine off to rotate the distributor.
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  #3  
Old 08-19-2006, 05:26 PM
crashly crashly is offline
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Default msd 10 spark plug gap

Quote:
Originally Posted by bill jones
-I would like to say that I have tested one of the MSD10's many years ago and that thing took a ton of battery power---lots of amperage.
-It would drain a battery so fast it's just about incomprehensible.
-It seems to me like it used something on the order of 30amps at high rpm.
-----------------------------------------------
-I see where the MSD catalog says the MSD10-plus only takes 6 amps at 8000 rpm.
-So maybe MSD has changed something to significantly reduce battery amperage requirement but I would suggest that you might think about spin testing the distributor to the equivelant of about 8000rpm and check the amperage draw.
---------------------------------------------
-I can also tell you that the MSD10 box I tested was scary as hell and I'd suggest that you realize this thing can very likely do you serious harm if you get bit by the secondary spark.
------------------------------------------
-If I was going to use one today with your engine I'd start with the plug gaps at about .022" to .025" and change up or down about .002" at a time if you aren't happy with what happens at .022" to .025".
------------------------------------------
-I have seen many people grab ahold of the distributor cap to rotate the distributor to adjust the timing while the engine is running and I believe that would be asking for trouble.
-Personally I would shut the engine off to rotate the distributor.

Thanks for reply.
I see the msd 10 has more?? power than a pro mag 12....
This is good, should burn all the fuel now. Have an alternator on car, soo this should help, especially when i warm is up in stageing lanes is should charge up. Was thinking about .035-.040 gap. Run .022-.025 with msd 6al, even went down to .015 but no change, engine still breaks down under load/high boost.
Car runs crank trigger, so timing should be done at front... staying away from "bitey " parts.

cheers
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  #4  
Old 08-19-2006, 10:03 PM
bill jones bill jones is offline
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-I just looked at the specs on MSD's website and that shows the MSD10-plus uses 26 amps at 8000rpm rather than the 6 amps listed in the catalog.
------------------------------------------------
-Then thinking back I was mistaken and finally realized it was an MSD8 I tested that used oh so much amperage---and MSD says that unit uses 36 amps at 8000rpm.
--------------------------------------------------------
-Personally I would not try as wide a plug gap as you are talking about until you have tried gaps in the mid .020".
-Part of the reasoning for that is---with these high powered ignitions the spark is going to GO somewhere and it will always take the path of least resistance.
-The wider the gap inside the engine and the higher the boost pressure and cylinder pressure----the spark becomes very reluctant to take that path and will usually find some other metal that is grounded to jump off to instead.
------------------------------------------------------
-So if the spark doesn't ever get into the chamber and nothing in there gets lit off then bad stuff happens.
-The spark will rather jump a full inch or more out in the open air than to try to jump across a .035" gap with nearly 3 atmospheres of pressure against it.

-When I test various ignitions I sort of like to know how wide of a gap the ignition systems are capable of jumping in open air and as you increase that gap at the end of the plug wire the spark is actively looking for everything that is metal & grounded and it quite often becomes REAL hard to keep all the spark energy going to the wide gaps I want it to jump.
---------------------------------------------------------
-It's your car & engine but I would be conservative on plug gaps and very concientious about the distances of the secondary wiring to ALL grounded metal and apply some effort towards insulation of the tight areas.
----------------------------------------------
-7.1gpm is pretty serious power---something like what? 2500hp? so if you have an ignition misfire that's a 312hp momentary hole in the power curve that can't be good.
-I'd vote against starting out with wide plug gaps.
--------------------------------------------------
-I think that having nearly 3 atmospheres of inlet pressure is going to require 3 times as much electrical energy has to be able to get across the same gap that racers are used to with a normally aspirated engine.
-Just because you might have that much energy available doesn't necessarily mean it can get across the plug gap without serious attention to the secondary paths of each plug wire---and the inside of the distributor cap.
---------------------------------------------------
-What are your intentions for eliminating the ionization inside the cap?
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  #5  
Old 08-21-2006, 08:36 AM
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msdtech22 msdtech22 is offline
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I would concur with Mr. Jones. To do away with the ionization in the cap, try venting the cap. Drill a 1/4 inch hole midway up the side of the cap between two of the poles and then drill another hole 180 degrees across from the original hole.
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  #6  
Old 09-01-2006, 06:28 PM
crashly crashly is offline
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Default msd 10

Quote:
Originally Posted by bill jones
-I just looked at the specs on MSD's website and that shows the MSD10-plus uses 26 amps at 8000rpm rather than the 6 amps listed in the catalog.
------------------------------------------------
-Then thinking back I was mistaken and finally realized it was an MSD8 I tested that used oh so much amperage---and MSD says that unit uses 36 amps at 8000rpm.
--------------------------------------------------------
-Personally I would not try as wide a plug gap as you are talking about until you have tried gaps in the mid .020".
-Part of the reasoning for that is---with these high powered ignitions the spark is going to GO somewhere and it will always take the path of least resistance.
-The wider the gap inside the engine and the higher the boost pressure and cylinder pressure----the spark becomes very reluctant to take that path and will usually find some other metal that is grounded to jump off to instead.
------------------------------------------------------
-So if the spark doesn't ever get into the chamber and nothing in there gets lit off then bad stuff happens.
-The spark will rather jump a full inch or more out in the open air than to try to jump across a .035" gap with nearly 3 atmospheres of pressure against it.

-When I test various ignitions I sort of like to know how wide of a gap the ignition systems are capable of jumping in open air and as you increase that gap at the end of the plug wire the spark is actively looking for everything that is metal & grounded and it quite often becomes REAL hard to keep all the spark energy going to the wide gaps I want it to jump.
---------------------------------------------------------
-It's your car & engine but I would be conservative on plug gaps and very concientious about the distances of the secondary wiring to ALL grounded metal and apply some effort towards insulation of the tight areas.
----------------------------------------------
-7.1gpm is pretty serious power---something like what? 2500hp? so if you have an ignition misfire that's a 312hp momentary hole in the power curve that can't be good.
-I'd vote against starting out with wide plug gaps.
--------------------------------------------------
-I think that having nearly 3 atmospheres of inlet pressure is going to require 3 times as much electrical energy has to be able to get across the same gap that racers are used to with a normally aspirated engine.
-Just because you might have that much energy available doesn't necessarily mean it can get across the plug gap without serious attention to the secondary paths of each plug wire---and the inside of the distributor cap.
---------------------------------------------------
-What are your intentions for eliminating the ionization inside the cap?
Thanks for your reply. Tried the msd 10, wow had to put a bunch more fuel into cylinder( changed main pill .035 "). Had no success with .030 plug gap, run out of time, will try .020 next time at track, alternator kept up with msd 10. only turn engine to 6600.
----------------------------------------------
-7.1gpm is pretty serious power---something like what? 2500hp?
sorry bit way out there..... more like 3.2 gal @ 6600.... pulled off fuel system and made a flow bench to see what was going on.
Have heard about drilling dist. cap will try one thing at a time ...

thanks again. will watch replies will interest.
Crashly
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  #7  
Old 09-01-2006, 10:35 PM
bill jones bill jones is offline
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-one thing that I'd think needs to happen when you are running an alternator is: we've been told that the msd needs to be grounded to the battery----so I'm thinking that the alternator probably should also be specifically grounded to the battery.
---------------------------------------------------
-I'm not exactly sure why but I think the couple of volts difference might possibly create some sort of problem.
-I have and maybe other guys are trying to connect their electrical stuff to the alternator to get that extra couple of volts to the ignition etc---and I've heard one pretty knowledgable person state that digital stuff in particular doesn't like the alternator for a power source because of the several volt differences.
---------------------------------------------------
-Maybe the MSD techs can comment on that.
---------------------------------------------------
-regarding venting the cap.
-I have several applications where I have connected a suck hose like from a header evacuation system or from a vacuum pumped engine to where I have a positive air movement induced thru the distributor cap.
-I pull the air out the bottom and allow the air into the top of the cap.
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  #8  
Old 09-01-2006, 11:03 PM
crashly crashly is offline
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Default msd 10

Quote:
Originally Posted by bill jones
-one thing that I'd think needs to happen when you are running an alternator is: we've been told that the msd needs to be grounded to the battery----so I'm thinking that the alternator probably should also be specifically grounded to the battery.
---------------------------------------------------
-I'm not exactly sure why but I think the couple of volts difference might possibly create some sort of problem.
-I have and maybe other guys are trying to connect their electrical stuff to the alternator to get that extra couple of volts to the ignition etc---and I've heard one pretty knowledgable person state that digital stuff in particular doesn't like the alternator for a power source because of the several volt differences.
---------------------------------------------------
-Maybe the MSD techs can comment on that.
---------------------------------------------------
-regarding venting the cap.
-I have several applications where I have connected a suck hose like from a header evacuation system or from a vacuum pumped engine to where I have a positive air movement induced thru the distributor cap.
-I pull the air out the bottom and allow the air into the top of the cap.
Bill, thanks again for you input. The msd is grounded to battery. I read the install several times before starting car. This is a good idea. Will try the the plug gap change to .020 asap.
thanks
crashly
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  #9  
Old 09-02-2006, 02:19 PM
bill jones bill jones is offline
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Location: SLC Utah
Posts: 411
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-what problems did you have with the .030" plug gap?
-what sparkplugs are you using?
-Obviously you must have seen some major power increase with having to add more fuel?
-------------------------------------
-When you have serious ignition power you need to pay a LOT of attention to EVERYTHING metal that is grounded vs your secondary wiring---as that spark will jump off as much as a full inch to metal ground rather than try to get across that small gap inside the cylinder with all that pressure.
-Crisscrossing the wires across the cap can be improved by having the wires come out in a radial fashion---so that the spark doesn't jump out from the inside the boot----from one wire terminal to another.
-------------------------------------
-If you increased the power with the additional fuel---maybe you need to back the timing down another couple of degrees also.
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  #10  
Old 09-02-2006, 06:32 PM
crashly crashly is offline
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Default msd 10

Quote:
Originally Posted by bill jones
-what problems did you have with the .030" plug gap?
-what sparkplugs are you using?
-Obviously you must have seen some major power increase with having to add more fuel?
-------------------------------------
-When you have serious ignition power you need to pay a LOT of attention to EVERYTHING metal that is grounded vs your secondary wiring---as that spark will jump off as much as a full inch to metal ground rather than try to get across that small gap inside the cylinder with all that pressure.
-Crisscrossing the wires across the cap can be improved by having the wires come out in a radial fashion---so that the spark doesn't jump out from the inside the boot----from one wire terminal to another.
-------------------------------------
-If you increased the power with the additional fuel---maybe you need to back the timing down another couple of degrees also.
bill: the .030 plugs were fine with low boost( 12.5) , once the boost was turned up, the engine miss fired and started to pop, bang and carry on. Haven't decreased the plug gap yet.
also the other problem is, we lunched a torque converter, and had another one made, larger( upfrom 9 inch to 11 inch). This brought the stall rpm down, and had to put MORE fuel into engine to stop lean backfiring out the turbo.
the timing is already down... down to 22-24 degrees. locked.
thanks for looking
crashly
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