FrontEngineDragsters.Org Forum
Drag Racing Discussions => Front Engine Dragsters => Topic started by: SaltandPepper on March 26, 2019, 02:42:09 PM
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OK fellas, I need some education here. I installed all my NOS system and everything seems to be working as should, all I have to do is retard my timing a few degrees as a last step but this is kicking me pretty good. Last year I ran it at the strip without touching the timing. When I put a light on it the timing was set to a white mark the previous owner had at 38-40 degrees and the engine ran well. When I move the crank trigger to attempt to retard it a few degrees I simply lose spark. When I put it back I run again. Run great when the light shows 40*, 50*, even 60* but put it one notch below that white mark and I have no spark at all. I am running a crank trigger to a MSD-7A ignition box. Is there something about this particular box that I just don't know about? I tried to google it but can find no info....there is plenty of info on a MSD-7AL but my ignition box clearly lacks the L. I am hesitant to run my NOS without the proper timing set. I got a feeling this ignition box may have been manufactured in the time of the steam engine. Any help on this would be appreciated.
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I cannot help you resolve your problem.
But as a matter of information I feel most people put too much timing in their engines which yields less-than-optimum performance. Adding compression, increasing volumetric efficiency through better induction and cams, adding blower OD, adding nitrous all usually mean you need LESS timing than stock, not more due to increased flame front propagation speeds, especially in view of advancements made in fast-burn combustion chamber technology. Igniting the mixture early produces negative work as you are building cylinder pressure with piston travel on the way up. The only exception I can think of is when a big piston dome gets in the way of flame travel, slowing things down. Big domes are passe anyway.
Taking timing out from your current timing seems directionally correct, with or without N2O. Keep working at it. Check your rotor registry.
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Something tells me this Ignition box is set to run at 38-40 degrees and more advanced. After putting some thought and effort into the internet I believe I need the MSD timing retard module that will allow me to set this timing back to 30-36 degrees to run my NOS. My problem is that this module has a 2 pin setup which plugs directly into the MSD-7......which does not offer that feature. If this is true.....do I need to upgrade my ignition box to accept a timing retard module or buy one that already has that feature built into it? I would like to hear others thoughts before I go spending that type of money.
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Have you checked rotor phasing in the distributor?
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Yeah BK, it is right on the money.
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Decided to go with a newer MSD ignition box to attempt to fix my problem....time for an upgrade on it also. The MSD-7AL-3 should make things a lot simpler and has the ability to retard the timing up to as much as 20*. Looks like a pretty good device for strict racing, I guess we will see.
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The 7al3 is perfect for what you are doing ! It has a lot of great features like a 2 step and timing control !