Rev limiter for Dura-spark

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I'm a complete newbie to straight line racing.

Now that the drivetrain should withstand the torque, I am working toward taking the 250/Comet to Test and Tune days, Lebanon Valley. It's a thrill to open it up on the road but the tach climbs fast with speedo way past legal.

Looking to install rev limiter setup with my current ignition or simplest alternatives. I would like adding some confidence in RPM containment as 250 at WOT still pumps past 5K along with my adrenaline.

I'm currently using DS-I dist. and HEI trigger.






PS Please explain huge tachs with lights and knobs in shiny rows of "muscle clones" at cruises. Cosmetic or critical?.

thanks
 
8) it seems to me that msd has a rev limiter that will work with the duraspark ignition. you might have to go through a ford motorsport dealer to get one though.

as for the large tachs with the lights and knobs, they were originally designed for pro stock cars back in the early 70's. the shift light was added a couple of years later so that the driver didnt have to try to read the tach with all the vibration the drover has to endure during a run. the knobs came later to allow for adjusting the rpm at which the shift light comes on, and some tachs have a memory that will let the crew chief know just how high an rpm the engine actually hit. also some high end tachs will allow the crew chief to download the run as the tach sees it to a computer for evaluation. i wish we had something like that when i was a crew chief many years ago. of course laptops were not even thought of back in 1979.
 
Quick followup ?' Now that I think about it, how do rev limiters work - does engine fire along at power or does engine cut power if preset is crossed?. So the RPM calibration on the huge tachs isn't talking to a rev limit box just the rpm indicator lamp?, would seem to make sense unless irev limit is safety crowbar system.

thanks
 
8) the big tachs were created to be easy to read quickly.

as for rev limiters, there are three ways they work depending on the system. on an EFI system a rev limiter cuts the fuel flow off to keep an engine from reving higher. the other two types use the ignition system to control rpms, one design backs the timing down to limit the rpms, and the other shuts off random cylinders to limit the peak rpm. a hard rev limiter will jump into action the second the rpms hit the limit. a soft limiter will start pulling back the power a couple hundred rpm short of the rev limit.
 
I hope MSD has updated their rev limmiters. Years ago the msd boxes would pull out cylinders at random. Any rev limmiter that pull out cylinders at random isn't the best way to slow down a engine. Most of the ones that do that are the one where you hear a lot poping and banging when on the limmiter.
I know they are currerently hard to find but the unit that crane made worked extremly well.
ONE note though the units in the crane catalog will NOT work with six cylinder engines. Six cylinder rev limiters were made to order. This is because they are not random cutout boxes.
Good ones from whomever will cost more that the old tech way.
 
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