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View Full Version : Question about MSD 8724 Rev limiter. Update. Issue resolved.



nucjd19
05-18-2021, 04:19 PM
Quick question for the Hive mind.
I have installed an MSD 8724 Rev limiter on my engine ( BPE 347 Carb ) and installed per the instructions with a good ground on the frame. The white trigger wire connected to the neg terminal on the coil with the green also connected to the negative on the coil. Finally the red is connected to the positive on the coil. I installed per the diagram on the MSD instructions. Now, the weird part. IT states it comes with a 6k,7k, and 8k module for the limiter but when I opened the box there was a 3k in there too. So I was like SWEET I will drop the 3k in there as sort of a governor while I go kart and test stuff. So, I fired it up but it will happily rev past 3k with no problems. Here is the diagram I used.
https://thefactoryfiveforum.com/attachment.php?attachmentid=148018&d=1621372679
So even though the diagram shows the white and green wire directly tying into the negative terminal should I directly splice the white wire into the trigger wire coming off the points? OR is it pilot error with poor crimps. Any advice is appreciated. Picture for your time.

https://thefactoryfiveforum.com/attachment.php?attachmentid=148014&d=1621370838

Railroad
05-18-2021, 04:35 PM
The white or the green should not connect to the coil, probably disconnect the distributor wire from the coil and connect it to the white or green. This would regulate the pulse to the distributor, through the box and chip.
The black dot that says (indicates connection) is throwing me a curve. Something is not shown?

Make sure your engine is grounded to the frame, battery.

What type of distributor are you using? Your rev limiter will work only with specific types of distributor.
No personal experience, but have read to not use with MSD 6 or higher number boxes. I think it will work with a MSD 5, Mallory or Pertronix distributor.

TMartinLVNV
05-18-2021, 04:41 PM
I have the Pertronix rev limiter on mine. I'm confused as to why there are two wires going from the rev limiter to the negative side of the coil. If white is the trigger, what is the green for?

Nothing should be going to the distributer itself. It is hooked up to the coil only.

On the Petronix, there is a ground, ignition (coil +), and coil - connection only.

Railroad
05-18-2021, 05:23 PM
Per the diagram, I guess the white or green might become a shunt when the rev limit is reached,,, making a soft miss.
I am still thinking the dist or engine needs grounding.

nucjd19
05-18-2021, 06:36 PM
Thanks for the info guys. I grounded it to the frame. I will re read the instructions again. I will look at my MSD distributor and cross reference the unit as well.

Wait... I think my little brain is starting to figure it out. So the white will intercept the trigger and then the green ties to the negative on the coil allowing the limiter to set between the distributor and the coil. I will reread my instructions again.

nucjd19
05-20-2021, 06:31 PM
Went back and Read the instructions. Instructions said to splicethe white wire into the trigger wire from the distributor. Once I did that and slapped the 3k module in it would sputter the minute I hit 3k. So I am all good. Thanks for your suggestions everyone!