Technical Cool old rev limiter question

Has anyone ever used one of these?
How is it wired?
How well do they work?
I'm sure the screw in the side is for adjustments.
I have seen other styles of cable driven rev limiters over the years but never this style. The moroso sticker looks like early to mid 60s. Later 60s stickers dont have the triangle on the logo. Thanks.

 

The adjuster says one 360 degree equals 1000 rpm.

 

Looks self explanatory if you'd open the side cover. Has to be only an adjustable governor with the option of how one would like to connect leads.

 

Interesting. Any chance you can open it for a picture of the guts?

 

I would wager a guess that the hot wire off of the ignition switch headed to the coil would go to C, then another wire from the NC terminal to the + side of the coil, when the preset RPM is reached it interrupts the ignition circuit. If I'm right I'd imagine the engine would buck quite a bit when it bounced off the limiter.

 

Haven't found any instruction's for C NC NO terminals. I'll guess C - ground. NC - neg. terminal of coil. NO - ground signal to in car indicator light with constant or key power.

 

from 1969. The date code on the microswitch is how I know.

 

Good info so far. Has anyone used one? Any clues on when they were made? It would look cool in a car with a matching moroso cable driven tach. I have run across a few cable splitters. Some of the parts were common in the early pro stock days.

 

like I said, 1969 date code on the switch in there. That matches what I know about the Moroso logo on the outside.

I have a couple of the newer round ones, never did try them out...I fixed my shifter instead.

 

I must have been typing while you were posting. The round units that screwed up and down I believe were the newer style. I see them in pics of early pro stocks. Thanks squirrel.

 

The switch contacts: C is common
NC is normally closed
NO is normally open

 

Normally Open and Normally Closed. C could be common, or whatever they call it. Normally open = a switch that is open in normal position, and closes when activated, normally closed is the opposite.

 

Those limiters could be rather rude as they shut the ignition off period. Depending on how much over ride or action movement in the micro the ignition would turn back on. Even just a hundred rpm drop means 400 no fires. Nice batch of fuel to ignite when turns back on!

 

Im trying to figure out the adjustment.... the pics show the adjuster screw on the outside of the box, next to, but a distanced from the cable input, but I don’t see anything inside of the box that it is adjusting.

 

There are pictures of two different boxes. Some had an exterior screw, some without.

 

I think it adjusted a hidden spring inside the shaft, which affects the weights. More spring pressure, higher rpm

Sent from my Trimline

 

See spring left of governor weights. The adjuster screw will cause shaft to telescope over it's self and change the spring rate.

 

I pulled the cover off and had a look. The screw when turned pivots the switch up and down. The contact for the switch moves closer or farther away from the disc on the shaft. The weights pull the disc down toward the switch closing the switch. The spring on the shaft centered between the weights pushes the disc up away from the switch.
I might try this in my four speed chevelle. I would set it rather high to be used in the event of a missed shift or broken drive shaft. It would be the last resort to before the rods came out.
Now that we know how it works and what the contacts mean how would it hook up? I'm no electrician.

 

If it has points, connect NO to the coil negative, and C to ground. This will ground the points when it over revs. If it has MSD then connect the wire from the ignition switch to NC, and the ignition wire from the MSD to C. This will be like turning off the ignition switch when it over revs. There are other ways to wire it also.

Sent from my Trimline

 

Thanks. I think it would look cool in the chevelle wired to a Corvette tach drive distributor. You wont see that set up very often on cruise night. I have a good matching tach and some cables laying around the shop so I could make it all work.

 

The unit I posted stated 7000 rpm written in marker. A fixed unit now that I've seen racer-x's unit.

Unit I posted


vs racer-x unit.

 

I dont see the adjusting screw on your box. Maybe yours came pre set. It would be interesting to know which vetsion came out first.

 

Both boxes are adjustable. The instructions on the inside of the cover tells how. If you notice, cast into the inside bottom of the box, there are four or five buttons. (next to the lid screw boss opp. the shaft side) There is also a screwdriver slot in the sheet metal bracket for the switch. The one with the exterior screw is just handy! (but may let the switch vibrate, because the switch hold down screws are not tightened after adjustment)

 

Hi. If you look at the shaft just on each side of the 2 weights you can actually see a coil spring over the shaft. That is what the outer screw is adjusting. Jimmie

 

It's not my box. It's one I found while researching (it's for sale on the net) for information and instruction's to your unit. Any info that I wrote on how it works and how to wire it is purely a guess on my part.

 

The shaft with the weights and large disc slides on the inner shaft. When the weights fly outward it pulls the shaft and disc down to the switch. The adjusting screw makes the switch pivot closer or further away from the disc.
More rpm pulls the disc further down the shaft. The inner spring returns the disc back to its original position. Syncing the movement of the disc travel and switch position must be how the final rpm limit is set. I have been playing around with it.
I can really see getting rid of my msd and putting on a Corvette tach drive distributor. I'm setting up my car with a 427 having all period correct parts. This box would definitely be a conversation starter. To take it a step further there was a timing cover produced to put the distributor in the front of a bbc. That way it would be front and center. My friend runs a cover like that. There are alot of cool period correct parts on this engine. I would like to do something similar but without the manafree. Snowflake heads are for sure going on along with a factory six pack or four barrel.

 

I just got off the phone with the guy that has the 55 chevy I posted a few pics of. The front drive is made by sommers brothers. They can be found in magnesium and aluminum. He thinks he has a extra to sell me. Water pump spacers are required.

 

GM performance makes one to use a SBF distributor on an LS. First one I see for a BBC. Cool.

 

Trouble is you get a truer timing reading with the distributor on the tail end of the camshaft due to the camshaft twisting.. Maybe a roller cam would work..