Register now to get rid of these ads!

Technical Cool old rev limiter question

Discussion in 'The Hokey Ass Message Board' started by racer-x, Sep 25, 2020.

  1. 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. 20200925_113510.jpg 20200925_113400.jpg 20200925_113409.jpg 20200925_113451.jpg
     
    kidcampbell71 and squirrel like this.
  2. The adjuster says one 360 degree equals 1000 rpm.
     
  3. 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.
     
  4. G-son
    Joined: Dec 19, 2012
    Posts: 664

    G-son
    Member
    from Sweden

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

  5. 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.
     
    Johnny Gee likes this.
  6. 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.
     
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 46,871

    squirrel
    Member

    from 1969. The date code on the microswitch is how I know.
     
    Dick Stevens, fauj and Tman like this.
  8. 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.
     
  9. squirrel
    Joined: Sep 23, 2004
    Posts: 46,871

    squirrel
    Member

    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.
     
  10. 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.
     
  11. J. A. Miller
    Joined: Dec 30, 2010
    Posts: 1,409

    J. A. Miller
    ALLIANCE MEMBER
    from Central NY

    The switch contacts: C is common
    NC is normally closed
    NO is normally open
     
  12. G-son
    Joined: Dec 19, 2012
    Posts: 664

    G-son
    Member
    from Sweden

    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.
     
    Johnny Gee likes this.
  13. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,602

    seb fontana
    Member
    from ct

    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!
     
    squirrel likes this.
  14. TRENDZ
    Joined: Oct 16, 2018
    Posts: 201

    TRENDZ

    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.
     
  15. grumpy gaby 2
    Joined: Aug 10, 2019
    Posts: 101

    grumpy gaby 2
    Member

    There are pictures of two different boxes. Some had an exterior screw, some without.
     
  16. squirrel
    Joined: Sep 23, 2004
    Posts: 46,871

    squirrel
    Member

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

    Sent from my Trimline
     
    seb fontana likes this.
  17. See spring left of governor weights. The adjuster screw will cause shaft to telescope over it's self and change the spring rate.
     
    seb fontana and squirrel like this.
  18. 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. 20200925_184724.jpg 20200925_184747.jpg
     
    kidcampbell71 and j-jock like this.
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 46,871

    squirrel
    Member

    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
     
  20. 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.
     
    j-jock likes this.
  21. 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
    [​IMG]

    vs racer-x unit.
    [​IMG]
     
    Desoto291Hemi and kidcampbell71 like this.
  22. 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.
     
  23. grumpy gaby 2
    Joined: Aug 10, 2019
    Posts: 101

    grumpy gaby 2
    Member

    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)
     
  24. ol-nobull
    Joined: Oct 16, 2013
    Posts: 1,510

    ol-nobull
    Member

    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
     
  25. 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.
     
  26. 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. 20190330_084516.jpg 20190330_084531.jpg
     
    kadillackid and Johnny Gee like this.
  27. 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.
     
  28. H380
    Joined: Sep 20, 2015
    Posts: 445

    H380
    Member
    from Louisiana

    GM performance makes one to use a SBF distributor on an LS. First one I see for a BBC. Cool.
     
  29. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 1,327

    Elcohaulic
    Member

    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..
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.