governor linkage woes.

[MacGyver]

I'm having a *really* hard time getting my governor linkage to work. The trouble spot is the area shown inside the yellow oval in this photo.
http://sweetwatergems.weirdstuffwemake.com/geek/images/lister_2112b.jpg

That little sliding doo-dad there simply refuses to play nice. It's fine in the "opening the rack" direction, but once the fuel rack is full open, attempts to close it bind up that sliding linkage thingy and it simply will NOT move. If I give a tiny push on the end of the rack itself then it will pop loose and move the rest of the way pretty freely.
It's like the geometry is just plain wrong, and it acts like one of those old VW jacks that works by wedging the moving parts against the support post.

At first I figured it was because the bore where the piece slides was so poorly machined (it looked like someone used a cutting torch instead of a drill to blow the hole), but even after careful cleaning up it wasn't any better.

After wasting a couple hours on it I finally I figured I'd fix it by drilling out the hole and pressing a brass sleeve into it so it would have a decent sliding surface.  That was no help at all and it binds up just as bad as it did before.

I don't see any choice at this point but to make a new bell crank piece and try and design the damned thing so the geometry isn't so stupid.

Has anyone else had this problem with their linkage?

I'd sure love to see photos of a REAL lister linkage up close and with the rack in the fully closed position. Any chance someone could send me a good close up photo?

Thanks for any insight y'all can offer!

[Doug]

So are you getting discouraged yet?

I think Goerge B ( Utterpower ) has photos of a govener fix on his site. Did you gte the CD with the Listeroid fixes he sells?
Suposedly there are a lot of tips and tricks in it.

[MacGyver]

So are you getting discouraged yet?

I think Goerge B ( Utterpower ) has photos of a govener fix on his site. Did you gte the CD with the Listeroid fixes he sells?
Suposedly there are a lot of tips and tricks in it.

Discouraged *yet*? Hell, I was discouraged a month ago!
But actually I think I've worked through most of the "obvious" problems and I'm on the home stretch now and rather less discouraged than I used to be. 
This is one of the last things to be fixed I think. (God knows what will happen when I start it)

Yeah, I've got Georges CD and there's lots of good tips on it but I didn't see any fixes for this particular problem.

It's very strange. Even now that all the involved parts have a nice fit and finish it just won't work. There's still a very specific spot about 10% in from "rack full open" where it just binds up solid when trying to close. Something about the geometry just makes it lock right up.

[t19]

I'll go take a couple of pictures and send them too you of my Listeroids

[Tom]

Could the pin be a bit loose in the hole? That might allow the assembly to get cocked and bind. Also have you tried (well I'm sure you have but I have to ask) sliding the parts and putting pressure in the direction of force when it is closing to see if you can feel the binding.

And another possibility, how smoothly does your rack move? Could the binding be there?

[ronmar]

Is it binding while running, or just while you are working it by hand?  If it is binding as you are working it by hand, perhaps you should leave it alone, and don't do any further modifications till it is running and you can experiment with it then.  Because of the short top on the bellcrank that the yoke plugs into, it can't be too tight a fit as it will never have enough surface area to allow it to slide smoothly in and out when under side loads.  If you make it too tight, it will jam.  One thing in this crude linkages favor is the nature of the governor flyweights.  The natural acceleration and deceleration of the 4 cycle engine causes the linkage to be pretty much always in motion.  Because of this, I think that you will find that when running, that motion will keep the linkage from binding. 

The one on mine is quite loose and has worked fine for over a year now.  In fact, I actually added a very light spring stretched across the opening of that 90 degree bellcrank to gently hold that sloppy yoke fitting at one end of it's travel to improve throttle response.  I first put a small rubber band there, but refined it with the spring:)

Shown Here at the full throttle position.  If I hold the bellcrank, I can work the rack back and forth perhaps a little more than 1/32 of an inch.  This spring in combination with Georges governor spring mod gets me 58-62HZ full load to no load.  I can probably refine this a bit with a better main governor spring or a pair of springs, but as this is plenty of RPM control for domestic power generation, I havn't seen the need to mess with it... 



Ron

[Quinnf]

Steve,

The linkage requires that the pin slide in and out of the yoke on the end of the bellcrank as it rotates.  It seems awkward, but it does work.  Your pic shows the thing goobered up with paint which is how they usually arrive.  All you need is to make sure the plane the bellcrank is rotating in is parallel to the movement of the fuel rack.  I carefully bent one arm of the bellcrank until the pin slid in and out easily and had no further problem.  You've got to do that VERY carefully because cast iron does not like to bend.  Just a slight tweak was all that was necessary to eliminate the side pressure on the rack.  Get it lined up and it will move easily.

Quinn

[JohnF13]

Steve;

One other thing - as you have had that assembly apart, you may have put it back together with the yoke 180 degrees out.  I know it doesn't seem to make sense, but sometimes in building these things the Indians aren't, well - let's call it "too accurate".  Occasionally the slot in the yoke is offset slightly and this can cause binding. Clean up the paint as Quinn suggests, then put it all back together with the yoke oriented in the position that it works the best.  As others have said, this is not generally a problem when the engine is working, but if you are overly picky when going over it you can actually find problems that are not there when running the engine.  Also, do the governor mod that George B has described - it's cheap, easy and will ensure your machine works a lot better.

[hotater]

If a pin binds in a hole it's usually because the end of the pin is too sharp.  Grind an angle on it.

[MacGyver]

Thanks everyone for all the suggestions, and especially to Andrew and Ron for the photos. I'm overrun with house guests this week and it'll be a few days before I can look at it again.

I'll be posting more about the problem soon.

Thanks!

[rf]

Hello MacGyver, I had the very same problem, I polished and champered the clevis pin and it still would stick.
 I've uploaded three pictures in a rar file with some explanation which can be downloaded at this web site. ( http://www.badongo.com/file/8842449 ) It is a very simple fix and in my case the problem is eliminated.

 Please... no comment on my lack of dremel skills.

Regards
Rf

[MacGyver]

Thanks to everyone who responded... and especially Andrew and Ron for the photos.

I got a chance to fiddle with the linkage again today, with absolutely no luck.

Here's what I'm sure I know so far:

1) There is absolutely no paint or filler putty on any of the friction surfaces. That photo I showed was taken the first day that I got the engine, so *everything* was still contaminated with green paint. Getting all the paint off of the places it shouldn't be was the first thing I did before I even attempted to make the linkage work.

2) The binding is definitely coming from that sliding post and hole setup. All the other linkage parts move freely and easily with no binding at all.
The rack moves in and out easily even with a good amount of side force applied and I'm sure that's not the problem.

3) The binding only occurs in a very specific spot, and only in one direction.(closing the rack)  Everywhere else in it's travel it's as smooth and nice as can be.
    If the rack is never opened more than about 90% of the way, It's fine. It's just one very specific spot as you begin to close the fully open rack that's a problem.

4) When working the governor arm (that comes out of the cam cover) by hand, the thing will lock up every time at that one spot, and it locks up SOLID. If I tried to put enough force on it "force it to pop free", I think something would bend or break first. It doesn't just "feel a little tight there", it locks up as solid as if it was welded.
HOWEVER, when it's locked up (and I'm still trying to close the rack with the governor arm), if I put my finger on the end of the rack and just give it a very gentle nudge inward, then the whole thing pops free and closes easily. You can *see and feel* that little post straighten up slightly in it's bore and let go. That damned post and hole setup is definitely where the trouble lies.

5) At first I just assumed it was because of the terrible raggedy "staircase" finish inside the hole, so the first thing I did was to ream the inside of the hole some to clean it up and also to grind the end of the post to a psuedo ball shape so that there were no square corners to dig into the side of the hole. As I cleaned it up, at first it seemed to get a little better, but it was still horribly unacceptable. But then as I reamed it out further it got way worse again and there was obviously too much clearance between the post and hole.

6) So... I drilled the hole out bigger and tapped it for a 1/8" brass pipe nipple. I took a nipple and cut it off to the right length and screwed it into the hole and drilled it out until the post just fit nicely into it.  Voila!  Instant brass bushing!
When I was satisfied with the fit between the "bushing" and the post I made a second bushing to toss in the tool box. That way if it ever wore out I'd have spare that I could change in seconds with a pair of pliers... Clever, eh?

And when it was all assembled with it's new slick fitting bushing did it work perfect?   NOT! ... it was just the same as before.


SO.  Here I am back at square one....
One of the things I've noticed from some of the photos I've received is that the bellcrank pivot bolt on mine may be located somewhat more to the right (closer to the injector pump) than the ones in the photos. Maybe that and/or other subtle geometry changes are causing a problem when that post/hole setup is at just the right angle. Shit, old VW jacks worked on the principal of "wedging" a steel post in a bored cast iron hole and it worked very well. I can only assume that the same principles are unintentionally at work here.

I just can't go with the suggestion that it will probably be fine when running, with some vibration, etc...
It's just *way too bad* to even entertain that thought. If it locked up when the rack was closed, I *might* give it a test that way, but since it locks up when trying to close a full open rack THAT sounds like a major hazard to me and my loved ones and I ain't going there.  If I can't fix it to my satisfaction I'll sell it for scrap before I'd attempt to run it the way it is.

Fortunately it's a pretty low tech piece, and I'm quite certain I could build a new setup in less time than it's taken me to troubleshoot the old stuff so far...

Heh, I just read the post and looked at the photos by RF.   EXCELLENT!
I'll give that a try next.

[MacGyver]

rf,

Thanks very much for the photos!  I think that's the solution I was looking for!

[listerdiesel]

One of the problems with the setup is that the arm wants to describe an arc and the pump rack wants to describe a straight line.

The sliding yoke is an attempt to square the circle, but it does depend on a good fit and lunrication of all parts.

There are a couple of things that could help:

Fit a solid link like a cycle chain link (but bigger) between the arm and the rack so they can describe their own paths. It ain't perfect but might be better than what you have now.

It appears to be a problem of geometry conflicts as much as anything else, and really requires a bit of good engineering to make it work.

Our 15hp Diter (Spanish) diesel engine has something equally awful, leading to extreme wear of the injection pump rack bushes.

Peter

[MacGyver]

One of the problems with the setup is that the arm wants to describe an arc and the pump rack wants to describe a straight line.

The sliding yoke is an attempt to square the circle, but it does depend on a good fit and lunrication of all parts.

There are a couple of things that could help:

Fit a solid link like a cycle chain link (but bigger) between the arm and the rack so they can describe their own paths. It ain't perfect but might be better than what you have now.

Thanks Peter,
I've been thinking about a setup like you described that uses a chain link as a "connecting rod" to better convert the rotary motion to linear.
I've also considered a method that uses a "fork" that sticks up from the arm and engages a small roller bearing bolted to the rack.

I'll probably try RF's method first and se how that goes before I redesign the thing.