Governor drift - Help please

[veggie]

Hi All,

The last 4 times I ran my engine, I have had a hard time getting it to hold a set speed.

When I apply load (say 1.5kw) the engine bogs down to 57hz and stays there (only 1/2 loaded).
So, I increase the speed a bit to get 60hz while it's loaded.
When I release the load, it revs up to 68hz. !!
I add load again, it drops right back to 56...57...58...57 and does not recover.

If I adjust the linkage to get 59hz to 60hz under 1.5kw load, it slowly revs back up to 68 HZ when the load is release (takes about 30 seconds to reach 68hz).

I have previously done the spring modification to reduce any play in the linkage.
Although there seems to be excessive play at the pin joint on the rack.
Very loose Clevice pin fit.
Could this loose pin joint create the symptoms described above or am I chasing two different problems here ?

Has anyone else had to solve this loose plunger/bore fit at the rack connection ? If so, how did you solve it ?


Cheers,
Veggie

[Ronmar]

Have you tried a spring across that angled linkage and yolk shown at the end of your video?  I have a VERY lightweight spring very lightly loaded, connecting between a ring(between yolk and rack) that is around the pin that runs thru the rack, across that 90 degree bellcrank to the pin that connects to the vertical rod that runs down to the governor bellcrank. this takes the slop out of those pins and  really cleaned up the lag and overshoot in my governor linkage. It must be a very light spring force, as too much spring tension will cause the yolk connected to the rack to bind.  


I also did the "Utterpower mod" and took that lower hooked adjuster out of the main governor linkage and ran it thru a block bolted to the crankcase where the spring was originally attached. The spring is now connected to where the hooked adjuster was originally with a cotter pin.  This also greatly improves governor response.

[BruceM]

I had the same performance problem, caused by the yoke pin binding.  I drilled out the arm for a bronze bushing from ACE glued in with weldbond, then drilled the bushing to fit the pin after I smoothed and polished it.  Both the pin and the arm looked like they had been machined with a chain saw. 

Check your pin/arm joint for binding when under pressure.



 

[Jens]

In addition to all the previous suggestions, check out the ease of movement in the injector rack. The symptoms you report are exactly what I saw when the pump was gummed up. The gumming up is apparently due mostly to high temperature. When Thumper was in it's own sound proof box, the injector pumps gummed up regularly but when the whole engine room was sound proofed and the engine enclosure was removed, the problem went away.
BTW, we are talking about 500 hrs before gumming so if you are still running a show engine rather than a work engine, this is unlikely to be an issue.
Point is, the governor has limited power and unless everything moves VERY freely, you will get issues. Some speed droop is normal although your issue seems a bit extreme.

Jens

[veggie]

I had the same performance problem, caused by the yoke pin binding.  I drilled out the arm for a bronze bushing from ACE glued in with weldbond, then drilled the bushing to fit the pin after I smoothed and polished it.  Both the pin and the arm looked like they had been machined with a chain saw.  

Check your pin/arm joint for binding when under pressure.
 

The pin and bore were definitely binding.
Terrible finish on the "machined" surfaces.
A week ago I polished the surfaces and lapped them with valve grind past. Then polished the pin with emery.
Glass smooth.

BUT, they still bind because there is so much clearance in the bore that the pin cocks at an angle and grabs the bore.
I too thought of a bushing to get the clearances back to something respectable. Perhaps that is a good upgrade to perform.

[BruceM]

With the bushing I was able to support the yoke pin more fully, so that there is almost no exposed pin when the rack is closed. Measure yours with the rack closed, and then add a 1/16 less height when gluing in a bronze bushing.  The bush and pin polish job is cheap, at least.

The length of engagement of the pin and sleeve should be increased, and these parts need much better fit and finish.  It seems likely to me that something was copied incorrectly or was "value engineered" too much. 

[oiler]

Try to give the vertical arm half a turn longer....it worked on my genuine 6/1

[veggie]

BruceM,
The machining is done and the clearances are matched.
The rod slides nicely in the yoke with minimal play.
When lightly oiled it's as smooth as butter  

Oiler,
Thanks for the idea of adjusting the vertical rod.
I will give that a try, but first I need to know exactly what we are effecting by adjusting that rod.
Eg: What is happening to the system when we make it longer or shorter. ??

And how do we know whether to lengthen or shorten?, based on what symptoms ?

Anyone ?

veggie

[veggie]

*** UPDATE ***

Here is some feedback for anyone else who is "tuning" your governor linkage.

View your clevice / IP rack alignment from the top.
Mine was out of alignment enough to create drag once assembled.
I added a machine washer on the Clevice lever shaft between the engine block and the lever in the appropriate thickness to bring the joint back into alignment.
(approx. 0.025" thickness)
Now the linkage is free and smooth.

I tested the engine and the governor is now very responsive.
62 hz unloaded and 60 hz Loaded.

The circle in the picture below shows the interference.

[BruceM]

Good post, Veggie.  That's a new one and I'm sure it's not unique to your engine. That much side force on the yoke pin would certainly make it bind up unnecessarily.

Bravo, you're governor response is looking good.

Best Wishes,
Bruce

[Hugh Conway]

Still working on that seemingly universal gov problem here. In a no load to 2800W load situation, I have 5Hz difference.

What I've done so far:

Utterpower mod on the spring/hook.

Bushed the top clevis, and extended the bushing a bit. Never had any binding beforehand, just lots of slop.....in fact so much that it was not necessary to drill our the bellcrank in order to fit a bushing!

Bellcrank pivot bolt bearing surface and thread sections were not parallel, bolt wobbled as it was screwed in, moving the bellcrank side to side. Made a new bolt.

Made new, slightly larger diameter pins for all the clevis ends, drilled clevis' and bellcranks to give close tolerance fit.

Found top clevis binding on the rack due to misalignment of the top bellcrank (probably the reason for the original bent pivot bolt.
Carefully (!) bent the bellcrank a few thou to eliminate any binding.

Everything moves freely as individual parts and as fully assembled. The slop in the linkage is gone.

Changed adjustable rod to find optimum length.

Originally, I had about 8Hz difference between no load and 2800W load, all the above has netted me 3Hz. Now have 5hz difference, maybe that's the best I can hope for.

I am in a remote area, so have had a spot of bother in finding different gov springs, but perhaps that's the next step?

Open to suggestions for further refinement.

Thanks for any input.

Regards to all
Hugh

[Tom Reed]

Well you've covered everything except for the weights and ring on the cam shaft. Since you've gone as far as you have, the cover can be removed without pulling the flywheel by removing the studs. The ends of the weights should be rounded where they contact the ring. If that looks good try a softer spring.

[BruceM]

+1 Tom's suggestion.  Softer spring until it hunts.  I had to use two springs, one was close but hunted, the second was a very soft add on.  2 Hz is hard to get, be happy with 3Hz full to no load.

[Hugh Conway]

Thanks to Horsepoor on LEF, I think we have a winner in the governor spring hunt.
I posted the below on LEF, and wish to share it here. This spring modification worked for him, and it worked incredibly well for me.

Quote from: Horsepoor on September 26, 2013, 10:06:57 pm
Home Depot stock number is 759 541 and comes in a pack of two different size springs for a total of four. The sizes are: 7/16 in X 2 inch X .062 in with a safe working load of 18 lbs - these are the two you don't want to use. In the same package is: 9/16 in X 3 in X .054 in with a safe working load of 9.55 lbs - this one worked well for me out of the box. So for a couple dollars you may have a repeatable solution. Remember, where the India guy decided to drill the stud hole for the other end of the spring is probably random but I hope it will be close.
Great find, Horsepoor.
I bought a package of these springs on Ebay (not available from Home Depot Canada) Tried one as you suggested.
With all my previous governor mods, the best I could do was a 4Hz range. Included in mods were an assortment of springs. (See my above post)
Just installed this spring and gave it a try.
JKSON 6/1 driving Utterpower PMG

Results...........DRUM ROLL..............

No load 60.4 Hz
3150 Watt load (measured with Kill-a-Watt meters on both legs) 59.4 Hz

Pretty damned good.
Get yourself a package of these springs and give 'er a try. Sure works on my engine too!

Cheers,
Hugh

[Horsepoor]

Hugh,

Thank you for the compliments. I have achieved 2 hz from zero load to full load on both my listeroids. But, the search for prefection has continued. I recently may have found the ultimate solution for at this site:

http://www.governors-america.com/products/governors/Analog/ECC-Series/ECC328-12 

I asked for a price, if it is less than $200 I am going to buy one.

Bruce