Author Topic: that spring thing  (Read 2226 times)

32 coupe

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that spring thing
« on: January 15, 2018, 11:28:47 PM »
My 25/2 running about 720 rpms runs out of steam at 5k load.

I believe the governor spring is too heavy.

The linkages are free and easy to swing from stop to full throttle. No binding.
I added a spring or two to take all the slop out. Time was not a factor so time
was extended for proper set up.

Injector timimg, pretty much the same deal. I spent hours setting and adjusting
timing on valves and injectors.

Starts well, runs good.

With that said I am convinced the govenor spring must be on the heavy side.

Near a 5k load the engine is working harder and the hz will drop from 60/61 to 57/58
on the gen head. 11kw "stamford"clone, so I don't think thats the problem.

The rpms are dropping about 45.    720 to about 675 give or take.

The exhaust temps are within 4 degrees of each other under load.

Cooling temp leaving the heads near 190/200 with return at 160 or so.

I would think the beast should easily pull 8 or 10kw before it starts to
load up.

I say softer spring.   

What y'all think ?


Gary




 
« Last Edit: January 15, 2018, 11:48:01 PM by 32 coupe »
Metro 6/1 turning a ST 7.5 KW gen head
Changfa 1115 turning a ST 15 KW gen head
Ashwamegh 2/25
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dieselgman

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Re: that spring thing
« Reply #1 on: January 16, 2018, 12:03:20 AM »
Try it and see... sounds like you have covered the bases pretty well. You should not run out of power before maxing out that genhead. Of course, your engine will need some break-in time before developing its full horsepower potential.

Some thoughts... the 25 horsepower rating was provided by whom? And at what rpms? And how did they determine that horsepower? If you are running well under the rated speed then your power ratings will also have to be adjusted.

Any black smoke? What amount of fuel rack is being used under the max-load or overload condition? If the pump is not opening up, then look further into governor control... especially the linkages.

dieselgman
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BruceM

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Re: that spring thing
« Reply #2 on: January 16, 2018, 12:33:36 AM »
Counterweights in the governor may also be an issue if they were downsized for much higher rpms than you are operating at. 

I'd certainly try a softer, longer spring.  My 6/1 is still running on a combo of two soft springs in parallel; best match I could find.  You know you've gone too soft when it hunts. 


32 coupe

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Re: that spring thing
« Reply #3 on: January 16, 2018, 01:27:14 AM »


It's an Ashwamegh 25/2 @ 1000 rpm.


The rack is open 20 to 25 % ( this just a guess) never the less, still plenty
of rack left.

It has 20 or so hours on it. I ran it with the junk 7.5kw head loaded with
4kw or so.

No black smoke.

I can rest my hand on the throttle linkage and bring it right to speed. 61/62 hz @  720 rpm.



Still thinking, even with the reduced rpms,  it should still pull 8 or 10 kw.

I will look for some springs in the next few days and see what I can come up with.


Thanks for your input.

Gary


Metro 6/1 turning a ST 7.5 KW gen head
Changfa 1115 turning a ST 15 KW gen head
Ashwamegh 2/25
John Deere 110 TBL
New Holland TC 30

"I was sitting here reading this thinking what an idiot you are until I realized it was one of my earlier posts !"

38ac

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Re: that spring thing
« Reply #4 on: January 16, 2018, 01:46:47 AM »
The longest and softest spring that will give the required RPM without causing the engine to  hunt  will give the best governor action due to the fact it will have the most constant rate of pull over the length of movement. That is why too light a spring will cause the engine to hunt as Bruce said.  I have seen CS Listers in Amish engine sheds that had screen door springs stretched to a custom bracket.
Sometimes the governor weight forks will have flat spots and thus not operate smoothly and will cause what you are experiencing.
There are several versions of 20/2 some are overbore and operating at 800 rpm some are standard bore running at 1000.  A standard bore engine operating at 800 rpm would be about 16HP while a big bore would be something over that. Either way you should be able to pull over 5kw
« Last Edit: January 16, 2018, 12:03:15 PM by 38ac »
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