Author Topic: Type of Rubber for LoveJoy, ST -> ChangFa  (Read 5689 times)

Rainbow-Farm

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Type of Rubber for LoveJoy, ST -> ChangFa
« on: September 28, 2006, 06:38:45 PM »
The LoveJoy type coupler (universal joint) comes with BUNA or HYTREL rubber. According to the manufacturer, the softer buna is more appropriate. The Hytrel is almost as hard as plastic. I have been warned about too hard and I have been warned about too soft.

I will order the thing with the buna spider, unless I find reliable real-world experience otherwise... hey, how about, what is buna, anyway?

:-)

Do not trust the "grid" folks!

Rainbow-Farm

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #1 on: September 28, 2006, 06:45:13 PM »
P.S. The machine shop here is ready to make the drive (same style as the Allmand direct drive for ChangFa). The reason for doing it this way is I know exactly what I get. It will be machined perfectly for my engine and generator.

Well, I found one ready-made. "They" probably figured out the right rubbers and stuff.

« Last Edit: September 28, 2006, 10:11:37 PM by Rainbow-Farm »
Do not trust the "grid" folks!

Doug

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #2 on: September 28, 2006, 07:22:38 PM »
For that matter at Petters to that list, no one seems to be buying theadapter or the coupling/output shafts for the flywheels when they import these engines. Kind of dumb selling an engine you can't bolt anything too.

Doug

mjn

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #3 on: September 29, 2006, 03:04:11 AM »
My Changfa 195 is coupled to the ST head with a Lovejoy L-150 with a "buna" spider.  Given the sort of hammering that a single cylinder diesel engine produces, I think the softer rubber would be better than the harder plastic.

When I was putting my generator together, I made a quick measurement to determine the shaft heights.  I was so eager to start producing electricity, that I did not put a dial indicator on the shafts to determine how far off I was.  My eyeball said "looks close enough".  It turns out the axial alignment was off by about .060".  I ran about 100 hours before I caught on.  When I pulled it apart, there was no visible wear on the spider even with rubbing back and forth .060 on every revolution. 

Changfa 195 7.5 kw ST.  WVO conversion http://martin.nile.googlepages.com/
Metro 6/1 DI Listeroid. Pumping water for fire control.
1933 Stover CT-1 hit and miss
1936 Farmall F-12 -- unrestored, still used to mow the field

Rainbow-Farm

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #4 on: September 29, 2006, 03:27:23 AM »
Thanks, MJN, that is all valuable input. I do not know what a dial indicator is, but I have been wondering how you align those puppies, figured there must be some gizmo that will do it.

I remember your tale of how you put it all together. I enjoyed your site very much.
Do not trust the "grid" folks!

mjn

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #5 on: September 29, 2006, 07:03:14 AM »
You can probably do just fine with a straight edge along both halves of the lovejoy.   Getting the horizontal axis lined up is fairly easy, you just push the ST head back and forth until both shafts appear to be perfectly straight.

The vertical alignment is trickier.  In my case, I needed to add a series of shims under the feet on the ST to bring it to the same level as the Changfa.  As long as you are not in a hurry (as I was) you will be just fine.

I'm glad you enjoyed my website.  In my spare time this summer, I've been rebuilding an old shed to become the "Casa de Changfa".  I'll need to get a trench dug for the power cables and something better than dirt for a floor.  Hopefully I get that done before it starts snowing.
Changfa 195 7.5 kw ST.  WVO conversion http://martin.nile.googlepages.com/
Metro 6/1 DI Listeroid. Pumping water for fire control.
1933 Stover CT-1 hit and miss
1936 Farmall F-12 -- unrestored, still used to mow the field

europachris

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #6 on: September 29, 2006, 12:38:04 PM »
My Changfa 195 is coupled to the ST head with a Lovejoy L-150 with a "buna" spider.  Given the sort of hammering that a single cylinder diesel engine produces, I think the softer rubber would be better than the harder plastic.

When I was putting my generator together, I made a quick measurement to determine the shaft heights.  I was so eager to start producing electricity, that I did not put a dial indicator on the shafts to determine how far off I was.  My eyeball said "looks close enough".  It turns out the axial alignment was off by about .060".  I ran about 100 hours before I caught on.  When I pulled it apart, there was no visible wear on the spider even with rubbing back and forth .060 on every revolution. 




I found temperature is an even bigger issue.  I had a little Honda gas motor coupled with Lovejoy direct to my 3600 rpm head for a while, and the engine heat would conduct along the crankshaft, heat up the coupler, and soften the rubber spider enough that it would just fall apart.  Also compounding the issue is the Honda didn't have a lot of flywheel, so it pounded the spider pretty good.

Chris

dkwflight

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #7 on: September 30, 2006, 12:56:12 AM »
Hi A bigger issue is the size of the unit. I believe the Horsepower ratings of this type of joint is for electric motors. To get any kind of life from them you should order the largest one that will fit.
Dennis
28/2 powersolutions JKSon -20k gen head
Still in devlopment for 24/7 operation, 77 hours running time

europachris

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #8 on: September 30, 2006, 01:40:03 AM »
Hi A bigger issue is the size of the unit. I believe the Horsepower ratings of this type of joint is for electric motors. To get any kind of life from them you should order the largest one that will fit.
Dennis

Correct.  Lovejoy publishes a selection table that covers the type of driver (electric motor, single or multiple cylinder engine, etc) and calculates the size of coupler required.  Definitely pick the biggest one that will fit.

Chris

mjn

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Re: Type of Rubber for LoveJoy, ST -> ChangFa
« Reply #9 on: September 30, 2006, 06:39:03 AM »
I have the lovejoy specs in an old MSC catalog:

seriesrated HP
at 1750 rpm
max rpmbuna-nurethanehytrel
L0955.59000194 inch-lbs291 inch-lbs561 inch-lbs
L10011.970004176261134
L11023500079211882268
L150355000124018603708
L190495000172625924680

Spider types:
    Buna-N -- oil resistant, temperature range -40 - 212F.  1º angular misalignment
    Urethane -- greater torque capacity, temperature range -30 - 160F. 1º angular misalignment
    Hytrel -- high torque and high temperature applications (-60 - 250F)  .5º angular misalignment


An ST 7.5 head has a 38mm shaft.  My catalog lists the L110 as the only series available with that shaft size.
I am using an L150 that I bored out to 38mm and I'm quite happy with it so far.

I have never found the coupling to be more than barely warm even after extended operation. The flywheel adapter only touches the flywheel in 3 places, so I suspect it tends to isolate the coupler from any engine heat.

Changfa 195 7.5 kw ST.  WVO conversion http://martin.nile.googlepages.com/
Metro 6/1 DI Listeroid. Pumping water for fire control.
1933 Stover CT-1 hit and miss
1936 Farmall F-12 -- unrestored, still used to mow the field