Puppeteer

Author Topic: Lister CS crankshaft / flywheel balancing  (Read 10042 times)

dieselspanner

  • Hero Member
  • *****
  • Posts: 726
    • View Profile
Lister CS crankshaft / flywheel balancing
« on: October 02, 2015, 03:53:44 PM »
Hi All

After a summer of running a B&B interspersed with plodding up and down the Canal du Midi on an 80 year old barge I finally got back into the shed and on with the CS project

As I've posted before the basis is a '34 ish hopper cooled 3.5 hp bottom end with a 6.5 hp cylinder and a strange iron piston.

 I've no idea what the flywheels came off or if there is any difference in the cast in balance weights between the models, so, following this link

http://modelenginenews.org/etw/etw_bal/p2.html

I set up test rig with a pair of ball bearing rollers borrowed from a mate, they run very nicely.

The calculation suggested that a weight of 4.744 kg - 10.45 lbs should be hung from the crank pin

I discovered that the flywheels, are around 800 grams - 1.75 lbs - short of counter weight.

As the smaller piston for would weigh less, and there's every chance these may be the original flywheels, this doesn't seem too far out.

If anyone has a smaller piston, rings and gudgeon (wrist) pin they could pop on the wife's scales whilst she's watching Jerry Springer, I'd be interested to know what the weight is. mine was 4.026 kg - 8.75 lbs.

As usual, any help, comments, suggestions and advice will be welcome.............

Many thanks

Stef

Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

cujet

  • Hero Member
  • *****
  • Posts: 957
  • Lister power rules!
    • View Profile
    • www.cujet.com
Re: Lister CS crankshaft / flywheel balancing
« Reply #1 on: October 07, 2015, 02:41:58 AM »
On a single, I see no reason to worry about the static balance. The weight will always be opposed to the crank throw. Simply run the engine at the chosen rpm and measure the vertical and horizontal acceleration.

You can now use a iphone app or, yes, your finger to measure vibration.

Too much vertical acceleration means insufficient counterweight. Too much horizontal "shuffle" and the counterweight is too heavy.

For a single, the best you can do is to match vertical and horizontal acceleration.

Now, before you start yelling at me for suggesting using a finger to measure acceleration, I do this all the time. However, I also have an ACES 20-20 balancer with various accelerometers. For Lister level vibrations, it's very easy to correlate measured vibration and "finger feel". Simply push your index finger hard against the block in the area of the cam drive gear. First vertically, then horizontally. You will be able to feel a difference.

It is quite likely that weight will need to be added to the flywheel, opposed to the crank throw. I use 1OZ stick on weights. Most singles are underbalanced.
People who count on their fingers should maintain a discreet silence

dieselspanner

  • Hero Member
  • *****
  • Posts: 726
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #2 on: October 09, 2015, 11:57:56 AM »
Thanks for that, Cujet

My main concern was that I'd start it up one day and have a wildly vibrating 300 kg lump of mismatched parts trying to destroy it's self!

It was much easier to do a little investigation at this point to ensure I'm going (all be it slowly!) down the right road.

Regards Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

cujet

  • Hero Member
  • *****
  • Posts: 957
  • Lister power rules!
    • View Profile
    • www.cujet.com
Re: Lister CS crankshaft / flywheel balancing
« Reply #3 on: October 13, 2015, 12:15:56 AM »
Diesel,

Most Listeroids have some counterbalance. However, it's possible to build one without any counterbalance. They "hop" without counterbalance. But they do not "shuffle". As one balance has been traded for another.

The magic number for any single cylinder engine hovers around 50% counterbalance. However, the Lister is a bit different, in that it uses counter balance weights located quite some distance out on the flywheels. Inertial effects depend on RPM, so, with that in mind, it really is best to balance it while running at your chosen RPM.

People who count on their fingers should maintain a discreet silence

dieselspanner

  • Hero Member
  • *****
  • Posts: 726
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #4 on: October 13, 2015, 12:02:45 PM »
Cujet,

I got to the figure of 800 grams extra counter balance by adding metal pipe fittings with magnets, in the same position where I would add 'stick on' weights, I'm pleased that the answer has come up 'light' rather than 'heavy', it's easier to add than subtract!

I'll carry on with the build and sort it all out once I've got past the first smoke stage, with a bit more confidence now.

That having been said I must be one of the slowest on here!

Thanks again

Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

38ac

  • Hero Member
  • *****
  • Posts: 2324
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #5 on: October 13, 2015, 02:22:11 PM »
I didn't bother to do the search but somewhere in one of the prior balancing threads I measured the counterweight cast into a Lister 6/1 flywheel in a manner that anyone with a 2" shaft and some straightedges,  some string, a can and a scale can duplicate. Lister did not balance individual engines however they did make sure that the off set weight fell within certain guidelines. If your engine has a cast iron piston and 24" flywheels you can use the off set weight I listed and the engine will be very well mannered as can be seen in the video. Do not add or subtract weight in any other position that in line with, or directly opposite the crank throw or you will be chasing your tail for quite some time.

I am not allowed to call this smooth operation, call it what you wish,,,
[youtube]9kSJ56EKZ5s[/youtube]
Collector and horder of about anything diesel

38ac

  • Hero Member
  • *****
  • Posts: 2324
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #6 on: October 13, 2015, 03:19:44 PM »
I looked up the other post. Here is my high tech jig and the weight you are looking for.

What is going on here is back yard bob weight calculating. Picture is pretty self explanatory I think? Add weight to the can until it hags as shown.
For the purposes of balancing an individual engine you don't even need a scale. Just make both flywheels the same and you will be ready to reinstall your flywheels and go to the running tests and adjustments. This particular flywheel is again from my Dursey built 6/1 I weighed the can once I got it correct and it weighed 2 lbs 1 1/2 OZ. This figure should be good for any engine with 24" flywheels and a cast iron piston. If you have otherwise it is of no use what so ever.
Collector and horder of about anything diesel

dieselspanner

  • Hero Member
  • *****
  • Posts: 726
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #7 on: October 17, 2015, 11:31:58 AM »
Thanks for that,

Bush engineering at it's finest!!

That'll give me something for a comparison

Cheers Stef
Tighten 'til it strips, weld nut to chassis, peen stud, adjust with angle grinder.

jetmax

  • Newbie
  • *
  • Posts: 23
  • I like oily my hands then clean !
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #8 on: May 24, 2017, 03:13:32 PM »
Hi sir , first I respect to you to much .
Second .. I have  slavia 5 hp diesel  since 2 year I am working on it , at the moment well condition . Its 800 rpm . Bu after 250 rpm its start to jump  , may I use your solution in my engine olso ? Aluminium piston  I have .
 Best regards
 Jetmax


I looked up the other post. Here is my high tech jig and the weight you are looking for.

What is going on here is back yard bob weight calculating. Picture is pretty self explanatory I think? Add weight to the can until it hags as shown.
For the purposes of balancing an individual engine you don't even need a scale. Just make both flywheels the same and you will be ready to reinstall your flywheels and go to the running tests and adjustments. This particular flywheel is again from my Dursey built 6/1 I weighed the can once I got it correct and it weighed 2 lbs 1 1/2 OZ. This figure should be good for any engine with 24" flywheels and a cast iron piston. If you have otherwise it is of no use what so ever.


cujet

  • Hero Member
  • *****
  • Posts: 957
  • Lister power rules!
    • View Profile
    • www.cujet.com
Re: Lister CS crankshaft / flywheel balancing
« Reply #9 on: July 22, 2017, 02:06:40 PM »
If an engine is jumping or hopping at 800 RPM, a good guess is that the counterweight is not heavy enough. Another good guess is the weight required will be significant. Also, the weight will need to be opposite the crank throw.

Try increasing weight incrementally in this position by 2 ounce increments, (or about 60 grams) . You can even work your way up to the point where the engine no longer hops but shuffles back and forth some. Just to see where the "best" point is.

Make sure to note the results on every run.

And, don't be afraid to use your index finger, pointing, and pressed hard against the block. Do so horizontally and vertically. It will give you a good idea of the intensity of the vibration in each direction.

Remember:

1) Too much vertical vibration = not enough counterweight
2) Too much horizontal vibration = too much counterweight
People who count on their fingers should maintain a discreet silence

jetmax

  • Newbie
  • *
  • Posts: 23
  • I like oily my hands then clean !
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #10 on: September 19, 2017, 06:34:39 AM »
Thank you vry much for kindly interest .
I done what you sad , I increased counterweight whit frigider door magnets, worked well doesnt jump any more in high speed  . And olso doesnt move horizontal.

But  around 250 rpm or 300 rpm just for short time its hoping after this rpm engine doesnt move horizontal or vertical . ?.?

Any  advice  make me happy .
Mesut

starfire

  • Sr. Member
  • ****
  • Posts: 282
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #11 on: September 19, 2017, 06:46:55 AM »
Everything has whats called a resonance frequency Jetmax, it varies on the rotating mass and bulk of the stationary parts. Mounting the engine to a heavy substantial base will tame it. Any single on a trolley, especially with rubber tyres will hop around at some frequency or RPM..... this could be the fascination for these things to run at a slow RPM at shows where trolleys are common. Once they start hopping and moving around like a demented robot, it can be very frightening.
Cujet is on to it, run the engine at its sweet spot, or if necessary, balance it for the one particular RPM range you need.. Reciprocating mass can never be totally balanced.

BruceM

  • Hero Member
  • *****
  • Posts: 3054
    • View Profile
Re: Lister CS crankshaft / flywheel balancing
« Reply #12 on: September 19, 2017, 03:59:55 PM »
+1.  During post start wind up and shut down, even my very well balanced Listeroid 6/1 does have a speed where some movement is obvious.  Balance for your operational rpm(s), and make your mount solid enough to keep it tame for the rough speeds.  Good explanations by Ronmar and Starfire!