A fresh look at engine balancing at home.

[Quinnf]

I put out a request on the other forum for anyone with that information, or a genuine vintage Lister piston and rod that can be weighed.  That information and the one measured genuine English Lister 6/1 flywheel counterweight (thanks, 38ac) would let us know how close the 65-68% figure Dave determined empirically was to the original engines.  David Edgington goes on to explain in detail around page 38-39 in his book how they actually balanced flywheels, but he didn't discuss how the flywheel counterweight was determined, or what that value is.

He DOES say that the 10/1 was balanced with a weight of 3lbs 2 ozs, or 50 ozs that was placed in the circular hole in the web of the 10/1, centered 7 1/16" from the center of the crankshaft.  Presumably adding that weight at the specified location neutralizes the balance of the 10/1 flywheel so it can be statically balanced. 

The wide variation in counterweights on Indian 'roids obscures what the proper weight is.  It might be close, but if we knew how a _real_ Lister 6/1 was set up, we'd have a better benchmark to work from.

Quinn

[dieselgman]

I see that Edgington provided some detail for one of the flywheel types...

"To the flywheel with 2-kidney shape holes (9 x 4 inches) was added a spherical hole 3 11/16" in diameter to assist with the balancing process of each individual wheel which was balanced to within 2 ozs. at a radius at a point taken inside the rim. This was done by bolting a special dummy tool (weighing exactly 3 lbs. 2 ozs.) to the edge of the spherical hole. Balancing from 1972 involved the drilling of 3/4" holes to a maximum depth of 2-inches, with a maximum of 5 in number, to the inner rim face. Maximum run-out was .005 inch on diameter or sides of rim. The spherical hole was usually positioned at the opposite side to the key-way at B.D.C. and provided the best compromise between reciprocating and rotating forces."

dieselgman

[Quinnf]

Right, so the hole was essentially an un-counterweight.  A light spot in the flywheel, rather than a heavy spot. 

[xyzer]

[snip]  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. [snip]

So that's 33.5 ozs.  Dave, I calculated 28.9 ozs for your Vidhata, so that's pretty close to what 38ac measured on his _real_ Lister 6/1.  Of course, we don't know what the piston and rod weights were on that engine, so can't get too excited.  Sure would be nice to chase this detail down and determine how Dursley was balancing their engines.  Even though they recommended bolting them to a concrete block, I expect they had the weights calculated so as to minimize dynamic forces as much as possible.  

Quinn

Nice piece of info! If we add the weight of the crank pin and use a 67% we would be getting closer. The originals had much better quality control and quality. I have a picture of what appears to be a flywheel being balanced. it had a rod in a shaft with a adjustable weight near the en....Better yet here is a picture I just had to find it................an hour later...... If you keep your piston,rod, weight close you could balance like this.

[38ac]

 

[ronmar]

I count 830 RPM or therabouts...

[38ac]

I count 830 RPM or therabouts...

Whoa! I better get a real tach back in the shop. My ear tach aint worken too good.

[dieselgman]

Yep, sounded a little fast for a 6/1 to me also!

dieselgman

[xyzer]

38ac
You are right about chasing your tail try to add and remove the weight in the right spot. The chalk mark is a little behind the heavy spot. I would say you have it looking real good. Now get a head on it get the operating rpm dialed in and pull a load. You might have to add or subtract some weight to get it perfect under a load. You have a damn good headstart.

[Apogee]

Don't forget that on the Indian clones the flywheel key might not be in the correct location.

Food for thought,

Steve

[Tom]

Good point about the load xyzer, my 6/1 settles right down under load.

[fabricator]

I count 830 RPM or therabouts...

Ron how in the heck are you doing that? Slowing the video down somehow?

[38ac]

Don't forget that on the Indian clones the flywheel key might not be in the correct location.

Food for thought,

Steve

Covered about halfway down page one,

[ronmar]

I count 830 RPM or therabouts...

Ron how in the heck are you doing that? Slowing the video down somehow?

No, I count out 100 exhaust/firing notes while running a stopwatch.  I count in groups of 10 and use fingers to keep track as I work to 100 by 10's and stop the watch. It is fairly easy once you get into the engins rythum.  It is easier if you can watch something like the oil pump plunger or a rocker arm.  100 firings or pump strokes or rocker movements = 200 RPM.  I divide 60 by the time on the stopwatch, then multiply the answer by 200 and I have a pretty close estimate of RPM.

In this case I counted 100 cycles(200 RPM) in 14.5 seconds.  60 divided by 14.5 = 4.137 X 200 = 827 RPM...  I did it twice, my first count came out close to 838 RPM.  I was a little more confident of the second count so I rounded it to 830:)  That high RPM is approaching  the limit of my counting ability.  Add to that the less than real sound and no real visual reference, there is some margin of error:)

[fabricator]

That has got to take some practice, my margin of error would be 500 rpms.