8/1 shake

[potter]

Hi guys could sure use some pointers  . I haue an original 8/1 driving a st 5 head this has run without a flaw for the last 150hrs. About a week ago on going to shut down it was vibrating like crasey,I shut it down and my first idea was to check gib keys to see if they may have worked loose but both were tight. I next restarted to check R.P.M. thinking somthing on the gov had come loose but this was right on. I haue put about 20 hrs on it like this it has not gotten any worse but will soon shake itself to bits, any ideas.
potter

[compig]

For a dramatic problem like that to suddenly occur there must be something obvious wrong. The engine balance seems to have changed substantially so I think you need to start a careful examination of the possible factors. Remove the inspection cover on the crankcase and have look at the crank ,  rod & piston. Are there any other symptoms like noise ?  Does load make any difference ?

[potter]

Thanks Compig, no there are no noticible noises except for the rattles from the shaking, the engine sounds fine this is why I have not opened the inspection door as of yet  The only change that I can see is the setup is on a start-o-matic original base mounted to two yards of concrete this was pored into soft sandstone and has now shaken itself loose  I do not know if this is a cause or effect.

[compig]

Original CS's are normally very smooth in operation so I doubt the foundation is the cause , more likely that the vibration which sounds quite severe from your description has caused the foundation to break up.  I would be inside the crankcase looking for the problem.

[potter]

Thanks i am going to open it although i dont think the problem is inside  that said this is probely where ill find it  . When I rebilt it I did reverse the flywheels I dont think this makes a diferance  ( holes seem to line up the same) Iput the groved wheel on the pump side any thoughts? .

[compig]

If it ran smoothly with the flywheels transposed then it probably isn't an issue. Thing is with a CS it's a very simple engine so there are very few things this could be. I presume you have checked for loose bolts etc ?  Try this , lock one flywheel up somehow then try to rock the other. Any give and it's not looking good  !! Thats almost the worst case scenario though !  The 8/1 has an aluminium piston , wonder if a bits cracked off ?

[potter]

Thats what I was thinking but it was secured to the bedrock and maybe this was hiding the inbalance untill it lost its grip . I did already try locking one wheel and moving the other,ill open it in the morning if I find nothing I guess ill have to pull the gib keys and try reuersing the flyweels, whithout a puller not looking forward to this  .

[oliver90owner]

Potter,

Don't know whether Lister actually balanced anything on the later engines - certainly they didn't on early production, as flywheels were same numbers.  That said, if any balancing has been carried out, swapping the flywheels round will make things as bad as, or worse than, original.  As you say, bolted down tight may not show until it loosens itself.  So I think your decision to change them back is a good idea.  150 hours should not present any problems for key removal with an appropriate tool.  It is thirty or forty years of corrosion that can make gib key removal interesting.....

Regards, RAB

[potter]

Well I opened the inspection cover the insides still looks pristine, all nuts and bolts tight piston skirt all intact no hunks of anything in the sump.I can only put it to I was trying to shake the world (lot of recent earthquakes  ). So I guess I am down to switching flywheels and the whole setup, this may wait till after huracane season. If anyone has switched flywheels before I sure would like to know their results.
potter

[compig]

Good advice , if it's torsional vibration the crank will be at serious risk.

[potter]

I wish it were so easy , if I change the flywheels around it means I have to also spin the engine around to realigne the pulleys  which means the exhaust and coolant systems have to be totally changed  .

[potter]

No I am using the original start-o-matic pulley on the gen head so twin v belts the flywheels have two kidney shaped holes and a single round hole in the solid casting balancing is in the flywheels.
thanks potter

[abbamovers]

Potter you must return the flywheels to their original config.
In David Edgington's book 'The Lister CS Story'  quote on page 38 " Unravelling the flywheel conundrum- Working with the help of David Harris I have assembled a comprehensive list but there will almost certainly be variations of some of those listed here.
It is interesting, with this range of engines, how several specific flywheels were fitted singly, meaning the starting handle side was different from the opposite side, while others were matched pairs "

He also goes on ( David Edgington ) to state that the flywheels were balanced on the kidney flywheels using a special dummy weight with extra balancing holes drilled in the inner rim face.
"From 1972 on, it involved drilling 3/4inch holes to a max depth of 2inches to a max of 5 holes with a max run-out of .005" on diameter or sides of the 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."

So in other words leave things the way they were.
If I were you I would get a copy of David Edgington's book as there is much more info on this topic with part numbers, dimensions and such for the price it is well worth it.
Quinnf has also stated the above in his beta test engine that he describes in detail on George B.'s  site utterpower and I think somewhere else on  listerengine.com involving balancing also, read it.
It is better to put the engine right and redo everything all over again, especially if this is an original CS, or you can kiss your engine goodbye.
.

[oliver90owner]

it means I have to also spin the engine around to realigne the pulleys   which means the exhaust and coolant systems have to be totally changed  .

Err...turn the generator around instead?


if they are different between right and left side (or for that matter if they are reversible as in staying on the same side but being flipped around)

As I said previously, flywheels on early CSs were the same part number, so not balanced separately.  I am not surprised later ones were balanced , what with the change to aluminium pistons and later technology, while probably still using the original casting moulds for the flywheels.  It would appear that the balancing was for side-to-side balancing (dynamic) rather than for reciprocating masses.

RAB

[M61hops]

I would look at the rims to see if there are balancing holes drilled.  If there are no holes I wouldn't change the wheels.  If there are balanceing holes I'd change them back to factory locations.  When I added weights to my 6-1 flywheels I was shocked at first at where they ended up!  By trial and error I found that my engine needed almost a pound on each wheel about 90 degrees ahead of the cast weights!  I think this is so that the weights are going down at the time the heavy piston & rod stop going up when they reach TDC.  I would not have guessed where to put the added weight even though I was guessing that the reason my engine jumped off the ground was caused by the piston & rod reversing direction.  If the factory did indeed dynamic balance the wheels to that engine it would make a tremendous difference if they were swapped side to side!  Sometimes you just have to do what you have to do  !              Leland