The sad truth about idler gear falures.

[rocketboy]

The failures are caused by two things, both known by the Indians.

1. The gear casting quality is (was) lousy causing fatigue failures usually near the timing marks.

2. The real bummer is that many many  engine cases had the big hole (idler gear shaft boss) in the case machined  "not straight" so the idler gear sits at an angle. The only fix is to toss the case and get one with a straight hole (or re-bore and sleeve etc). It's a bummer but it's a known defect in many listeroids.

I was told by a maufacturer the gear will fail by 400 hours if it's got a crooked hole. The teeth wear rapidly to a point and then bang.

Rockeyboy

[sawmiller]

Hi Rocketboy
How do we tell if we have one drilled  wrong.

Regards
Tim

[MeanListerGreen]

Might be able to check the run-out of the gear by affixing a magnetic based dial indicator, turning the gear and that should show the irregularities.

[dkwflight]

Hi I was able to reach up in the 28/2s crankcase  and rotate the idler gear back and fourth by hand. I was able to make it clunk back and forth so I have to assume there is too much clearance in my powersolutions engine.
Dennis

[Halfnuts]

It should tighten up when the engine warms, and you have to allow something for the oil film.  A dry geartrain will always be looser and noisier than one at temperature and coated with oil.  However, that's not to say that there MAY be excessive clearance.

Halfnuts

[dkwflight]

Hi I read some where that .005-.010 thou is proper clearance for the gear mesh? If it were anywhere close to that I don't think I would get the "Clunk" I was hearing.
Perhaps I could get a wire feeler in place? I will buy one and try it.
Dennis

[sawmiller]

Dennis
The gears tighten up when the cam lobe hits the lifter then get loose when it get's past the lifter. Make me think it's a valve spring problem. Anyway the wear is on both sides like hitting back and forth.
Regards
Tim

[dkwflight]

Hi I know the pressure on the gear comes and goes. In fact I had to move the flywheel to a point where I could feel the clearance.
Joel e-mailed me and said my engine should be set up with about .011 thou cleartance cold and it is suposed to have a brass gear.
I don't remember a brass gear, I'll look again and check with a magnet.
Thanks for your help
Dennis

[rleonard]

I had to replace the Idler in my Lister 16-2.  I was able to manage a slight discount, but list price on a Lister Idler gear is $345.29.  The shoulder bolt is $120.00+  What, are we still paying for the Revolutionary War?

It fits nice.  Should be much quieter now.  Still going back together.

Bob

[rgroves]

I had to replace the Idler in my Lister 16-2.  I was able to manage a slight discount, but list price on a Lister Idler gear is $345.29.  The shoulder bolt is $120.00+  What, are we still paying for the Revolutionary War?

It fits nice.  Should be much quieter now.  Still going back together.

Bob

Do I assume right, that you bought parts directly from Lister-Petter? 
That company has a policy across the board of giving little or no support to old products from their own line.  That's true of their whole line of industrial engines too.
So they charge through the nose for "Original L-P parts" that may or not have been made in the UK.  And that's why there's a big Indian manuacturing base for L-P aftermarket parts. Quality is generally pretty good too. It's easier to detect crap masquerading as parts before they are assembled into an engine.

All the best

Russell

[mobile_bob]

after having looked into the gear problems on the listeroid twins there seems to be a myriad of issues or problems that have been reported

1. the shaft bore is not square with the crank and cam, causing the gear to wear out prematurely
    wearing the teeth to points and then the worn thin teeth break off.

2.  the timing marks apparently cause stress risers, and lead to teeth breaking off at the root. wherein the teeth look to have little wear
     associated with #1 above.

3.  is there a #3 cause?

i am trying to compile a definetive list of checks to do on mine before setting it up to run and shipping it to its end use location half way across the country.

also i am wondering whether lubrication of the gears might be an issue.  how are these gears lubed? splash? drip? or what?

bob g

[jimmer]

.

also i am wondering whether lubrication of the gears might be an issue.  how are these gears lubed? splash? drip? or what?

bob g

These gears run in the open and should not be lacking for lubrication.

Try taking your dipstick out when the engine is running.

How that much oil comes out of a tiny hole is beyond me.

jim

[GuyFawkes]

after having looked into the gear problems on the listeroid twins there seems to be a myriad of issues or problems that have been reported

1. the shaft bore is not square with the crank and cam, causing the gear to wear out prematurely
    wearing the teeth to points and then the worn thin teeth break off.

2.  the timing marks apparently cause stress risers, and lead to teeth breaking off at the root. wherein the teeth look to have little wear
     associated with #1 above.

3.  is there a #3 cause?

#3 could be machining accuracy / tolerances, hardening and surface treatment finishes, actual grade of material and method of casting / cooling / crystal structure

Problem here is if the culprit is #1, no amount of fiddling #2 and #3 will help much, you need to re-jig and re-line bore the block.

setup of work for line boring like this takes longer than the boring process, so I suspect they just stick the castings in a jig and drill with an old knee mill, so accuracy is only as good as the variations between castings, swaerf between casting and jib, etc etc etc.

[rleonard]

Russell,
Your question "Do I assume right, that you bought parts directly from Lister-Petter?"   The answer is yes... and no.  My local Amishman/Lister dealer has a rather complete inventory of NOS Lister parts.  As dealers were shedding their inventory, he was buying it up.  He has boxes and shelves of parts.  All genuine Lister, not copies. 

Parts are high, but if you want the real thing for your genuine Lister, he is a source.  We're in central Illinois.

Bob