broken-clone-gear
I am looking for your help! I need more pictures of broken and/or failed Lister or Lister Clone gears. There are a number of gears that sharpened themselves to a razor edge on the tip of the teeth, do you own one? When was the last time your reached up inside your engine to feel the end of the teeth on the idler ans cam gear? They need be square on the end, check it now, if they are sharp, a train wreck could happen at any time, and they’re ugly!
Please forward any pictures you have to: george@utterpower.com
I think you’ll enjoy hearing some of the information that comes out of this study.
GB
is it too early to place bets?
i used to think it was the stamped timing marks set up stress risers
but looking at this gear i am thinking not.
is it too early to ask a question?
bob g
Fact is, there are a lot of gears that failed with zero punch marks on them. I beleive there are many root causes, not just one.. but a good friend has retrived soem very interestign data that we will all fidn interesting! I can’t talk about it till his article gets published, and I would like a few Cam Gears to share with him, and we will post the more interesting gear failures here. If you have a cracked crank gear you can take a good macro of.. that woudl be great too.
Yes, Yes, I know, there’s at least two people in our WW community that thinks a steel gear metal fixes it all..
“Fact is, there are a lot of gears that failed with zero punch marks on them. I believe there are many root causes, not just one.. ”
I have to totally agree with that statement. Broken teeth or teeth worn to a sharp point are 2 different symptoms of the idler gear issues. In my dabbling of the offset bolt I did find a consistent issue with the idler gear bolt location. Could the excessive backlash gear slapping find an imperfection of a steel tooth? Has a bronze gear ever surfaced with a broken tooth or did they just wear sharp? Lots I never really discovered and am waiting to hear other views. Have there been any failures after correctly installing an offset bolt?
Dave
Dave,
Thanks for your post, I do consider your efforts to correct the gear problems in the Lister Clones being among the most thoughtful. As I mentioned, there were two other people who were ‘marketing’ their superior idler as a cure all.
I guess it’s what Salesmen do… Will em ever learn?
In an attempt to answer your question, we need note other efforts to identify gear problems. One noteworthy observation was a machinist who taught me the basic measuring of a gear by placing dowel pins between the teeth on opposite sides, and measuring them all the way around with good calipers. The data I collected from folks like yourself who are careful in their measurements showed that there were plenty of poorly made gears out of Rajkot to be purchased, the hobbing job very poor very different measurments from tooth to tooth! …. as if the operator had no clue the teeth need be cut with some accuracy. Of course, there are other things we suspect wrong, and one is the materials used, and as I write, there is another person who is doing research, and nearly ready to publish his findings. I can only say that those who make gears elsewhere make every effort to get the material just right at the foundry, and we need always question the composition of the gear material. We add to that another observation I’ve made over the years, ….The worst of parts are sometimes found in assemblies, while the parts sold as spares are often far superior. Could this be the result of the assmebler shopping for the lower price, so his margin is larger once he has a container load order? India does make a lot of good parts, you need only look at Mico Injection pumps to know they can do it right with great percision everytime.
Now for the Bronze Idler Idea, this came out of need, and after consulting with a gear making company in America… a Company that has made gears for generations and likely has seen it all. They wanted a fortune for an idler made on their equipment, which lead Joel Koch (a man dedicated to finding a solution) back to India to a gear making company.. Well, it was the JKSon company that made or had made a VERY good and heavy bronze gear, others were made, but no where near as good as the gears JKson supplied. So the results are a more complicated study.. Fact is, some engines that spit out stock idlers in four hours ran for 3000 plus hours with bronze gears. But you know the problem of repportign with any accuracy… we really need people like Noel Douglas who relies on Stationary engine power to operate. The average DIYer just doesn’t run the hours to tell much of anything. We do know the good Bronze gear mitigated troubles, and there’s been silence from those who are running them following the complaints they had.
While there’s a few others who offer the gear that cures, I’m confident I haven’t compiled enough questions yet. I do know that bronze gears are typically used in worm gears, I know that striaght cut gears have long sine been abandoned in favor for quieter designs and few would fool with the idea of using them today for the same purpose or investing the time to scientifically investigate the merits of the bronze idler.
Dave, I think we would agree..a quick check of the gears to assure they were hobbed correctly, and that the center bore of the idler and the idler shaft have proper clearance, proving that oil can get in between the shaft and idler gear.. AND doing out best to assure a proper idler gear shaft location are some of the basic things we as DIYers can do.
The use of a Bronze idler, if we have accurate crank, cam, and idler locations, we likely don’t need it. But I will always wonder if it could help control wear and help keep ferrous metals out of the all important crankpin bushings.
No doubt in my mind, the upper crank pin bushing should be pulled at intervals and inspected anyway, as mentioned, the bottom one can look perfect when the top one is showing severe signs of wear and or contamination. I believe the amount of embedded ferrous in the bushing can cause premature wear at the crank pin, IF there are problems with the gears, I think they can shed a lot of ferrous material, and it can embedd in one of the worst places possible.. the crank pin bush 🙁
Interesting stuff. Waiting on pins and needles here for the other shoe to drop.
It seems that the offset idler pin or bushing fixed the problem with the inadequate meshing of the idler and cam gears. Prior to my putting an eccentric bushing around the idler spindle the gears made a loud “clack-clack” as the camshaft rotated. I suspect it was the accumulated stress of the meshing/unmeshing of the gears that caused the failures. If it turns out that there was another cause I’ll be very surprised. I wonder how much variation in the location of the idler gear spindle there is engine to engine. I suppose we’ll never know.
It would sure be interesting to be a fly on the wall at the place that does the machining to see how they locate the crankshaft and idler holes when they machine the crude castings.
I agree with you about using the straight cut gears. Didn’t someone say he was using helical cut gears? Haven’t heard anything about that in some time.
q.
Several things need happen, I need know that an article has hit the news stands, I don’t want to short the man did soem of the interestign research.. sorry for the delay..
Do you still sell idler gears? Either the good quality iron jkson ones or the bronze you were either selling or advocation about 5 years ago?
I purchased 2 Kirloskar 8-1 s 14 years ago,in the rep of Panama,they are our sole provider of power on our Island.Only one has been used as of now,with a little over 23000 hours up we get our gaskets ect ect from from bangor main,and having been born on the Seychelles Islands and raised in east Africa since 1942 I grin when I read about all the EXPERTS and guess what? the listeroids are a lot better than the old Listers.
John, I’m glad your experience witH ‘one’ Listeroid has been good. It does remind me of Noel Douglas in Fiji who had run 30,000 hours on a Lovson LG8. But Noel has lots of experience with a lot of clones and knows that they Are a bit like a pig in a poke, lately he has been breaking gears on the crank,he’s so good at changing them now, he can do one in a half hour…
To coin an old East African sayin,the average person that has purchased a Listeroid,is as thick as two short planks.
As a contractor to the Republic of Bobuhtaswana in the then South Africa for 10 plus years,we never had any failures with the timing gears of the Listeroids that were not caused by an error on the part of opperater.Over 30 Units in the field,mostly as Pump Units I only recollect two failures,and both were caused by the Fuel Pump Cam Follower Guide Bolt being too tight and gaulin.Also Multigrade Oil was always used 15 W 40 and all with Ally Pistons,and Chrome Liners
Interesting observation, I remember a whole batch of engines where many destroyed idlers right out of the crate. I’m trying to visualize a properly spill timed engine with that bolt too tight, maybe I’ve been away too long?