Author Topic: is .010 idler backlash anything to worry about and other questions?  (Read 4188 times)

bearhawk

  • Newbie
  • *
  • Posts: 26
    • View Profile
    • Photos of the teardown and buildup
Greetings,
This is my first post but I feel like I know some of your personalities as I've spent a lot of time reading many posts in this forum and reading through files on a popular CD in the last few months. 

I recently bought a new PS 6/1 that was originally purchased in 2005 from a guy who was a part of this forum years ago.  It was never run other than at the "factory" and that was obviously the truth.  It had all kinds of oil in it that resembled cosmoline which was good as it did protect the parts from rust inside but bad because it contained abrasive sand.  Anyhow, I'm told it was "made by" JKSON but find nothing on the engine that would tell me that.  Under the crankcase it says "TF" (means Too Funny) who must be the foundry and the cylinder block says "SC" (means Same Chump).  I have the engine completely torn down and am cleaning up the sand (found little bits in several places of the crankcase, especially on webbing, the worst though was under the piston).  I'm going through everything.  The main conn rod bearing is trashed and there are marks on the crank journal but they can be cleaned very easily.  The cylinder block was extremely rusty inside (the coolant area) and the liner was pitted (from the test run water) so I took a lot of time soaking it down the homebrew penetrant and finally got the liner out and cleaned up.  The flats in the cylinder block weren't pitted at all so the o-rings have a nice surface to seal against.  I was worried I'd get it together and have the o-rings leak due to pitting.  I have been taking a lot of photos so I can post later.  Overall, I think I have a lot of good parts to work with.

When I took the cylinder off, the conn rod out, and the tappets out I checked the backlash on my ferrous idler gear.  I put a dial indicator on a tooth of the idler and rocked it back and forth as it "clanked" on both ends.  I got .010" of idler tooth movement between the idler hitting the crank gear until the idler hit the cam gear.  I know I read in one post .005" is the limit but most listeroids have had .025-.045"  Should I worry about .010" backlash?  I'm an aircraft mechanic and have worked on diesels for over 20 years outside of aviation.  The aircraft mechanic side of me says it's out of spec so fix it but the fact it will never fly says it might just be OK.  I have two new bronze gears and a new ferrous one (I got a ton of parts with the engine).  It sounded like the the bronze was helping the symptoms but not fixing the problem.  Does anyone know if the offset idler bolts cured the idler gear breakage?  Mine doesn't have any stamped marks other than the pin pricks from a spring loaded center punch when I marked it before removal.  I will try out the other ferrous one to see if it's less than .010".

Also, when going back together what do I put at the top end of the cylinder block (or top end of the liner) to keep coolant from seeping up between the liner and block?  Do I use silicone just below the lip?  I thought there'd be an o-ring groove 1/4" or so under where the lip is but none was found and no place to put one.  It just seems like coolant will leak up there.  The lip sticks up proud between .007-.008" above the block with no o-rings.  What do I lube the o-rings with?  KY jelly is good to rubber :-)

Since the engine had sandy oil the liner is glazed inside.  Yes, I can still see hatching but it's smooth as glass.  I'll hone it.  If the ring end gap is good can I rejuvenate the rings with 1000 grit paper?  It seems I need to scuff them up.  I don't think I will need new rings as these ones just have half an hour on them or so (with bad oil). 

Thanks,
JD
2005 Powersolutions/JKSon 6/1 with ST-10
Yanmar 2v78 V-twin diesel for a motorcycle
Yanclone single cyl 12hp diesel in a Cub Cadet
http://www.youtube.com/user/bearhawk767
http://listerenginegallery.com/main.php?g2_itemId=4911

Tijean

  • Full Member
  • ***
  • Posts: 208
    • View Profile
Re: is .010 idler backlash anything to worry about and other questions?
« Reply #1 on: March 20, 2011, 12:53:10 AM »
Lots of territory to cover; on the backlash; you have to take a number of readings as the bore in the idler may not be concentric. One I saw appeared to be broached rather than turned. You also have to consider what the lash is between idler and cam. It may be considerably different than between crank gear and idler. The power pulses are severe compared to a multi cyl. engine so the less slack in the gear train the less hammering that gets concentrated on the same few teeth on crank and cam gear. Gear train hammer is exponential so reducing clearance by half is a huge benefit. Either here or on Listerengine.com there is instructions to make an adjustable jig to measure exactly how much offset you need on the idler. Minimal clearance makes a big difference in how quiet you can make the engine as well as expected life of drive train and perhaps lead away from camshaft breakage that has been seen.

As long as cylinder liner projection is even and not too great, the head gasket should simultaneously squash seal to both the liner and the adjacent head surface so there is no need to attempt to seal the liner to block gap. For the O rings lube I used dish soap but I suspect KY jelly would be dickety poo as well,  :D

If that unit has an oil pump I would recommend removing every line and ream the ends as it appears they were cut with a saw and lots of metal flash ready to let go where it should not. Seats in oil pump need work to make pump even halfways self priming. The valve rockers can likely use some alignment tweaking and resurfacing of the tips of the rocker arms.

The honing and piston fit were beautiful in mine. Ring gap was almost too tight by the .003 per inch dia. rule of thumb. If you are not in a hurry pulling it entirely apart and refitting things can be pleasant and even worth a few laughs.
Frank

10/1 Jkson, ST5 gen. head

38ac

  • Hero Member
  • *****
  • Posts: 1812
    • View Profile
Re: is .010 idler backlash anything to worry about and other questions?
« Reply #2 on: March 20, 2011, 01:34:42 AM »
What Tijean said x2

Dont mess with the rings anything you try to do to them by hand is messing up.  Personaly I dont like to use soap on the liner sealing rings but others use it and I have even seen it specified by over haul kit Mfgs. I use the same lubriplate assembly grease that I use on the bearings. I dont have enough Listeroid operating experiance to  give you any realities for the idler gear. I can tell you that When I redid my 6/1 Metro I had lots of back lash too. I looked over the bronze gear. left it in the box and got the backlash right on the original iron gear ( It had no punch marks other then light ones I put in it for timing marks)
Collector and horder of about anything diesel

bearhawk

  • Newbie
  • *
  • Posts: 26
    • View Profile
    • Photos of the teardown and buildup
Re: is .010 idler backlash anything to worry about and other questions?
« Reply #3 on: March 20, 2011, 02:17:57 AM »
Thanks Tijean for that info.  I didn't think that the idler gear might not have the hole in the center...how silly of me!  I'm learning about Indian Standards.  On the cam do I also just put the dial indicator on the cam gear and measure it there too?  I'll look for the posts regarding the adjustable jig.

38ac, how did you make the backlash right?  Offset idler bolt? 

Does anyone know if someone still makes the offset idler bolts?  I'd rather use the ferrous gears if I can and fix the problem if need be.
2005 Powersolutions/JKSon 6/1 with ST-10
Yanmar 2v78 V-twin diesel for a motorcycle
Yanclone single cyl 12hp diesel in a Cub Cadet
http://www.youtube.com/user/bearhawk767
http://listerenginegallery.com/main.php?g2_itemId=4911

Tijean

  • Full Member
  • ***
  • Posts: 208
    • View Profile
Re: is .010 idler backlash anything to worry about and other questions?
« Reply #4 on: March 20, 2011, 03:26:06 PM »
I built up with weld material and machined the idler eccentric. Got lazy and just put a .035 thick shim under one jaw in the three jaw chuck. That gave me somewhat larger than that amount of actual offset but did not measure it. Some fellows have made a two piece idler with both parts eccentric to be variable but I worry a bit about rigidity. Actually would like to see larger than the 1/2 inch diameter existing. I think the bronze might take the shock better than cast iron teeth but that is just my feeling. You can spend a fair bit of time taking off the burrs and nicks from both crank and cam gears and polishing them up a bit to save a lot of iniatial wear and tear on break in.
« Last Edit: March 20, 2011, 11:30:43 PM by Tijean »
Frank

10/1 Jkson, ST5 gen. head

38ac

  • Hero Member
  • *****
  • Posts: 1812
    • View Profile
Re: is .010 idler backlash anything to worry about and other questions?
« Reply #5 on: March 21, 2011, 01:51:20 PM »
Like Tijean I made up an offset idler bolt only differance being I made it up from scratch. 

 I admit to having limited experiance with these engines in hours of operating but neither do I believe in engine demons or magic so I tend to apply past experiance to them. My opinion basied upon the 4 Indian engines I own is is the Indians have at least three problems on thier hands with idlers in no order of importance:
 A- Accuracy of the hole for the bolt
 B- Accuracy of the gears
 C- Materials and heat treating

My opinion of the bronze gear deal is it is probably the only bandaide that can be applied in the bush but when apart in a shop there are better fixes.  My Metro had about 5 hours on it when I got it and almost .030 of backlash and the idler gear was being beat to a quick death, Id bet that gear would not have run 35 hours.  There is realy not a huge load on that gear train given the size of the gear teeth. The problem is given a .030 head start things will quickly degrade. As documented by others the Indians did them selves no favor by placing the timing marks on cast idlers with a sledge hammer either :o
Collector and horder of about anything diesel

bearhawk

  • Newbie
  • *
  • Posts: 26
    • View Profile
    • Photos of the teardown and buildup
Re: is .010 idler backlash anything to worry about and other questions?
« Reply #6 on: March 26, 2011, 06:46:12 PM »
Seats in oil pump need work to make pump even halfways self priming.

I took my pump apart and noticed I have the 2 steel check valve balls but the outlet one should have a spring right?  Mine has no springs on the balls.  What did you do to the check and also improve the valve seats for the check valves?  I can't see how to do much in there but I must be missing something.  The pump piston seal was also torn on mine.  I have a replacement so I will put it in.

2005 Powersolutions/JKSon 6/1 with ST-10
Yanmar 2v78 V-twin diesel for a motorcycle
Yanclone single cyl 12hp diesel in a Cub Cadet
http://www.youtube.com/user/bearhawk767
http://listerenginegallery.com/main.php?g2_itemId=4911

Tijean

  • Full Member
  • ***
  • Posts: 208
    • View Profile
Re: is .010 idler backlash anything to worry about and other questions?
« Reply #7 on: March 26, 2011, 11:52:59 PM »
I think the force of gravity is all that seats the balls. The seats in the pump body appeared to have ridges like you get when interrupting a cut with a tool so I lapped them in. The balls were rather irregular and I found some close enough in size and much rounder, from a scrap ball bearing. The seal had about a third of the lip forced the wrong way; I will change that out when I have the engine down to install hollow dipper and un-grooved upper half style rod bearing shells.

There are a few similar "lack of fine tuning" details that probably typical of many off shore products.
Frank

10/1 Jkson, ST5 gen. head