K161 cylinder walls

[zanepetty 117]

Does this look bad to you guys? The cylinder wall is black on the side facing the valves. Hope you can see it. If you need better pics let me know. Thanks.

Edited March 15, 2015 by zanepetty

[WH nut 553]

How does it measure out?

[zanepetty 117]

I don't have anyway to measure it. I just want to make sure it's not scored. It's s a fresh rebuild. But I didn't know idling too low was hard on these engines. I would always let mine idle to warm up and it idled to break In. And I'm sure it was under 1209 rpm

Edited March 16, 2015 by zanepetty

[bmsgaffer 2,043]

I'm no expert by ANY means, but to me it just looks like it was wearing a little fast in that spot, but not too bad. I think the 'black' you see is actually just a polished surface, so its reflecting the light. On all the rest of the cylinder, it looks like you can still see the hash marks from honing.

 

So, hard to say without measuring, but as long as shes not smoking I wouldn't worry about it. If you want to be extra precautionary, it looks like you can just re-hone the cylinder and then make sure you bump up your idle to insure good oiling.

 

EDIT: you can gently run your fingernail around the inside and if you don't feel it catch on anything I think it is not scored.

Edited March 16, 2015 by bmsgaffer

[zanepetty 117]

Well I guess I would have to dissassemble to re home though correct?

[bmsgaffer 2,043]

Yea you would have to pull the crank, rod and piston out and (of course) have the oil pan off so no shavings get in oil...

 

So my vote is don't worry about it   (But again, not an expert)

Edited March 16, 2015 by bmsgaffer

[chazm 412]

I don't have anyway to measure it. I just want to make sure it's not scored. It's s a fresh rebuild. But I didn't know idling too low was hard on these engines. I would always let mine idle to warm up and it idled to break In. And I'm sure it was under 1209 rpm

 

A fresh rebuild  ????     How many hours  ???  and you have the head off already...what was the issue ??   Looks like it starting to score @ the dark area in the 1st pic & also in the last pic.  Like Brandon said ...need to do the old fingernail test         As a rule of thumb you run a fresh rebuild med to high RPMs to seat the rings    

[zanepetty 117]

I had no clue about the rpms when I did this. Its my first rebuild. I guess I can feel a slight change in texture when running over the marks but My nail doesn't get hung. I'm not sure if it needs to be re bored or not now. That would be my luck. 😔

[Theroundhousernr 589]

   The marks at top dead center, from the pictures, I see nothing to worry about. Its the vertical scoring in the bore that could cause it to burn oil / lack compression due to blow by. If it is just light scoring " hardly can feel with your finger nail " then maybe you can run it a little more at higher rpm then under load and it might reseat if lucky. If you can feel these grooves, they will tear the rings up and they will never seat right. Best case, It might just need more lube and some time. Possible , re hone and set of rings. Worst case, needs an oversized piston.

 

  Just curious, what made you open it up? Did someone warn you of your break in procedure? Also , reviewing the pictures again, it shows the scoring to be on both intake/exhaust and starter side of motor. Is this a new aftermarket piston? Was the piston and bore measured before putting together. Could have been running lean and hot, which caused some scoring from piston to bore tolerance being off. Just giving you some more ideas.

 

  Generally, break in is done at med rpms under no load, run up to operating temp. Then drain, inspect and replace oil. Torque head bolts. Then second run, drive it around a little and give it more of a range on rpms. Let cool. Final run, is give the motor a load and run it good and hot. Change oil, and check head bolt torque a final time then treat it like the rest of the herd. Everyone has different methods on this procedure but I find this to be the safest and you can change oil on the second run if nervous, to check for any funny sparkles.

 

  Some people just go and run it like its a broke in motor and never look back.

Edited March 17, 2015 by Theroundhousernr

[zanepetty 117]

I opened it up because I was told to let it idle for 30 mins for break in. I also let it idle to warm up every time I run it because that's what I was told to do. And it's my luck that the worst usually happens so I figured I would take a look. It also puffs smoke when throttling up or down. So I guess I just need to take the whole engine apart and redo it?

[Theroundhousernr 589]

Sounds that way

But it would help if you answered my questions. I and others could help better

[zanepetty 117]

Ok. I opened it up because I realized that my break in info was wrong and I was worried I had ruined it. The piston is kohker brand 2 15/16 size. The piston was measured before it was bored. My bore was originally 2 7/8.

[Theroundhousernr 589]

Here is whats got me scratching my head. The piston in the picture is marked STD as in standard bore? So would indicate it was not bored just honed with new rings. The honing looks fresh but it is the piston is standard.....

[oldredrider 2,547]

Personally, I don't think you have anything "wrong". I would put it back together and run it like a worker. The smoke on throttle up should diminish as the rings seat. Seating rings can take up to 8 hours. Run it for 30 minutes (as you normally do) let it cool down and re torque the head and enjoy your tractor.

I would change the oil after about 3 to 4 hrs of run time.

[zanepetty 117]

There are two bores that were stock to the k161. Mine was originally 2 7/8. It was bored out to the larger 2 15/16 bore which is still standard. I hope your right old rider. This thing is a pain.

[Theroundhousernr 589]

Oh ok. That makes sense. Never had one.

[Coadster32 793]

I 'd agree with not ripping it all apart for a few puffs of smoke. Agreed that it might not have been broken in properly, but it still could be done. These motors take a pretty good beating. IMHO, it's only work ripping apart if it doesn't work, or it smokes like crazy. By the looks of the pics, the vertical scoring doesn't appear to be any deeper than the hone that you can still see. Good luck.

[WH nut 553]

Put it back together and run it like you intend to work it. You haven't run it long enough to seat the rings. I never take it easy on a rebuild. Put it together and start working it.

[Fordiesel69 226]

I had replied to your PM.  I have pics of a fresh M14 and M12 that I am too lazy to upload, they are 3MB a piece.  It shows similar patterns as yours.  I believe you need to wait at least 50 hrs to make a determination.  DO NOT!!! rip it apart over that minor bore polishing.  Rings will often not seat equal for quite some time.  Work the engine hard, then ease off, then hard again, and ease off over and over.  Just like a tractor trailer engine.   

[Theroundhousernr 589]

I agree with everything being stated but you really can't make a sure judgement call from a picture. If the marking is no deeper than the honing marks, then of coarse run the engine for awhile. If the marking is indeed scoring, then you have some trouble. But if you can see thousands of a difference through an image, I applaud your skill.

[zanepetty 117]

Thanks so much for the replies guys. I'll post how it goes after some time.