First Start Up of New Rebuilt K301 Question

[Polaris2007 4]

Okay, so I fired up my newly rebuilt K-301 for the first time today. The engine was bored out, new piston, rings, rod, valves, valve guides, block was decked, head was flattened. The engine had a lot of smoke on startup, because i liberally coated the cylinder walls with oil during the assembly phase. But now, after about 15 nimutes of running, it still is smoking quite a lot. About like an old tired engine that needs rings really bad. Is it normal for a newly bored engine with new piston and rings to smoke like that for a while, maybe until the rings seat in? Although this is my first small engine rebuild, i have done a few car engines, and they did not smoke at all. I used one of the Stens rebuild kits from ebay. The instructions for the oil control ring was VERY vague, and the diagram made just about no sense. The little spring thing between the upper and lower oil control rings was a different design than the one that came out of the engine, and since the instructions were useless, I put it together in the only way that I could get it to work. I'm wondering if I somehow screwed this part up? Does anyone by chance have a close up photo of one of these Stens pistons with the oil control ring assembled on it?? :)

[wheelhorse656 20]

you should always let a rebuilt motor sit for about 2 weeks. that gives the rings time to set to the cylinder just let it sit for a few weeks then trie to fire it up! :)

[rmaynard 14,986]

you should always let a rebuilt motor sit for about 2 weeks. that gives the rings time to set to the cylinder just let it sit for a few weeks then trie to fire it up!

What's going to happen in 2 weeks that won't happen in 2 hours? I'm a bit curious about your statement.

I have seen single-cylinder engines go right from the rebuild bench to the tractor with no wait time and no smoke except for a small amount of lubrication burn-off.

Just curious.

Bob

[TT-(Moderator) 1,129]

Kinda puts a damper on between-rounds rebuilding of dragster engines too, huh? :)

[chris11 184]

Kinda puts a damper on between-rounds rebuilding of dragster engines too, huh?

TT let me get back to you in two weeks Ill let you know. Where i work at the race shop. we build them and run them on the chassis dyno run the rpms right up.

[chris11 184]

Maybe you broke a ring.

[wheelhorse656 20]

hey bob, i just have heard let them sit for a few weeks. i did rebuild a motor and fire it right up and mine smoked. i talked to a friend who rebuilds motors and he told me its a good idea to let them sit for a few weeks. im not exacly sure what it dose either. but i let it sit for a few weeks like he siad and it stoped smoking. so i thought i would just throw it out there. :USA:

[Polaris2007 4]

It's been about three weeks since I installed the piston. I must have broken a ring. I'm going to pull the piston and check it out.

[Polaris2007 4]

:) :)

[tommy3horse 3]

Hey guys;

The Kohler book clearly states that the "run-in" period is about 5 hours using straight 30 wt. oil. This "run-in" time and special weight oil allow the rings to seat properly, thus sealing the cylinder. I use only Kohler parts in mine and the K301 I rebuilt 4 weeks ago smoked a bit for 3 of thoise 5 hours, then stopped and ran clean. I changed the 30 wt. oil to 10w-30 synthetic and it is a real powerhouse.

Oh yes, I started it 2 days after I was finished it, absolutely no waiting is necessary. Good luck!

Tom

:)

[Save Old Iron 1,564]

Polaris,

one thing I have not seen mentioned is the finish of the bore in the cylinder block.

Other than a broken ring, improperly gaped ring or a piston groove that's "mucked up",

bore finish can have a tremendous effect on how rapidly rings will seat. A poorly honed or non honed bore wall will not allow some rings to seat and seal properly - regardless of how long the engine has been run.

When you take the piston back out, the bore should have some "roughness" to it - a mirror finish is not a good thing and will not allow rings to seat properly.

Look for a good crosshatch finish on the bore. With 5 hours run time, there should still be some evidence the bore was finished with a crosshatched pattern.

[WH nut 553]

As long as the piston and rings look ok and you have the ring staggered take her out and work it hard to seat the rings. Oneother thing. If it smoked bad before you rebuiit it, it could be oil left over in the muffler that needs to be burnt off. Work it to seat the rings

[FarmerJim 5]

Polaris, I rebuilt a k301 early this spring using one of those stens kits and I gotta agree the diagrams are all but useless.Long story short, my engine ended up setting for about 2 months and I was nervous about the first fire-up but I had lubed the snot out of it when i assembled it and It fired up with no smoke and has not smoked yet(Maybe I just caught a lucky break for a change).

[WH nut 553]

I have used stern on several motors no problem. The oil ring is just like any other. expander in first then lay in the the top and bottom ring. The other 2 ringg either inside tyapper up or dot up. Pretty simple

[Polaris2007 4]

Update: So I pulled the K301 out of the "C" in preparation of doing an autopsy on the piston rings. After I had it sitting on the bench I thought "Damn, i should have started it up without the dipstick in place, just to make sure I didn't screw up the breather." So then i figured it is not to late. I tossed the battery up onto the bench, poured some gas into the little jug, and after about 5 minutes of wiring, I had it running on the bench. Same symtoms.....no smoke at idle, but apply ANY throttle and it smokes like a @#$%. So then I pulled the dipstick and started it. Same thing. So it is not a messed up breather assembly. Piston comes out tomorrow. Update on condition of rings to follow.....

[Polaris2007 4]

Okay, so I got the piston out. WH nut had said that the top two rings go "inside taper up, or dot up". When he says "inside taper" is he refering to the small chamfer on one of the inside corners of the ring? Well....I paid no attention to this when i installed the rings, and I ended up getting the top ring in with the inside chamfer facing up, but the next ring down was backwards....I got the inside chamfer down. Would one of the top two rings being installed upside down cause a significant amount of smoke? I could see that being the case if the chamfer was on the outside of the ring where it contacts the cylinder wall, but why would it matter on the inside of the ring? The oil ring looked okay, but I have a question about it. To anyone who has installed one of the Stens/rotary brand pistons and rings: When I First tried to install the expander for the oil ring, I found that if I tried to butt the ends together in the groove, the ring was to long, and protruded out past the side of the piston. The solution I found was to overlap the ends of the expander, letting the very end "corrugation" lay into the "corrugation"at the other end of the ring. I had to slightly bend open the corrugation on one end to enlarge it enough so the corrugation on the other end would lay inside it nicely, like two spoons in your silverware drawer. Did enyone else run into this??? Any help is appreciated :)

[WH nut 553]

The oil ring is wrong the ends but up together. Now the othe two rings only fit in certain grooves. I dont remember how to tell without the package, You maybe able to tell by measuring the ring in the groove with a feeler gauge. As far as the chamber, it has to do with the way the ring fits. Now back to the oil ring, al the rings will expand past the pistion, but will compress with a ring compressor

[Polaris2007 4]

Okay, I took my piston with the rings all still on it, just as it came out of the cylinder, to this guy at work who is an engine expert. WH nut called it.....I messed up on the oil ring expander. i should have butted the ends as he said instead of overlapping the ends. By overlapping the ends, it made the expander fit tightly all the way into the groove, instead of pushing out to the cylinder walls. this left the outer edge of the two oil rings unsupported at their outer edge that contacts the cylinder wall. This allowed the rings to "flip flop" like windshield wipers(not quite so extreme), and let oil get by, hence the smoke. New set of rings and a gasket set are on their way. Should be up and running again this weekend if I don't have to work, but I probably will have to. I'm just happy that i found a definite answer, and have a clear path to the fix. :)

[WH nut 553]

Good to hear. Now when you get the new rings, study the packet they come in each ring has its own groove. Just remember to watch for the taper or dot. A lot of times they color code the ring so you know which groove

[daemon2525 5]

WH nut,

I thnk that on the Stens piston and rings that the grooves and rings are the same size.

I do believe, however, that one of them is chrome plated and goes in the top

groove.

Yup, with all of the dots up.

[Polaris2007 4]

A couple things...... Although the rebuild kit I bought off the internet advertised the parts as being "Stens/Rotary", all the components came in plain white boxes with only a part number printed on the box...there was no brand name anywhere. So there was no indication of the brand of the parts. They looked to be of very high quality. good looking castings machined to a fine finish. The upper two rings were identical in every way, including thickness. There were no dots on them anywhere, and they were the same color. Both had a small chamfer or taper on one of the inside corners. There was no instructions to show whether this chamfer goes up or down. I learned from WH-nut that this chamfer goes up, and that th eoil ring expander ends are to butt up to each other. I will install the new ring set accordingly. One other question: Should i file the stens/rotary rings to the spec in the service manual? The end gap was around .005 for the upper two rings...quite a bit tighter than the kohler specified .010 to .020, so I filed the ends to achieve .015" was this the correct thing to do? I plan to do this to the new set of rings too, unless I hear otherwise. Lemme know...... Thanks again guys.

[sorekiwi 761]

I'd file them to the gap specified in the Kohler manual. You dont want to chance them butting together.

[WH nut 553]

Yes, go ahead and file them to get the right end gap

[Polaris2007 4]

Okay then, I will definitely file them to spec if needed. I'm just sitting around here waiting for the rings and gaskets to show up. I was planning on having them last friday, and I was going to put her together Saturday, but they didn't show up. This engine is going in a C-101 (will actually be a c-121 now) that is to be my snow removal rig. I have a blower and a plow for it, but no deck yet. Anyway, the tractor's paint was not in great shape, so Saturday instead of putting the engine together, I gave the tractor a "1 Day Restoration" Haha. Removed the grease with acetone, quick wire brushing of loose paint, tape over the decals that really should be replaced, one coat of Rustoleum rusty metal primer, two coats of Valspar IH red, peel tape, and PRESTO!! It's a classic "50 foot paint job". Don't get any closer than 50 feet away and it looks GREAT!! Seriously though, It doesn't even come close to the job I did on the C-120 that Micah has now, but I think it will be fine for a "beater snow rig" I'll post some pictures in a day or two.

[WH nut 553]

Where did you orfer parts from. I think I get mine from One man small engines, or something like that and they show up next day