what does a knocking rod sound like?

[Patrick62]

when it rains it pours...
Okay, blue splitter is having a problem. This machine has split a LOT of wood, it probably don't owe me anything. Figure it did the lions share of 300 cords a year for atleast 6 years... Kohler Command CH15. One heck of a engine, my hat comes off to think of the hours and hours of turning a 22gpm pump at 3600rpm. Kurt fired it up today and it sounded like a REALLY loud rap like a really loose lifter on a chevy. It is that sharp a sound. Engine still runs but sounds terrible. This engine has oil pump and filter, and I have a gauge on there. Pressure is normal. Follow the hunch, and pull the valve cover. nothing looks funny here. start it up, and the valves are opening/closing. pulling it over by hand, and I notice a oddity with the action of the exhaust valve. Intake opens piston goes down... then the exhaust opens just a bit... then compression and then the exhaust valve opens like it should. then intake again and the extra opening of the exhaust valve again. WTF ? Is this Kohlers idea of EGR ?? or something even weirder?

Like I said, this engine has pretty much 2000 hours on it, starting to blow by a little. I am wondering what my best course of action is here. Take it apart and try and fix it. or just hang another engine on it?

Another Kohler? Try for a Chonda? I don't know if it really needed 15hp, but the 22gpm pump calls for 12hp, and I am at elevation up here. 15 seemed sensible. I don't ever recall it struggling tho.... Might get by with a 13 or so?

Thots and feedback appreciated

 

[jwade]

i think i would go with another kohler the old one has given you pretty good service.

 

[Rookie1]

First, the rocker arm action is the automatic compression release. As you can see it bleeds off some pressure while turning over slow. Once it gets running it stops by centrifugal force.
Second I would check the oil and see what it looks like. You may have to cut open the filter to see metal in it. But from what you say it's probably on its way out.

 

[zogger]

Doesn't hurt to price parts out if you like what you have. New kohlers are not cheap. Harbor Freight engine that size will be considerably cheaper.

Throw a harbor freight on now for a fast replacement, start rebuilding the kohler?

 

[GVSII]

when it rains it pours...
Okay, blue splitter is having a problem. This machine has split a LOT of wood, it probably don't owe me anything. Figure it did the lions share of 300 cords a year for atleast 6 years... Kohler Command CH15. One heck of a engine, my hat comes off to think of the hours and hours of turning a 22gpm pump at 3600rpm. Kurt fired it up today and it sounded like a REALLY loud rap like a really loose lifter on a chevy. It is that sharp a sound. Engine still runs but sounds terrible. This engine has oil pump and filter, and I have a gauge on there. Pressure is normal. Follow the hunch, and pull the valve cover. nothing looks funny here. start it up, and the valves are opening/closing. pulling it over by hand, and I notice a oddity with the action of the exhaust valve. Intake opens piston goes down... then the exhaust opens just a bit... then compression and then the exhaust valve opens like it should. then intake again and the extra opening of the exhaust valve again. WTF ? Is this Kohlers idea of EGR ?? or something even weirder?

Like I said, this engine has pretty much 2000 hours on it, starting to blow by a little. I am wondering what my best course of action is here. Take it apart and try and fix it. or just hang another engine on it?

Another Kohler? Try for a Chonda? I don't know if it really needed 15hp, but the 22gpm pump calls for 12hp, and I am at elevation up here. 15 seemed sensible. I don't ever recall it struggling tho.... Might get by with a 13 or so?

Thots and feedback appreciated

I'd give serious consideration to rebuilding your engine.Find a good small engine mech.and let him have at it.2000 hours is a lot of time on a small engine and it has served you well.Go with a low cost engine for now while the Kohler is being rebuilt.

 

[sb47]

If you plan on rebuilding the existing motor, I'd do it now before more damage is done.
If you plan on replacing, I'd first try a heavier oil or Lucas oil and see if the noise calms down.
If your going to replace, I'd run it till she blows.
2000 hours dosn't seem like that many hours to me.
I think you should have gotten way more hours then that .

 

[Patrick62]

I am going to "hang on" to the engine, and eventually see if it can be rebuilt.
I have ordered another Kohler today, same engine. The time to make a decision was today. Small engine warehouse had one left... for 500 clams.
which is what I paid for the other engine years ago. I can't be cruel enough to "run it til it blows". I don't know what happened in there.... yet.
I am willing to try another Kohler tho.... I like the design. and Parts are available. I might take it down and get Clint to help me with the machine work and rebuild it. Never hurts to have another decent engine around.

 

[sb47]

Sounds like a good winter project when your stuck in the shop.
I've seen motors knock a long time and just keep on running.
Too bad you had a problem but it sounds like you got a good deal on the replacement.
Try running conventional oil during break in and then switch to synthetic and see if this one last longer.

 

[Patrick62]

I like that idea... we'll break it in for about 20 hours on 10/30 then switch it over to synthetic!!!!
Excellent idea there....

Winter project... Yea!

 

[steved]

Skip the Lucas products...they are mediocre at best.

I have found that Kohlers seem to respond well to 5w40 diesel-rated oils. I've used Rotella or Schaeffers, but any of the big names would work (Delo, Amsoil, etc.). I've been running Schaeffers in all my equipment for the past ten years or so (Rotella prior to that), anything from the small 6.5HP B&S on the splitter to the 25HP Kohler Command on my Grasshopper 61" mower. My old K-series Kohlers seem to be lasting a lot longer between rebuilds, and none of them use any oil between changes. I've put over 100 hours on a single fill in my generator alone (17HP B&S) and that oil drained looking like amber honey (goes in green)...and that was over the period of four years, same oil and filter in the sump, changed it finally just last week. Compared to my neighbor's equipment, my drain oil at 100 hours looks cleaner than what is in their sump at 25 hours.

I'm a firm believer in synthetics and/or diesel-rated oils now. I think the air-cooled environment of OPE is a good place for the extra expense of a full synthetic oil and/or a heavy-duty engine oil.

Now I will say, I'm experimenting this oil change with the Grasshopper, I changed the oil last night and decided to see if dropping from 5w40 to Schaeffer 5w30 would make any difference in power (thicker oils are harder to pump). I can already tell the starter spins it over faster. But I'm likely to change back to 5w40 after a couple mowings, just because what I was doing was working well for me...although dropping to a "one-oil-fits-all" would be nice...

 

[steved]

You don't need to start with conventional for break in...that's a myth. Think about all the cars that come from the factory with synthetics in the sump these days...a lot of GMs are factory-filled with Mobil1.

 

[Patrick62]

excellent advice there, many thanks.
This engine was a "take off" from a pressure washer. It has a few hours on it already. I will "fill 'er up" with a synthetic as soon as it arrives here. I think the diesel oil would be a touch thick for this engine. Especially when I am running it at -10

 

[sb47]

I like to use conventional oil during break in because it lets everything seat properly.
Once break in is done, then switching to synthetic will stop the wear.
Running it through a few heat cycles will help seat the gaskets and heat treat the piston.
Run it till it get up to operating temp. and then let it cool completely before you run it again.
Do that a few times when it's new and it will break in better.

 

[steved]

Again, synthetics will not retard breakin of components.

 

[steved]

excellent advice there, many thanks.
This engine was a "take off" from a pressure washer. It has a few hours on it already. I will "fill 'er up" with a synthetic as soon as it arrives here. I think the diesel oil would be a touch thick for this engine. Especially when I am running it at -10

I use to change viscosities based on the time of year...but a fully synthetic 5w40 should still flow down to -40 (if I remember the literature right). It doesn't get that cold around here, so I can run a 40 weight year round.

 

[sb47]

I think the thinner oils are for start up during cold seasons. Once a motor has been running and is up to operating temp, viscosity is not that much an issue.


Lucas oil works on noisy motors because it has a clinging property's to it. It's kinda stringy or tacky and clings to parts better then just regular oil.

 

[steved]

But Lucas has almost zero antiwear additives...it is a thickener and tacifier that dilutes the additive package of the oil its added to...run a thicker oil, it will do the same thing and protect better.

 

[Patrick62]

There are 4 things certain in life.
Death
Taxes
Broken engines
oil threads

opcorn:

 

[sb47]

I guess individual results may vary.

 

[CTYank]

excellent advice there, many thanks.
This engine was a "take off" from a pressure washer. It has a few hours on it already. I will "fill 'er up" with a synthetic as soon as it arrives here. I think the diesel oil would be a touch thick for this engine. Especially when I am running it at -10

Unlikely for diesel lube to be too "thick" (viscous). Diesels are especially demanding about lubing the ring/cyl interface. That's the focus- keeping that lubed and sealed. Any significant wear there is not acceptable. Thus the specification for "compression ignition" engines.

Funny thing about how the numbers that describe oils obfuscate. Actual viscosity #s were deemed long back to be too much for folks to handle, so API/ASME went to viscosity indices, which kinda worked since the viscosity/temp curves for most single-grade mineral oils were similar. Easy to "get" the difference between SAE 10 and SAE 30 for most folks.

Then came multigrade oils, with their additive "viscosity improver". But, ferinstance, a 10W30 is progressively higher viscosity than a straight-10 as temp drops, AND progressively lower viscosity than a straight-30 as the temps rise. A very crude approximation that diverges at the low and high ends from what you might be led to believe. IOW, a scam.

Then we have (full) synthetics, which are like none of the above for viscosity curves with respect to viscosity indices. Way lower viscosity at very low temps, way higher viscosity at very high temps. Almost like constant viscosity. Of course the original synthetic oils were developed for megabuck jet engines operating where air temps were around -70 F, and some engine internals were at 400-500 F. Easy then to see how they help engine cranking at -20 F and don't go up in smoke in Death Valley in August. Much more to the story, of course, all of it good for full-syn IMHO.

What to do: absent mfg VI recommendation, find a full-syn that enables cranking in Jan. and oil pressure in Aug. For me, change once/year, even if it doesn't need it. Might have to double interval. Experiment carefully- oil's cheap, not engines.

Thus ends my annual oil thread contribution.