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murph

poss rebuild kohler mag 14

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murph

Is there a average hour amount that i should start thinking about a rebuild.Still runs good recent head gasket,showing a little oil getting by ring (smoke on start up ) 720 hours now.If so is there a aprox price i would be looking at to have it done? thanks gavin

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JAinVA

I have an m16 with over 1200 hours on it. Runs good  but uses about a quart of 30w every 8 to 10 hours.It is down on power as compared to a K series 16hp I have but the 341 has very few hours on it.I have no intentions of a rebuild of the m16 at this time.No serious smoke except at start up.The block would need to be bored.Somewhere over a $100 in my area.New piston and rings,plus gaskets $150.00 and then maybe valve guides,new or reground valves.Around here regrind on the crank is $75.00 If you farm this work out maybe $500 or $600 for parts and labor in my area.You would still have to break the engine down and reassemble it.JMHO,JAinVA

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pfrederi

If the smoke bothers you you could pull the piston hone the cylinder to deglaze it and put in some new aftermarket rings.    May stop/reduce smoke and wouldn't cost much.

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jdleach

Paul brings up a good point.

 

In the old days, one often did a "shade tree" overhaul if funds were not available for a true rebuild. 

 

These sorts of overhaul were only done when there was no evidence of significant wear on the crank and cam. As he pointed out, you could get a gasket kit and a standard ring set (if it has never been bored). You then dismantled the engine, cleaned up any ridge at the top of the bore, removed the piston, then de-glazed the bore with a hone. Best hone to use is the "berry" type,  leaving a nice 45 degree cross-hatch pattern. One must make sure to remove as little metal as possible, yet get a good pattern. To improve compression, you then lap in the valves with valve grinding compound. Again, lap only to a clean up.

 

Of course, you clean up the engine parts thoroughly both before, and after the work. Assemble the engine, adjust the valves, and there you are. If wear isn't very bad on the bore, crank, etc., you can sometimes get upwards of 50-60% more life from the motor, perhaps more.

 

Shade tree overhauls are not a bad option if money is tight, you have a basically decent engine to work with, and you do not plan on thrashing the motor afterwards. 

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can whlvr

most of my small engines smoke at start up,i wouldn't worry if it doesn't smoke aftrer that,ive had kohlers that have 3000 hours and still goin,and I have a 312-h that had 300 and smoked so bad I coyuldn't drive it till I rebuilt it,keep the oil clean and full and she will run along time

Edited by can whlvr
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murph

good stuff guys I REALLY appreciate the advice,

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MalMac

On a Kohler 14 mag, The piston that is used is a Mahle Piston. There are no aftermarket rings for them. Standard size rings for them are extreamly difficult to find. Matter of fact that crank in that motor does not like anything other than what came in it from the factory. (found out the hard way) 

 

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murph

thanks good to know,smoke seems to have leveled off after head gasket replacement,think I will change out oil one more time replace with rotella 30 t heavy duty

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Wheel-N-It
On 10/3/2016 at 5:25 AM, MalMac said:

On a Kohler 14 mag, The piston that is used is a Mahle Piston. There are no aftermarket rings for them. Standard size rings for them are extreamly difficult to find. Matter of fact that crank in that motor does not like anything other than what came in it from the factory. (found out the hard way) 

 

Can someone go into a little deeper detail on this? I'd sure like to learn more about this as I have two Wheel Horses with M14's

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MalMac

Wheel-N-It, I'll try to explain without out writing a Novel. The piston that is used in Mag14's is a Mahle Piston. It was put in to try and cut down on oil consumption I believe. The Mahle piston has to use rings that are designed for it only. There are no aftermarket rings for this piston that I know of. This Piston can only be used with the new style rod. When I redid one of my Mag 14's I took out the balance gears and used a aftermarket rod and a standard Kohler  Oem piston and rings that can be used in a K series. The engine ran but had a vibration that was ultra sonic. You could not even grip the steering wheel or keep your feet on the floorboards. So I took it back apart and started to investigate. I finally found buried in a paragraph on Brian Millers web site. That Kohler Mag 14's and 16's can not be run without balance gears or should not be run without them and that the crank is way different as far as balancing is concerned. Plus the crank is more or less designed to be run with that Mahle piston and new rod. So I put the old Mahle piston in and bit the bullet and found a NOS set of standard rings because it only needed honed. Put new bearings and spacers in the balance gears and reassembled. Engine back to running flawlessly. I am sure there are exceptions and there might be other ways of doing things. I just took it for granted that Brian Miller knew more than I did about the balancing of the Mags. I rebuilt a number of K series with great results. This was my first Mag and I screwed it up because I did not know about Mahle pistons and the different cranks in them. First time I ever put grenade gears back in. 

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Wheel-N-It

Thank you MalMac for helping me understand this. I had learned along the way here at RS not to remove the balance gears on a Magnum engine, and I appreciate you reminding me of this. This Mahle Piston thing has really got my curiosity up and I'm going to try to learn even more on this subject. Thank you for giving me some more knowledge regarding Kohler Magnum engines. I do love Kohlers!

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MalMac

I can tell you this, that Piston is super costly, When I tore mine down because it had a bad oil ring, I chose to try and use a OEM K series piston. Because I could not find at first a set of standard rings for that Mahle piston. When I did I could not swallow the cost. I found that I could buy OEM K series piston and rings and rod for what just the Mahle ring set cost. Like I said I found out the hard way that the crank and that Mahle piston is designed to work together. There is part of me that wonders if the standard piston and new rod with the balance gears in would have worked? Then again the question of that crank came up.

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murph

Any thoughts on the rotella 30 T heavy duty? Any better oil to use?

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JAinVA

MalMac,

    I saw your original post when you first rebuilt your M series engine.I took to heart the crank/piston/rod  combination you outlined.I am in the process of reringing an m14.It is a standard bore with balance gears.The thing that puzzles me is that the stock piston looks nothing like a Mahle piston.It is full in diameter at the piston pin like a K series.Am I missing something?This engine had around 300 hrs on it when mice ate all the electricals.I got it as an inexpensive project.The crank looks identical to several 321 cranks I have.I believe you had vibrations with your setup but balance gears and their timing concern me.Any insight would be appreciated.

Thanks in advance for any advice you care to share.JAinVa 

Edited by JAinVA
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Wheel-N-It
11 hours ago, murph said:

Any thoughts on the rotella 30 T heavy duty? Any better oil to use?

Good stuff

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MalMac

I am not sure what you have there in your Engine. I suppose its possible that Kohler could have put standard K series Pistons in at first. The crank should have some differences in their counter balance. That's why from what I understand is the reason the Mag 14's and 16's have to use the balance gears. In the service manual it says nothing about the Mahle piston. It just describes the different styles of pistons and what Rods go with what type of piston. Since the manual does not really refer to the Mahle piston, I wonder if that piston was used after manual was printed. If you get on Brian Millers web page and look under balancing it describes the different cranks used and shows pictures. There is a lot of info on his site and it took me reading it a couple of times over. The timing of the balance gears is most critical. I do not have a tool and have to use the method described outline in the service manual. (All the more reason to hate balance gears) 

All the vibration was my fault because I used my knowledge and experience from rebuilding K's. Found out the hard way that though very similar they do have differences. 

I also must note that my first rebuild was a  Mag 16. It was for a friend. If I remember right the only piston at that time that was offered in the size needed was the Mahle.

per my normal "leaving the balance gears out" we re-assembled it and the engine ran fine. I did contact him back when I found out they need to be back in there. According to what I have read, there have been reports of Mag 14's and 16's breaking cranks with gears left out. I am not exspert on this my any means. I am just sharing what had happened to me so the next guy that might run into this won't go down the path I did through ignorance of being complacent in his or her knowledge of rebuilding motors. Be glad to share any information I have that might help.

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JAinVA

MalMac,

    Thanks for the insight.Like you I have spent a lot of time pouring over Brian Millers notes.I have had the M14 crank and 321 crank sitting in my lap next to each other and can't see any differances in the counterweights.I just may put the 321s together first and leave the K14 alone for now.Thanks again for the insight and reply.Luck,JAinVA

Edited by JAinVA

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