M-18 Kohler

1811woody · #1 10-29-2010, 11:06 AM

Need to rebuild the M-18 (smokes and uses oil) from my 1811 looking for a rebuild kit any suggestions as to where to get the most bang for the buck. I hope to rebuild this myself for less than $1000.00 Thanks Doug

BCDSFCRET · #2 10-31-2010, 08:45 PM

My 1811 was smoking and using oil. All I did to repair the engine was remove it from the tractor. I pulled off the cylinder jugs. From there I honed the cylinders and installed new piston rings. The piston rings came from ebay. I used the $26.00 ones and they worked just fine. The 1811 does not use a gasket on the cylinder jug to block. Use high temperature RTV black. Do not use too much on the mating surfaces. I did not take the head off the cylinders. this will save you some more money. I have about $60 in my engine and it runs good and does not use oil anymore.

1811 · #3 11-12-2010, 12:05 AM

when you say you honed the cylinders did you use the bristle type with the balls on the o.d.? and did you remove material, if so how much? and the rings you bought were they oversized?

BCDSFCRET · #4 11-12-2010, 09:05 AM

I used the old style hone with 3 stones on it. I think the type you stated would work just as good or better. I do not have one.
On top of the piston it will state STD. .010 or .020. Use only the rings that are marked on the piston.
Remember you are only scoring or taking the glaze of the cylinder wall. This glaze will come off in 30 seconds.
Good luck.

ol'George · #5 11-12-2010, 09:11 AM

FWIW,
Generally when an engine is re ringed, it is recommended to DEGLAZE the cylinders to allow the new rings to seat properly.
Most manufactures say you can be as much as .005 oversize and still use the std. rings.
Honing denotes removing a larger amount to go to the next available oversize piston/rings.
It is much better to remove nothing, just a light deglazing of the walls to insure a quick seating of the new rings, if cylinders are in speck.
Deglazes are usually spring loaded stones, emery cloth or the mentioned ball type.
Hones are mechanically expanded stones usually done in course grit first and a finer finish set to the required oversize.

BCDSFCRET · #6 11-12-2010, 05:20 PM

There is a difference between honing a cylinder and booring a cylinder.
honing is used to take off the mirror claze. Booring is when the cylinder is brought to a engine machine shop.

ol'George · #7 11-12-2010, 06:14 PM

FWIW,
As I said in my previous post, deglazing is removing the polished finish from a cylinder in preparation for re ringing.
Honing is removing a significant amount to allow for oversize piston/rings
If a job is to be done right, it is bored to remove any irregularities in the wall to insure it is not tapered or egg shaped, usually leaving .003-.004 to be honed to the finished size.
That is how I do it.

Many small shops only use a hone to go oversize and not bore, as they lack a boring machine or a Bridgeport mill, or other similar equipment.
I have seen it many times, it usually works out acceptable.
If a shop is really honest with you, they will tell you they just hone to oversize, as it takes quite a bit of time to set up/indicate a block to get it square.

1811 · #8 11-13-2010, 01:07 AM

If I have the ability to bore a cylinder jug and hone to size. Would it be worth doing to an engine with 2300 hours on it? Also how much oversize can it be before having to buy bigger pistons?

ol'George · #9 11-13-2010, 08:58 AM

If the bore measures in tolerance, not egg shaped or tapered, just lightly deglaze it and put in new rings.
If it is scored or out of spec, then it should be bored & honed to the first oversize available, usually .010
Sometimes engines must be taken to a larger size as it will not clean up @ .010 or .020.
Depending on the engine, and what pistons are available, denotes the max. you can go.
If going to oversize pistons, always give the pistons to the machinist so he can fit to the proper clearance.
FWIW, on a auto/truck engine usually you will find it will clean up at .020-.030
with most manufactures recommending no more than .060 as the water jackets get thin over that.
There are exceptions like the big 2 cylinder John Deere Diesel tractors that go to +.125 but we are talking 6-1/4" Daimeter pistons
The pistons in the M-18 Kohler are forged Mahle --very good & highly regarded --and not inexpensive.
hope this helps

Matt G. · #10 11-13-2010, 12:02 PM

I might be wrong but I think you can only go .020" over on the KT and Magnum twins. If not that, then .030" over is definitely the max.