Kohler M16S rebuild

[meadowfield 1,900]

Some of you may remember me acquiring the engine for bendy from a Toro greensmaster mower at Mallory park a year ago. It was well used and cheap at £50...

It started and runs ok, but it's clear it needs some attention due to the oil burned and dripped on the floor.

When I pulled the head last year it looked like this!

And upon changing the oil I got this!

So armed with the knowledge it runs ok, but is a little tired I ordered a rebuild kit from the states. It was better value than from the UK - even including shipping and tax. I basically got everything but the valves.

So here's the thread, with the engine starting on the bench

With tinwork and ancillaries removed

Flywheel removed - after make a small puller

And head.... It's not got any better since I last checked!

[jparkes43 27]

oh it was in a bit of a state. not doing the valves? i thought that would be important. good luck

 

james

[slf-uk 914]

I am thinking of doing the same on an engine, so I will be very interested to see how you get on with the rebuild kit.

 

I'll pull up a chair and closely follow this thread

 

Iain

[Stormin 4,458]

I'll sit next to you Iain, if that's OK?

[meadowfield 1,900]

It's bring your own refreshments guys

[Stormin 4,458]

It's bring your own refreshments guys

 

Typical Tyke!

[slf-uk 914]

No problem Norm, I've got the beer and crisps ready. It would be good to see the next instalment before the beer runs out though

 

Iain

[meadowfield 1,900]

Here you go,

First instalment

The piston and rings look reasonable, but closer inspection shows heavy scoring and erosion due to being coked up.

I thought it was oil ring stuck to the plug, but apparently not.

From the bottom end, some light scoring on the big end journal. It's 4 thou out of round and 6 thou out at its maximum. Just within acceptable tolerances for what I'll be using it for.

Pic shows cam to left and balance gear to right, which will be coming out. I dislike the rattle from it!

[Anglo Traction 1,016]

Here you go,  First instalment   

The piston and rings look reasonable, but closer inspection shows heavy scoring and erosion due to being coked up.

I thought it was oil ring stuck to the plug, but apparently not.

From the bottom end, some light scoring on the big end journal. It's 4 thou out of round and 6 thou out at its maximum. Just within acceptable tolerances for what I'll be using it for.

Good to see you covering this Magnum build on here Mark. I've only done 'K's, so interested in any differences.

I see it has the 'D' style Piston and the same damage I had which necessitated a re bore.............. Hope you don't have that problem.

Those Stens rebuild kits are pretty good quality.

That is a fair amount of acceptable wear on the Crank Journal on the Mag16 . I had to have my 'K301' Crank re-ground due to being only 0.001" out of round ! (max allowed was 0.0005").  

Presume you have a Fixed Jet Carb on those ?.  Glad to see your also pulling the Balance Gears . 

Good luck and I'll follow your progress as much as poss.

Regards

[meadowfield 1,900]

Richard,

 

like I said - just about within tolerance for what I'll be using it for.

 

 

It's not going to be worked hard, but does need to run properly and not haemorrhage oil. Either through drips or burning...

[Stormin 4,458]

You say your going to pull the balance gear. Are you going to leave it out or replace?

[meadowfield 1,900]

it's coming out - it's what makes most of the rattle on a k or magnum. Especially when you rock the crank to feel for big end wear. They are always really rattly!

[Stormin 4,458]

No detriment?

[meadowfield 1,900]

Apparently not, most engine rebuilders say leave them out. I'll let you know if there's any vibration...

[Tom 215]

Following this closely also. I have read that many people taking the balance gears out with no problems. It will be interesting to see how you get on with the rebuild kit.

Tom

[Wristpin 400]

Not going to enter into the rights or wrongs of balancer weight removal other to wonder that if removal is OK why did Kohler go to the bother and expense of fitting them?

Anyway, lurking in the depths of the tool box is the Kohler "special tool" for setting and locking them during reassembly.

Edited March 10, 2015 by Wristpin

[meadowfield 1,900]

Well it's been a busy day!  6am this morning We drove 30 miles up to Horton in Ribblesdale to do one of the three peaks before breakfast!

 

Then it was back to the rebuild.

 

Here's the crank and cam out...

 

 

the infamous balance gears - which run on small needle bearings - same as the high low idler in an 8 speed!  They are incredibly loose - I'd say the bearings were shot!

 

 

 

after a good degrease, the valves were lapped - both in pretty good shape. Probably the gallons of oil that have been through them!

 

 

them the bore was honed, again it's in great shape at the top but a little worn where the oil rings have been.

 

 

a little light scoring

 

 

cam back in place, note the timing mark - and the ACR lobe to the right - it's a little worn but still functional!

 

Also the two pins to the left where the balance gears lived

 

 

crank back in and timing marks aligned

 

 

 

that's pretty well it!

 

Piston is in, but no pics - just lots of swearing

[Stormin 4,458]

Your motoring along with that.

[the showman 4,074]

Looking good Mark , have you left the balance gears out ?

[HeadExam 1,783]

I've heard many shops leave the balance gears out, one guy I know that rebuilds them put a weld spot on them to hold them in after installing new bearings, it can removed in the future with a tad bit of grinding. These engines run a little rough at low RPM or idle without them, not to big a deal if you have ISO mounts, but on solid mounts the whole tractor  will wobble like a pub meister. I don't think it's a big risk to leave them in as long as you install new ones properly or weld them in, to each his own.

[meadowfield 1,900]

yes they are out!  

 

Shakin horse might have some competition

[slf-uk 914]

Great progress, a couple of questions if you don't mind. Did you measure the bore for roundness and to see if it was within specification or just look for visual wear? Have you degreased all the parts or just the valves?

 

Thanks

Iain

[meadowfield 1,900]

I didn't measure the bore, visually it looks good. If i spend any more money in the engine I can buy a whole tractor with an engine. Currently the £170 I have in it will now not burn oodles of oil or drip everywhere!

Everything has been cleaned in petrol, blown with airline and then cleaned again.

[Anglo Traction 1,016]

I can't predict any balance/vibration issues on your engine size, but my fully rebuilt K301 with the b/gears out, has only a brief, minimal vibration period at 1900 rpm and disappears at 2100.

I presume you obtained the rebuild kit from the same guy in US (Kevin, bat4kids). Good service and endorsed by many in US.

My reasons for leaving them out we're based on the considerable US opinion and experience with these engines over many years of this practice. Other than to mention that several lower hp size engines did not have them installed.

Yes, cost to reinstall the gears is also a consideration, especially if you do it properly and/or have to replace the gear shafts as well as bearings etc.

If it makes you feel any better Mark, I put 350 quid into my engine!.

So far it is still singing like a brand new engine, but after only a few hours running.

I'm sure you'll be happy with it when it fires up.

[meadowfield 1,900]

Richard,

Yes it was from Kevin, great kit of parts. All the shim gaskets for setting end float as well as seals, piston, con rod. All gone together really nice. Shame the engine has seen a hard life and zero maintenance. The oil was just a sludge and massive amounts of carbon built up everywhere.

On the same advice I've left the gears out. Bendy will work but never flat out. Its a tickover to 1500 rpm kinda machine. Plus I might run it straight stack just for maximum effect