Picked up an 1811 last night.

[olds45512]

Originally Posted by sorner

Is that the one I saw of you (I think it was you) on YouTube wet sanding the head by hand?

That wasn't the actual head but it's the same process.

[sorner]

Well now here's a strange discovery. I got the M18 removed, and I decided to pull the heads to look at the bores before I do anything else, and the bores look completely smooth, no scoring. Looking down into the bore I can see plain as day the rings around the piston. I don't have anything here to check the clearance but it is uniform all the way around the piston and I would say its about a spark plug gap of space. I can touch the piston head and it has some slop in the bore. I figured the bore was worn, and I measured it with my bore guage, and came up with 3.124". I went to the manual and it says the maximum wear limit is 3.128". It's possible I could be off by a couple thousandths, but I'm thinking the M18 is not going to be usable as is and needs some work to get it back right.

[sorner]

I no longer own an 1811. A friend of mine was looking for a roller for a loader project, and I had this one so I sold it to him. I kept the M18 though, and I plan to take it apart and go over it to use in my 1912. I am a little sad though because the M18 will not be quite as stout as the Onan as far as raw power and torque, but it'll do unless something else comes along.

[sorner]

I worked on disassembling this tonight and got it all apart and popped the flywheel off, and found the seal right there waiting for me. The seal feels pretty pliable and not hardened like something that has age on it. Is this normal, maybe someone replaced the seal with a cheapo Chinese one and it’s a hair smaller? Or should I put some permatex around the outside and stick it tight?

[ol'George]

The M-18's run about #95 compression in decent shape.
Do not put sealer around the crank seal.
Too easy to plug the oil drain back passage, and they were meant to be installed dry

FWIW:
There was a change in seal O.D from the series 1 to the series II & magnums
Series 1's were a tad smaller on the OD.
make sure you get the magnum/series II seal.
Not saying someone installed the wrong seal,
but I have found it in the past.

[J-Mech]

Originally Posted by sorner

IOr should I put some permatex around the outside and stick it tight?

Originally Posted by ol'George

Do not put sealer around the crank seal.
Too easy to plug the oil drain back passage, and they were meant to be installed dry

I bet that has been answered at least 4 times on here in the last week.....

[sorner]

Thanks... I've asked the question about seals before on different engines and if they should get stuck in with a sealant or not. The answers here always seem to be "not". But I have found other sites where people recommend doing it, I guess they all don't know what they're doing. I would prefer not, because if I ever have to do it again I don't want to be dealing with cleaning that chit out of it.

The seal that came out of it says Philippines on it, so I guess it wasn't made in China. I don't know if it was a genuine Kohler or an el Cheapo after market, but I have a genuine Kohler Magnum M18 seal on order now, and back to waiting for parts..

I found the source of the rattle that I thought might have been piston slap, the muffler end cap was loose where it is crimped, which I thought was weird. The muffler is in good shape, not a lot of rust on it. So I went around the entire edge with my cable crimper tool and pinched it all down nice and tight again, and it is no longer loose. So, once the seal is in and this engine is cleaned up the plan is to drop it into my 1912 as is while I take apart the Onan and find what's wrong with it and decide what to do next with that. I can't stand having this 1912 in my garage taking up space, I have some work for it to do.

[J-Mech]

You know that M18 isn't a "drop in" replacement right?
Wiring to do, driveshaft to fit.....

[john hall]

Originally Posted by sorner

I found the source of the rattle that I thought might have been piston slap, the muffler end cap was loose where it is crimped, which I thought was weird. The muffler is in good shape, not a lot of rust on it. So I went around the entire edge with my cable crimper tool and pinched it all down nice and tight again, and it is no longer loose. So, once the seal is in and this engine is cleaned up the plan is to drop it into my 1912 as is while I take apart the Onan and find what's wrong with it and decide what to do next with that. I can't stand having this 1912 in my garage taking up space, I have some work for it to do.

Friends with a TIG welder make good muffler repairs.

[J-Mech]

You mistook a rattle in the muffler for piston noise?
Experience is knowing the difference.