M18 engine head milling
 

Last month, bought a 4.5 acre house/property. I was going to buy a zero turn, but in the barn was the previous owners 1811 that's been at the property since it was new. After using it a bunch, I'm saying F a zero turn, because I love this mower. It's nostalgic, the hydro system makes for an efficient and effortless mow. Plus, has a 50" deck. Had to put an ignition coil on but it's a solid runner now.

Is there a norm for head milling to run on 93? Carb jets to match?

Valve adjustment specs?

Is there an engine code I could search other than m18?

Anything else I should know?

Why run on 93? Just use 87 and it will be fine.

You say that now. ��

Ditto.....no point in running 93 Octane.

The 1811 rolled out of the Factory with a Kohler M18-24506 Engine in it.

Welcome
 

Another 1811, great! What kind of shape is it in? Snap a bunch of pics and post them here for us.

I just got an abandoned 1811 last year and I've been going through it to fix the neglected items. I'm impressed with the quality. I posted a lot of pics of my repairs that might interest you.

I bought a dozer blade and a snow thrower for it too.

I'm near Annapolis MD. How far away are you?

Higher octane is for engines with high compression, it basically keeps the fuel from igniting early in high compression engines so there no need for it in a garden tractor engine.

You don't need 93 octane. Where on earth did you get that idea?

I love Cub Cadet tractors..... but I'd rather mow with a ZTR. Way more efficient. Especially if I had 4.5 acres to cut, which is a ridiculous amount. I'd keep the 1811 for chore work. Get some other attachments for it....but I would get a ZTR. Or maybe in your case a 12' batwing finish mower, lol.:biggrin2:

Didn't Sam have a setup for sale??

Who said anything about needing 93 now? Lol. Did anyone read my post or was I not clear (I dunno how I could have been clearer)? I'm wondering if there is a "run of the mill" milling (pun intended) amount that will increase compression to run safely on 93 octane.

Otherwise thank you for the info.

Mower is in good shape, have all kinds off attachments as well. Obviously the old man original owner loved it. I think it's perfect for my yard, half the property is woods, other half grass. It's also a mix of flat, hills, and....rocks. a zero turn wouldn't really save me a lot of time

You can run it on 93 the way it is, no milling required. You don't have to have high compression to run 93.

Why do you feel the need to run 93?

Not to piss on yer parade, but
M-18's are a flat head engine, (and a dam good old one.)
Once you go milling the head other than say .040 you begin to shroud the valves.
Even then I'd clay the head to see what the valve to head clearance is.
As far as 93 or more octane, it is a waste of money and a decrease in power on a low compression engine.
Now if you are wanting to build a competition engine, pop up pistons, relieving the cylinder, special design CNC head, larger valves/ special cam,special flywheel rated above 4000, rpm's special intake/exhaust etc. etc. to name a few things, are a start.
But a flat head engine is not an inherently power house design to start with.
They are made for work & torque.
If you are looking for factory specifications look in the service manual available from kohler free, or here on our site.:beerchug:

I read your post. And I don't mind pissing on your parade. :biggrin2:

You don't need, nor will 93 octane gain you anything. George hit the nail on the head. This isn't a high performance engine. It's a flathead lawnmower engine. Run 89 and be happy. If you don't like that answer, sorry.

Your tractor. Do what you want.

But if it runs good, leave it alone. You can run 93 in it all day long. It won’t hurt anything, but you’re just burning money. Higher octane rating just means it won’t detonate until a higher temperature/pressure. That’s all. You can always run high octane fuel in a lower compession application, it’s just a waste of money. Go get some 100LL if you’re so inclined.

That being said, I do run 91 no ethanol in all of my small engines just because some of them sit for a long time between uses and I feel better about having 91 in there to start with vs 87, and I don’t go through enough gas for it to be a major difference in cost.

Maybe. I've never ran any of my small engines on 93 that I can recall, but I tried it in my Honda motorcycles. Actually got less mileage, and ran worse. Engines just weren't set up for higher octane. I'd bet the Kohler would be the same..... and I've been turning wrenches long enough to feel pretty safe with that statement. :biggrin2:

You're totally missing what I'm saying, maybe this isn't the place for this particular question?


Safe running on 93 octane is the *compression target*. My goal could be 112 octane as a compression target or c16, requiring more milling to achieve the appropriate compression ratio, but that'd be silly. I'm not talking about pouring 93 octane into my gas tank when I get home.

Correct, low compression and high octane will run worse, with timing the same.

I don't mind that answer, just thought there'd be more people on here that would understand my question. No worries.

.040 in my world is quite a bit (automotive).

I think everyone understood the question. Ol'George answered it quite well. Not to mention that such a slight amount of milling alone would probably not yield enough gain in compression to make the 93 work the way you intended

.040 in automotive is quite a bit because its done to multiple cylinders. It adds up!

Thanks for your replies. What I meant by .040 being quite a bit, is that .040 mill would yield almost an entire point of compression on many variants of head. Compression doesn't add up between cylinders, but if you meant a power increase adding up I can agree with that.

Yet another new member who doesn't realize the people he is talking to. :bash2:

We know what you want, we know what you mean. We understand the question. The answer is NO. :beatdeadhorse:

And.... You were looking for power increase. Were you not?

I say ya mill it. Put some cam 2 in it.. Throw the governor in the trash and add a hole in the head for some nitrous!It should be a short but fun ride

Judging by the many responses of "pointless to run 93" or "it'll run worse", with only one or two responses about milling to yield the compression, I couldn't tell...i might be new to your special forum, but I articulated my questions with specificity.

Sure, in the form of a compression increase. Also, to take it a step further, probably whatever port work that could be done, if any, that would promote velocity

Please make sure you dyno before and after. I would love to see the massive HP gains from this. :biggrin2:

Your hobby is messing with cub cadets, for whatever reason, is it not? My hobby/passion is building; race cars, trucks (exploration, rock crawling), boats, and engines for all. This isn't a quest for earth shattering power, it's an inexpensive way to make something more efficient and tinker with, it's about the act of doing it. Compared to my other vehicles and projects, it also is a cheap way to have fun (probably a reason for a lot of small tractor pullers). Making it more efficient and more powerful is a by-product of the project. I'm not entering in any races, pulls, etc, just doing what I like to do.

I don't understand the arrogance here, it's a lawn mower forum.

I'd still be happy to have a discussion, if anyone is so inclined.

The only specific question you asked is:
The answer is emphatically no. Yes, you can mill the heads. Yes, you can port and polish the valve ports. Yes, you can drill the carb jet and give it more fuel. NO, IT WILL NOT GAIN ENOUGH COMPRESSION TO RUN 93. Will it gain power. Yes. Very little. There is basically nothing available to get what you desire. The K series Kohlers are one of the most popular engines to build up. Even those need major, major work to get high enough compression to see gains from higher octane fuels. But you don't have a K series.

Even if you got the compression up enough to justify the fuel, not you have a fixed timing engine. You would have to either figure out a way to change the mounting of the magneto, or figure out how many degrees you need to go up, and make an offset key. Or, convert to crank trigger ignion. Then, where do you mount the trigger? Most are set up to mount to the PTO end, which your tractor has a PTO mounted.... so that's out.

Wasting your time....

You don't understand the arrogance because you think you are talking to a couple dumb rednecks who play with lawn mowers. Coop, George and I all are seasoned experienced tech's who build engines. I build and play with these "lawn mower" engines. We are arrogant because we know what the f*** we are talking about.

Before this great debate gets locked I'm gonna go ahead and say that it's nice to see coop and Jon on the same side for once.:beerchug:

Actually, I never spoke to any of you like a bunch of dumb rednecks. Ive been around enough hobbies to respect others passions, even if I don't understand them (honda crowd comes to mind)

Arrogance because you know what you're talking about? I could have gone without all of that nonsense, and you could have skipped to your last response which was informative, despite the arrogance yet again.

J-mech: you can't increase the compression enough from milling alone to justify using 93 octane

Pray: ok, I guess the compression is so low in stock form that milling won't increase enough to get to 93?

J-mech: correct, you can mill .0xxx and run xx fuel, with xx carb/jets to start

Pray: thank you for your expertise, afterall, I came here to seek info from those with experience.

Or

J-mechs last post, very informative

Pray: so the m18 simply is not worth messing with for the reasons you listed?

J-mech: yep, unless you want to throw a lot of money at a custom setup.

Pray: thanks!

That simple

Yeah.. One of my hobbies. I have also owned several race cars and fast boats and such over the years that I built. I raced them on a track. Not while I was mowing 4 acres of grass. My tractors are for work, My cars are for fun.

Im surprised you had not asked if doing this would hurt your "work" machine that you mow 4 acres with. Yes it will. Any mechanic knows compression equals heat. These engines really hate heat.

Ok,
If you wanna mill .040 max off the heads, have at it, but check valve spacing first.
If you have build experience, you know compression increase gives you power increase from zero grunt rpm to what ever you feel comfortable winding it too.
I'd stay under 4000.
You will still be able to run pump gas el cheapo,-- the throttle response will be a tad"snappier"
If you put it on a dyno you will say, hell it wasn't worth the cost of the head gaskets.
But you will feel warm & fuzzy.

It took a lot to make power from a flathead back in the day.
One reason why the Chrysler "Hemi fire dome" was so coveted, till the Small block chevy took over, then every body jumped on the band wagon.
I have to laugh, remembering every weekend @ Detroit dragway when some engineer tried his idea of a better mouse trap.
I was lucky enough to be witness to it all.:beerchug:

Isn't it grand watching two of them hammering the new guy. Touche:beerchug:

I ignored this statement earlier.... because it isn't really what the thread is about. You obviously have never ran an Exmark. (Or any good/name brand ZTR mower.)
These old tractor mower are very good.... but nothing mows like a ZTR. Much higher blade tip speed, much better deck, better stability, ability to turn on a dime.... all equal much faster mowing times. It's silly to think that a ZTR wouldn't save time. Not willing to justify the cost, well that is understandable. Simply not wanting one... also understandable. But saying it wouldn't save any time is kind of an ignorant statement. Even a good ZTR with a smaller deck would mow circles around a tractor mower.

What we're all trying to say is "Welcome to the 2nd friendliest Cub Cadet forum on the web!"

he he.....

The first 500 times this topic about hp gains came up, those guys got the nice version. :biggrin2:
Once guys realize that it’s not worth it and their feelings are healed up, it’s all good.
You can take it however you want, but we never lead people to do things that we have seen/tried and failed. We aren’t mindless cheerleaders here.

I think it is time for the OP to do what he wants. He has been given a lot of information. He can do what ever he likes with it. After all, it is his information, his time, his money, and his Engine/Tractor.

:beerchug:

Yep, I got my ass kicked to get it, but I can't say I didn't get what I came for.

No one is looking to kick your ass. This forum is leans more towards the side of Cub cadet preservation than racing or pulling. That however does not mean no one hear does things along the lines of building HP. Also does not mean the information given was not accurate. Do what you like with your machine of course, but IMO if I were relying on that machine to cut all that grass I would just want to make it run well in a stock form. :beerchug: