M Rebuild

Anonymous-0 · Dec 29, 2009

Hey

I have a '42? M that was burning oil like crazy. Ive never done a rebuild before and of course, Im not looking to spend a bunch of money, although I will be working the tractor discing, moving hay, and cultivating, so I do need a reliable tractor.

Ring gap on compression rings are between .25" and .375"

Ring gap on oil ring is .5"

Pistons are 3 7/8"

Compression was about 70psi on each cylinder

Lots of carbon deposits from burning oil.

I take it I should buy a manual, but any input?

Where do I get parts?

Thanks

Andrew Z · Dec 29, 2009

you can get the parts right here on the site, their prices are very reasonable.

Andrew

Anonymous-0 · Dec 29, 2009

JUST A THOUGHT. BEFORE YOU ORDER A BUNCH OF PARTS. HAVE THE HEAD REDONE. HAD A ALLIS WD I BOUGHT WOULD NOT START,WEAK COMPRESSION I ASSUMED THE WORST. PULLED APART TOOK HE HEAD IN WHEN THEY PULLED THE HEAD OUT OF THE HOT TANK THE THE VALVE SEATS FELL OUT. CRACKED IN 3 PLACES. NEW SEATS, VALVE JOB,COST ME $171 PUT TOGETHER 2ND CRANK AND RAN.

Jeff Z. · Dec 29, 2009

Get a manual. It will help you alot. From the numbers you posted it sounds like it's ready for rings.
Don't get too crazy on some of the engine specs.
These engine are very forgiving if your off a bit.
Get the ring gap as close as you can but don't go crazy trying to get it perfect.
While the head is off it is always a good idea to do a valve job, guides and springs.
Have the head milled for trueness.

Allan in NE · Dec 29, 2009

Hey Chris,

Just trying to help, okay?

If you're gonna do it, do it right. Don't jack around with just replacing a set of rings. That NEVER, EVER works. It'll be burning oil again before the summer is out.

Replace the sleeves, pistons and rings as a set, replace all the bearings and have that head redone by a reputable machine shop.

Oh, and that ring gap thing.......don't worry about it as it's just not that important. If the piston assembly will compress into the hole, yer good to go.

Like I say, I've been spinnin' wrenches for 60 years and I'm just trying to save you some greif.

Allan

old · Dec 29, 2009

Parts that is the easy part. 100s of places to get them. The tractor barn in Republic, O'Reilly"s has them etc etc etc. As for what you need to do you first need to figure out how wore the engine is. Most likely a simple ring job will not do much other then waste your $$. Pull the engine and have a machine shop check it out as for as how close it is to spec. Then go from there. Warning you can easily get more into and engine then the whole tractor would sell for. I.E. just a sleeve kit will cost you around $700 and then you still have a lot of other parts you will need.

NDS · Dec 29, 2009

Old and Allen are right on if tractor is going to do much work BUT do you want to spend more on engine than whole tractor is worth? Have found that ring, bearing and head job will usually run for a few hundred hours if things are not too badly worn.

Anonymous-0 · Dec 29, 2009

Thanks for all the info! One thing is you can always spend more money.

Ill have the head looked at before I proceed.

Could anyone give me bearing size/tolerance or possible an out-of round tolerance on the sleeves?

Red Mist · Dec 29, 2009

Chris:
Wow, thst is a lot of ring gap. Rule of thumb for ring gap: .004" per inch of bore. 3-7/8" bore would be about .015" - .016". Stagger gaps around piston, trying to stay off thrust side of pistons.
P.S.: I vote for proper rebuild rather than "patch" job.
[b:3f195ada61]Do it once; Do it right[/b:3f195ada61].
mike

Allan in NE · Dec 29, 2009

Anything over .0055 to .006 is gonna push oil.

Gotta think about it this way: The rings are only a tiny, tiny portion of the wearing surface compared to the sleeve wall.

What maybe 1/1,000 of the area (X 3)?

Allan

glennster · Dec 29, 2009

chris, if you"re gonna go thru the motor, do it right the first time, then your done with it and you have a good reliable tractor. you can get the overhaul kit about anywhere, last one i bought for my super m came from yt here. some advice i"ll pass along. take the crankshaft to a machine shop, have them check it and have THEM get the main and rod bearings. if you dont have a sleeve puller, have the machine shop pull the sleeves and install the new ones (in case the deck needs to be surfaced.) my sleeves stuck out too high. the i&t manual isnt a bad manual for the price. pull the lower cover off the oil pump, check it for wear, and be sure the relief valve moves freely. be sure to mark each lifter when you take them out of the bore so they go back in the same hole. check the clutch when you pull the motor out, now would be the time to replace it if needed
also, check the ring gear on the flywheel to see if its chewed up. they can be flipped over if not too bad, new aftermarket ones are reasonable too.

Anonymous-0 · Dec 29, 2009

Yeah, that was not with the piston in the block,
which doesnt really tell you anything, I imagine.

Thanks for the rule of thumb though.

Red Mist · Dec 29, 2009

(quoted from post at 15:09:37 12/29/09) Yeah, that was not with the piston in the block,
which doesnt really tell you anything, I imagine.

Thanks for the rule of thumb though.

Ah-ha! Now, the rest of the facts are revealed to us. Remove the rings from the piston and push them squarely into the bore about 1" down. THEN measure the gap.
mike

Andy Martin · Dec 29, 2009

Am I right that you are measuring the ring gap with the pistons out? If so, pull the rings off and measure the gap with them in the cylinder bore. Use the piston upside down to get the ring in square. Then measure the ring gap and it will tell you something.

I never fix them "right" and I have very good results with H's and M's. My primary M got new rings and no valve job twenty years ago (was fouling out plugs) and still pulls my Vermeer 504 Super G for about 400 bales every summer. After I'd stuck the rings in it ran terrible and I felt I'd not fixed it when I realized it still had the last set of fouled plugs in it. I don't replace plugs just because I'm working on the tractor.

I can't speak to newer tractors and if you've got the money it's fun to make everything new again but I only fix what's wore out because if you are using it it will continue to wear. I only replace the bad tire too, and get all the life I can out of the other ones. Some respectable folks replace all four tires "while they're at it".

I have never regretted doing a partial job and I depend on my tractors year round.

Red Mist · Dec 29, 2009

Well, there you go, Chris. Don't fix them right.
mike

Jay Snyder · Dec 29, 2009

Yeah That is a lot of ring gap. It should be .015 or so. I use a service manual for all my tractors. I have the original service manual from IH but I also have a IT manual. Get a manual for sure it will help you a bunch.

Andy Martin · Dec 29, 2009

You need to get a manual to get the specifications. I&T manuals are good if you have mechanical experience or have someone to help you.

You can use a ring at various levels of a sleeve to estimate sleeve wear but it is best to have a micrometer to determine if the sleeves are within specification. If they are they don"t need to be changed. If they are close, I would not change them. Rings and head gaskets are really cheap.

Same with rod and main bearings. You need to know how to use plastigage and get the bearing clearance measured so you can decide whether you need new bearings or to have the crank worked on.

You"ll get lot"s of good advice here, and you"ll notice I am in the minority on this subject but I think it is important for you to understand you can succeed without spending $1,500 to $3,500 to make the tractor useable.
Some engines are truly worn out but some just need rings and maybe bearings. They turn so slow if you keep oil in them they will last a long time.

r4etired · Dec 29, 2009

Each person has there own opinion on repairing old tractors.Mine is it all depends on what you expect the tractor to do after rebuilding. If you are going to plow a couple hundred acres and continue to work it hard I would say you could justify a 1200-1500 dollar rebuild. If it is going to rake hay or run an auger go the cheap route. I hate to spend more than the value of the tractor to rebuild one.

Andy Martin · Dec 29, 2009

Yeah, my motto is

"I've never found time to do it right, but I've always found time to do it over."

The key to success in that is that I rarely have to do it over. Pay attention and do what needs to be done and move on.

My grandpa's M has a lower radiator hose which is a little too short (my deceased uncle put it on) and when it popped out in a hay field we wedged a cedar stick behind the flat cast pipe to help keep the hose connected. That's been four years or more and it's still holding. I'll replace it when I get a chance but the tractor gets used a lot and the lower hoses are hard to get longer ones in place so I just make sure the stick hasn't fallen out occasionally. I probably need to post a picture of that.

We can have different experiences without any of us being wrong.

SDE · Dec 29, 2009

I replaced the rings in my 400. Had the crank ground and new bearings. After I had it back together, I realized that new sleeves and pistons would not have been that much more time or money. I did not have the cam or the head worked on.
I am happy with my tractor. I work the snot out of her when I need to, otherwise i use it mostly for light work.
Stee

John M · Dec 30, 2009

I dont think Ive ever set the ring gap on any of my tractor rebuilds. Now back in my dirt tracks days I did, but on my tractors, nah!

NDS · Dec 30, 2009

No doubt an out of frame blueprinting high dollar overhaul is best but back when we were USING Hs and Ms my Dad would pull one in shed and do want the perfectionest would call patch job and tractors would go out and run more in one year than vast majotity of letter series will run from now till Jesus comes.

sflem849 · Dec 30, 2009

(quoted from post at 07:03:09 12/30/09)...tractors would go out and run more in one year than vast majotity of letter series will run from now till Jesus comes.

I like it! If you have followed some of the threads I have participated in I have stated that fact in not such a creative way. I remember one from the guy in CA with the H. He thought he needed to replace every bearing in the trans and this and that...if you have the money, do it! IIRC he barely had enough money to afford the tractor for a while. Most of these tractors won't see 100 hours before Jesus comes

100 hours is A LOT if you aren't using them on a farm. Tractor rides will pile up hours, but they certainly aren't working hours.

Red Mist · Dec 30, 2009

(quoted from post at 19:27:27 12/29/09) We can have different experiences without any of us being wrong.

I can agree with that.
mike

Andy Martin · Dec 30, 2009

That's the key to success on this forum, mutual respect for the other guy.

Sharing ideas and recognizing there are multiple solutions to any problem, and that the one you've used previously may not be the best solution in a different instance.

It has always interested me that you can learn something from even the new guys who don't know much and the know-it-alls (who usually don't nearly as much as they think they do). It aggravates me to learn something from one of those guys, but it happens.

I sometimes advertise my cheap ways knowing I'll get shot at, but never hit, because I only speak from my experience and try to leave the door open for alternate views.

It is also very interesting that the original poster may never respond even on a long string, and furthermore the original question may not be the valuable topic in a string.

See ya around.

Red Mist · Dec 30, 2009

It is also very interesting that the original poster may never respond even on a long string, and furthermore the original question may not be the valuable topic in a string.

See ya around.

Ain't that the truth! I sometimes wonder if the guy making the original post ever comes back and reads the answers provided - let alone considers leaving a "Thanks".
Oh, well. We aren't here to teach manners, I guess.
mike

Anonymous-0 · Dec 31, 2009

Well, I do appreciate all the help.

At this point, I plan on getting the head looked at and Ill go from there. I can get some help on whether I need new sleeves or main bearings, etc.

Actually I am glad that there is a long thread here with alot of opinions, its nice to know theres a couple of different ways I could go here and Im not stuck just spending a ton of money, or simply ringing it.
Thanks

Farmall freak · Dec 31, 2009

The complete overhaul kit is cheap and comes with everything for the engine. If you do it right the first time it will run for another fifty years.

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