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Gregor

A Tecumseh Tale

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Gregor

I have some posts in the Wheel Horse tractor forum about my Tecumseh motor that came on a tractor I bought. If I could I would delete all those posts and simply start over with what I now know now, that's what I am going to do here. Start over. Here is the tag on the motor shroud. As you can see, it says, HH60-10513A. According to Tecumseh, that is not a good number, and it doesn't exist. This is not going to go good, I can tell. The motor was stuck when I got it. A pipe wrench on the pto pulleys freed it up pretty easily. That's when I decided I wanted to save the motor and rebuild it if I could. I have never rebuilt a single cylinder 4 stroke in my life, but wanted to try. Took the head off, piston and valves had some carbon build up, but nothing excessive. I took this as a good sign. Apparently the motor did run at some point. I pulled the motor from the tractor and opened it up. This is where things start to go down hill. Things are pretty crusty in the crank case. Governor assembly is completely rusted, crusted, and useless. Piston and rings don't look too bad. Crank journals are passable. Nothing seems to be broke, no bits of metal inside. I cleaned up the piston, crank. cam, lifters, valves, and valve seats. Every thing looks good. I move on to the block, and things go down hill in a hurry. This is what I find. Cracks in the sump cover and block. After some polishing on the block, I am not completely convinced it is a crack, and not just a casting mark. I would like some opinions on this. At any rate I start the search for another block and sump cover, but first I do some measuring. The piston measures 2.72" . The Cylinder measures the same. Keep in mind I m not using $500 Starrett calipers here. The rod journal on the crank measures 1.86".  I finally get a look at a manual containing Tecumseh facts and specs. HH in the model number denotes Heavy Duty Cast Iron. My block is aluminum. Piston and bore spec for an H60 is 2.62". The rod journal for an H60 is 1.06"/ My rod journal measures 1.88", (which is the spec for an H70) All of these specs can be found on pages 95 &n 96 in  the manual.

https://www.allotment-garden.org/rotavator-manuals/Techumseh-L-Head-Engines-Manual.pdf

My question are, what do I have, and is it worth saving. Is it an H60 bored .10 over, with an H70 crank? Could the manual be in error? I really hate to have my first attempt to be a failure, but you have to cut your losses at some point and move on. From what you can see, do you think the crank case is cracked?  1 more question. Anyone have an 6 or 7 hp Tecumseh they would like to sell?  Thanks Greg

20201123_123815 (2).jpg

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before pic.jpg

20201127_195456 (2)-2.jpg

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squonk

Tecky parts are getting harder and harder to find. What model tractor are we talkin here? If originality isn't an issue, Throw a good Kohler in it.

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Gregor

It is a 656.  A 1966, or so I have been told. I like to keep things original, but if it's not possible, I will go motor shopping.

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Bill D

Those are cracks.  The looks like an old snowblower engine.  The engine is toast and not worth rebuilding.  Find a good used Tecumseh Snow King engine with a one inch crank and throw it in there.  Any large frame engine from 6-13 HP should work.  Install an air cleaner and reuse your starter.  You may have to rig up an electric fuel pump unless it's gravity fed.  Easy swap in my opinion.  Bill  

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jabelman

As @Bill D , given the cracks not worth the time and money.  Search around for a snowblower if want another tech engine.  The engine on my commando 6 is off an old blower.  

also as @squonk said the older tech parts are getting harder to find and very expensive too

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oliver2-44

The piston measures 2.72" . The Cylinder measures the same. Keep in mind I m not using $500 Starrett calipers here. 

if your measuring the top of the block with a caliper, your not getting a good reading in the bore wear area.  Use a ring from the old engine and follow this procedure bt 953 nut to see how much wear you really have. 

 

 

1 hour ago, Gregor said:

This first picture sure looks like a crack. does it show up on the back side of that part? 

20201128_120308.jpg

before pic.jpg

This bottom one could be a crack or a casting line. I would grind a section of it with a dremel and see if it has any depth or goes away. (edit) I now understand that lower picture is where you polished on the block and the line went away.  I would polish the rest of the line and make sure it disappears. I think your on the right tract thinking that is a casting line on the block.  What say you @Ed Kennell

Can you swap the sump from the original engine to make one good one?

 

 

Edited by oliver2-44

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Gregor

The ring gap at the top of the cylinder is .082. In the center, .109. At the bottom, .071. According to the book, bore spec for a 7hp. is 3.062. The top of my cylinder is 2.75. The center is. .017 greater than  the top.  If I add the 2 together, that comes up to, 2.767, which is still less than the spec for an H70.  Am I figuring all this correctly? (my head hurts) According to the book, ring gap for a 6 or 7 hp is suppose to be .010, unless I am reading the specs wrong. Can this cylinder be sleeved, or bored to H70 specs? Maybe I am trying too hard to save this thing. The sump definitely has a crack. I can see daylight through it. I have a new one coming. I think I am going to take the block up to the machine shop that cleaned and checked the block for my first Massey 14. I am told they can determine if it's a crack or not. Hoping for the best.

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ZXT
1 hour ago, Gregor said:

The ring gap at the top of the cylinder is .082. In the center, .109. At the bottom, .071. According to the book, bore spec for a 7hp. is 3.062. The top of my cylinder is 2.75. The center is. .017 greater than  the top.  If I add the 2 together, that comes up to, 2.767, which is still less than the spec for an H70.  Am I figuring all this correctly? (my head hurts) According to the book, ring gap for a 6 or 7 hp is suppose to be .010, unless I am reading the specs wrong. Can this cylinder be sleeved, or bored to H70 specs? Maybe I am trying too hard to save this thing. The sump definitely has a crack. I can see daylight through it. I have a new one coming. I think I am going to take the block up to the machine shop that cleaned and checked the block for my first Massey 14. I am told they can determine if it's a crack or not. Hoping for the best.

Honestly, you could spend $500 on it to get a non-original (to the tractor) Tecumseh running again, but why? At the end of the day you still have a Tecumseh. It's quite literally a $20 snow blower engine. Some people like Tecumsehs and have had good experience with them, but I haven't had exceptional luck with them. Certainly not good enough luck to spend that kind of money on. If it was original to the tractor and you wanted to keep it 100% correct it would be one thing, but it's not.

 

The HH120 on my C-120 ran ok, but the starter died. A starter was $40, but I couldn't bring myself to spend that on it being a Tecky. I had a complete K321 that needed a rod that I got for nothing, found a crank on ebay for cheap and a rebuild kit for $89. Put the engine together, and I've never looked back since. I have maybe $150 in it and it will run circles around the Tecumseh in terms of starting (carburetor was garbage, as is typical with them) and power. 

 

My :twocents-02cents: is find a Kohler of similar HP (or a Tecumseh if you're set on keeping it the same brand) on CL or FB marketplace for cheap and run it!

Edited by ZXT

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ebinmaine
6 hours ago, ZXT said:

but why? At the end of the day you still have a Tecumseh. It's quite literally a $20 snow blower engine

Gotta agree with that logic. 

 

Your desire to save an antique is very admirable but what you have appears to have little to no value either to the tractor or as a collectible by itself. 

It also appears, IMHO, to be a collection of non matching engines cobbled together by a PO. 

 

Honestly, I wouldn't try to save it given those considerations. 

 

 

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Tractorhead

The 656 as far as i knew had normally only the H60 Cast iron Engines in.

 

I agree also with the rebuilt meanings here,

an HH60 with cracks seems also for me not worth the time and money you must throwing in them.

 

Whatever decision you take, when a Swap must be done, i would also thinkering about an Predator Engine.

 

 

 

 

 

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953 nut
11 hours ago, Gregor said:

If I add the 2 together, that comes up to, 2.767, which is still less than the spec for an H70.

 

11 hours ago, Gregor said:

I think I am going to take the block up to the machine shop that cleaned and checked the block for my first Massey 14. I am told they can determine if it's a crack or not.

You can't average the cylinder wear, the greatest deviation from standard will determine how far the block needs to be cut. 

:handgestures-thumbupleft:    Taking it to a machine shop is the right thing to do.

PS     I think I would have to pass up the block you found on marketplace!             :scared-eek:

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ebinmaine

@Stepney Spenser would one of the blocks you brought me work out for him?

 

 

@Gregor lemme confer with the Mr above and see if I've got something that would help you out. 

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Gregor

I do have a cylinder hone, but I have no way to replace the valve guides. Maybe my small engine guy can do it. Honestly, after considering everything, I think it's time to move on to another motor. I could spend 100's on this short block, only to discover the coil or charging circuit is bad. I know I would have to have a new carburtrator. According to Taryl anyway. I would like to find an 8hp Kohler. I think I could connect the control cables on that. I have been looking at Harbor Freight Predator motors. My concern with them is, the ability to connect the choke and throttle cable. If nothing else, I would like for this tractor to at least function correctly. Their 6.5 hp motor has a 3/4 shaft, and I need 1". Also they are not electric start. I would consider an 8hp, if it fits under the hood, but there are still the control cable issues.

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ebinmaine
20 minutes ago, Gregor said:

new carburtrator. According to Taryl anyway. I would like to find an 8hp Kohler

He's been known to crab-u-taters as well. Not sure if the technical differences but I'm sure it's important. 

 

I do realize the inexpensive and basically reliable nature of the HF engines. I really prefer to use older cast iron stuff. 

 

The issues with a Tecumseh are:

Carbs can be..... Finicky. 

Ignition system NEEDS to be set RIGHT while disassembled. If it fails the parts for small blocks are tough to find. 

Other than that they're a fine little piece of machinery that's well built. But the ignition is a deal breaker for many. 

 

A Kohler engine is IMHO a better choice because of the ignition system being external and adjustable/replaceable from the outside while the engine is together. 

 

If you truly want originality you can absolutely get a techie and get it running WELL. There's a LOT of information online. I can share a few videos I've saved if you like. I have them set aside for help when we get around to reassembly on Trina's Pony tractor (a 657) with the original engine. 

 

If you want long term reliability, EASE of maintenance and repair, and general strength DO go for a Kohler. 

 

Don't be concerned about the cables. They're inexpensive and readily available like most parts for a Horse. 

 

 

If I have a techie here you can use it's yours for the freight from Maine.

BUT!

I can't honestly say it would be a good engine without ever having started it myself. 

 

 

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Gregor
2 hours ago, ebinmaine said:

Don't be concerned about the cables. They're inexpensive and readily available like most parts for a Horse. 

 

I'm not concerned with finding cables, it's being able to hook them up and operational, that worries me. Maybe it's easier than I think..

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ebinmaine
11 minutes ago, Gregor said:

. Maybe it's easier than I think..

Absolutely. 

Not even close to difficult. 

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Gregor

I ordered a 6.5 hp Predator engine from Harbor Freight. Maybe someday I will find the K181 I wanted, but this will do for now. BUT! Come HE!! or high water, this 6hp. Tecumseh is going back together. I ordered a new carb and rings.basing it on the fact that it is an H60.  It may never run again, but I'm gonna give it my best shot.

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jabelman
29 minutes ago, Gregor said:

I ordered a 6.5 hp Predator engine from Harbor Freight. Maybe someday I will find the K181 I wanted, but this will do for now. BUT! Come HE!! or high water, this 6hp. Tecumseh is going back together. I ordered a new carb and rings.basing it on the fact that it is an H60.  It may never run again, but I'm gonna give it my best shot.

In the name of science you should jb weld that crack and see how long it holds

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Gregor

The sump cover is being replaced. I took the block to the machine shop that did my K321. They assured me it was a casting mark. We shall see. To be honest, my biggest worry is the crank. I have stated before that I have never been into a 4 stroke before, and I know nothing about them. Checking the rod journal specs on my crank, and comparing them to a spec sheet, I have a crank from an H 70. Would a 60 run with a 70 crank? I don't know, but going by the carbon build up, this motor did run at one point. The 70 has almost 1/4" more stroke. The only way I can see of accomplishing this is with the crank. Maybe I am over thinking this, or could be I am just plain thinking wrong. If I am, someone tell me please. Thanks  Greg

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305

has it been determined if the block is H60 or H70?   what's on the blower shroud really doesn't matter since someone could...and probably did...swap it

 

i will buck the trend here and say i do like the Tecumseh engines, but agree they are not worth putting any serious money into. you can find them at garage sales, craigslist , marketplace for cheap.  i bought a great running 6 horse Sunday for $50, i have my eye on another but holding off since the asking price is $75...gonna let him stew a bit

 

i have a shed full of H60's and H70's.....i run  them hard for a few years and when they give up i just swap them out

 

i do have a new old stock HH60 short block that i plan on completing with parts from wrecked motors. i will probably take better care of that one

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305

can you post a picture of your connecting rod?  there is a BIG difference between a H60 and  H70 rod

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Gregor

I looked up everything again.(took a while) All that did was confuse me more. On page 95 of this manual, https://www.allotment-garden.org/rotavator-manuals/Techumseh-L-Head-Engines-Manual.pdf  (if you want to look it up), it says cylinder bore for an H60 is 2.62"  On page 96 it says cylinder bore for an H70 is 3.06". Mine measures 2.75" This lead me to believe I had an H60 block bored 10 over. Doesn't that make sense? NOW I notice on page 95 it says cylinder bore for an H70 is 2.75" Why the discrepancy in the specs in the manual? Or am I reading the manual wrong?  So....If I do in fact have an H70 block, I just ordered the wrong rings. Here is a pic of the piston and rod. The number stamped on the rod is 25 026 if that means anything.

 

tecumseh rod.jpg

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305

H60 has a bore of 2.625 and a H70 is 2.750....that is not a 10 thousands (.010)  difference but is .125.   that's an 1/8 inch

 

overbore pistons for both motors were available at one time , now they are practically  non existent

 

that connecting rod is for a H70

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