Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have an HH60 engine on a 1981 or so Troy bilt tiller. It ran fine for years but the summer broke a rod. (I think it was low on oil). I have taken the engine apart. No gouges in the sylinder or holes anywhere. There is a small ridge at the top of the cylinder that you can barely scratch a fingernail on. I put the old piston and rings in and my hand over the top of the cylinder. It seems to have alot of suction/compression when pulling the piston from the bottom.

There is aluminum on the crankshaft . I will try the muratic acid trick I have read elsewhere on here.

Question is, is this worth rebuilding? I like tinkering with stiff but money is a conern. I like this motor because it has electric start on it. ROds are expenesive as the one for my model number says it is 40 bucks.

Should I re-ring it? I have a cylinder hone from harbor freight I bought the other day. I have never used one. I dont have a ridge reamer but might be bale to rent one at Autozone.

It ran well before this happened except now that I recall a week or so before it went, faint white smoke cam out of the exhaust when it was reved up.

ANy advice? Do I need to mike everythign out to an automobile's engine precision or since this is a tiller just clean the crank, bolt a new rod and rings and go with it?

I have been takign off parts and cleaning them. The head did seem to have alot of carbon but was easily cleaned.

I think it may have been rebuilt before as the engine paint is oversprayed in places. The piston was stammped STD which I assumes means it is stadard sized.

Thanks again!

Thanks so much. I guess 31 bucks is not bad. Part of me wants to just buy a 200 dollar 5 horse Brigs and be done with it but I already have the thing apart and am learnign alot.

One think I am worried about is once I get all this aluminum off the crank that my journal might ba a little undersized. Will this be a huge problem. I will say this thing ran great right until the rod broke.

I am afraid of putting too much money in this in case it is a failure. I am thinking rod, rings, basic gaskets. What do you guys think? DO I need anythign else?

I am really, really intrigued on what the actual difference would be between the 34750 rod and the 3180C rod. The specifications for the crankpin and throw are the same. When I have looked online at ebay the inside of the cases look the same with the exception of one has a place for a crankshaft bearing and ones like mine use bushings.  I really wonder if they are interchangeable? Does anyone know what the difference would be? I have yet to find an actual picture of the 34750 rod.

By the way, I called every local Techumseh dealer and non of them have new old stock for the rod.

It seems no one has the 37450 rod. I checked with the guys at Tulsa and they did not have it either. Someone else emailed me and thought the 3180C would work, that the only difference was the other number had a separat oil dipper that attached to the rod bolts where the 3180C was a one piece unit. But I am not sure if he knows for sure or not.

I have found the 3180C on AMazon for 17 dollars. WOuld it be stupid as a learning experience to get this but it back togther bare bones with maybe new rings and see what happens?

I did email the company that makes the 3180C and they said it shows it should work. Again, not getting definite answers.

Hi Stryped.  I, too, am looking for a 34750 connecting rod.  Did you determine if the 31380C would work?

I've had local dealers call Tecumseh directly to help determine this... to no avail.  They are unwilling to give any information.

Thanks in advance,  Techjunkiedb (Dan)

I recently purchased a Troy Built Horse for real cheap, because the egine had no compression. Few days later when I got time to tear into it found the connecting rod busted. Like others, I am committed to leaving the original engine on the tiller, so that leaves no option but the repair. Plus, I might get my wife to use this since it's got electric start.

So.....I ordered a rebuild kit from a guy selling them on ebay for 69.99 plus S&H. I'll be getting a new piston, rod, rings, and gasket set. I think the connecting rod it comes with is the 3180C. I'm guessing the 37450 is the original part and the C is an aftermarket. Plus, from the photo's it looks as if the oil dipper config is slightly different. If it interferes it's nothing a file or grinder won't take care of. I can always fashion my own dipper out of some sheet metal.

I'll post a reply to update you all (if anyone is still reading this thread) to see if the C version of the rod works. Actually the rings and the piston are in great shape but since I've got it out I'm going to hone for about 30 secenods, re ring it. Since it's cast iron the walls are not scarred or ridged at all. Also planning on pulling the valves and maybe clean them up with some lapping compound.

Happy tilling....

Cool, let us know how it works out...

I think the a,b,c designation on the part number is a mod from the original design drawing...

Friiy

ive been all over the internet looking for the 34750 rod.  ive called all the Tecumseh authorized dealers/repair shops in my area and even got put on a list where dealers all over the us will look at their stock to find that connecting rod.  it is NOT available to my dismay .  I even tried contacting a few custom engine part manufacturers and the cost is prohibitive on making a few one off rods (each rod would be something like $200). the best option we have is to use another rod from a different spec HH60 tecumseh engine.  the only two options i have been able to find are as follows:

http://www.psep.biz/store/tecumseh_connecting_rods.htm

stens 510-218 connecting rod ($15.95)
tecumseh 31380c connecting rod ($29.95)

unfortunately, I'm pretty sure i read a thread where somebody tried using the 31380c connecting rod and the rod failed after approximately 100 hours of use.  i dont know what condition his engine was in.  i dont know if the crank journal where the connecting rod attaches was undersized contributing to abnormal wear and premature failure.  i dont know if this person changed his oil every 25hours of use or more.  there are MANY unknowns but what i am sure of is that he was able to get the engine running for some time before it failed.  since we all have concerns with this connecting rod, I would use it and treat the maintenance of the engine as if was under the MOST extreme conditions.

just my two cents.

Have you called Jack's small engine and asked if there is a short block still available for that model?

Friiy

Im in the same spot as Stryped above.  i talked my father into rebuilding his HH60-105126J engine out of his 1986? Troy Bilt Horse tiller.  i removed the engine and stripped it down to its individual components to evaluate the repair job.  first off, broken connecting rod.  he told me that he ran the engine dry once some years ago, filled it up with oil, still ran good so didn't think much about it.  just recently, he loaned it so somebody and after he got it back,  he only had it running for a few minutes before it threw the rod.  so immediately i think that the rod failure was because of theat incident years ago.  no big, just replace the rod.  well we have it apart, lets replace all the wear items.  so off we go to buy all the seals, gaskets, breather tubes, air filters, gasket sets for the entire tiller, reverse disc, belts, engine oil, spark plug, etc.  in the meantime, im cleaning and inspecting the engine.  i cleaned off all the aluminum from the crank journal and it mic'd at just .0004" undersized from factory ( i cant remember the number right now).  there were no grooves on the crank from the oil seal so thats a good sign.  i removed the little bit of carbon build up at the top of the cylinder and find that there is no ridge at the top of the cylinder.  as it is, there is still some cross hatch visible in the wear area of the cylinder! so no extreme wear for an engine over 20 years old.  the  bore is .001" over factory delivered spec. so im sticking with the standard sized piston.  im replacing the valves and going to lap the valves to the block but the new valves have to be set on the clearance so there is some work for me there.  the deck was straight and just needed a little carbon removal.  the head was a little tweaked so i stoned the head to get it flat, removed the carbon and chased the threads for the spark plug.  so far so good.  i even went so far as to sandblast the exterior of the engine ase well as all the rusted parts of the tiller itself.  my father wats to paint it the original factory Troy Bilt red so we'll see how that goes.  the valve guides are not worn so i feel confident in that this engine can be rebuilt to factory spec.

Now the bad news.  tecumseh part number 34750 connecting rod is no longer available.  no aftermarket company offers it.  the local authorized repair shops cant get their hands on one.  there is no new old stock available........   #%WE*@#(?!   Then i come to find out that Tecumseh is no longer in business?!  not that big of a deal but you have to understand that if i couldn't buy the rod, i was going to make it from scratch using aircraft grade aluminum (7075 or 7050).  the problem with that idea is that i was hoping beyond all hope to get detailed specs from an engineer at Tecumseh (the bored guy sitting at a desk that can fax me a print of the actual rod so that i can duplicate it).  i called everybody.  i even got a repair shop to give me their Tecumseh contact number and spoke with very nice and understanding woman who told me that Tecumseh will be back very soon and that when it does, i might be able to get the prints then.   im an impatient person.  i cant wait that long.  so i do what comes easy to me.  i plow head first into the internet.  if it is available, if it can be found, i like to think that i can find it.  im pretty good at finding stuff.  but that rod is NOT available.  the closest thing that i can find is the 31380C connecting rod as it is also for the HH60 engine but for a DIFFERENT spec engine.  as far as i can decipher from other peoples posts, the 34750 rod and the 31380c rod are the same length.  the only difference i can tell is the oil spash at the end of the rod is now integrated but NOT necessarily the same configuration as the 34750 rod.  the 34750 rod had a steel oil splash that could have been designed to pull the oil up (hooked end?) during the exhaust and compression strokes.  the cast aluminum cap on the 31380c rod doesn't have that configuration.  i have read a post where a guy put his engine back together with the 31380c but was stating that he was having a very difficult time getting the engine to start.  my vote on his problem if a poorly adjusted carb.  im a firm believer in taking your equipment to the experts when it comes to adjusting things as finicky as carbs.  im going to do that for my fathers tiller as we probably need to have the carb rebuilt and readjusted for use with the hh60 engine. i dont know how to do it, ill let somebody else figure it out.  if any of you are local to these people, they do top notch stuff.  and they also have all the microfiche from the older model engines on site.  99% of the time, they were able to get the parts i needed for a reasonable price.


since the 31380c rod is the only rod that WILL fit the engine, i may just buy the rod ($ 17-26 depending on oem or aftermarket as well as supplier) and draw it up in Solidworks (3D modelling program) so i can get the center-to-center distance correct as well as wall thicknesses around the pin and journal.  then proceed to make the rod out of the 7075/7050 AL.  im not terribly pressed for time but i would like to get my father tilling again as he does enjoy working in his garden and doenst have the greatest back health so getting him his tiller working  again would be a godsend for him.

Okay, i just received the 31380c Tecumseh rod, rotary brand piston and ring set.  in the ring set, the instructions stated how the rings were to be installed on the piston so i did that.  easy enough.  next is testing the fit of the piston in the bore.  the instructions for the rings said that the ends may have to be filed to get the right clearance or fit in the bore.  so that's something to look into.  the 31380c rod was the last rod my local supplier had.  shen she tried to get another tecumseh rod from her supplier, they couldn't get one.  so it looks like maybe the 31380c rod may be going the way of the dinosaur.
Tomorrow, im going to draw up the rod then try and get the engine put back together this weekend (new oil seals, plenty of assembly lube, and i need to grind the new lifters for the right clearance)
ill take a few photos of the parts as well as the build and host them on my website.  ill post the links here so you all can see the progress.  also, i have the following files in PDF format.  for those who want them, send me a message and ill send you the links where you can download them.

Tecumseh Technicians Handbook
TECUMSEH-MODEL-HH60-105126J-PARTS-LIST
tecumseh-troubleshooting
Horse I user manual from MTD

pics so far

http://www.leavittdetailing.com/saved_files/horse_rebuild/0726081905.jpg

http://www.leavittdetailing.com/saved_files/horse_rebuild/0726081913.jpg
http://www.leavittdetailing.com/saved_files/horse_rebuild/0726081914.jpg
http://www.leavittdetailing.com/saved_files/horse_rebuild/0726081917.jpg
http://www.leavittdetailing.com/saved_files/horse_rebuild/_MG_0829.JPG
http://www.leavittdetailing.com/saved_files/horse_rebuild/_MG_0848.JPG

http://www.leavittdetailing.com/saved_files/horse_rebuild/_MG_0869.JPG
http://www.leavittdetailing.com/saved_files/horse_rebuild/IMG00001-20090327-1210.jpg
http://www.leavittdetailing.com/saved_files/horse_rebuild/IMG00002-20090327-1210.jpg