Honda RT5000 multi-purpose sub-compact tractor engine tear down

[SilverLakeFab]

I purchased a Honda RT5000 4x4 subcompact tractor a couple months ago and I was told it had a seized engine. I finally got to start the tear-down last night and I figured I would share the project with the folks here. I've attached a few pictures of the machine to show where I am right now. So far, the front body panels have been removed, the clutch has been removed, a bunch of parts have been unbolted from the engine, and the rubber engine mounts have been unbolted. All that's left is to unbolt the engine from the drive-shaft to remove it from the engine. Where I quit last night was fighting the motor at this stage. It was late and the U-Joint splines are stuck together, so I unbolted the U-joint adapter from the flywheel, but since there's a screen attached to that in the motor cowling, I have to unbolt the cowling the hard way (all the bolts go in from the back side).

As mentioned above, I was told that this engine had a seized engine, but I pulled the head off (yay simple push rod engines) and the piston wasn't stuck (I was able to push in further into the cylinder by hand). However, the piston is no longer attached to the crankshaft either. Who wants to guess how many pieces the connecting rod will be in when I get the side cover off the motor? I'm guessing 5. Even with a catastrophic failure like this one, I should be able to rebuild this whole engine for about $140. Not bad!

I'll post more pictures and info on this little project as I go on with it.

 

[SilverLakeFab]

Here's the problem!

I was close with my guess of 5 pieces for the connecting rod, but I'll say I'm right because of the part of the piston that I dug out as well. I was hoping that the crank was usable, but it's toast as well. It looks like I'm in for a piston, connecting rod, crankshaft, and cylinder bore. It's less expensive than it sounds though. If I can get this with a first oversized piston, I'll be golden, as a cylinder bore is only about $30.

Honda GX340 Roller Kit with Crankshaft Piston Rings Con Rod Pin and Clips GX 340 | eBay

I'll post info on what I end up doing.

 

[SilverLakeFab]

I cleaned the block and found a good size crack. It's a 20 minute fix and it'll be welded up tomorrow. This is probably the easiest broken case weld job I've ever had to do. I'll post pics tomorrow.

 

[Don87]

Looks like 2 cracks(3 if you count the tee), but keep us posted. With my welding capabilities..............I would bury it with my Massey:laughing:

 

[Kernopelli]

Those are cool little tractors. http://powerequipment.honda.com/pdf/manuals/31752601.pdf if you don't already have it. I have always hoped to run across one somewhere at a price I couldn't pass up, just to have one. Never read anything about the 11HP models being short on power ( even with 1100# combined F/R lift capability). How cool would it be to find one of the later 3cyl diesels w/ factory FEL and backhoe!!

 

[SilverLakeFab]

The case has been fixed and is ready for an over-bore (0.25 mm should do it; the bore doesn't show much for wear). I've posted pictures of the fixing procedure below, but none of me actually welding (I can't do four things at once, only three ). The first step is to press the case back into shape. When doing this, you have to be aware that you may cause other cracks to occur (pretty common). Next, clean the weld area as much as possible. When welding anything aluminum that contained oil, you WILL fight through poor weld quality when you put down your initial filler bead, as no matter how clean you think the area is, there will always be residue within the crack itself. Even if you put the thing through an ultra sonic cleaner, it will NOT be clean, so you have to be prepared for that. Also, when possible, do the external weld first, as it's easier to fight the contamination of the puddle from the outside. Next, the filler is melted in thoroughly. I'm not looking for a pretty stack of dimes with this weld; I need an evenly melted in weld with full penetration and strength. Next I cleaned the inside of the case again, as any time aluminum is exposed for over a minute, it will have corrosion. After doing the outside weld, the inside weld is easy, as almost all the impurities have been burned and floated out of the remaining crack. Of course, I went over the weld area twice to ensure a super flat weld so I don't have a clearance concern. This was a utility job that doesn't have to be super pretty, but to show that I can do pretty aluminum welding, I've posted a sample picture of my nice looking work.



Pretty work examples:

With that out of the way, the block will be pressure washed tomorrow and brought to Sanel's machine shop (in Concord, NH) for an over-bore. If I had to have the case welded up by another shop, it wouldn't be worth it, but now for $30 and about 45 minutes of my time, the case/cylinder will be good as new! I still think I'll be out of this engine rebuild for just under $200. I can't complain about that.

 

[ssls6]

Nice looking repair job.

 

[SilverLakeFab]

Thanks! I'll post more picture of the reassembly when I get the block back from the machine shop and the parts arrive to rebuild it in a couple weeks.

 

[Don87]

Nice work. :thumbsup:

 

[Kernopelli]

Excellent job!!! As much equipment as we have and welding/fabrication we do just to keep things ( wife calls them toys....from the amount of work/repair sometimes I think junk may be more appropriate!) going around here, we aren't set up to do Al welding/repair.....and you obviously know the art of TIG welder. That is the next form/(ART!!) I want to set up, learn and put to use. Can't wait to see the progress. Are you going to do a complete restoration? I'm sure you've already been all over the net, but I see Formula H, Middletown, NY, Honda Power Equipment and 5000 Tractor Sales and Service has a number of OEM parts but they're sure proud of them!!