Coupling 5.5hp honda to a hydraulic pump

[marimus]

You mentioned taps, does that shaft have outside threads or inside threads like for a bolt ?

If the shaft is tapered, it will have a nut that keeps the accessory on. If it is a straight shaft, it will have an inside threaded hole.

A Honda pump engine will have a straight outside threaded shaft.

GX160TX 5.5hp Horizontal 5/8" Externally Threaded Shaft, OHV, Cast Iron Sleeve, Low Oil Shutdown

That picture is exactly what I have, a 5/8" Externally Threaded Shaft.

I think mabey I should go with a bigger engine to run the logsplitter, so I won't have any issue mounting it and I can get a bigger hydraulic pump to start with. Probably a 13HP Chonda to start with, or a second hand Honda.

 

[jlsanborn]

I don't think I'd thread a coupling half onto the shaft. I think you'd eventually pull the threads (5.5hp impact driver). A larger engine with a keyed shaft is probably a better investment.

 

[marimus]

I don't think I'd thread a coupling half onto the shaft. I think you'd eventually pull the threads (5.5hp impact driver). A larger engine with a keyed shaft is probably a better investment.

Yeah i'm thinking I might get a new pump to mount on this 5.5HP, and get a 13HP to run the logsplitter.

Thanks for your help and advice everybody.

 

[brokenot]

If it came off a water pump it is a tapered shaft.

Most, (if not all), small engine driven water pumps are a straight shaft with threads. The tapered shaft engines you'll find are for generator applications.

Since this is a GX Honda, replacing the crankshaft takes about a half-hour if you've done it before. Maybe 1-2 hours if it's your first time. If you're careful during disassembly, you can do the job without having to replace any gaskets. Once the crankcase bolts are removed, tap the crankcase cover with a plastic mallet to loosen it. If you try to pry it off with something like a screwdriver, then you'll have to buy a gasket. Removing the flywheel from the taper on the crank is a bit harder, but if you put pressure on the back side of it, (won't take much), by wedging a chisel between the flywheel and block, and then tapping on the end of the crankshaft, (with the flywheel retaining nut protecting the threads), it'll pop right off. The timing gears are clearly marked for easy lining up upon reassembly.

eBay has lots of OEM used GX Honda stuff, as well as a whole bunch of GX knock-off parts. Here's an example:

CRANKSHAFT ASSEMBLY WITH PISTON FITS HONDA GX160-GX200 - eBay (item 250784961505 end time Mar-14-11 11:03:03 PDT)

The knock-off stuff can usually be identified by the seller's description, because they'll say things like "fits GX Honda" or replaces GX Honda".

 

[PILOON]

Another option would be to use a short section of the defunct pump shaft that mates the engine shaft.
He could weld whatever he needs to that mating part.
Then again perhaps the OD of the pump shaft might just fit a stock lovejoy, and if not the section could be turned on a lathe to fit.

 

[brokenot]

Another option would be to use a short section of the defunct pump shaft that mates the engine shaft.
He could weld whatever he needs to that mating part.

There usually isn't any pump shaft in these.....the pump impeller threads directly onto the engine's crankshaft threads after the inner pump housing half is already bolted onto the engine's side. Once the inner cover is bolted on, the mechanical seal goes on next, followed by threading the impeller on.

Then again perhaps the OD of the pump shaft might just fit a stock lovejoy, and if not the section could be turned on a lathe to fit.

I took a vertical shaft Honda GX crank to our local machine shop a few years ago to have two steps machined into it, because I was replacing a worn out Tecumseh engine on a towable mast-style post hole digger. The digger manufacturer contracted with Tecumseh for a special crankshaft size that extended down into the digger gearbox, and was then stepped down twice. A quarter inch or so for a bearing, and then again to mount the gearbox clutch. Nobody else offered an engine with the correct crank dimensions, so I called the machine shop and they quoted me ~$100 for the job. I dropped it off and when they called a day or so later to say it was done, they said they'd honor their original price quote this time, but wouldn't do it again for that kind of money because they went through two bits during the machining. They did have to remove quite a bit of material.

Check this setup out. They're going from 20mm down to 3/4" though....so they're only removing .037" of material with this cut:

YouTube - Honda 6.5 hp GX200 "rare type of turning"

When all is said and done, if you have to remove the crank for machining, you won't accomplish the job for less than it costs to replace it with one that has the correct dimensions already. And if you do machine it down to a common Lovejoy coupler dimension, you'll still need a method of retaining the Lovejoy half on the shaft. Bottoming out a setscrew against the crankshaft won't do it.

 

[Travelover]

Pretty clever video turning the crank on a lathe with the engine running.

I think I'd pop for a $100 Greyhound 6.5HP engine at HF.

 

[brokenot]

Pretty clever video turning the crank on a lathe with the engine running.

Yup....I'd do it on an engine that I knew had nice, high quality bearings, and a crank that couldn't walk all over the place while it was running. It would be a little tougher to get good results on something like my Tecumseh snowblower engine. It runs fine and does a good job, but I can watch the crank walking in and out about an eighth of an inch while it runs under no load. While the crank's side-to-side oscillations aren't anywhere near that, I imagine they're not quite up to "lathe-quality" tolerances either...

 

[JoelD]

Pretty clever video turning the crank on a lathe with the engine running.

I think I'd pop for a $100 Greyhound 6.5HP engine at HF.

DIDO, keep is simple.

Joel

Those motors get great reviews, I picked one up for 99 last week to drop into a small wheel horse tractor I've got.

Joel

 

[com12man]

Those are pretty much the two options I didn't want to hear :laughing:

Oh well, its just a little bit of extra work I suppose. I'll have to check and see what taps I have...

Honda 5.5 16mmx1.5 fine thread pitch. drill for tap is a 37/64ths take a love joy half and fill it in with a mig welder then drill it and tap it done deal