Kubota engine rebuild - seeking advice

brad8526 · May 5, 2020

I'm not an expert mechanic so I'm hoping anyone with more experience than I would be willing to help me out. I've got a Kubota B8200 that was losing power. I'm replacing the injectors and head gasket and while I have the head off I figured I'd ask you experts on the forum if the cylinder walls of my engine look OK. I took pics from either side and would like to know if you see any problems that should be addressed before I continue.

Thanks

Gem99ultra · May 6, 2020

Since you're only doing the head gasket & injectors, from my view, it looks good enough to cap it off and call it done. If you rake your fingernail over the top edge of the cylinder you can get a pretty good idea of how much wear you've incurred. From my chair here though, I think it looks pretty good.

Now - IF you were going to pull the motor, or do any bottom end work, I'd definitely mike the cylinders and see if they need to be re-bored. At a minimum, I'd hone the cylinders and go back in with new rings and bearings. However, I suspect that's much further than you'll want to go.

brad8526 · May 7, 2020

Thank you Gem99ultra for the reply. I got the head put back on today and I'm still waiting on a cap for one of the valves (I managed to lose one when I took it apart) and after a valve adjustment I'll try firing it up. Wish me luck.

Gem99ultra · May 9, 2020

Hope you find that cap though. I lost a wingnut once when doing a pre-race head check on my old Dodge. As soon as I fired it up, I found it. My son, 3 years old at the time, sitting on the fender, and watching Dad work had decided to "help" Dad, and dropped the wingnut down the carburetor. I found pieces of that wingnut in both heads.

By the way, in my prior post I mentioned "mike" the cylinder. That wouldn't do; "mike" might not like that! My fast fingers should have typed "mic" the cylinders.

Jstpssng · May 9, 2020

^^^^^
That sounds like a spelll check error to me. We knew what you meant anyways, though.

goeduck · May 9, 2020

Jstpssng said:
^^^^^
That sounds like a spelll check error to me. We knew what you meant anyways, though.

Spellcheck is your worst enema

BrokenTrack · May 9, 2020

There really is not enough information to determine an answer for you unfortunately. If I knew the hours on the engine, or if the engine was making WHITE smoke, I might be able to help you better. That is a sign of a blown head gasket.

As for determining the amount of rebuild, there are varying amounts.

I just put a new head gasket in my generator engine (Perkins 4.108). It only had 2607 hours on it, so I did not bother to rebuild the head: it looked pretty good.

Your cylinders looked pretty good to me though.