Do you foresee any problems?

[Old Man]

1st time in the engine. The head came off easily- no broken head bolts. I’ve only cleaned the block with a plastic scraper. I’ve included some pics. No built up crud only discoloration. Do you see signs of any possible trouble? Could I and should I clean the block with a wire brush on a drill?

[ricky racer]

From what I can see, everything looks pretty good. Why did you pull the head off? A wire brush on a drill should do a nice job of cleaning everything up.

[SamsFarm]

Is this a trick question?

[Old Man]

LOL. Nope. Not a trick question. I’ve never rebuilt an internal combustion engine although it’s been on my bucket list for a long time. My Cub had low compression in all cylinders and smoked a bit so I thot “ now’s my chance”. Just wasn’t sure how the block should appear. I’ve learned so much from the members of this group that it gave me the confidence to dive in. Thanks to you all.

[Stevetractor]

Just something to consider before you spend any money. These engines turn slow and with 70 years of wear, need a proper rebuild. Bore block, turn crank, new valves, springs, guides, plane head and manifold. I’m not trying to be negative at all either. But I have learned that by doing a proper and complete motor job these little engines really come alive. I also usually rebuild, distributor, governor, check oil pump, and check oil pressure plunger and spring while I’m at it. By following everyone’s help, hopefully you can get yours going, but it’s really hard cutting corners on motor work. I’m also lucky I have a great machine shop in my area and can do the tear down and assembling myself.Good luck and have fun.

[Glen]

Hi,
The valve seats in your pics look rough and pitted some. I would have someone grind the seats while the valves are out of the engine. The seats need to be smooth with no pits in them.
Rough valve seats can cause the valves to leak, and then the compression is less, and the valves may burn, they are not made to have hot gasses go under the faces, or sealing surfaces, when the engine is running.
The valves should be ground also, you need to take them to a valve grinding machine, at an engine shop.

Below is a page from the Cub service manual, showing the correct valve seat angles.

http://farmallcub.com/rudi_cub/www.clea ... -01-24.jpg

Below is the Cub service manual, it has lots of info. I would read section 1, the engine section.
There is a contents beginning on page 1 of most sections.

http://farmallcub.com/rudi_cub/www.clea ... index.html

The cylinders can wear in a slightly egg shape, then new piston rings won't seal in the cylinders. The new rings are round, and if worn, the cylinders aren't.
The cylinders need measuring with engine measuring equipment, to see if they are still round.
Reboring makes them round again.

The head bolts need non hardening sealer put on their threads as you put the head on.
The bolt holes go into the engine water jacket, and the coolant can run up the threads without sealer.
The coolant can leak out the head gasket without sealer on the bolt threads.

[ricky racer]

If you've got a good tractor, you'll never regret doing a complete rebuild. I went through my '53 and it has never given me a minute of problems. It always starts when ever I ask it to and it runs like a top. Lots of folks struggle keeping their Cubs running but then again they just put band aids on problems that could be remedied with a little effort. Keep in mind, most of the cost of the rebuild is the machine work needed. How much machine work will be reveled once the engine is torn down and checked out.
Shop around for the machine work as cost can vary quite a bit depending on the backlog of the shop and their desire to do the work. The last Cub engine I rebuilt was in 2019 and I posted the costs that I incurred in the rebuilding. You can maybe use it for reference. viewtopic.php?f=1&t=105338&p=834166&hilit=cost+of#p834166

[Eugene]

Take the engine to a macnine shop. Have everything measured and the block boiled/cleaned.

They will advise you on the necessary work and the cost.

The machine shop will be less expensive than purchasing the specialized tools that the machine shop will have on hand.

[k hutchins]

You didn't say why it needed a "rebuild" other than the fact that rebuilding was on your "bucket list".
Low compression, knocking, oil/coolant leaks?
I'm a believer of "if it ain't broke don't fix it". You can go complete rebuild with all the shop work suggested, which can be expensive. Or if there aren't major issues you could do some judicious checking and just replace or fix the issues found. Which can also get expensive depending on what's needed for replacement parts.

[Gary Dotson]

At a minimum, you'll need to get someone with precision measuring equipment (and the skills to use them) measure your cylinders, crankshaft and such, to see where you're at and how you need to proceed from here. If cylinder wear is not too great, you may get away with a ring and valve job or maybe not. It all starts with a thorough evaluation.