1970 Hydro 147 Engine Overhaul
 

Well it's that time of year, I've had the Cubby for just a few months as the free John Deere finally passed away. I'm excited to have such a great looking classic tractor although everyone keeps asking me why I'd buy such an old thing instead of getting something new. To me new=crappy low quality stuff you'll just end up throwing away in 5 years. So I've just pulled the K321 for a rebuild. My question is are there any sneaky details I should be aware of when doing the rebuild? The cylingder walls look ok, nice and shiny, I've yet to put the calipers on it to see what it measures. It was blowing smoke, and I see by removing the head that there's a source of oil, seemingly from the intake valve, which I assume can be remedied with some new valve seals. I found a good kit on eBay for $80 that has all gaskets, piston, rings and oil seals, so I should be good on that and there are various sources for the carb rebuild. Looking forward to a winter in the basement scrubbing 30+ years of oil and gunk out of the thing and get it back to business in the spring. So any good tips and wisdom are appreciated, thanks again ! I'm new to the Cub scene, but got sucked in right away when the 147 came off the trailer !

Keep track of which bolts went where in the head.....and which ones had washers, which did not....

In the front pic it almost looks as if you had a head gasket leak...check that head for flatness.

There's lots of good rebuilding stuff on the net....CHeck out Bryan Millers sites....google will find them. I'd get them for ya but with the flu I don't even feel like looking for a new cub right now. :BlahBlah:

I haven't done a small engine yet....done dozens of BB & sb chevy's....but, I'd assume if there's no ridge, you could get away with a hone & new rings. But with single piston and/or air cooled engines, they probably go out of round....I'll need to know myself.
Does a block NEED to be bored on these?

First thing you will need is a Kohler Service Manual if you don't have one. The manual can be found in Only Cub Cadets Technical section. Pay close attention to sections 10 thru 12.

You will need a better tool than a caliper to measure. Micrometers, telescoping gauge or a bore gauge is what you should use to measure the bore. Page 11.2 in a Kohler Service Manual has good infomation on how to measure a cylinder bore. The Kohler manual wants you to measure 6 places if you use a micrometer and a telescoping gauge. The majority of the Kohler blocks I rebuild (rebuild 2 to 4 a year) need bored because they are out of spec or they will be out of spec after you hone the block. Number 1 problem I see is too much taper in the cylinder wall.

The following part(s) are replaced when I rebuild a Kohler motor:
1. piston
2. connecting rod
3. governor gear (plastic version)
4. points push rod (aluminum version)
5. head bolts
6. gaskets
7. crank seals
8. grind valves-replace as needed
9. check valve guides-replace as needed
10 check cam lobe that the points push rod rides on-sometimes the push rod will wear a groove in the lobe.

If your Kohler motor has balance gears-throw them in the trash can. I don't reinstall them.

Any motor that needs more than a .030 oversize piston gets sleeved.

The block is cleaned in my parts washer and them cleaned with soap and water in the sink in my garage. I use an assembly lube when I reassemble a motor. Lube is applied to crank journal, cam and crank bearings. All threads are tap before the motor is put together.

The $80 epay specials aren't the best quality. I use only Kohler parts on my own motors and prefer to use Kohler parts on any customer's motor. Kohler parts are a little more expensive...worth it in my book.

I have a few motors that just had a "hone and new rings" special done to them before I work on them. You may get a few years life out of that. Most times the piston is burnt in the exhaust valve area. It doesn't work that well on Kohler motors or small or big block Chevys.

Thanks for the info on Kohlers. The motor I had in my Camaro was a 66 427. .030 over, 12.5:1's, big roller. Used to yank it, drop it off for honeing, pick it up that nite, assemble run it the next day. Ran 9.80's. I reringed it probably 40 times in 10 years.....actually ran better right before I sold it...itwas so loose, use to shift it @ 9500!!!
So, reringing does work, all depends on the situation.
I won't try it on a tractor engine....doesn't seem all that much of a savings.

Thanks !
 

Lots of good advice, I figured it would be best to get the cylinder machined by a pro and go to the next sized cylinder. I do see that Kohler parts are a few bucks more, but probably for a good reason. I'll stick with the good stuff and send the engine out once I get it stripped completely down. Thanks again for all the knowledge, I do have all the parts/service/owners/Kohler manuals downloaded and printed out in a 3 ring binder, ever so handy along with all my digital pics of where stuff was before it was taken apart. Wish me luck in the coming weeks of cleaning, tagging and teardown. Happy Turkey Day to all !

Getting it back together
 

Well it's been lots of sanding, grinding, wire wheeling and many new parts to buy, but it's finally shaping up and soon should be the first start of the rebuilt engine. Here's a few pics of where I'm at right now. Pretty much new everything, piston, rings, bearings, seals, gaskets, still waiting for the Bosch blue coil and points saver to arrive in the mail. Thanks for all the advice in which way to go about it. I've only worked on 2-cycle stuff, so this was an interesting experience. I found a 70 half buried in a dirt mound at my girlfriends parents, probably the next challenge, but first I need the 147 back in action for grass cutting so i can give back the 1250.

Thanks for the update pics. Your 147 will be awesome! :beerchug:

Nice , looks like you are doing a nice job on your motor and the paint looks awesome . Have you finished ? Would love to see some pictures of it all together

very sharp.... I'm getting ready to start on the paint and "pretty" on my 127. Any tips on the painting?