Getting 1250 back into good condition

[nix1650]

built in august and november of 1976

[Zipper]

I can see hatching on the cylinder walls! It is a bit hazy also. Only markings on piston that I can find is 235802. I cannot feel a lip at all at the top of the cylinder. There is a faint yellow paint pen marking next to the head. 4XXX. Wondering if this could be a machie shop marking to identify block. Maybe it has had a overhaul at some point. I original owner had passed away and his brother sold it to the guy I got it from.

Is it possible this has been rebuilt and the head bolts were never re-checked? They were not hard at all to take off. Not loose but not locked down super tight. Maybe I should get new head bolts before putting iit back together.

It is going to be down for a few weeks with everything else I have going on. I want to refreshen the paint during this time.

In the original pictures it showed the common tarry black on the fins. Is this oil or carbon? If it is oil, should I at least get new rings? I am really tight with the budgets right now so I am trying to keep this to a minimum iif possible.

[john hall]

On air cooled engines it never hurts to carefully run a tap in the block to clean up the threads. Don't know what the book says about using head bolts over, couldn't hurt to change them--use quality bolts though. If money is tight, I'd clean up the head (face it) and top of the piston, get a new gasket and put it back together, maybe with new bolts (at least clean the old ones and run a tap in the block). You'll have less than $25 in that compared to Lord only knows what if you open the engine up. The way I see it, when you open an engine up you have to be prepared financially for everything to be junk--meaning block bored, crank turned, valve guides, new valves, facing head, new piston and rod. At least with the Kohlers you can usually use the crank bearings over.
By the way, run a putty knife over top of the piston and see if you see the size--STD, .010, etc.

[Zipper]

I did get the carbon cleaned up good except ii need to get a wire brush to get around the valve grooves. For some reason mine have all disappeared. Lol

There is no other stamping on the piston that I can see. My job is looking for these and while once in a rare instance, they can go unnoticed when painted over, this one would have to be completely hidden for me not to see it.

Yeah, I want to open the pan and then I don't. I just know if I do I won't just stop there. Already pricing head gasket versus full gasket kit versus gasket kit with piston and rings to the one with a crank... I just keep saying, it only a bit more... :0)

Other than the carbon, everything seems to look good. I realise you cannot judge a book buy it cover.

Do all these engines pack up with dirt so badly? Mine looks like a dozer coming in for cleaning after a long season of work. :0)

[Zipper]

Last weekend I sanded and painted the body tub. Soon I will get the frame and rear degreased and spray them.

My welder friend wanted the cradle this weekend so I opened up the block tonight. I think everything looks good inside. No major wear that I can see.

NO BALANCE GEARS! So I guess that answers that! BTW, it's a 1976 engine. I think it also means a upper dipstick would be in the way if it did have them.

I will post a couple pics from inside the block. Speak up if you see any concerns please!

[J-Mech]

I guess you don't really know much about engines. Not really anything to look at under the pan as far as wear. The rod and crank could be shot and you wouldn't be able to see it. Unless you plan to go further, button it back up. All your doing is creating potential leaks by taking it apart just to explore.

There is no "body tub" on a tractor. No idea what part you were referring to.

In the post above this last one, you talk about looking for some marks or something.... you talk about them being painted over. If you were looking for marks on the piston, pistons are never painted. The size will be stamped into it, unless it's an aftermarket piston and it's standard. Then it may not have any markings, but that's not usually the case. I'd say you just don't know what to look for.

Pics help.....

[Zipper]

Johnathan,

took the pan off so we had it as reference to do the cradle mod. I didn't remove it "just to explore".

I may not have written the paint statement fully enough. At work I have to identity part assemblies. During manufacturing they are often heavily painted for preservation during storage. When we receive these parts they can be unknown and I am the one responsible for identification before they can be sold to the customer. There was no " paint" on the piston. The only identifying marking is a 235802 stamped offset from the middle of the piston. Nowhere on it was STD stamped. I was hoping that yourself or someone else would know what that stamping meant.

A previous post or yours on this thread also indicated "i would find see if it has a lip wore out of the cylinder. I'm sure it will, but how bad...??". I replied that there was not a noticeable lip at all in the cylinder wall but had no response from you. You and Nix turned the thread into a battle over balance gears. Opening the pan has ended that one.

When I said body tub I meant the fender pan. Here in the northwest we would cal that a tub or a body just like on a jeep.

As far as my knowledge of engines goes, this is the first time I have ever opened a small engine up. I am very capable of working on things but need a bit of guidance and understanding first, and that is why I am here. The experience on this forum is vast and extremely helpful for people venturing into new things.

There is so much information here that it sometimes gives you overload. Just like the balance gears on this thread. I appreciated Nix for telling me I had a 50/50 chance. I also appreciated you telling me I didn't. What becomes very unhelpful is slamming people over this kind of stuff. Google links to so many threads here. When searching for cub information online, this forum is probably the first hit. It reads really bad to someone not familiar to your comments and makes the forum look very hostile and unfriendly. Please try to remember that you have a very big presence here as you post more than most. You are a ambassador here with a great deal of knowledge and I am sure it is very appreciated. This forum is here for people to ask questions because they are unsure. Yes, sometimes they are absolutely ridiculous in nature, but to them they don't have this knowledge yet and are looking to learn. A teacher is the most valuable asset to any society. In order for them to teach, they have to have someone lookin up to them with respect.

[johncub7172]

Originally Posted by nix1650

the 301 aqs engine HAS balance gears. all the QL engines I have rebuilt have had them in but are removed in the rebuild

Correct. The k321aqs in my 1450 had them until I removed them. My first 1450 did not have balance gears. But to say the Quiet Line aqs engines never came with balance gears is a very false statement.

[J-Mech]

Originally Posted by Zipper

The only identifying marking is a 235802 stamped offset from the middle of the piston. Nowhere on it was STD stamped. I was hoping that yourself or someone else would know what that stamping meant.

Its likely a part number. No way to look it up, as the piston itself isn't called out alone. A new piston comes with a wrist pin and clips. (Example) Kohler has part numbers for each of those parts, but then combines them in a kit. So, the aluminum piston itself has a part number, but not one that you can really reference easily. May of may not be Kohler, but Kohler most always stamps their pistons.

Originally Posted by Zipper

A previous post or yours on this thread also indicated "i would find see if it has a lip wore out of the cylinder. I'm sure it will, but how bad...??". I replied that there was not a noticeable lip at all in the cylinder wall but had no response from you.

Not sure what it is you want to know or are asking. A worn cylinder will have a lip at the top where the rings stop. If you say your engine doesn't have one, then it isn't wore very bad.

Originally Posted by Zipper

When I said body tub I meant the fender pan. Here in the northwest we would cal that a tub or a body just like on a jeep.

Ok. Well, on a tractor it's called a fender pan. A body tub is on a Jeep. I'm familiar with Jeep (or automotive terms), but this is a tractor. It has a fender pan. It has hoods and side panels too, but no rocker panels. It has nothing to do with your location. A Jeep has a tub no matter where you are, and a tractor has a fender no matter where you are.

Originally Posted by Zipper

A teacher is the most valuable asset to any society. In order for them to teach, they have to have someone lookin up to them with respect.

I teacher's job is to teach. It's not my job to gain your respect. I have the information, and I am happy to share it. However, anymore, my patience is short with low information people. I don't like to begin with "Engines 101" 700 times a year with people on here. If I decide you have some basic knowledge and are willing to learn, I shell out info. If not, I move on and let someone else start at the beginning.

Let me tell you a story. My instructor in college was a great mechanic. He was also a real hard a$$ and most everyone hated him. My class was the largest he ever had of around 24 students. Twice the size of average enrollment for that course. I think there are 4 of us who still turn wrenches. Most all quit within a few years. Why? Well, honestly most of them didn't have the gift. The instructor only taught to the higher level students. You had to keep up. Did that make him a bad teacher? I don't think so. The "bad" mechanics fell out, and the "good" ones are still at it. And ALL 4 of us were successful, either owning a business, or managing shops for someone else. We were the top of the class.
Story 2: My first job as a mechanic was for a local shop where I was going to college. I hadn't even graduated yet. The owner of that shop made my college instructor look like a puppy dog. He swore at us a lot, told us we we didn't know anything, smoked like 3 packs a day..... BUT..... he was one of the best mechanics I ever knew. (The list only has a few people on it.) Although he told us we didn't know anything, he also would tell us what we didn't know, and make sure we understood. (We, as in my to be best friend. We met in college and worked our first job together. We are still very close friends and both still mechanics.) He taught us more than we will ever remember.... and we made him a lot of money, because he taught us well.

Being a teacher isn't about coddling, or even connection. It's as much up to the student to be willing to learn. No matter what the delivery was, we always knew Cook would teach us how to do a job right. It wasn't always fun being berated by him.... but we also knew he liked us, which helped. Guess those two men gave me a chunk of my personality.

[OldSkull]

Mr Zipper Honesty is a great quality! Just for telling the truth about your level of experience with small engine you deserve the respect of everyone.

There is one thing I don't understand in your previous statement, you said it was the first time you work on small engine, can we presume you have work on bigger engine before? If so have you ever check the cylinder bore of your previous job? Even if no major damage is visible on the cylinder wall you always need to check the bore no matter what size of engine you work on period.

You can spend $50 on a cheap .001 2"-6" Dial bore gauge who still need to be adjust with another precision tool before you use it or you can use a set of telescoping gauges and a cheap caliper. No matter which method you choose, the human eye can't beat that.
Good luck with your 1250 restoring job.