1963 Cub loboy

[Paul 300 U]

For starters I'm no mechanic but picking up experience mostly by using this forum and digging in.
I purchased this cub knowing it needed work. I fixed a few things to make it useable but now I'm getting serious about getting it to run better. It blows a good bit of blue smoke. In winter it did ok plowing snow. This summer I put a 60 inch mower on it and it really struggled to cut my lawn. In 1st gear, full throttle it would stall on a small incline with medium high grass. (My 1997 MTD, 18 HP with a 48 inch deck breezes right through.) The blades are in good shape and I do believe the front of the mower was slightly higher than the back. I grew up with a 50's cub and in my recollection this one lacks power.
After a bit of research but limited time I decided to at least do rings and valves. As you can see pistons and valves are out. With the naked eye, nothing seems out of the ordinary. My plan was to replace rings, valves, guides springs and hone the cylinders and lap valves. I wasn't planning on new pistons unless needed. The oil pressure gauge always reads good. I did not do a compression test. The caliper measurements on the current piston and bearing are within range. Before I start buying parts I'm checking in here for thoughts and recommendations on what to buy and do. I'm looking forward to your questions and comments.
Thanks! Paul

 

[Farmall m farmer]

You can do what you want but if it was me you are all ready in you might as well do it all maybe not main bearings but at least I would do on top of what you said rod bearings

 

[dhermesc]

Agreed, If you are that far in - do it right. A rebuild kit for the rotating mass is $450 on Ebay - pistons, sleeves, rings, bearings and gaskets. Does NOT include valves. To be honest before you tore that far into into it I would have guessed that was most likely your issue - valves needed adjusted or ground. Honing and new rings might be tempting if everything is in good condition as you describe - but I hate putting in a bunch of used parts as I reassemble an engine.


Steiners has new pistons and rings for $219 + $99 for the gasket kit + $48 for rod bearing kit.

Jensales has a pretty decent rebuild kit with piston, rings, rod bearings, main bearings and gasket kit for 169.23(?).

https://www.external_link/products/...r-in-frame-engine-overhaul-kit-c60-loboy.html

 

[Janicholson]

Agreed, If you are that far in - do it right. A rebuild kit for the rotating mass is $450 on Ebay - pistons, sleeves, rings, bearings and gaskets. Does NOT include valves. To be honest before you tore that far into into it I would have guessed that was most likely your issue - valves needed adjusted or ground. Honing and new rings might be tempting if everything is in good condition as you describe - but I hate putting in a bunch of used parts as I reassemble an engine.


Steiners has new pistons and rings for $219 + $99 for the gasket kit + $48 for rod bearing kit.

Jensales has a pretty decent rebuild kit with piston, rings, rod bearings, main bearings and gasket kit for 169.23(?).

https://www.external_link/products/...r-in-frame-engine-overhaul-kit-c60-loboy.html

Not a flame, No sleeves in that engine the pistons run in the block casting.

 

[Janicholson]

For starters I'm no mechanic but picking up experience mostly by using this forum and digging in.
I purchased this cub knowing it needed work. I fixed a few things to make it useable but now I'm getting serious about getting it to run better. It blows a good bit of blue smoke. In winter it did ok plowing snow. This summer I put a 60 inch mower on it and it really struggled to cut my lawn. In 1st gear, full throttle it would stall on a small incline with medium high grass. (My 1997 MTD, 18 HP with a 48 inch deck breezes right through.) The blades are in good shape and I do believe the front of the mower was slightly higher than the back. I grew up with a 50's cub and in my recollection this one lacks power.
After a bit of research but limited time I decided to at least do rings and valves. As you can see pistons and valves are out. With the naked eye, nothing seems out of the ordinary. My plan was to replace rings, valves, guides springs and hone the cylinders and lap valves. I wasn't planning on new pistons unless needed. The oil pressure gauge always reads good. I did not do a compression test. The caliper measurements on the current piston and bearing are within range. Before I start buying parts I'm checking in here for thoughts and recommendations on what to buy and do. I'm looking forward to your questions and comments.
Thanks! Paul

Please remember the engine has about 10 HP when new. So 18 in a dedicated mower with 1/3 the weight or less is going to win. Jim

 

[Jim.ME]

Agreed, If you are that far in - do it right. A rebuild kit for the rotating mass is $450 on Ebay - pistons, sleeves, rings, bearings and gaskets. Does NOT include valves. To be honest before you tore that far into into it I would have guessed that was most likely your issue - valves needed adjusted or ground. Honing and new rings might be tempting if everything is in good condition as you describe - but I hate putting in a bunch of used parts as I reassemble an engine.


Steiners has new pistons and rings for $219 + $99 for the gasket kit + $48 for rod bearing kit.

Jensales has a pretty decent rebuild kit with piston, rings, rod bearings, main bearings and gasket kit for 169.23(?).

https://www.external_link/products/...r-in-frame-engine-overhaul-kit-c60-loboy.html

Remember YT and PartsASAP sells those parts for about the same money, and they provide this site. Your link was blocked as they frown on advertising for the competition.

 

[Paul 300 U]

Please remember the engine has about 10 HP when new. So 18 in a dedicated mower with 1/3 the weight or less is going to win. Jim

Jim, I think I'm going to replace the valves, springs etc and piston rings. In your opinion, if I were to get new pistons, do you think the crater pistons are worth the money to get the extra horsepower?
Thanks!
Paul

 

[Paul 300 U]

Remember YT and PartsASAP sells those parts for about the same money, and they provide this site. Your link was blocked as they frown on advertising for the competition.

That's a good point. I need to consider that more often. Thanks, Paul

 

[Paul 300 U]

Agreed, If you are that far in - do it right. A rebuild kit for the rotating mass is $450 on Ebay - pistons, sleeves, rings, bearings and gaskets. Does NOT include valves. To be honest before you tore that far into into it I would have guessed that was most likely your issue - valves needed adjusted or ground. Honing and new rings might be tempting if everything is in good condition as you describe - but I hate putting in a bunch of used parts as I reassemble an engine.


Steiners has new pistons and rings for $219 + $99 for the gasket kit + $48 for rod bearing kit.

Jensales has a pretty decent rebuild kit with piston, rings, rod bearings, main bearings and gasket kit for 169.23(?).

https://www.external_link/products/...r-in-frame-engine-overhaul-kit-c60-loboy.html

I know your right. I try to balance the work required versus the cost. I've got 2.5 other tractors that always seem to want money too.! Thanks for the input and researching the cost as well as the link. . Much appreciated! Paul

 

[Janicholson]

Jim, I think I'm going to replace the valves, springs etc and piston rings. In your opinion, if I were to get new pistons, do you think the crater pistons are worth the money to get the extra horsepower?
Thanks!
Paul

Yes. They can add 2+ hp over stock (which is a lot at 10hp. Jim

 

[Paul 300 U]

Yes. They can add 2+ hp over stock (which is a lot at 10hp. Jim

Thanks Jim

 

[Butch(OH)]

Jim, I think I'm going to replace the valves, springs etc and piston rings. In your opinion, if I were to get new pistons, do you think the crater pistons are worth the money to get the extra horsepower?
Thanks!
Paul

We cut our lawn with several Cubs for 15 years and they struggle with a 60" mower. If it's runs on all 4, not smoking, burning oil or missing then you will gain practically nothing by overhauling it. Been there done that. We had the compression high enough on the last one it would ping on regular gasoline and still wasn't enough to run the mower right. The extra HP kits may help it a bit but your still going to be in low gear and don't get behind on cutting.