149 engine teardown for cam replacement

[sawdustdad]

I usually wait for the machine shop to tell me what they need to bore to before I buy the new piston and rings and rod.

Not too tough to put it back together just follow the manual very carefully. Shimming the camshaft and the bearing plate are the two things that require you to use trial and error, take your time and don't be afraid to take it apart and try again. If you don't have feeler gauges, you'll need a set.

Seating the crankshaft oil seals is another that you need to read the instructions carefully.

Be sure the oil hole in the connecting rod at the crankshaft bearing is facing the correct way (toward the camshaft IIRC). Make sure the oil dipper doesn't hit the oil pan. I've had to trim them before on a K241 with a flat oil pan.

All of this is explained in the manual. Take your time and it'll be a great learning experience.

[twoton]

Just a couple of things that come to mind;

Make sure that you have a clean work area and that you keep everything clean and organized. Is the machine shop going to clean the block for you? If not you will have to clean it yourself before you start. And, using a tap, clean out all the threaded holes in the block.

Use an engine stand if you can.

Get a gallon bucket and put a couple of quarts of 30 weight in it. Dip all your moving parts in it before assembly.

Did you get your replacement cam yet? Remember, you will have to set the camshaft end play;

http://www.onlycubcadets.net/forum/s...317#post388317

Take your time and be careful installing your new rings. You don’t want to deform or break them. You might find it helpful to use ring expanders;

https://www.amazon.com/dp/B0009OMYC4...V170RD6O&psc=0

Clean up your timing marks and highlight them with a white or yellow paint pen. And remember, you can set the timing using the static method while the engine is on the stand or workbench. You might find this easier than after it's installed in the tractor;

http://www.onlycubcadets.net/forum/s...080#post276080

If you have a dial indicator, it is a good way to set the piston at TDC when you adjust the valve - tappet cold clearance;

http://www.onlycubcadets.net/forum/s...227#post338227

While you’re waiting on the machine shop, you can plane the head;

http://www.mgonitzke.net/cubcadet/tools/headgasket.pdf

https://www.youtube.com/watch?v=L1jF...ature=youtu.be

And rebuild the carb';

http://www.mgonitzke.net/cubcadet/to...rb_rebuild.pdf

Get a couple of quarts of Brad Penn break in oil;

https://www.amazon.com/dp/B002RF8IN2...V170RD6O&psc=1

Follow Merks advise for breaking in your freshly rebuild motor;

http://www.onlycubcadets.net/forum/s...0&postcount=19

Don’t rush it. Anything worth doing is worth doing twice if that what it takes to get it right.

[jbrewer]

I'm going to save this list of really good ideas for my turn at rebuilding one of these. Thanks for posting them.

[J-Mech]

Originally Posted by jbrewer

I'm going to save this list of really good ideas for my turn at rebuilding one of these. Thanks for posting them.

Read this before you do.....

Originally Posted by twoton

Just a couple of things that come to mind;

Make sure that you have a clean work area and that you keep everything clean and organized. Is the machine shop going to clean the block for you? If not you will have to clean it yourself before you start. And, using a tap, clean out all the threaded holes in the block.

Machine shop better clean the block. They have to after boring it. Only a really bad shop wouldn't give you back a clean block. Most shops you have to tell them NOT to paint it too, or they will. That said, mine are usually pretty clean before I take it to them. They still will tank it after boring it.

Originally Posted by twoton

Use an engine stand if you can.

You don't need an engine stand for a K series. I don't even use a stand and I have at least 3 engine stands. Set it on a bench. It's not a big motor.

Originally Posted by twoton

Get a gallon bucket and put a couple of quarts of 30 weight in it. Dip all your moving parts in it before assembly.

Don't do that. Just use an oil can. Dipping parts in oil gets it everywhere. No reason to make such a mess.

Originally Posted by twoton

Did you get your replacement cam yet? Remember, you will have to set the camshaft end play;

http://www.onlycubcadets.net/forum/s...317#post388317

That's in the service manual..... he better remember to do it. It's part of the steps of overhaul, just like setting the end play on the crank.

Originally Posted by twoton

Take your time and be careful installing your new rings. You don’t want to deform or break them. You might find it helpful to use ring expanders;

https://www.amazon.com/dp/B0009OMYC4...V170RD6O&psc=0

These piston rings are small. You don't need that tool. You can use your hand. But whatever.

Originally Posted by twoton

Clean up your timing marks and highlight them with a white or yellow paint pen. And remember, you can set the timing using the static method while the engine is on the stand or workbench. You might find this easier than after it's installed in the tractor.

NOTE: You must be referring to the marks on the flywheel. Be specific, there are two sets of timing marks on the K series. The set that are internal, and the set that are external. Doesn't hurt to mark both, but you are talking about the ones on the flywheel. Painting them white is definitely a good idea.

Originally Posted by twoton

If you have a dial indicator, it is a good way to set the piston at TDC when you adjust the valve - tappet cold clearance;

http://www.onlycubcadets.net/forum/s...227#post338227

You do not need to do that. It's is ridiculously unnecessary. The cam closes both valves before the piston is very far off the bottom of the compression stroke, and opens them again when it almost reaches the bottom of the power stroke. If you can't find a spot with your eye in 300 deg of crank travel, you're blind. Only thing you have to watch on this engine is that the exhaust valve isn't sitting on the ACR. If you set valve lash while the cam cover is off, and you should, this is easy.

You don't need a dial indicator to set anything on the K series. You can even set crank end play with a feeler gauge. Book tells you how.

Originally Posted by twoton

While you’re waiting on the machine shop, you can plane the head;

http://www.mgonitzke.net/cubcadet/tools/headgasket.pdf

https://www.youtube.com/watch?v=L1jF...ature=youtu.be

Yep.

Originally Posted by twoton

Get a couple of quarts of Brad Penn break in oil;

https://www.amazon.com/dp/B002RF8IN2...V170RD6O&psc=1

You should always run the same oil the engine is going to use normally to break it in. People who invented "break in oil" are just making money selling to people who don't know. It's a gimmick.

Originally Posted by twoton

Don’t rush it. Anything worth doing is worth doing twice if that what it takes to get it right.

Good advice here.



Sorry twoton. I like you man.... I really do. Just sometimes you go above and beyond, and it's too much. Not all the things you see other people do on this site are necessary, or good.



Here's my advice:
1.) READ the manual and FOLLOW it!
2.) Ask questions if you need help.

[jbrewer]

Good to see some of Matt's old links still work. There's some good info there on home plating.

[Mr Bob]

Thanks for all the good info. Every one has their way of doing things. If that way works for you then that is all that matters. Thank you twoton and Jmech.
I will refer to the service manual and I am sure I will be asking help for specific things.When I took the engine apart, the camshaft gear was only aligned about half way with the crank gear. I thought that was not correct but I do not know how to correct it if needed. The machine shop called this morning. The cylinder only needs honed. Piston checked ok. Connecting rod needs to be turned .010 under. They will tank the block before and after honing. They will grind the valves and seat, lap them in and install the springs. Going to get a new piston ,.010 over and rings. I will ask them to install rings and piston. I could probably do this but I feel they are more apt to do it correctly. I am making a small work bench with two saw horses and a plywood top. Will be taking it slow and keep things as clean as possible. Thanks for all your help and have a great day.
Bob

[Alvy]

Bob I have a question. Did you give the machine shop the specs of the 321? Not to second guess them but there are specific go/no go measurements of taper, out of round, and thrust/face for it. They sound like they nailed it with the crank journal needing to go .010” under but that piston really looks like it got beat around for just a hone to work. Again, it’s only worth a couple questions to them, maybe they have a B.A. hone but to take out that much material to get it straight again I would think they’d have to bore “.020 or even .030” to get that out. If any other goo hoos more saavy want to chime in please do, just expressing my humble opinion.

[sawdustdad]

Surprised they didn't want to bore the cylinder.

There is a type of hone that will get the cylinder true again, don't remember exactly what it is, but it serves the same purpose as boring, but only when a few thousandths are needed to be removed. JMech will know what I'm talking about. Or maybe Alvy called it a BA (bad ass?) hone. Not sure the correct name.

You might ask them how they are honing. Generally, that does not true the cylinder, just renews the cross hatch pattern. Unless they use the special hone that does true the cylinder.

Did they tell you to get the .010 over piston and rings? Or had you already purchased them? Did they decide to just hone because you gave them the piston and rings before they mic'd the cylinder? So are they just trying to accommodate your new piston rather than boring it .020 like it really should be? You should ask.

Not trying to nitpick, but these are a few questions you should ask to be sure you'll get a good result.

If they put a new piston in an egg-shaped cylinder because they didn't bore when they should have (perhaps because you gave them the piston and rings to use) then you'll have a short lived engine. Perhaps measured in dozens of hours rather than hundreds of hours.

Lots of us have been through these situations and learned from our mistakes, just trying to help you avoid some of these pitfalls.

[J-Mech]

Machine shops use rigid hones. I'm not going to say every shop.... but every shop uses a machine rigid hone. Put the block in, and it does the work for them. Don't have to manually run it up and down.

This one is pretty fancy. Some have ones this nice, others don't but they all work the same way.
https://www.youtube.com/watch?v=jx4tRAU_Tp8


Mike, I didn't think the piston looked that bad. I'm not surprised that a honing is all that it needed. If they caught the crank, I'm sure that they checked the cylinder. OP said he was going to get a .010" over piston, I'm taking that to mean he does not yet have one.

[twoton]

Originally Posted by Mr Bob

...... The machine shop called this morning.......

Good to hear of your progress Bob and will be looking forward to your updates!