K181 Build

[ri702bill 8,316]

5 hours ago, WHX?? said:

Thank you Squonky...

BTW my QA man came up with the same dims as me using a vernier... 

The QA guy has the required experience to use his measuring tools properly, after all, ya dont't go to the kid bagging groceries at the Piggly Wiggly and say "hey' Johnnie. Wanna make some side cash and check the rod clearance for me"?? UNLESS Johnnie has used Plastigage before!!!

As I said, Plastigage requires NO expensive measuring tools nor the experience to properly use them, A perfect backyard home mechanic tool.

Done.

[squonk 41,068]

8 hours ago, WHX?? said:

 

What it doesn't mention in that thread is I suck at math what with having ony nine toes and four fingers... don't listen to me. 

 

Well no wonder you don't own a micrometer! 

[Sailman 1,291]

7 hours ago, ri702bill said:

As I said, Plastigage requires NO expensive measuring tools nor the experience to properly use them, A perfect backyard home mechanic tool.

Done.

I am assuming you use the plastigage with the existing rod caps even though the rod likely will be replaced?

[ri702bill 8,316]

You could - a good start if you have never used it and to gather info as to what gap you have now...

[Rick3478 428]

8 hours ago, ri702bill said:

 

As I said, Plastigage requires NO expensive measuring tools nor the experience to properly use them, A perfect backyard home mechanic tool.

Done.

 

I would point out that Plastigage provides a single point of measurement between *two* parts.  That single point of measurement may be sufficient for new parts that have just been machined and are known to be flat or round (in this case).  But for used parts that are likely to be oval, bellied, bent, etc, a more thorough dimensional analysis of both parts is in order, and that's best done with calipers, verniers, micrometers, and such.

[953 nut 55,190]

9 hours ago, Sailman said:

I am assuming you use the plastigage with the existing rod caps even though the rod likely will be replaced?

Presuming you are planning to use the existing connecting rod or to practice using plastigage that is fine. I always check the crank at bottom of the stroke and then repeat with the crank at ninety degrees from bottom to be sure the crank is round.

[Sailman 1,291]

Good news I think but baffled.....I took @WHX?? advice and took the head off before the oil pan. I had put some marvel mystery oil in the spark plug hole to prep the piston for removal in case it was stuck. So what i found was a stuck exhaust valve. See pics below. Piston, tappets and intake valve all move fine by rotating flywheel counter clockwise. I put some Kroil on the valve stem and gently tapped with dead blow hammer but no movement. Thinking of getting in there tomorrow with carb cleaner and brass brush to try to clean it up. Any suggestions?

Now for the baffling part....I had rotated the flywheel before disassembly and I SWEAR it did not move. That is why I assumed it had a broken rod like the K-161 in my 701. It did make a sucking sound which I guess was the intake valve?

So I pull the head off and lo and behold...the piston move up and down just fine. I'm confused!

The piston has std stamped on it and cylinder looks clean. Is it supposed to have that small hole in it. Any and all comments are welcome. I really appreciate you experienced guys helping me out here.

 

[WHX?? 48,814]

Keep at that valve just what you been doing.  It will free up. You can pull the valves then for better cleaning. 

The hole in the piston is normal centering mark from when it was machined. 

Move the piston down and get us pics of the bore. You may not even have to pull the piston.

I would now pull the pan for inspection and further cleaning. 

 

[Achto 27,565]

50 minutes ago, Sailman said:

So I pull the head off and lo and behold...the piston move up and down just fine

 

13 minutes ago, WHX?? said:

ove the piston down and get us pics of the bore. You may not even have to pull the piston.

 

@Sailman did you clean the top of the piston before taking the picture? Reason that I ask is because the top of the piston looks awfully clean. When they are this clean when you pull the head off this indicates piston wash (piston being washed off by engine oil) Indication of bad rings. 

Edited February 14 by Achto

[WHX?? 48,814]

My next suggestion Dan after a look at the bore is to have it measured.

By the way dingle berries came in for my hone job. 

Edited February 14 by WHX??

[Sailman 1,291]

12 hours ago, Achto said:

 

@Sailman did you clean the top of the piston before taking the picture? Reason that I ask is because the top of the piston looks awfully clean. When they are this clean when you pull the head off this indicates piston wash (piston being washed off by engine oil) Indication of bad rings. 

 

Yes I did clean the piston so I could read the markings...STD. Will take pics of the bore tomorrow.

12 hours ago, WHX?? said:

My next suggestion Dan after a look at the bore is to have it measured.

Will do. I have a set of Central Tool co telescoping bore gauges coming from fleabay. Picked up a set of HF micrometers today. Going by a machine shop to have them calibrated. The 1 inch gauge seems correct by measuring with caliper and zeroing out the micrometer but the 2 inch gauge seems off by .002 to .005. I know they are not the best but if they calibrate ok should serve my purpose.

Edited February 14 by Sailman

[RED-Z06 2,221]

1 hour ago, Sailman said:

 

Yes I did clean the piston so I could read the markings...STD. Will take pics of the bore tomorrow.

Will do. I have a set of central machine co telescoping bore gauges coming from fleabay. Picked up a set of HF micrometers today. Going by a machine shop to have them calibrated. The 1 inch gauge seems correct by measuring with caliper and zeroing out the micrometer but the 2 inch gauge seems off by .002 to .005. I know they are not the best but if they calibrate ok should serve my purpose.

If you were looking down the plug hole you were looking at the block between the bore and valves im pretty sure

[Sailman 1,291]

Here is picture of the bore with piston all the way down. Looks smooth. No dings or scratches that I can see. Still trying to get the valve to budge. No movement yet.

[953 nut 55,190]

9 minutes ago, Sailman said:

Still trying to get the valve to budge.

Try some gentle upward pressure on the valve and spring using a small pry bar of some sort. Don't hit the valve head too much for fear of bending the stem. May want to remove the build-up on the valve stem before doing too much.

[RED-Z06 2,221]

Ive had luck putting vice grips ad gently as possible around the head, and heat the guide/stem, and just give it some gently twist, see if it will budge...once it moves in any direction you're home free.

[Sailman 1,291]

20 minutes ago, 953 nut said:

Try some gentle upward pressure on the valve and spring using a small pry bar of some sort. Don't hit the valve head too much for fear of bending the stem. May want to remove the build-up on the valve stem before doing too much.

That is a good suggestion. Will try that tomorrow. I have used carb cleaner on it and the stem is pretty clean. Still seeping the Kroil every day. Pretty careful with the tap tapping on the valve head. Hard to believe how stuck it is.

[Sailman 1,291]

18 minutes ago, RED-Z06 said:

Ive had luck putting vice grips ad gently as possible around the head, and heat the guide/stem, and just give it some gently twist, see if it will budge...once it moves in any direction you're home free.

Might try that too. I have a rubber strap wrench....might be less chance of damaging the valve head.

Thanks.

Edited February 15 by Sailman

[WHX?? 48,814]

Patience is your best friend Saildude on a stuck valve. Something which I have none of. 

[Sailman 1,291]

Whooo Hooo! Patience, Kroil, tapping with dead blow, carb cleaner and rotating the tappet against the valve....has paid off. Stuck valve is free. Also stuck choke on carb finally loosened up too. At this point I am going to check measurement in the bore and if it is good I don't see any reason to pull the oil pan. My goal was not to have to do a total rebuild so if all works ok might just go with that. Not sure if I should pull the valves and clean and lap or clean it as best I can and put it back together. It will not be a heavy used worker, just a fun tractor for grand-kids to drive occasionally. Will true the head, new points, have rebuilt the carburetor and will use new gaskets all around. Thoughts?

 

[WHX?? 48,814]

10 hours ago, Sailman said:

At this point I am going to check measurement in the bore and if it is good I don't see any reason to pull the oil pan. 

Sounds like a good plan. 

The only reason now to pull it would be for cleaning but oil additives and frequent changes would help that. 

I would still pull the valves for cleaning & lapping. 

Just so you know pulling the piston automatically requires a hone job and new rings. If the rod was not installed wrong on mine I would not have pulled the piston. 

 your measurements reveal no out of spec taper or round. 

Edited February 16 by WHX??

[RED-Z06 2,221]

3 hours ago, WHX?? said:

Sounds like a good plan. 

The only reason now to pull it would be for cleaning but oil additives and frequent changes would help that. 

I would still pull the valves for cleaning & lapping. 

Just so you know pulling the piston automatically requires a hone job and new rings. If the rod was not installed wrong on mine I would not have pulled the piston. 

 your measurements reveal no out of spec taper or round. 

Ive never heard anyone say pulling piston out requires new rings and hone out?  Rings spin on the piston while running, whats the logic to having to replace rings?

[WHX?? 48,814]

13 minutes ago, RED-Z06 said:

pulling piston out requires new rings and hone out?

 

I'll let @Achto elaborate but it comes from building Harley motors in that if the piston leaves the jug it gets new rings.  Something about they won't reseat I think... worn to the shape of the bore? 

I don't subscribe to the theory that rings  spin on the piston.  If they do why bother  to stagger end gaps? 

[Achto 27,565]

47 minutes ago, RED-Z06 said:

Ive never heard anyone say pulling piston out requires new rings and hone out?  Rings spin on the piston while running, whats the logic to having to replace rings?

 

Piston rings will rotate some unless they are pinned as in the case with many 2 stroke engines. Break in or where in needs to occur in order for the rings to seat properly. Once you remove the rings from the cylinder they will never seat properly again and you will have an oil burner that has a compression loss. 

 

Then of course there is the recommendations from page 11.9 in the Kohler manual.

 

[WHX?? 48,814]

5 minutes ago, Achto said:

they are pinned as in the case with many 2 stroke engines

I guess I have seen that on chain saws. 

[squonk 41,068]

4 hours ago, WHX?? said:

 

Just so you know pulling the piston automatically requires a hone job and new rings. If the rod was not installed wrong on mine I would not have pulled the piston. 

 

Undo the rod cap with the crank all the way down. Push the piston up and spin it. Done it many times on SBC's and Chrysler tootally two's