k161 help

[wheelhorse66 10]

my k161 smokes really bad, is it the rings/ if it is how hard is it to put rings in it?,or could the bore be bad if it is how do i check?

[rmaynard 15,409]

Rings, valve guides, valve stems and a worn cylinder, all can contribute to smoke. The only way to see if it is rings is to pull the piston. While it is out, the cylinder can be measured for wear with a cylinder bore gauge.

[wheelhorse66 10]

OK how do I know if the bore is bad

[chazm 413]

Once you have the engine torn down, look at the bore, if it is mirror shiny & no hone marks left thats a good indicator there is wear. To check the bore you will need to mic it. 

 

Chasm  

Edited January 8, 2014 by chazm

[rmaynard 15,409]

Unless you have a cylinder bore gauge, the only way to check the cylinder is to take the engine somewhere that has the proper tools such as a machine shop or small engine shop.

[Fordiesel69 259]

Pull piston out, take the rings off , and slip a .006 feeler gauge in between the piston skirt and cylinder.  If you can put the piston in by hand with the feeler guage in place, the bore needs to be resized to the next avail size up.  If you would need tools to force the piston in with the feeler guage, the bore will be "decent enough" to hone and install new rings, with assumption there are no scratches or rust damage.

 

This is a backyard trick, and not proper in terms of how a machinest would do it.  But it will work if you can't afford, or don;t have a local machine shop.

[wheelhorse66 10]

OK I have a scratch on the cylinder wall do I just hone it out Or do I have to have it bored

[slammer302 2,155]

Some would say you need to. The main thing you need is get the bore checked and make sure its not wore or out of round my dad has a k161 and the bore is all scratched up and it doesn't smoke at all

[sorekiwi 761]

It depends on how deep the scratch is.  If its deep enough to allow a loss of compression, then the cylinder will need boring.

 

I give them the fingernail test, if I drag my fingernail over it and it "hooks" then it needs attention.  If I cant feel it, it will probably be OK (assuming the bore itself is unworn and round).

[wheelhorse66 10]

It only has one scratch on the cylinder but the piston was full of scratches I think if I buy a new piston and rings and hone it a little bit I think it might be alright,but I was getting some of yaws opinions on it before I done it.

[wheelhorse66 10]

do i have to replace the connecting rod if i put a new piston and rings in my k161 engine?someone told me you should but i just want some opinions on here.

[rmaynard 15,409]

Did you have the rod and crankshaft journal measured? If so, and it is okay, than it is not necessary to replace it when replacing the piston.

[wheelhorse66 10]

what do you mean by measured?

[rmaynard 15,409]

The inside (bearing surface) of the rod, and the journal of the crankshaft wear over time and usage. I would not go to all the trouble of replacing the piston only to have the rod be worn. However, you can't just replace the rod without measuring the crankshaft journal. There is no way of knowing what size rod you need without measuring it. Take the whole engine to the machine shop and have it spec'd. That means have everything measured to be sure it is within specifications provided by Kohler. If anything is found to be out of spec, you will be able to decide what you need to do. Rods come in STD, .010 undersize, and .020 undersize. If you need an undersize rod, the crankshaft will have to be ground to match it.

 

Unless you have precision measuring tools in your toolbox, and most of us don't, you can't get accurate measurements without having a pro do the measuring for you.

[WH nut 553]

I always replace the rod with a new piston and rings. I have had old ones break in short order

 

 

 

 

Any job big or small, do it twice or not at all.

[wheelhorse66 10]

How can I tell if my k161 is large bore or not

[buckrancher 2,679]

2.875 is the small bore k161

 

Brian

[wheelhorse66 10]

Thanks then mine is small bore.does anybody know were I could get a piston for small bore k161 eBay just has big bore

[rmaynard 15,409]

There are currently several 2-7/8" (2.875) pistons on eBay.

Edited January 9, 2014 by rmaynard

[VinsRJ 721]

Is there any rocking of the piston in the bore? How bad of a ridge is there? If any....

[Fordiesel69 259]

It depends on what YOU want.  One scratch will not be much of an issue unless you want it perfect.  What matters is if the bore is too big and the piston is loose.

[Fordiesel69 259]

K161 & K181 share the same piston.  The crankshaft (stroke) is different.

[WH nut 553]

You said it was smoking bad. I assume you tore it down to fix that issue. Take it to the machine shop if you want it right. It doesn't sound like you have the tools to make all the measurements and verify its condition.

[chazm 413]

              

 

Chasm 

[Fordiesel69 259]

Keep one thread going on your engine topics, way to many threads going in all different directions.

 

You do NOT have to replace the rod, if it is wearing well, is in spec, and is not scored.  No joke, some aftermarket rods are out of spec when new, and your 40+ yr old used rod may measure better.  So it all depends.  Some aftermarket rods however are very high quality, and are just as good as kohler.

 

There are new rods that are called posi-lok and are genuine to kohler, which came out when the magnum engines were introduced..  They use studs with nuts for a better, more secure fit of the rod cap.  I have not seen any aftermarkets this way.