K181 valve job

[adsm08 1,434]

Ok, so soon I will be delving into a job I suspect I will come to regret trying before it is done.

 

The 855 needs a valve job. I did a cylinder leak down test and couldn't get it below 55%, no matter where I held the crank. Seems like all the leakage is out the exhaust valve. I get nothing out the carb, nothing out of the oil fill/dipstick tube, but it is audible at the muffler, and with the exhaust removed I can feel it coming out the port.

 

On this engine, how do I get the valves out, should I replaced springs/seals while I am there, what is the cam to valve clearance spec, and does anyone lap these valves, or do you guys just replace them outright?

 

I've done home-brew valve jobs on push-rod car engines, but this is a slightly different beast.

[ebinmaine 63,137]

 

 

 

[953 nut 51,681]

Everything you need to know is in the Manuals section here, look in the Kohler Service Manual.

[pfrederi 17,147]

K181 valves are not adjustable.  If the gap is insufficient you have to grind/file some off the end of the valve stem.  (Go easy i have a noticeable tick on one i took off a bit too much).  Too big a gap you have to buy new valve.

[stevasaurus 22,230]

Everything you need to know...pretty easy if you buy a couple of tools.  and Yes...lap the valves.

 

 

[squonk 38,928]

If you need the seats re-ground, a machine shop should do it. Buy new valves and have the shop adjust the gap

[adsm08 1,434]

9 hours ago, stevasaurus said:

Everything you need to know...pretty easy if you buy a couple of tools.  and Yes...lap the valves.

 

 

 

The only one of those tools I don't already own is that particular style of valve spring compressor. Mine is for overhead valves.

 

7 hours ago, squonk said:

If you need the seats re-ground, a machine shop should do it. Buy new valves and have the shop adjust the gap

 

Valve grinding and cylinder honing I have the equipment for, mostly. This this engine I may need a different style of valve lap tool since mine goes around the valve stem like a drill chuck on a bit. Since these valves are in the block with no access to the stem I'd need to get one of the ones that suction-cups to the face.

 

Frankly, from the looks of it crank polishing, and possibly installing a new piston on the rod are the only things I don't have the equipment for. If these are interference fit wrist pins I can't get them in myself, my freezer doesn't get cold enough. My hone set might also be the wrong size, but it wasn't exactly the correct size for the engine in my truck either and that thing's only performance issues aren't going to be solved without welding extra cylinders onto the block or putting a blower on it.

[stevasaurus 22,230]

Here is mine...picked up most from e-bay and HF.  The valve spring compressor is a good one to have.

 

[Slimshady 0]

On 5/15/2020 at 2:35 PM, pfrederi said:

K181 valves are not adjustable.  If the gap is insufficient you have to grind/file some off the end of the valve stem.  (Go easy i have a noticeable tick on one i took off a bit too much).  Too big a gap you have to buy new valve.

 

[Slimshady 0]

Hi do you know witch valve goes in witch hole had mine out didn't mark where they came out of and they are different in length thanks 

[stevasaurus 22,230]

The larger one is intake, the smaller one is exhaust    I'll bet you are talking about the tappets.

 

 

 

 

 

 

 

 

With the tappets, you might be able to place and put in a valve and check clearance to determine which is which.

 

 

[Snoopy11 5,713]

Might want to take a look at the following:

 

On 10/11/2021 at 12:27 PM, Snoopy11 said:

For the valve seats...

You can take a sheet of Emory cloth, cut out several 2" x 2" squares and poke a hole in the center.

 

Sticking the Emory cloth squares onto the valve, you can reach into the valve chamber and turned the valve stems with your fingers, while keeping light pressure on the valve head. Rotate the squares back and forth on the seat, switching from medium grit to fine grit as needed.

 

Don