NEED ADVICE on Kohler 301Head Gasket repai

[Sailman 1,294]

Found a decent C-120 auto plus attachments. PO used it for plowing garden but it sat for last few years. He said he thought something was wrong with the engine, maybe a rod knocking. It runs real smooth at low prm and sitting at higher rpms BUT when I put some load on it it bogged down bad and started smoking and then a pinging noise. Suspect it was head gasket due to oil weeping out right side of engine.

Soooo I pulled the head today and was pleasantly surprised as it looked good. Std piston with no wobble, gaps in bore or ridges in cylinder. Valves looked good (holding paper tight on closing) and after clean up all seems good. Used carb cleaner, brass brush and finished off with 1000 grit.

First picture shows where the oil was leaking over the gasket. Plan to plane the head before installing new gasket.

Next 3 pictures show the cleaned up parts.

BUT... as i was finger tight cleaning bolt holes with 5/16 tap I had 1 hole that the tap just went in and out with no threading! Bolt seems to tighten up fine. Have video showing tap.

Tempted to just see if the bolt will tighten up to specs and go with it. Was snug when I broke the bolts loose.

Any thoughts on what I should do??

[Sailman 1,294]

picture of gasket (oil weep on right side) and cylinder bore.

[Sailman 1,294]

And of course the disappearing 5/16 tap....

Just when I thought it was all going swimmingly...

Sorry for the noise, fan running in shop.

[WHX?? 49,460]

Tap/bolt  size should be 3/8-16 thread. Looks like things cleaned up real nice. Possibly could have a broken ring(s).

[Sailman 1,294]

Last questions,

1. Can I check / adjust the valve lash before I put the head back on? Seems ideal to tell piston TDC with valves closed.

2. Set the points gap at the same time (putting in new points)

 

Really appreciate the help and advice from the folks on this forum. The 120 makes my second horse. (yes, I know...I was warned...) Much simpler than the GT 14 and lots of attachments.

Thanks!!

[Achto 27,908]

12 minutes ago, Sailman said:

BUT... as i was finger tight cleaning bolt holes with 5/16 tap I had 1 hole that the tap just went in and out with no threading!

 

2 minutes ago, WHX24 said:

Tap/bolt  size should be 3/8-16 thread

 

[Sailman 1,294]

Any way to check the rings without pulling the piston? Would I not have oil on the piston, fouled plug or scoring on the cylinder with broken ring (s)?

[Achto 27,908]

2 minutes ago, Sailman said:

1. Can I check / adjust the valve lash before I put the head back on? Seems ideal to tell piston TDC with valves closed.

2. Set the points gap at the same time (putting in new points)

 

You should be able to do both with the head off.

[Sailman 1,294]

3/8 huh....well that solved that issue...

[953 nut 56,120]

As long as that bolt will torque to 30 Ft/Pounds it should be all right. Be sure to do another round of torquing after the first run.

[WHX?? 49,460]

Yes you can check them with the head off. I forget the actual specs but some guys go to the tight side to help with valve clatter. 

30 Richard ??? I go 35 then just a smidge over after 1st run.

[WHX?? 49,460]

Use a thread lube. Anti sieze works for me but oil will do. Use a new gasket. 

[Sailman 1,294]

I believe there is a specific order to tightening the bolts too. Will look it up in the kohler manual.

New head gasket from "I save tractors" ok?

[Achto 27,908]

8 minutes ago, Sailman said:

Any way to check the rings without pulling the piston? Would I not have oil on the piston, fouled plug or scoring on the cylinder with broken ring (s)?

 

If you pull the piston out you will have to replace the rings.

 

If the piston was carbon covered when you took the head off, then your rings are good. If the top of the piston was clean then you rings are bad. A small amount of clean piston around the outer edge is acceptable, less than 1/8" clean area.

[WHX?? 49,460]

5 minutes ago, Sailman said:

I believe there is a specific order to tightening the bolts too. Will look it up in the kohler manual.

New head gasket from "I save tractors" ok?

Yes in the manual and yes I save has acceptable gaskets.

[Sailman 1,294]

Carbon covered...please elaborate. I had some crusty build up that had to be scraped off, maybe 5-10% top of piston. Also had carbon layer (not crust) that took a good bit of scrubbing with brass brush and carb cleaner to get to clean piston top (able to see the STD).

Was also some carbon build up between the valves and piston. Is that carbon covered?

[Achto 27,908]

22 minutes ago, Sailman said:

Carbon covered...please elaborate

 

The piston on the left has severe oil leakage past the rings. The piston in the middle has more oil leakage past the rings than I would care for. The piston on the right is what you would like to see when you pull the head off. The rings on this piston are sealing properly.

Edited June 30, 2020 by Achto

[Sailman 1,294]

Sorry I am confused....your first post stated the opposite of the examples in the pictures.

 

"If the piston was carbon covered when you took the head off, then your rings are good. If the top of the piston was clean then you rings are bad. A small amount of clean piston around the outer edge is acceptable, less than 1/8" clean area."

[Achto 27,908]

6 minutes ago, Sailman said:

Sorry I am confused....

 

Apparently I am too. Read it again I fixed it.

Edited June 30, 2020 by Achto

[The Tuul Crib 7,338]

7 minutes ago, Achto said:

 

Apparently I am too. Read it again I fixed it.

and l stay that way !! 

[Sailman 1,294]

WHoo HOooo! Mine looked like the piston on the right. Lightly covered in carbon. So rings ARE sealed as they should be...right?

[Achto 27,908]

2 minutes ago, Sailman said:

So rings ARE sealed as they should be...right?

 

Signs say yes.

[The Tuul Crib 7,338]

3 minutes ago, Sailman said:

WHoo HOooo! Mine looked like the piston on the right. Lightly covered in carbon. So rings ARE sealed as they should be...right?

Have you done a compression check ?

[Sailman 1,294]

Have not done compression check. Engine ran fine no smoke until it was loaded up. Looks like it had a head gasket leak and my guess is the head needs planing. Will do that, install new gasket, check the valve lash, new points and see what she does.

If I still have issues then, will do a compression check. 

Will keep all posted.

Thanks for all the help!

[oliver2-44 9,922]

If thats a Kohler, it has ACR (Automatic Compression Release) at slow rotating starting speed.  You cannot do an accurate compression check on them.

If you have access to the precision tools, or know someone who has them, now would be a great time to record the cylinder bore measurements at near top and at bottom of stroke.