Should I remove the head?

[CD Long Jr 95]

Since I'm waiting on parts & God only knows the last time she ran, should I remove the head and have a look see?

[Retired Wrencher 6,242]

It’s always good to remove the head and check for carbon buildup. And sand down the mating surfaces. Like this in this picture. Also sand down the head itself on a nice steel flat table. I try to get it as flat as you can, as you go, you can see where the low spots are and the rest is all high spot. Also, I try to use steel head, gaskets like they originally put on these engines. 

[CD Long Jr 95]

57 minutes ago, Retired Wrencher said:

It’s always good to remove the head and check for carbon buildup. And sand down the mating surfaces. Like this in this picture. Also sand down the head itself on a nice steel flat table. I try to get it as flat as you can, as you go, you can see where the low spots are and the rest is all high spot. Also, I try to use steel head, gaskets like they originally put on these engines. 

I worked in Industrial Services. We had 40K psi JetEdge water blasters. We had to lap the valves when they wore down. We used a sheet of glass, various grits of sandpaper, wet with WD40 & sanded using a figure 8 pattern. That's what I intend to do with the head unless directed otherwise.

[ri702bill 10,880]

Decarboning the combustion chamber, valves & the head actually are recommended routine maintenance items per the Kohler manual. It also gives you a chance for a look-see at the valve seats, valve faces, and to determine if there is too much clearance from valve stem to guide. The exhaust valve & seat have a particularly rough life. Also note the amount of carbon on or missing on the piston. Sooty carbon tells you the engine was running too rich; a burnt exhaust valve reveals a too lean condition. Carbon missing all around the outer 1/4" or so on the top of the piston indicates oil getting by the rings.... if so, it may be time to dig deeper. With the piston at BDC you have an opportunity to ckeck the cylinder bore for size, roundness, and taper - if you hac access to the proper measuring equipment. Do note the overall tightness of the head bolts upon removal. Are they all about the same as far as the force to break them free or not.?? One or more loose ones tell you the head was not properly torqued. If you look closely, the engine can tell a lot....

 

Head gasket torque & sequence. I cannot stress enough how vital this is. It is not a set it & forget it one time process. Look at the Kohler manual for the correct torque pattern, sequence of progressive steps, and info on re-torquing after a thermal up to temp and cool down cycle, running the engine with no load. The manual tells you to repeat as necessary - it does not tell how many times. My personal worst was a 6 HP Tecumseh - I had to thermal cycle it and retorque the head seven times to get consistent recommended torque reading when cold. This is due to the composite gasket compressing each cycle until it is "happy" between the aluminum head and the cast iron block...

Edited Sunday at 03:36 PM by ri702bill

[lynnmor 8,327]

2 hours ago, CD Long Jr said:

I worked in Industrial Services. We had 40K psi JetEdge water blasters. We had to lap the valves when they wore down. We used a sheet of glass, various grits of sandpaper, wet with WD40 & sanded using a figure 8 pattern. That's what I intend to do with the head unless directed otherwise.

 

Just know that glass is not always flat, so check that.  The figure 8 pattern is good, just change your grip and rotate the head from time to time.  I have a high quality vertical band saw with a ground cast iron table that I use.

[oliver2-44 11,127]

Just a note of caution. The head bolts on either side of the exhaust are know to seize and break. 

Liberal us of penetrant, time, and a open a little/close a little, repeat are one possible method of removal.

But some still break.  

[CD Long Jr 95]

2 minutes ago, oliver2-44 said:

Just a note of caution. The head bolts on either side of the exhaust are know to seize and break. 

Liberal us of penetrant, time, and a open a little/close a little, repeat are one possible method of removal.

But some still break.  

So if I spray around the bolt it will creep in? Glad ya said this, 1/2inch impact was lookin' pretty good & the air compressor was warmin' up.

Edited Sunday at 03:04 PM by CD Long Jr
Thought of additional info.

[oliver2-44 11,127]

2 minutes ago, CD Long Jr said:

So if I spray around the bolt it will creep in?

That's the only option, give it a tiny shot ever hour when you walk by for several days. 

tap on the bolt head and give it small open close wiggle to help it work in. 

Those bolt make come out fine or they make be stuck. Caution from putting the gorilla force on them is all you can do.

[andrewLL 30]

This bolt sheared on me recently (see my post) I had put oil on it for a number of days and also heated it up to try and get some penetration. Fixed it by drilling out and using a helicoil.  However on removing the valves to clean and reseat I noticed a portion of the thread was xxopsed in the exhaust port. Not sure if this is normal or a faulty casting.  Anyway, good luck.

Edited Sunday at 11:54 PM by andrewLL

[953 nut 63,504]

9 hours ago, oliver2-44 said:

That's the only option, give it a tiny shot ever hour when you walk by for several days. 

tap on the bolt head and give it small open close wiggle to help it work in. 

Those bolt make come out fine or they make be stuck. Caution from putting the gorilla force on them is all you can do.

One other trick is to attempt to tighten the bolt a bit more, they were only torqued to 45 foot pounds by Kohler so there will be some room to go without fear of breaking.

[ri702bill 10,880]

Once all the bolts are out, you need to chase the threads - by hand. Don't be a hero and chuck up the tap in a cordless drill. Yes the hand method takes longer, but do you really feel like extracting a snapped off tap??

[Retired Wrencher 6,242]

1 hour ago, ri702bill said:

Once all the bolts are out, you need to chase the threads - by hand. Don't be a hero and chuck up the tap in a cordless drill. Yes the hand method takes longer, but do you really feel like extracting a snapped off tap??

 

Always good to tap and die the all holes in head and bolts. Or for that matter I do all areas that look like there is build up grease or foreign material.