M12 head removal

[CD Long Jr 106]

I just wanna say you guys made a believer outta me! Look at the head bolts, they have Liquid wrench the entire length. That spray, hammer every time you walk by a wait a few days really works! Head bolts all seemed to be the same tightness. 2 whacks with the heel of my hand and they came loose. Put a pick under the head gasket & it popped right off. Exhaust valve has a lot of debris around it. Cylinder walls are smooth, no nicks or gouges. The mule pulley guard nut came off with the same technic. Pulleys spin freely. I don't understand why the belt wouldn't come thru them. Haven't tried the tension adjuster yet. Found the regulator mounting bolts are loose. 

[oliver2-44 11,132]

Keep up the good revival/maintenance on that old horse

[Handy Don 15,527]

Nothing unusual jumping out at me from those images. Keep on going!
Good to see no erosion of the head or piston near the exhaust valve, too. Lotsa life left in that engine. 

Note the “fire ring” of metal on the inner circumference of the head gasket. Ideally, your replacement should have the same feature as this makes for the longest-lasting seal. 

[ebinmaine 76,356]

1 hour ago, CD Long Jr said:

made a believer outta me! Look at the head bolts, they have Liquid wrench the entire length. That spray, hammer every time you walk by a wait a few days really works! Head bolts

 

As I said in another post I've been using that - amongst other proven products  - for years. 

 

 

Remember to replace the head bolts with new Grade 8 when reassembling. 

 

 

 

One other rusty bolt removal trick. 

TIGHTEN the bolt just a tiny bit. 

Then loosen. 

Repeat multiple times going a little more each time. 

 

[gwest_ca-(File Mod) 11,909]

That last picture is likely the low oil relay. The regulator should be in the blower housing over the flywheel.

[CD Long Jr 106]

1 hour ago, Handy Don said:

Nothing unusual jumping out at me from those images. Keep on going!
Good to see no erosion of the head or piston near the exhaust valve, too. Lotsa life left in that engine. 

Note the “fire ring” of metal on the inner circumference of the head gasket. Ideally, your replacement should have the same feature as this makes for the longest-lasting seal. 

I don't remember who, but one comment said to get a steel head asket.

[CD Long Jr 106]

22 minutes ago, gwest_ca said:

That last picture is likely the low oil relay. The regulator should be in the blower housing over the flywheel.

Yes sir, it's a relay. My mistake. 

[CD Long Jr 106]

Finished the head clean up. Found a use for the PB Blaster. Seems to cut carbon pretty good. Sprayed the head, waited 30 minutes and hit it with the Dremel using SS brushes. 

[peter lena 9,633]

@CD Long Jr  good going on that mr long ! totally agree on the exposed condition , would take advantage of that  , with  that rislone , zinc  varnish cutting  action , enhance that , and helps maintain clean / clear  rings , think  I  would start it off  with a  10-30  shell rotella, for a lubrication  heating transition , for initial engine wake up . get some  time on it  , would bet that engine will be  happy . would also  change out that  rubber hose fuel set up , probably  totally  broken down , the more of it you  change out , the better . also a tank cleaning  , remove the  tank  lower fuel valve , replace it ,  like a filter  just after  fuel valve ,and another  close to carb  . you are doing  very good , your not crazy , we are , pete   

[Handy Don 15,527]

1 hour ago, CD Long Jr said:

I don't remember who, but one comment said to get a steel head asket.

The fire ring and metal-clad gasket is what the commenter meant. There is gasket material as a middle layer between the metal outer layers. 

[ri702bill 10,885]

What I see is the engine is worn but not worn out. As Don said, there is plenty of good life left in it. The "clean" side of the piston top is common, tends to run a little cooler than the exhaust side. The clean ring does not go completely around the top of the piston - that's good. Rings are somewhat worn but doing their job. Turn the engine over by hand to where the exhaust valve is the highest off the seat. Inspect & clean the valve face & seat. Severe pitting or any cracks require a partial teardown...

The metal fire ring is found on the OE head gasket - newer versions do not have it....

 

[CD Long Jr 106]

2 minutes ago, ri702bill said:

What I see is the engine is worn but not worn out. As Don said, there is plenty of good life left in it. The "clean" side of the piston top is common, tends to run a little cooler than the exhaust side. The clean ring does not go completely around the top of the piston - that's good. Rings are somewhat worn but doing their job. Turn the engine over by hand to where the exhaust valve is the highest off the seat. Inspect & clean the valve face & seat. Severe pitting or any cracks require a partial teardown...

The metal fire ring is found on the OE head gasket - newer versions do not have it....

 

Will do. Thank you. More before & after pics of the valves tomorrow.

[8ntruck 8,449]

@ri702bill  Does your description of the appearance apply, in general, to all small F head engines?

 

I've got a KT19 and a late 60's 10 horse B&S that I am planning on doing some work on later this spring.

[ri702bill 10,885]

For the horizontal shaft versions, yes.

Vertical shaft models have similar, but not identical issues. I ruined a 6.75 HP Tecumseh LEV by not decarboning it. A large chunk of loose carbon fell to the bottom - the cylinder wall - and scored it so badly it had almost no compression...

[kpinnc 16,461]

Looks great so far to me. You've got a solid machine and it looks like you are doing everything right. 

 

Keep it up and this tractor will last another 30+ years! 

[WHX?? 53,596]

19 hours ago, Handy Don said:

Note the “fire ring” of metal on the inner circumference of the head gasket.

 

15 hours ago, ri702bill said:

The metal fire ring is found on the OE head gasket

Yes and I have yet to find those gaskets in the 8 HP flavor. Big blocks most all aftermarket ones ... like Stens ... have it.

 

I would glass the head before putting it back on. 

[8ntruck 8,449]

14 hours ago, ri702bill said:

For the horizontal shaft versions, yes.

Vertical shaft models have similar, but not identical issues. I ruined a 6.75 HP Tecumseh LEV by not decarboning it. A large chunk of loose carbon fell to the bottom - the cylinder wall - and scored it so badly it had almost no compression...

Ah.  The KT19 has horizontally opposed cylinders, so it would be more like a vertical shaft engine.

 

Guess I'll move that one ahead of the 10 hp B&S in the work list.