Warped heads

Userj8670 · #1 02-23-2015, 03:15 AM

Seen a few posts where people have had a warped kohler head on their cubs. I had one myself that needed replaced last year on my k301. Was curious what causes this and can it be prevented?

J-Mech · #2 02-23-2015, 08:14 AM

The heads are aluminum. The heating up and cooling down causes them to warp. It can no more be prevented than you can prevent the piston rings from wearing out. There are things that help, like keeping the carb tuned so it isn't running lean (hot) and replacing the head gasket every 5 years or so..... but it can't be totally prevented.

By the way, they can be planed..... replacing them because they are warped is completely unnecessary.

olds45512 · #3 02-23-2015, 09:03 AM

I've only ever seen one warped head that was beyond repair, the engine had apparently ran so hot that the fins were deformed and laying over and when I put a straight edge on it I could stick an 1/8th inch drill bit between the head and the straight edge. That's an extreme case but as Jon mentioned don't run it lean and replace the head gasket every few years and it will minimize the warping.

boyesreef · #4 02-23-2015, 09:05 AM

always make sure you blow out your cooling fins after every mowing season as well. ive replaced engines on garden tractors all the way up to $30,000 Kubotas due to mowing chafe. when i got my 1450 cub it was fairly pack with chafe and mouse nest. i actually had to pull the air cleaner tube and pull a shopping bag worth out of the flywheel. then blew air in till it came out clean. THEN remove the muffler box and pull it out of there. i hate mieces to pieces.

charlie105 · #5 02-24-2015, 08:20 AM

I have found Cayenne pepper powder to be an effective temporary mouse repellant. Doesn't take much, but it does have to be reapplied if it gets damp. Makes the little buggers miserable. Just remember that it's there !

Userj8670 · #6 02-24-2015, 12:17 PM

Quote:

Originally Posted by J-Mech

The heads are aluminum. The heating up and cooling down causes them to warp. It can no more be prevented than you can prevent the piston rings from wearing out. There are things that help, like keeping the carb tuned so it isn't running lean (hot) and replacing the head gasket every 5 years or so..... but it can't be totally prevented.

By the way, they can be planed..... replacing them because they are warped is completely unnecessary.

Copy that! The dealer is who told me that it needed a new head when I brought it to them a few yrs ago for service. What's the best stuff to remove carbon these days?

cadzag72 · #7 02-24-2015, 08:06 PM

I believe elbow grease is the best product

Userj8670 · #8 02-25-2015, 03:00 PM

Quote:

Originally Posted by cadzag72

I believe elbow grease is the best product

I agree but I was thinking maybe some brake cleaner on a towel carefully rubbed on might help

red211 · #9 02-25-2015, 03:10 PM

I just pulled one off the new to me 128 this morning. I pulled the engine out to do the clutch, I was close so it hit the bench for a tin removal and blow job. Couldn't see any signs of head leaking and went back and forth but then popped it off. Was starting to leak so I guess that was a good move. Scraped with a wood shim, carefully with a thin paint scraper and very easy with a flat blade screwdriver in the tough spots. Kind of like a dentist reaching for that different torture device when the one he is using isn't tough enough! I used some brake clean after first scrape, then again rechecking progress. Dropped it off for a quick mill to make it nice and straight while I picked up a head gskt. Getting ready to put it back on after the block and piston are cleaned up.