127 with K301 Warped Head

[proctoidpaul]

I've got a 127 I received from my Dad. It runs, but after about 20 minutes dies with a single "puff" and then won't restart until it cools.

Knowing that my Dad had new head gasket put on it previously, I pulled the head and with a straight edge have confirmed a very warped head on the front (muffler) side.

I've got new head and gasket coming. Engine fins/shrouds/screens are all clear. I know we had another cub as a kid (10 HP version) that also ended up with head issues.

Is there any prudence at trying to add additional ventilation "under the hood"? I was thinking of trying to add a small car radiator fan or something, if I could figure it out. Or is this just the eventual weak-point of these (otherwise wonderful) machines?

I've also read the tip in another thread about running the engine a little richer.

Any insight greatly appreciated.

Paul

[ironman]

You should read this....
It's in the Technical Library under (drum roll please)....
Tractors/Kohler Head Gasket Relplacement...

https://www.onlycubcadets.net/forum/...ead.php?t=5656

[finsruskw]

Are the fins on the flywheel also clean??
You will have to remove the blower housing to see.
If the fins are packed with mouse house mat'ls that may be an issue.
The heads can be resurfaced on a piece of sandpaper and glass. Make sure you use a "fire ring" gasket and torque the bolts in the proper sequence.

[dale c.]

is it the old style head with the tall boss the bolts go through ? if it is they tend to lay over sideways and won't stay torqued . the newer heads have a low boss and use shorter bolts

[Merk]

The best thing you can do is replace the head bolts with Kohler or grade 8 bolts.
Make sure the top of the block is flat too.

[proctoidpaul]

Thanks for all the tips! Engine is back together and so far running great. I did replace 4 of the head bolts with new Grade 8 bolts, because the new head I got was a slightly different design. All the of the bolts came up to the top of the fins, instead of being recessed. It also had a slightly different spark plug position, so I had to rework the shrouding to account for the position and then replace the now "missing" area of shrouding around the original spark plug position. Final modificaiton was that where the gas tank frame mounts, I had to put on one set of head "nuts" first and then slide the tank mount on with a seccond set of nuts on top. This put the tank mount only slightly higher than the original position, but was within tolerance of the mounting holes that wrap around the "driver" side of the shroud.

I confirmed all fins were present and clean, as recommended.

The old head was just way too warped to consider resurfacing it. The block looked great, and there was very little carbon (likely since it hadn't been that long since the gasket had been replaced.

Net, I'm going to assume, as stated in one of the posts, that this is just a design weakness with the aluminum head/cast block. I only plan on using the tractor for light duty going forward, so hopefully this will provide plenty of life for my remaining needs.

I do have a couple other questions on other topics, but will post those in other proper forums.

Thanks again, great resources. When I get a chance I'll try to post a couple pictures after my required modifications for the new head (which came from eBay).

Paul

[proctoidpaul]

Here are pics after installing the slightly different head.

Differences are:
-Longer bolts required (not recessed)
-Different spark plug position
-Nuts under and over the tank mount.