Flathead Kohler valve guide clearance?

I need some wisdom on valve guides, please. I am still working on my Kohler L600 generator engine. It is an inline 4 cylinder flathead. When I got it, it had been sitting up in a garage for maybe 15 years. A couple of valves were stuck in the up position. I got all of them freed up and out. The 4 exhaust valves were eroded/pounded around the face where they seat, so I am replacing them. One of the intake valves was rusted, so I replaced it. I bought a Neway valve seat tool set to cut the 45 degree and 15 degree. The Neway set came with a guide for the tool, and it is .311 at the top of the taper. It is supposed to snug down into the valve guides. It only snugged into one guide, so I bought a .001 oversized tool, .312 at the top, and it snugged down into the rest of the guides. So, I think my guides are between .311 and .312, which is what the manual calls for when new. The manual does not give a maximum size before replacement is needed. The intake valve stems are .310 and the exhaust valves are .308. Reading on the internet, it seems that clearance for intake valves should be .001-.002, and exhaust valves should be .002-.004. If those numbers are correct, then my clearance is fine.

But, when I drop the valves into the guides, they sure feel loose. I have nearly zero experience with valve guides, so maybe I don't know what I am looking at.

Any words of wisdom would be greatly appreciated.

Can you guys help me?
 
The guides are probably worn a bit "eggshaped", and your mandrel tightens on the non-worn area, making it seem like there is less wear than there actually is.

On one hand, for a slow-turning "side valve" engine, it will probably run for years with no issues from the worn guides. On the other hand, if you are restoring it to "as new" you may want to replace the guide, if they are available.

If not, an automotive machine shop should be able to easily (and at low cost) bore out the old guides and press new aftermarket guides into them. They do stuff like that every day.
 
Another option to consider for a slow speed engine not expected to operate for hours and hours would be the old, poor-man's remedy, Knurling the guides (if you can find a tool or someone to do it for you).

Not recommended for a keeper expected to operate for long periods but probably acceptable for your generator.

Dean
 
Thanks. I was trying to avoid taking the whole thing to a machine shop. The generator is still attached. I could press out the old guides and replace them myself if I needed to. I would just have to buy a .311 reamer.
 
I have one of those units. The generator is also the starter on the one I have. It has not run since the ice storm we had in 2007. I'd love to get it running again but need a wiring diagram so I could wire up correctly
 
Hi Old. The starter is also integral to the generator on mine. I bought it for $80, now it looks like I will have about $800 more in it before it is over. It needed more stuff than I had hoped.
 
I paid $85 for the one I have at an auction. Brought it home and got it running and that was back in 2006 and used it during the ice storm we had here in Jan 2007. I did try to see if I could get it to start last summer but it would not even spin over. The 220 volt output is messed up also
 
I second Dean's idea of knurling the guides if you are doimy a budget rebuild. The knurling process shrinks the ID of the guide and the reamer tool resizes the guide to restore the proper clearance. I have used this process on a couple of engines, one that I put an additional 100k miles on and the valve guides were still good. The groove that is formed in the guide holds oil which lubes the valve stem.
 
I would knurl the guides, it is important that you regrind the seats after any work to the guides.
 
How much for new guides ? I usually just replace them if they are replaceable. If not replaceable knurling or rebushing them are options. B7 all thread and some nuts and stacks of spacers and washers you can pull them up and out if there is not room to drive them on down through. Make sure you measure the valve stems for wear at the upper edge of where they ride in the guides.
 

Install bronze valve guides . The valves will also operate cooler due to improved heat dissipation .
We had one of those in a twin cylinder 5Kw three phase with the built in starter .
Traded it as part of the deal on a 30Kw pto generator and never regretted it .
 
I think the valve guides are bronze now. I
found a letter O drill bit that is .316 and
it would not fit in any of the guides. A
5/16 .3125 would fit in the guides, but
without much wiggle. So, I think my guides
may be .001 worn, so I am going to run the
engine and see how it goes. Thanks for your
replies!
 

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