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Valve Corrosion and guide wear

BruceMe

BruceMe

Well Known Member
I boroscoped my engine for annual this weekend and it all looked fine except for one exhaust valve.

I like doing things myself. I have the cylinder wrenches, valve tools, and access to an arbor press, is this something I can do myself? Pull the jug, drop the valve, seat a new valve, and put it all back together?

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Thanks!
 
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How is the leak-down test? It does look like it has been hot, but may just be solved ( arrested) with a new rotator and "grinding" the valve/seat insitu. If that is the case the valve can be pulled through a spark plug hole and stem cleaned.

I am not sure about the details of this specific engine but standard practice is to have a relief up in the guide for the distance of lift to accommodate deposits.

https://www.youtube.com/watch?v=3lA_ZrKoWZ0 This may help visualize.

To your question - - maybe. Are you thinking replacing the valve guide too?
 
Pull the jug, and take it to a shop that does cylinders for a living.
Minimum is replacing that corroded valve. That should include checking the guide, and replacing as necessary. And, the seat should be ground in the process.
Replacing a guide, and grinding the seat is not something you want to do without the proper tools, fixtures, processes.
 
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OKAV8r said:
Pull the jug, and take it to a shop that does cylinders for living.
Minimum is replacing that corroded valve. That should include checking the guide, and replacing as necessary. And, the seat should be ground in the process.
Replacing a guide, and grinding the seat is not something you want to do without the proper tools, fixtures, processes.
Click to expand...

+1 for this option. Your phots are fantastic. What borescope do you have?
 
You will need a valve seat cutter and the appropriate pilot to go in the guide. I do this on my Bridgeport. Clean up valve face on the lathe. If you don't have this equipment handy its easier to have a cylinder shop do the work. Problem is, every shop in the known universe is backlogged.
 
rocketbob said:
You will need a valve seat cutter and the appropriate pilot to go in the guide. I do this on my Bridgeport. Clean up valve face on the lathe. If you don't have this equipment handy its easier to have a cylinder shop do the work. Problem is, every shop in the known universe is backlogged.
Click to expand...

I plan to do this this summer. Made a pilot for the COTS cutting stones (a copy of the souix pilot) and adapters for int and exh as well as pressing tools to remove the guides. But think a mill is necessary to ream the guides. Might get away with a drill press if you can properly square the table. Also plan to cut the valves on the lathe. Be prepared that you may need to go up a size on the guides and will need to ream accordingly (sold in .005 OD increments).
 
Are you sure it is corrosion and not deposits? I was under the belief that the Lyc exh valves were stainless.
 
lr172 said:
Are you sure it is corrosion and not deposits? I was under the belief that the Lyc exh valves were stainless.
Click to expand...

I will do the rope trick first and pull the stem through the sparkplug and look it over. You may be right.
 
I wouldn't pull a cylinder based on the pics I see. comps, wobble values, valve rotators check, pics look ok to an untrained eye. :eek:
 
Generally speaking (writing really…) I’d say that this is a a good example of today’s over information…
Look long enough at anything, and you will always find something wrong, looking suspicious, needing remedy.

In the meantime others just fly :D
 
Without compression data we don't know the full story.
I've seen many a stem and valve look like this one and not be defective.
I'm sure if compression was up to snuff I'd just fly it.
The pizza looks fine.
Art
 
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