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  #1  
Old 12-10-2018, 08:29 PM
scattermaster scattermaster is offline
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Default valve rework questions

Hey guys,
'98 Ranger, 3.0-2wd-manual
204K miles.
Started blowing nasty brown stuff out of the coolant tank. Pulled the thermostat and ran it. Looking into the radiator, constantly getting a lot of bubbles. Thinking I probably have head gasket issues I pulled it apart.
Yep gaskets looked pretty bad.
So, while the heads are off I decided to pull the valves and check things out. Intake valves all look OK considering the mileage. The exhaust valves all looked pretty bad. The sealing surface was pitted pretty bad along with the usual build up.
My question is, how re-workable are they?
I have my own lathe so I decided to find out. I cleaned them up on the wire wheel first then re-cut the valves on the lathe until the pits were gone. After that I lapped them to the seats and put them back in.
Do you think they will hold up?
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  #2  
Old 12-11-2018, 05:53 AM
tomboy tomboy is offline
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Default Re: valve rework questions

How thin were the edge of the valves after you cut them, there's a limit, and what about the seats, they need to be ground and trued up also.
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  #3  
Old 12-11-2018, 02:40 PM
dvrich dvrich is offline
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Default Re: valve rework questions

At 204,000 miles, I would have done a complete rebuild.
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  #4  
Old 12-11-2018, 06:09 PM
scattermaster scattermaster is offline
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Default Re: valve rework questions

The truck is a "spare" that I don't use very often. This year I've already put a clutch and a new AC compressor/hoses and a water pump. Feelin tired of spending money and time on it. The truck was running OK. If it runs a little better with more compression I'll consider that a bonus!
Hopefully I got rid of the air bubbles in the coolant issue.
Might look at a rebuild in a few years, when I retire and can take my time.
Anyway, the thing with the valves is kind of an experiment.
I'll learn from it. If it work out well, I know I can remachine valves, and if it fails, I'll know it's a bad idea!

----------

Quote:
Originally Posted by tomboy View Post
How thin were the edge of the valves after you cut them, there's a limit, and what about the seats, they need to be ground and trued up also.
I didn't measure the edges but it didn't change very much. I think they still look good.
The seats didn't look like the valves. They looked surprisingly good.
I lapped until I had solid grey all the way around and uniform thickness.
Crossing my fingers but it's going back together.
I'll let ya'll know how it goes...
:-)
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  #5  
Old 12-16-2018, 10:44 AM
scattermaster scattermaster is offline
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Default Re: valve rework questions

Hey guys,
My engine is running pretty good now. I think the re machined valves re working perfectly.
It stopped blowing the nasty brown crap into teh radiator. I'm doing a vinegar flush now. Hope it helps clean up the coolant system.
I do have a CEL now. The codes are P0071 and P0074 which I think are related to the intake charge sensor. I haven't tested it yet. I don't know what the specs are but it seems pretty coincidental that I was good before I worked on it and now it's bad...
I
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  #6  
Old 12-16-2018, 12:05 PM
Dirtman Dirtman is offline
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Default Re: valve rework questions

Id be curious to see your wet/dry compression numbers. Seats and valves are generally cut together and lapping is just a finishing step. Not knocking you or anything just mechanical curiousity how well the valve cut only is sealing.
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  #7  
Old 12-16-2018, 05:22 PM
scattermaster scattermaster is offline
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Default Re: valve rework questions

Quote:
Originally Posted by Dirtman View Post
Id be curious to see your wet/dry compression numbers. Seats and valves are generally cut together and lapping is just a finishing step. Not knocking you or anything just mechanical curiousity how well the valve cut only is sealing.
I need to do a compression test, dry and wet like you said.
I'm curious too,but mostly about the rings.
After recutting the valves, I lapped them on the seats until there is a solid grey band all the way around the seats. So in effect the seats got lapped too.
I'm pretty confident that they are sealing as good as they ever have.
Well, crossing my fingers at least.
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