Cutting down valves

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pittsburghracer

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while restocking new and used valves I saved a box full of valves that were worn out. Has anyone ever used their lathe to say cut down a worn out 2.08 valve and cut it down to a usable 2.05 or a 2.05 to a 2.02 valve. Just thinking it wouldn’t be that hard to do and I hate scraping something still usable.
 
I've never done it on a lathe, but I think it would be much better accomplished on a valve refacing machine. I think the material valves are made of would be more easily ground, than cut with a tool.
 
while restocking new and used valves I saved a box full of valves that were worn out. Has anyone ever used their lathe to say cut down a worn out 2.08 valve and cut it down to a usable 2.05 or a 2.05 to a 2.02 valve. Just thinking it wouldn’t be that hard to do and I hate scraping something still usable.


Easy peesey.

Take a cast iron valve guide and cut a slit in it with a hack saw or similar tool along its length.

Use that to grab the valve. Slide it in the Chuck and use as rigid tooling as you have and use a tool bit (I love indexable carbide!!!) for stainless.

I never trust the dials on any lathe. I set up an mag base dial indicator on the cross slide and find my zero by just touching off of the valve.

Then I take off whatever I need. Say a 2.100 to 2.05 is .050 (I love simple math cuz I ain't too bright) and turn the valve until I take my .050 and then zero the indicator again. Now it's just swapping valves, Turing to zero and repeating.

I have some 2.100 and 1.600 5/16 stem valves out there I may turn to 2.05 and 1.50 and use them in my W2 junk build.

BTW...I know you get the procedure but I wanted to lay it out for guys who may not know how to do it quick and easy.
 
I've never done it on a lathe, but I think it would be much better accomplished on a valve refacing machine. I think the material valves are made of would be more easily ground, than cut with a tool.


The only issue with this is the heat from the stone and stone wear.

If you are using a water based coolant (I'd much rather use a WB coolant than oil any time I can) you only have to deal with stone wear and on 16 valves with truing you'll pretty much use up most of a grinding stone right there.
 
better method, is use a 5 C collet in lathe. doesn't hurt stem. you can cut down head diameters and cut new face on valve in lathe. then face on a valve facing machine. done many this way, less work is required.
 
better method, is use a 5 C collet in lathe. doesn't hurt stem. you can cut down head diameters and cut new face on valve in lathe. then face on a valve facing machine. done many this way, less work is required.


That's the best way but I don't have a collet set up for either lathe.

How are you Perf? Did you move??
 
I've done it with some 2.08 valves. Went from 2.08 to 2.02. I used a Sioux valve grinder.
 
Done it, valve machine. The backside of the head angle may change.. but just back cut it. Diamond stone cuts like butter, never get any part of you near them...they lay you open so quick.
Good use for marginless used valves, as long as the stems aren't worn too bad and even then they could work for dragstrip season with some good seals.
Finger mic them, jk.
 
Common practice around here with the Kohler garden tractor pullers is to cut down SBC valves, cut them for length too. The square oil seal groove is used for the keepers.
 
Common practice around here with the Kohler garden tractor pullers is to cut down SBC valves, cut them for length too. The square oil seal groove is used for the keepers.


You can also cut the keeper grooves in the lathe but you will need to use lash caps if you shorten the valve stem past the harden tip.
 
Damn zeros and decimal points. Lol

Reminds me of a smartass comment that got me sent to the office once in school. Our math teacher was arguing with me that zeros were just that zeros. They had no mathematical value. I quickly said "what if your tiny paycheck had a few more zeros behind it this week?" The class totally erupted. I quickly found myself in very familiar territory sittin in the office. But I was right, dammit. Even the Principal busted out laughing.
 
You can also cut the keeper grooves in the lathe but you will need to use lash caps if you shorten the valve stem past the harden tip.

The length is just about right with the stock seal groove location on the sbc valves, of course if the valves don't have them you must cut them. In that case I prefer to cut down magnum valves for their 5/16 stem. Then use after market kohler retainers which are 5/16.
I just had one in here for an over bore, that was ported to the point that most of the intake port was made out of Belzona, no kidding.
So, no do not scrap valves, you never know who can use them.
 
I’m not a machinist and never will be this late in life but I’m betting anyone with those skills could really zero in on getting your rocker geometry spot on
 
I’m not a machinist and never will be this late in life but I’m betting anyone with those skills could really zero in on getting your rocker geometry spot on

B3 Racing Engines can do it. Mike is awesome.
 
Just narrowed up some new 2.15 to fit these 428cj heads that had been valve jobbed to death, the 2.09 @ 45* is only to be had by Edelbrock (and is costly), but we still needed a bigger diameter valve to salvage the seated height, Mopar to the rescue.
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100_2483.JPG
 
Yes I’ve had one of his kits on my Edelbrock heads. The only thing I didn’t like was grinding on my 300.00 Harlan Sharp shafts


You mean to open up the mounting holes???

If you had them and wanted to be lazy ( I have them but I'm going to use them so I did what I think you did) you can use the W2 offset shafts and just redrill the oil feed holes.

Which now that I type that is a PITA. 6 of one, half dozen of the other I guess!!!
 
You mean to open up the mounting holes???

If you had them and wanted to be lazy ( I have them but I'm going to use them so I did what I think you did) you can use the W2 offset shafts and just redrill the oil feed holes.

Which now that I type that is a PITA. 6 of one, half dozen of the other I guess!!!



Mine worked out good elongating the mounting holes like you said. Those rockers ran in the 9.40’s on my 408 with zero issues but I didn’t really like doing that to my shafts. The kit only gave me so much room so sooner or later the grinder gotta get a workout.
 
I do it all the time when converting to 30 degree seats
but first I od hone the stems to see if they are worn, belled, bowed etc
 
I don't know about saving all valves, though. Valve stems can wear like an hourglass and that makes them hard to get an accurate and consistent guide to stem clearance. Unless you run positive stem seals, you are losing vacuum to too wide of clearances.
 
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