Cutting down valves

Small Block Mopar Engine

  1. pittsburghracer

    pittsburghracer Well-Known Member

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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.
     
  2. rustycowll69

    rustycowll69 Well-Known Member

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    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.
     
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    • yellow rose

      yellow rose Doctor of Thinkology.

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      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.
       
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      • yellow rose

        yellow rose Doctor of Thinkology.

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        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.
         
      • perfacar

        perfacar Well-Known Member

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        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.
         
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        • yellow rose

          yellow rose Doctor of Thinkology.

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

          How are you Perf? Did you move??
           
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          • pittsburghracer

            pittsburghracer Well-Known Member

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            Thanks guys. Lots of great ideas. I couldn’t see scraping them.
             
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            • RustyRatRod

              RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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              I've done it with some 2.08 valves. Went from 2.08 to 2.02. I used a Sioux valve grinder.
               
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              • MOPAROFFICIAL

                MOPAROFFICIAL Well-Known Member

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                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.
                 
              • toolmanmike

                toolmanmike FABO Staff Staff Member FABO Gold Member

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                Yep, grind them with a rock! .006 is only .003 from each side. LOL
                 
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                • yellow rose

                  yellow rose Doctor of Thinkology.

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                  I think you mean .060 and .030 but we get the cut of your jib.
                   
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                  • pittsburghracer

                    pittsburghracer Well-Known Member

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                    Damn zeros and decimal points. Lol
                     
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                    • Mopar Sam

                      Mopar Sam Well Fed Member

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                      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.
                       
                    • yellow rose

                      yellow rose Doctor of Thinkology.

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                      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.
                       
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                      • RustyRatRod

                        RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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                        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.
                         
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                        • Mopar Sam

                          Mopar Sam Well Fed Member

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                          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.
                           
                        • pittsburghracer

                          pittsburghracer Well-Known Member

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                          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
                           
                        • RustyRatRod

                          RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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                          B3 Racing Engines can do it. Mike is awesome.
                           
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                          • Max1196

                            Max1196 Well-Known Member

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                            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.
                            100_2482.JPG 100_2483.JPG
                             
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                            • pishta

                              pishta I know I'm right....

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                              Only Yellow Rose can say this! :thumbsup:

                              "One man's junk..."
                               
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                              • pittsburghracer

                                pittsburghracer Well-Known Member

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                                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
                                 
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                                • yellow rose

                                  yellow rose Doctor of Thinkology.

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                                  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!!!
                                   
                                • pittsburghracer

                                  pittsburghracer Well-Known Member

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                                  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.
                                   
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                                  • Wyrmrider

                                    Wyrmrider Well-Known Member

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                                    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
                                     
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                                    • rustycowll69

                                      rustycowll69 Well-Known Member

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                                      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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