How to chuck up engine valve and turn down stem .010" by grinding...
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  1. #1
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    Default How to chuck up engine valve and turn down stem .010" by grinding...

    Im dealing with a set of used rare valves that can be reused IF,,,the stems are turned down slightly, maybe .010-.015" via grinding.
    I get chucking up the head but how to support the tip end..?
    Either drilling a centering hole or putting it in a "cupped" end I've heard.
    I've got a little knowledge on this...only enough to get myself in trouble.
    Any ideas on how its really done?
    OR...someone whos already providing this service?
    Thanks

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    If you have equipment, no problem. Lathe and tool post grinder at least. cup both ends, grind area from beneath the head to retainer groove, to tolerance dimension. Grind the entire set. chuck in 4 jaw and grind from retainer groove to end.

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    valves can be centerless ground K line sold a machine to do this . K line also sell a system to machine worn out valve guides ~.030" oversize and sleeve with thin wall rolled with dog leg in it's length out of phosphor bronze. These are sized by ball broaching which closes any visible gap line . It is very reasonably priced .

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    I would grind them in a universal ,grip the head in a chuck,and put as many spring steadies on the stem as will fit....unless they are unusually long.......Ive found that a number of old valves were quite soft on the stems ,and easily lathe turned....Indian Chief ,IIRC,was actually a cast iron head welded to a soft steel stem.....Although ,my advice if the valves have cotter holes,ditch them and make some new ones with grooves for conventional collets.Although ,a broken valve stem cant do damage in a flathead,usually.

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    Might be easier to ream the guides to fit the valves? Common job in any automotive machine shop. Trues the guide as well. Win, win!

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    Several of the suggestions mentioned here should work IF you are sure they are not sodium filled. In that case I'd think very carefully before proceeding.

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    These are valves from 1927...no sodium.
    Thes stems in the middle area are really worn..the tip end and right above the head are the stock dimension of .437 so the tip and the worn area on the stems are what need to be reduced in diam. Of course the guides will be drilled/reamed out to accept new liners.
    I can find modern intake valves that will work as replacements after the stems are trimmed to length, new grooves cut but then I but new spring retainers and clips to fit the totally oddball size springs (no existing replacement there) Problem is, no exhaust valves exist that can be modified to fit.
    Also, not enough meat in the head to put in seats.
    So...if I can get away with just turning down the stem diam, and putting in new guides, I can reuse the original retainers and clips.

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    Long time since I did automotive work, we used to have a catalog Federal Mogul maybe? with all sizes of engine valves, it was not uncommon for us to order valves to modify to fit. I've only seen 1 of those K Line centerless grinders, it was in a large engine reman shop, 40 something years ago.

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    Centerless plunge seems easiest to me.
    How about a Dedtru which is a kind of a centerless surface grinder?
    Bob

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    Quote Originally Posted by CarbideBob View Post
    How about a Dedtru which is a kind of a centerless surface grinder?
    Too sensible.

    I'd suggest finding a Landis valve grinder. Rare as hen's teeth but then you could go into production and make thousands of these eonomically. You'll be rich, rich, I say !

    Okay, dedtru it is. Good idear, Bob. Or maybe find a shop with one of those little Royal Master centerless guys ?

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    I have done this a couple times for old motorcycles, 1913-1914 Thors. I used new valves, Pontiac 428 was closest fit. The retainer ends are much harder than the stem section. In this case the ends needed to be threaded, Grinding the stems was done in a CG, but could be done with a TP grinder.
    Although the valves used were intakes, and used in the place of the exhaust valve. This is a 750cc engine putting out 8-9 hp, I doubt they were over taxed in this application. They lasted from NY to San Diego in the last cannonball run, about 3200 miles.

    You can buy a cup center easy enough, not that pricey. Be sure to check for burrs at the very end of the valve, as the smallest burr will offset the valve tip.
    If the stem is good on the donor valve, I would open up the guide rather than grind the stem.

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    Manley can make you custom valves. Not sure what your budget is.

    Manley Performance
    http://manleyperformance.com/dl/custom_valves.pdf


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