Repaired power valve

How did you center bore and tap the end? A lathe I assume. I found 3 of mine pulled through and I need some for the weekend. My only chance of that is to fix them.
 
Actually I just used a combination square to find the center, center punched the hole and then checked it with a caliper. I drilled the hole with a small drill press, just made sure everything was level and square. Tapped the hole with a 5/16" hand tap and inserted a stainless bolt with permanent loctite. It took me about 1,1/2 hours to do it. I'm sure you could do it with a hand drill if you were careful but better if you have a drill press or even better with a lathe.
 
Marker said:
Actually I just used a combination square to find the center, center punched the hole and then checked it with a caliper. I drilled the hole with a small drill press, just made sure everything was level and square. Tapped the hole with a 5/16" hand tap and inserted a stainless bolt with permanent loctite. It took me about 1,1/2 hours to do it. I'm sure you could do it with a hand drill if you were careful but better if you have a drill press or even better with a lathe.
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How did you support the valve while you were drilling it? Also, did you also drill the hole for the cable and then put the slot in with a hacksaw or something?
 
I placed the valve in vice using a piece of cloth so I would'nt gouge it in any way, then I made sure the valve stem was level with the drill. I did this by placing a piece of round stock in the chuck and bringing it down beside the stem of the valve. it automaticaly runs level parrallel with the press, it's just the sides that you have to worry about. I can take pics of this if it would help. after the bolt was installed in the valve I then placed it on it's side making sure everything was level once again and drilled the hole through the bolt head and yes I made the slot with a hacksaw. the hacksaw was about ten thou bigger then the original slot but I don't think that matters too much, as long as the hole for the anchor is within tolorence.
 
Marker said:
pics of set up
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Ah, I see. Thanks a lot. One more question! It looks as though the head of the bolt is, well, no longer a bolt. Did you grind it down so its round? I'm going to attempt this tonight as I really need these things for the weekend. From what I can tell, the way you did it looks to have worked really well.
 
repaired PV

jaydaniels said:
Ah, I see. Thanks a lot. One more question! It looks as though the head of the bolt is, well, no longer a bolt. Did you grind it down so its round? I'm going to attempt this tonight as I really need these things for the weekend. From what I can tell, the way you did it looks to have worked really well.
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Yes I ground the head down and put permanent loctite on it, not sure if that will prevent it from backing out as mentioned by yamahasrx700.
 
it's a pin you would put in the side of the valve, through the bolt so it won't turn out, aka spring pin. it's a hollow pin, it has a slice right through the length of it, that way it shrinks a little when you tap into the drilled hole which would be just slightly smaller then the hole drilled. That's the best I can describe it for ya. It's called a roll pin because it's actually rolled into shape.
 
Good luck with loctite. The enviorment the power valve live in is fairly brutal. Even with the roll pin in the valve and bolt the bolt has play in it. I doubt Loctite will not last more then a couple seconds at full throttle. I used high stregth high temp bearing retaining Loctite and the bolt backed out. Thats why I pinned it.
 
Yamahasrx700 said:
I used high stregth high temp bearing retaining Loctite and the bolt backed out.
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Boy thats hard to believe,your threads must have been cut too loose, i
use the stuff allot in auto motive and heavy equipment applications
and if thats not brutal enough don't know what is...should hold

also the key is to let it cure 24hr's before the intended use, very importaint
 
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