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By Outlaw56 - 11 Years Ago
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I would like to enlarge a 5/8 inch hole in a billet aluminum pulley and pulley spacers to 3/4 inch. If I get a good quality 3/4" bit and enlarge the hole on a drill press, am I risking a centering issue with the pulley on the shaft? Is there one special drill bit that works better than another? Am I better off having a machine shop do it? This is the dual belt project on my Y blocks with using the double groove dampner with double groove alternator pulley and getting a water pump pulley that will work. I have a drill press.
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By steinauge - 11 Years Ago
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The 3\4" drill bit is going to give you a hole that is a few thousandths larger than the stated size.If that isnt a problem you will need to be very careful about center and be sure your pulley is secured in the drill press so that it cannot move! I usually do this sort of work in the lathe but I reckon it could be done in a good,stout drill press?
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By Outlaw56 - 11 Years Ago
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Do I need to buy a drill bit that is under 3/4"?
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By glrbird - 11 Years Ago
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Darrell
If you use an undersize drill and then Ream it to the size you need, it should work ( if the part DOES NOT MOVE in the drill press. You must have it centered, a last word indicator would be the best choice to center the hole on the press, You might save yourself time and money by using a machine shop to enlarge it for you.
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By MoonShadow - 11 Years Ago
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I've done this using a step drill and haven't had any problems. Each step sort of stops before cutting again. Chuck
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By charliemccraney - 11 Years Ago
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You should get it close enough with a drill press if you set it up carefully. You can use a 5/8" bit to line it up and then install a 3/4" bit to drill. You can also use the taper of the 3/4" drill to align it. Pull the bit down os it touches the pulley and turn it backwards a couple revolutions by hand to align it.
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By NoShortcuts - 11 Years Ago
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Enlisting a machine shop with an engine lathe to drill or bore the pulley hole undersize and then ream the hole to final size is the way I would approach this. Even if the machine shop only uses a three jaw chuck to hold the pulley, I'd have more confidence in getting the hole centered than depending on a reliable drill press set-up.
No keyway, Darrell?
Regards,
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By Outlaw56 - 11 Years Ago
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Charlie,
No keyway. This is the fan pulley not the dampner. The fan pully also includes a set of spacers which have to be enlarged from 5/8 to 3/4. Not sure I understand what you mean by "no keyway". I tend to think the machine shop is a good idea, but its not certian it will work until I can test it. Its like throwing a $100 bill (plus the cost of the machining) out on the crap table. Im already nervous about gambling the cost of the pulley and spacers, but then to add more to the cost using a maching shop to enlarge the whole just increases my loss if it dont work. The good news is if it works, I can at least let others know what components I have and what worked for me. If someone wants to double belt a dampner, water pump, and alternator, I will know what works (or does not work). Obviously double belting also opens up other windows for air compressor and power steering.
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By MoonShadow - 11 Years Ago
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It seems to me, a non anal type, that the center hole isn't that important. The pulley is drawn tight by the 4 bolts that are on a set diameter. I've used pulleys with oversize center holes and re-drilled some and never had a problem. At least not one that I could see. I would think if the center hole was a little off it would be quite apparent in the fan rotation. Anyway, that's my take on the problem. Not saying I'm right, just what I've seen. But again, I don't think like a machinist or engineer. Chuck
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By Hoosier Hurricane - 11 Years Ago
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Remember, the front spacer has to have a pilot to center the fan blade. If you just bore the spacer to 3/4 then you won't have that pilot. Unless your water pump has a fan mount included in the casting that you need, why not just put a 5/8 shaft water pump on it?
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By Outlaw56 - 11 Years Ago
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John,
I did not do a very good job of explaining "spacer". Its not the spacer between the blade and the pulley hub, its the spacer/s that may be needed to shim the pulley out a little to align with the dampner and alternator pulleys. I would definitely consider dropping down to the 5/8" hub if I knew what water pump to use. I would need one that has the same offset as the one I have now. Is there a difference between a car water pump and a truck water pump other than the 5/8 verses 3/4 shaft option?
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By Outlaw56 - 11 Years Ago
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Moon Shadow, I hear what your saying. Four bolts should hold the pulley if the hole for the shaft in the pulley is just a bit large. Makes perfectly good sense. Im always anal because no matter how hard I try, something is going to need to be done over. If I try to get it perfect, it cuts down my failures.
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By charliemccraney - 11 Years Ago
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Other than the shaft diameter, they pulley is a different depth. The car pulley is shallower if I remember right. That really would be the easiest way to go but if you already have the stuff for the truck pump, then it makes sense to stick to the plan.
At a glance, the light duty truck and standard car pumps will look the same so if you find a car pump and it looks like yours, it and a matching pulley will be a direct replacement..
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By Outlaw56 - 11 Years Ago
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I have a spare truck water pump. I will take with me to NAPA in the morning and compare to a car pump. I will let you know what I find out.
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By NoShortcuts - 11 Years Ago
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Oops! I didn't realize that the billet pulley and spacers were for a water pump.
I was thinking power steering pump or a blower motor... DUH!
A 3/4 inch drill bit or Chuck's suggestion of a uni-bit (?) will certainly do the job appropriately. Not a situation where even Charlie Brown would use a boring bar or reamer.
That said, I still would use a lathe to do the job. Drilling the pulley and spacers by a machine shop should not cost you much unless you arrive to have the job done wearing a fancy outfit and driving something flashy.
Let us know how you make-out, Darrell.  |
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By Outlaw56 - 11 Years Ago
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Well I reported to NAPA with a spare waterpump which matches the one on my 272. The guy opened the exchange asking of a Y block was a Chevy Engine. I asked him to start looking up 56-64 Ford Trucks with a 272 or 292. Nothing listed for a 292. I told him to try a 62 and bingo, he comes up not only with a water pump, but a water pump with a 5/8" shaft. I asked him if he was looking at a car. He responded no, a 1962 F-100 with a 272. I asked him if it was in stock. Nope, nearest one in Sacremento. Im in Montana. I asked him if it would be a big deal to order one to get it on the counter so I could compare it and take some measurements, (thinking it might be a perfect match with a 5/8" shaft). All the time this is going down, Im thinking......nothing available for a 64 but there is for a 62?
He responded to my question.....you would have to pay shipping. Ugh.
So, Im going to wait until I get my double pulley for the water pump and see how that lines up with the balancer. I thought the alternator double pulley and dampner double pulley lined up perfect. Then I remembered a previous post that hinted its pretty easy to think you have it square, but it could still be off. I put a carpenter square level on the surface of the dampner and sure enough, the alternator pulley is in 1/8"-3/16" too far in. It looks like I can shim it out behind the pulley far enough to make it square with the dampner. I want to use the dampner as the home base for everything else.
Once I get my double pulley for the water pump, Ill do some measuring and see if it looks like a little shimming behind the water pump pulley will bring it out to square. If it looks like it will work with a little shimming, then I will be back to enlarging the hole on the pulley and spacers from 5/8" to 3/4". My machine shop has a minimum of one hour and shop time is $60 per hour just for being in the shop.
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By Outlaw56 - 11 Years Ago
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Hoosier Hurricane (6/6/2014)
Remember, the front spacer has to have a pilot to center the fan blade. If you just bore the spacer to 3/4 then you won't have that pilot. Unless your water pump has a fan mount included in the casting that you need, why not just put a 5/8 shaft water pump on it? John, The spacer goes between the inside of the pulley and the mounting hub on the water pump shaft. Then the Fan spacer goes on, centers the fan, and bolts thru the fan blade, fan spacer pulley, pulley spacer and threads into the shaft hub. At least that what Im seeing. Otherwise, the pulley spacer would not move the pulley out to line up with the grooves on the dampner. Does that make sense or am I having an optical dilusion?
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By charliemccraney - 11 Years Ago
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That is such an antiquated policy with Napa. I don't usually bother going there for any of my truck parts just for that reason. Did you try any other stores?
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By Outlaw56 - 11 Years Ago
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No, its either NAPA or Orilley. There is a seasoned Y block guy at NAPA but he was off today and wont be back until Tuesday. Meanwhile I will stop by Orilley and see if they might have one in stock. The 62 Ford F-100 listing a stock 5/8" shaft really has me curious.
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By Ted - 11 Years Ago
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Outlaw56 (6/8/2014)
......The 62 Ford F-100 listing a stock 5/8" shaft really has me curious. The water pumps for the 1956 thru 1962 Y pickup engines use a 5/8” diameter shaft. For the 1963 & 1964 pickup 292 engines, the shaft size went to ¾”.
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By Outlaw56 - 11 Years Ago
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Thanks Ted, do the 56-62 water pumps have the same shaft hub off set as the 63 and 64?
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