62 water pump pulley
Just installed a 609 water pump and went to put the pulley back on and it hits the crank pulley. What diameter should the pulley be? I didn't see a number on the old one. They appear to line up ok, but touch. Need advise or suggestions.
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Re: 62 water pump pulley
John,
My original '62 340 hp has water pump pulley #3724816 GM stamped on the outside under the area that is covered with the fan installed. It is approx. 7 1/16 " in dia. and 2" deep from outside front edge to back of pulley edge.
Also, there is a spacer that fits between the inside of pulley and the water pump flange. Spacer is a circle with curved edges that sort of wraps around the water pump flange with four corresponding holes like the flange. Space is somewhere between 1/16" and 1/8" in thickness.
Hope this helps. Larry -
Re: 62 water pump pulley
Mine is just a 250 hp. I may have to try again tomorrow and see what fits.Comment
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Re: 62 water pump pulley
John--
Check the AIM and the judging manual. 250 hp and 340 hp are the same.Comment
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In Appreciation of John HinckleyComment
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Re: 62 water pump pulley
John The flange may have been pressed a little too far when the pump was rebuilt.Comment
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Re: 62 water pump pulley
Joe--
Contrary to GM documents,I've never found (in 34 years of studying them) anything but the 816 pulley on a 62--and have documented original-owner, high horsepower (and low horse) cars up to the 14,000 VIN range. I'm convinced they never used an idler pulley and never used a dual-groove pulley on a factory-built 62.Comment
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Re: 62 water pump pulley
Terry, I don't think the flange is the problem. They seem to line up ok (the valleys in the pulley and crankshaft pulley. It's the the two pullies that appear to be touching (lip-to-lip)?? I didn't get a chance to work on it today.Comment
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Re: 62 water pump pulley
John-----
Do you have the waterpump pulley actually bolted to the waterpump flange or is it just being supported by the pilot shaft? If it's the latter, it may "tip" enough to contact the crank pulley. When it's bolted up, though, this will correct itself.
If you have the correct crank and waterpump pullies, I don't see how you could end up with contact between them. Even if the engine had been excessively line-bored (unlikely), I still don't think it would change things enough to cause pulley contact.In Appreciation of John HinckleyComment
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Re: 62 water pump pulley
The pump is bolted and torqued to the block. Since I never took the shroud off when I removed, I took the fan blade off of the flange then the pulley, then the the pump. I am re-assembling in the same manner. Maybe I should have the whole assembly bolted together before placing over the pilot bolts and bolting to the block. Anybodys thoughts?Comment
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Re: 62 water pump pulley
John----
I don't see how the order of assembly should affect the final clearance between the pullies. The order of assembly might be important for ease of assembly but it should not affect issue under discussion here.
The distance between the waterpump shaft centerline and the centerline of the crankshaft is fixed and constant. It can only change SLIGHTLY due to line boring of the crankshaft bearing journals and, as I've previously mentioned, even if this occurred, I can't see enough resultant reduction in clearance to cause pulley contact.
Also, it should not matter what waterpump casting you use. All small block waterpump castings will produce an identical shaft centerline position relative to the block. Even considering manufacturing tolerances, I cannot see enough difference to cause the problem you describe.In Appreciation of John HinckleyComment
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Re: 62 water pump pulley
As best as I can measure, the crank pulley is 6 3/4 and the pump pulley is
7 1/8". Do I need to get a new pump pulley?Comment
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Re: 62 water pump pulley
John----
Your pulley dimensions sound correct to me. The waterpump shaft centerline-to-crank centerline dimension on a small block is 7.1". The radius of your waterpump pulley is 3.56"; the radius of your crank pulley is 3.375". The total of this is 6.935". So, there should be 0.165" clearance between the 2 pullies, as installed. Certainly, that's not a lot of clearance, but it should be sufficient.In Appreciation of John HinckleyComment
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Re: 62 water pump pulley
When finally installed, the two pullies will be very close to each other. But they shouldn't touch. Before they are bolted up, it may seem that they will touch because the clearance is so small. If one of the pullies is misaligned, because it is not fully seated, they will touch. But after you get both of them bolted up, you should be OK.Comment
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