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| | | | Joined: Nov 2010 Posts: 304 Shop Shark | | Shop Shark Joined: Nov 2010 Posts: 304 | I have a 1959 235 car engine in my 52 3100. It has a 216 water pump w/adaptor and I believe a 5/8 pulley. It has a 12 volt gen. with a 3/8 pulley.And the crankshaft pulley looks to be a 5/8. I read of everyone changing the crank pulley often on this site, but it seems to me that I would need to change the generator pulley to get em all to match. I am selling this truck this spring when it is done but I want it to be "right". What should I change or should I even worry about it? It's ran fine this way. I've read about water pump speed not being right with the wrong pulleys but if no damage to anything, who cares? Seems like u need to put on a lot of miles to do any damage. Very few people are going to put on high milage numbers. Some, but very few. Just wondering what the best course of action, if any, would be?
'52 3100 "once a Marine, always a Marine!!
| | | | | Joined: Aug 2011 Posts: 835 Shop Shark | | Shop Shark Joined: Aug 2011 Posts: 835 | Sounds like the generator would be the easiest to change, but I'm not familiar with your generator. Speed is going to be a function of pulley diameter, both the driver at the crank and the driven pulley at the water pump. So assuming the crank pulley is original, if the pulley at the water pump is the same diameter as the original 235 water pump, it will be turning at the same speed as the 235 pump.
Anyway, it is a pretty easy math problem to find out what speed the water pump will be turning for any given RPM of the engine.
If you mark a place on each pulley, and turn the engine over one revolution, make note of how many times the water pump pully rotates or what fraction of a rotation. You can use an old fashion protractor to help you out. Then you will have a ratio in degrees. So as an example, if the crank turns 360 degrees and drives the water pump 720 degrees this gives you a ratio of 1 to 2. So if your engine is turning at 1000 RPM the water pump will be turning at 2000 RPM. If the crank turns 360 and the waterpump turns 180, then you have a ratio of 1 to .5. So if your engine is turning at 1000 RPM, the Water pump will turn at 500 RPM.
Just a simple example.
Kurt | | | | | Joined: Jan 2001 Posts: 5,337 'Bolter | | 'Bolter Joined: Jan 2001 Posts: 5,337 | It has a 216 water pump w/adapter and I believe a 5/8 pulley. It has a 12 volt gen. with a 3/8 pulley.And the crankshaft pulley looks to be a 5/8. If the balancer and water pump are 5/8", then it makes sense to change the gen pulley to match.
See the USA in your vintage Chevrolet! My Blog | | | | | Joined: Nov 2007 Posts: 11 New Guy | | New Guy Joined: Nov 2007 Posts: 11 | I bought a NOS 5/8" generator pulley on eBay a couple of months ago for around $20 to make the change on mine. They do come up relatively often. | | |
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