Glad you are making progress C!
Ok, 1st update after initial "test" drive
Took the car for a 10-12 mile drive to get fuel about 2pm today. It was 109* out & HOT !! In town driving & stop n' go traffic with the AC on the entire time. The car reached 210*, but didn't climb any higher So far, I'm encouraged with the improvement.
As an added bonus, my digital volt gauge used to drop into the 11s at a stoplight. With the addition of the smaller water pump pulley, the alternator spins faster & stays in the 14 volt range...WIN - WIN
Glad that changing over to a smaller water pump pulley has helped with the cooling! With a 109* ambient temp running at 210* is doing pretty good!
But, about that alternator. If you didn't change the size of the crank pulley or the alternator pulley, you didn't change the alternator speed. It doesn't matter what the size of the other driven pulleys are or how many other driven pulleys are in the system, the speed is determined by the driving pulley and the pulley being driven. So, all that matters for the alternator speed is the size of the crank pulley and the size of the alternator pulley.
--------this !^^^^^^^^^^^^^^^^^^^^^^Glad that changing over to a smaller water pump pulley has helped with the cooling! With a 109* ambient temp running at 210* is doing pretty good!
But, about that alternator. If you didn't change the size of the crank pulley or the alternator pulley, you didn't change the alternator speed. It doesn't matter what the size of the other driven pulleys are or how many other driven pulleys are in the system, the speed is determined by the driving pulley and the pulley being driven. So, all that matters for the alternator speed is the size of the crank pulley and the size of the alternator pulley.
...I doubt I'll drive it much in weather like this, but I figured why not test it in the most extreme conditions...
Exactly.
But, if you want to, you can drive it in the hottest weather the metro area can dish out!
+I will throw in here. I drove my 505" fish yesterday , 96* w/ humidity. The hottest I have driven the car so far. Running a 17", 7 blade alum. fan that has a steel center( factory). A new flow cooler water pump, w/ a new jaguar 2765 clutch.. It ran at 195 for a while, then 198, the 202, held for a while, then in town went to 210 and held steady, got out on the 4 lane coming home started showing of a little, "really wanting to see how hot it would get w/ the new set up." It went to 216 and stayed there till I got home, and went to 220 after shut down. Not too worried about it now, but I think the shroud is too thick, as the clutch puts the fan almost inside the shroud, w/ only about 1/2" sticking out the engine side. I think the 10,000 rpm flex fan , belt driven would fit the shroud better and make it run a cooler (I think) , but I `ve been switching stuff around , experimenting so much, I`m tired of fooling w/ the dam pump bolts. The jaguar clutch to pump bolts were a *****, ended up using studs, getting all the nuts w/ lockwashers started before tightening any down, even had to file a spot on the clutch hub in one spot for a little more clearance to start the nuts! Anyone kick in here w/ thoughts ???You mentioned that you have a clutch fan. Are you sure that it is working PROPERLY ???
Yote
+I will throw in here. I drove my 505" fish yesterday , 96* w/ humidity. The hottest I have driven the car so far. Running a 17", 7 blade alum. fan that has a steel center( factory). A new flow cooler water pump, w/ a new jaguar 2765 clutch.. It ran at 195 for a while, then 198, the 202, held for a while, then in town went to 210 and held steady, got out on the 4 lane coming home started showing of a little, "really wanting to see how hot it would get w/ the new set up." It went to 216 and stayed there till I got home, and went to 220 after shut down. Not too worried about it now, but I think the shroud is too thick, as the clutch puts the fan almost inside the shroud, w/ only about 1/2" sticking out the engine side. I think the 10,000 rpm flex fan , belt driven would fit the shroud better and make it run a cooler (I think) , but I `ve been switching stuff around , experimenting so much, I`m tired of fooling w/ the dam pump bolts. The jaguar clutch to pump bolts were a *****, ended up using studs, getting all the nuts w/ lockwashers started before tightening any down, even had to file a spot on the clutch hub in one spot for a little more clearance to start the nuts! Anyone kick in here w/ thoughts ???
If your temperature was still climbing while at speed out on a 4 lane highway the fan isn’t the issue. At highway speeds the clutch shouldn’t even be spinning the fan, so the shroud shouldn’t be the issue. The fan should be about 1” inside the shroud, but being a little off will only be a small efficiency change, not a drastic problem.
So if your temps are climbing at speed usually the issue is that the radiator is on the small side (or plugged up), or you may have a circulation problem. The smaller water pump pulley would speed up the fan (when it’s spinning), but it would also spin the pump faster too. Which may help with the sustained speed temps.
Don’t really mean to disagree with others experiences but my extremely overheating stock 340 barely gets into normal operating temperature. All I did was to replace the thermostat and fan clutch.
Yote
I said I didn’t disagree with others. All I related was my experience. My problem was simplistic. Usually the best approach is to start with the simplest, easiest and cheapest possible solution to a problem until those possibilities are eliminated.
Yote
I know on a big block with A/C the water pump is pretty small. I imangine the same would apply for a small block.
Would overdiving high volume water pump cause cavitation or any other issues?
I doubt that it would be a major problem. Obviously it's possible, but unless the engine is going to be consistently operated at high rpm I don't think I'd spend too much time worrying about it. I run a HV water pump on my 340 and the March pulleys on it have a ratio of ~1.04:1, so, that's almost 10% higher than the factory ratio for an HV pump. I haven't had any issues with cooling on my car at all, and it's a 9.8:1, .060" over, 340 with iron heads and 3.55 gears that I frequently run up and down the freeway at a constant 3,500 rpm. Granted 10% overdriven isn't 35% like it would be with the factory small block pulleys.
Looking at the factory numbers and ratio's, and working off of the advertised gains for a HV pump (20-30%) it looks to me like what they were doing was keeping the volume of water moved by the pump close to the same for the two systems. Which probably means they had done the cooling calculations based on that volume of water being moved, and just held that as a constant. The AC cars suffer from the radiator air flow being obstructed by the condenser being mounted out front, so they had larger radiators and overdriven fans to increase surface area and air flow to compensate.
Now you could argue that they optimized the volume of water being moved for the whole system, which is why they wanted to keep it close to the same. So, running the HV pump with an overdriven pulley might not be as efficient. But of course that assumes you have a factory radiator that has the same resistance to flow as what was originally calculated. Aftermarket radiators with different tube sizes wouldn't be the same either.
There's a ton of stuff to consider. I wouldn't worry about it, but if I was having problems with cooling it is something to consider.