Bad water pump?

[john.thompson068]

Is it true that if there is any play in the water pump pulley that the pump is bad? I have an aluminum water pump on a 440 that has the main housing and the separate pump in the middle. The other day as I was installing a new fan I noticed that I can wobble the fan/pulley side to side a little bit even though it was tightened down to the pump. There is no leaking and last time the car was running there was no sound coming from the water pump.

 

[tpodwdog]

that shouldnt be there ....but.....its not leaking. i would have one at the ready coz it might be soon youll need one!

 

[john.thompson068]

If I have to replace it, I have to remove the shroud, box, radiator, and fan. If it is bad, I should just replace it now while all those parts are already off. Here is what I think I did wrong. The other fan hit the shroud under full throttle. By the time I got that fixed the ends of some of the blades were ground down some and I later discovered a couple blades that had changed position. I bent those back. It is not like I am totally derelict, look, the fan isn't as bad as I am making it sound. So the clearance problem sent shock waves through the bearings, and the fan blades being slightly deformed unbalanced the fan. I will not be surprised if the pump is bad. If this pump is bad that will be really bad on my part because this pump is a fairy new piece. It looks like later I will need you guys to help me pick out a pump, i.e. standard or high flow.

 

[67 coronet]

if it moves,replace it.it means the bearing is starting to fail.the weep hole leak only detects seal failure.fix it now before you get catastrofic failure.i have seen a flex fan stick through a hood before.not pretty!

 

[john.thompson068]

I am already looking. Should I buy a standard performance or high performance? And if I need a high performance pump, do I really need one of those $15 high flow thermostats?

 

[67 coronet]

no need for high flow stat,just good quality stock replacement is fine.performance pump is up to you,i have not had the need to run one in any of my motors,and i live in the desert(110+ degrees in summer)on my race motors i run electric,so totally differnt there.

 

[john.thompson068]

Well, I just remember somebody somewhere saying that a high flow water pump does not give the water enough time in the radiator to cool off because it is being circulated too fast. I really have no idea, and would just get the high performance one. I bought the whole water pump and housing as a set from MP so it is probably HP. Currently, I think the cheapest way for me to get an aluminum high performance water pump is a Milodon 16260 from Summit. It is the least costly one, and some of these pumps from Edelbrock are running over $200.

 

[john.thompson068]

Alright, I was getting all kinds of conflicting information on the Internet so I called Milodon. Milodon's tech guy says a high flow water pump increases water flow by 30% at all rpm ranges, and typically decreases temperature by 15 degree over a standard flow pump. He also says a stock replacement thermostat would be fine for a mild motor, but a high flow thermostat is better for a motor with compression and high lift cam which run hotter. That pretty much solves that.

 

[john.thompson068]

What is this about a water pump having a factory bypass hole?

"[SIZE=-1]Manufactured by Robert Shaw and modified by Stewart, these custom thermostats feature a balanced sleeve design and are constructed for high flow, high RPM applications. Strongly recommended for any performance application - must be used with Stewart Stage 2, 3 or 4 water pumps. Our Stage 2,3 and 4 Small Block Chevy water pumps do not have the factory bypass hole, therefore we put three 3/16” hole in our modified high flow thermostats, this moves the bypass to thermostat. This also allows air to escape on initial system fill making bleeding the cooling system much easier."[/SIZE]

 

[john.thompson068]

Good grief. I didn't know selecting a thermostat would be so challenging. Now I have to make two more tech calls tomorrow to figure out what is the deal with these Stewart/
Robert Shaw thermostats with the three bypass holes and all the conflicting information on their website.

 

[john.thompson068]

Okay, I had to call Milodon back to get a straight answer. So Chevy water pumps have a bypass going around the thermostat for some reason. I would still like somebody to explain the theory behind this. The only advantage to having three bypass holes drilled in the thermostat would be to allow coolant to flow through the system before the thermostat opens up which will make the car take longer to warm up. This is only an advantage for a drag car where the driver wants the motor to take longer to warm up during staging since a cooler motor can produce more hp. Another option here is a restrictor ring, but this could cause the engine to take longer than normal to warm up depending on your needs I guess. What I do know is that not running a thermostat will cause the car to warm up too fast especially with a high volume water pump and the motor will be down power if it is over 210. Again, this is in relation to a drag car looking for lowest possible E.T. Anyway, its all kinda crazy. I am going with a Mr. Gasket high flow 180.

 

[Cranky]

The bypass allows coolant to flow within the engine for more even warmup while the stat is closed. With holes in the stat, some amount of coolant will flow to the radiator....and an engine at normal operating temp will produce more power than a cold engine will. In all my drag race engines, I run them at least 180 oil and water temp. Cold oil won't boil off normal condensation either. Now I have had engines that ran better when they were colder but that usually has more to do with piston, ring and bearing clearances and a cold intake manifold.

 

[Sweet5ltr]

The bypass allows coolant to flow within the engine for more even warmup while the stat is closed. With holes in the stat, some amount of coolant will flow to the radiator....and an engine at normal operating temp will produce more power than a cold engine will. In all my drag race engines, I run them at least 180 oil and water temp. Cold oil won't boil off normal condensation either. Now I have had engines that ran better when they were colder but that usually has more to do with piston, ring and bearing clearances and a cold intake manifold.

I agree, I run a 160* thermostat and the engine runs around 180* while at idle/155-160* while cruising (both being deadlocked maximum, with minimal creep)-its a 451 w/ 11:0:1 CR. It seems to perform it's best at this temperature. When I ran the 180* Thermostat, it would run around 195*-210* before cooling down and this was with 9.75:1CR and Iron Heads.

I would opt for a basic, off the shelf "factory replacement" thermostat. Don't get too involved, its just a mechanical part that opens up and closes at a designated water temperature. As for your Water Pump, I would go with a FACTORY REPLACEMENT as well or a HD unit for A/C equipped cars. Do not stray away too far from factory components. I have found that many of the "new" parts on the market, do not contain the reliability or performance that many originally equipped parts contained. I run an aftermarket aluminum housing from mopar, with a factory cast iron HD water pump.