Electric Water Pumps

[Intrigued]

I believe that for a general rule they fuse a circuit for about 50% more than the expected use, so I bet your wiper circuit would'nt pull more than 10 amps at best. I think we have a pretty good ballpark estimate of what they'll pull, then.

I'd bet the 7 of the Summit could be matched by the low speed of the wiper motor. No use spending the $250-plus for that, huh!

[Coyote X]

The motor I messed with pulled 4 amps with a pair of vise grips loosely clamped over the shaft to give it some load while turning

Not a real accurate test but I would guess with properly figured pulley sizes to get the right rpms at the water pump a normal motor would pull 4-5 amps at most. Just as a rough guess I would say it can handle about 100W of power without burning up so 5 amps would be a safe load on the motor to keep it lasting a long time. At least this was with the motor I used. I don't think they are standard sized and there is probably a huge range of sizes of these things. The wiper motor on my Astro looks about twice as big as the one I tested so it can probably handle a 10 amp continuous load without any effort.

Really though without the thermostat there won't be much backpressure for the water pump to fight against so I really can't see the motor needing more than 2-3 amps to actually pump enough water to keep a 4 cyl cool.


On a side note it takes a bit more rpms than a cordless drill has to keep a big v8 cool. When I was putting my kit car together I didn't have a belt for it so I just chucked a drill on the water pump shaft and duct taped it to a board and locked it on full speed. The car would overheat slowly but it let me run it and get the bugs out of some of the other engine stuff. So when trying to estimate the pulley sizes I would say keep them close to 1:1 and that should give a good enough speed to the water pump.

[Christ]

I bet a dremel would have taken care of your overheating problem :P

14,000 RPMs seems a little excessive though...

[Intrigued]

Originally Posted by Coyote X

Really though without the thermostat there won't be much backpressure for the water pump to fight against so I really can't see the motor needing more than 2-3 amps to actually pump enough water to keep a 4 cyl cool.

Woohoo! 14 Grand! I could handle it! Don't know about the pump shaft seal though...

<climbs up on soap box>
We must remember though that an engine is designed to run best at a certain temperature range, so leaving out a thermostat is a no-no, since it will take a lot longer to get to the desired temp, and run less efficiently. I'm not sure that slower water flow to warm up is the best way, because you're balancing against keeping your heads (head) from overheating, and there's a lot of variables there...
<climbs back down from soapbox...>

Woohoo! 14 Grand! Put a tach on the thing!!!

[Christ]

Originally Posted by Intrigued

Woohoo! 14 Grand! Put a tach on the thing!!!

**Advertised** speed for certain Dremel tools. Never personally checked it.

[Intrigued]

Originally Posted by Christ

**Advertised** speed for certain Dremel tools. Never personally checked it.

Oh, I Believe! I just want to have a tach on the dash, so I can pretend that I'm pulling some REALLY SERIOUS RPMs...

[Intrigued]

What we need to do now is to find a wiper motor that lends itself to modding cheaply and easily. Something that had a shaft that would be easy to put a sprocket or pulley on. Anyone have any experience with that???

[Christ]

Originally Posted by Intrigued

What we need to do now is to find a wiper motor that lends itself to modding cheaply and easily. Something that had a shaft that would be easy to put a sprocket or pulley on. Anyone have any experience with that???

Smallest one I can think of - Rear wiper motor from a CR-X or Civic Hatchback - 88-91 models.

Actually, just about any rear wiper motor is small enough, I would think. Anyway, pretty much all wiper motors (that I know of) have a shaft on them that has an eccentric of sorts, which drives the wiper transmission, which drives the wiper arms, which drives the wipers themselves back and forth.

That said, you'd have to add onto the shaft, as it's (that I know of) usually only 1/2" or so long. You'd need something longer/thicker for the average tooth-belt gear.

What kind of speeds are we thinking to drive the water pump at? From OEM's, I believe it's usually driven pretty close to 1:1 w/ the engine at all times... this would be a consideration in what to use for the drive's tooth-cog. I'd think you could use the OEM crank tooth-cog if your water pump is already driven by the timing belt.

Also - how will you re-route the timing belt around the water pump's pulley/cog?

Suggestion: Pair of idler pulleys bolted on either side of the pump - above and below it - that will allow the belt to stand off at least 10mm from the pump's cog, 5mm from the new belt on the pump. This will allow you to use the OEM tensioner pulley to adjust tension, and it's normal slack will allow for the slack necessary to the belt due to the longer dimension needed to deflect the belt around the pump's pulley/cog.

Unfortunately, you can kiss the timing cover good-bye for this idea, or at least have to trim it up.

[ATaylorRacing]

From a drag racer with cars that do not take the aftermarket kits comes the following tricks:

On some Chrysler 2.0, 2.2, 2.4, and 2.5 four bangers we cut off every other fin on the water pump and have no problems with over heating. This also causes less drag.

Under drive pulley kits can also be used to cause less drag by turning the water pump and alt at slower speeds. My 98 Neon 2.0 SOHC motor picked up just under 2 mpg with this set up, as did my 94 Plymouth Duster with the Mitsu 3.0 V6.

On one of my 2.2/2.5 Chryslers I removed the water pump entirely and replaced it with a thermostat housing....2 of the holes lined up perfectly...I then ran an electric in line pump for a fishing boat holding tank (Water Guppy) with a simple 12V switch. The great thing about this is that I could circulate coolant through the motor while it was shut off in the pits to cool down between rounds when normally we would not get enough cool down time. Other guys saw this set up and simply used the in line pump without removing the original. They could also cool down quicker between rounds. Others did this too, but removed all of their pump fins. The last two cases were people that had no provisions to hook up a system when their pump was removed since there was no way to set it up. Yet even a few more would put a plate over where their pump was with welded on hose hook ups. Not every one can afford those kits, but the water guppy was around $20 back then!

[Intrigued]

Yikes! I hadn't thought of timing belt-driven pumps. That would be pretty hardcore to want to mess with one of those. I was thinking more of the belted types. Too GM ingrained, I guess...

If a person changed to a manual steering box, one or two deep-cycle batteries to enable stripping the alternator, and just bite the bullet on air conditioning (balance out the weight of the extra battery?), then the water pump would be the only thing left to go completely beltless!

...or at least not driven off of the engine, that is!