Water pump performance and headgaskets

[bjowett]

Here is a little blueprinting mod that was performed to help reduce stock water pump flow losses. If you examine the 2 pictures, the timing cover casting has, IMO, issues just prior to coolant port entering the block. That chunk right at the top...

A little porting to remove it...

I'd like to hear people's thoughts on this. Just another piece in the headgasket/PHH issue?

Aisin/Asco aftermarket pump... $75. Includes gasket and studs. They were kind enough to grind the "Toyota" off the front of the casting even...

 

[RavenTai]

It is hard to tell from the pictures but looks like there was a vane of sorts there before, did this vane look to be intentional or just a leftover from the cast clearance for seperation?

the way the fluid is routed inside the 1FZ I would think that improved flow would be desirable, unlike most engine the 1FZ continuously circulates fluid in the block even if the thermostat is closed, the thermostat directs fluid to the radiator or right back into the block to be recalculated based on coolant temperature unlike most systems where flow is just completely stopped by the thermostat. that shoudl help with local hotspots aposed to static fluid.

how much was a water pump from Dan?
are they truely idential impeller bearings seals etc?
where did you get it?

 

[concretejungle]

Interesting. I also wonder if it was there for a reason, or just left from the casting. Also, i was under the impression that you do not want the fluid to move too fast, otherwise you wouldn't allow the fluid to collect and remove the heat so to speak. I thought the fluid needed to stay around a little longer. I think i got that ideaology from robbie talking about some of the water jacket ports around the cyclinder and that they were a smaller size on purpose, to keep the water there longer.

 

[cruiserdan]

how much was a water pump from Dan?
are they truely idential impeller bearings seals etc?
where did you get it?

The factory pump, includes gasket, lists for $175.16, mudder $131.37.

 

[bjowett]

It appears to be one of those necessary casting evils of a mass produced part... I could be wrong. Does the 1FZ need increased flow? Maybe. The reduction in pumping losses is definetly important as it reduces the load on the pump bearing, which makes for a longer lasting part.... not to mention less power to drive it.

 

[Cattledog]

Looks like a casting leftover. Porting this seems like a good idea. If toyota wanted lower flow rates in the water pump, I would have figured a smaller/different impeller design.

I have never heard of too high of flow rates for a factory waterpump in any application. Most people in the aftermarket applications are looking for more flow vs stock. I can understand using different size ports within the block to manage thermal gradiants across the block. But not at the waterpump. Concrete/anyone have you ever heard of such an issue in another application?

 

[IdahoDoug]

Water flow is a tricky thing. I simply cannot accept that a cast part like that had an "whoops, forgot that thing" aspect to it. Toyota specified that part down to the thousandths of an inch and it is far more likely that structure had a function that not. What is it? Dunno - turbulence generator due to cavitation at higher RPMs? Something that reduced noise?

No idea. It's hard to argue against removing things like that to improve flow of course, but that implies its presence was accidental or overlooked.

DougM

 

[RavenTai]

CJ, I hate to disagree with Robbie he is a great guy and one of the most experienced land cruiser mechanics in the US especially with this engine. But this one comes up pretty regular in other circles I travel in, it is a common misconception, maybe it comes from people revere thinking water heating where you do indeed want the water to hang around for a wile But when working with metal cooling, more flow = more cooling, for several reasons.

You can read the short & sweet here 2 pages
http://www.ocforums.com/showthread.php?t=210844

Or a longer version here 17 pages.
http://www.ocforums.com/showthread.php?t=78055

And just about anywhere water cooled computers are discussed.

There are also some formulas of heat transfer through conduction that describe this action, major elements being thermal conductivity of the substances and the temperature difference between the two and surface area, if the water hangs around and warms up then the relative difference decreases and heat transfer slows, as soon as the water picks up any heat you want to replace it with fresh cool water from the heat exchanger.

Dan thanks for the price, personally I would stick the known factory part for that difference. But in the middle of an engine rebuild prices do stack up.

It appears to be one of those necessary casting evils of a mass produced part... I could be wrong. Does the 1FZ need increased flow? Maybe. The reduction in pumping losses is definetly important as it reduces the load on the pump bearing, which makes for a longer lasting part.... not to mention less power to drive it.

Weather the 1FZ needs more flow is hard to say, but certainly giving it the opportunity to get more cannot be a bad thing. I have been looking at those pics trying to picture why such a thing would be needed and cannot come up with any, the protrusion at the other lower end of the port certainly has a purpose in a centrifugal impeller, it peels of water not letting in make another cycle, the one at the top I cannot think of a purpose for.

Doug I would certainly agree that Toyota was aware of this bit of metal, question is was it there just for parting of the casts and they left it because they thought it was of not enough consequence to bother with removing or did they put it there for functional reasons unknown to us?