TD42 water pumps... what would you be prepared to pay

[jff45]

Any cavitation issues related to water pumps will be more due to high revving hot engines combined with poor coolant quality rather than water pump impeller gap.

Reducing the gap will increase the flow but then you need to be sure that the other components in the system can handle that. Also be wary of pumping coolant too quickly through the radiator..

I'm new to TD42 engines but I've done a fair bit of research since I started my conversion and I haven't come across any other mention of these engines having cavitation issues with standard water pumps.
This is why I found BA's original premise interesting.
As Cuppa mentioned, these TD42s have more of a reputation for solidity and longevity.

Here's a pic of the original water pump I removed from my engine. Not the slightest sign of cavitation erosion.

...IMG_2599.JPG

[nissannewby]

John is right. Cavitation will usually only occur at sustained high rpm. Cavitation is usually a supply issue so there is not enough water available to be pumped.

Machining will help to increase flow but is not enough of an increase to cause problems. It is still within the control of your thermostat and cap.

You dont have to machine it. You can just replace it with a new one.

[Bloodyaussie]

Thank you guys this is good stuff... in the end I have stayed with the stock pump but have just finished replacing the radiator.

Its a subject I had not heard of until a few weeks ago and the discussions varied... cheers for all the input.

[AB]

Some really good advice in this thread gents on this subject from knowledgable members, well done!

There are bucket loads of wrong information about this on Facebook!

[mudski]

Some really good advice in this thread gents on this subject from knowledgable members, well done!

There are bucket loads of wrong information about this on Facebook!

Thats why I don't use FB. I use NP Book.

Will be interesting to see what temps I will see when I'm up and running.

[Robo]

Any cavitation issues related to water pumps will be more due to high revving hot engines combined with poor coolant quality rather than water pump impeller gap.

Reducing the gap will increase the flow but then you need to be sure that the other components in the system can handle that. Also be wary of pumping coolant too quickly through the radiator..

I'm new to TD42 engines but I've done a fair bit of research since I started my conversion and I haven't come across any other mention of these engines having cavitation issues with standard water pumps.
This is why I found BA's original premise interesting.
As Cuppa mentioned, these TD42s have more of a reputation for solidity and longevity.

Here's a pic of the original water pump I removed from my engine. Not the slightest sign of cavitation erosion.

...IMG_2599.JPG

Going by the pic of impeller I'd hazzard a guess of some cavitation present given the partial & uneven cleanliness of the impeller.
wouldn't a even flow of coolant produce even deposits?.

[Robo]

John is right. Cavitation will usually only occur at sustained high rpm. Cavitation is usually a supply issue so there is not enough water available to be pumped.

Machining will help to increase flow but is not enough of an increase to cause problems. It is still within the control of your thermostat and cap.

You dont have to machine it. You can just replace it with a new one.

I used to own a boat and my take on cav is its also linked to power supply ( linked to rev's as pointed out by nissannewby )overtaking the ability of pitch of blade to grip the water.
gap and impeller design has heaps to do with cavitation.
nismo gtr performance pump ver's std pump,std & N1pump.jpg have larger blade but 1 less and a backing plate on impeller to take care of clearance on other side of pump case.
ie same as this post discussing decking to reduce turbulence on block side if pump.
so any improvement you can do should help.

[jff45]

Going by the pic of impeller I'd hazzard a guess of some cavitation present given the partial & uneven cleanliness of the impeller.
wouldn't a even flow of coolant produce even deposits?.

I think the uneven deposits are because these Jap import engines sit around for a long time.

I gave it a quick clean with a small brass brush and the muck just fell off it.
Trust me there's not the slightest sign of erosion.

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[jff45]

Also thought this might be of interest. I found this image in a thread where a guy was changing his water pump. He actually bolted a new pump onto this and is quite happy with the outcome so let's not get too worried with what we have..

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