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Water Pump Differences


Roy
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Was considering running a Davies Craid Water Pump and controller, but dont really have enough time to get it working right between now and when i will be trashing the guts out of the car.

So will be replacing the timing blet, idler/tensioner etc etc this week and on the topic of water pumps wondering what is available off the shelf.

I understand that the problem at big revs is cavitation with the std water pump. So you can go to an N1, only that affects the lower rpm flow on the street. Hence the Davies Craig which would have been the best of both worlds.

Is there any difference between off the shelf Nissan water pumps and flow. RB20, 25, 26, 30 etc. Does anyone have acces to Nissan FAST and able to tell me the respective flows of each. Perhaps conform that a RB25 pump can be used on an RB20?

The whole cavitation, high revs and high temps at the track will hopefully be less of an issue with the header system im going to setup instead of running the EWP.

Be much appreciated if someone with FAST can also tell me if the RB20 and RB25 idler and tensioner bearings/pulleys are the same

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The pumps are the same.

The idler and tensioners are the same also.

Oil pumps are the same.

Cam and crank seals are all the same.

Timing belts are the same.

hmmm....I could go on

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The pumps are the same.

The idler and tensioners are the same also.

Oil pumps are the same.

Cam and crank seals are all the same.

Timing belts are the same.

hmmm....I could go on

So an RB20 water pump is the same as an RB25 water pump??? Doesnt sound right but wouldnt surprise me.

Duncan..ill let you know how the header system goes, I may install it after a session at the tack and see if it makes any difference. If it doesnt ill just bin it

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I fitted an rb25det water pump to an rb20det and only 1 bolt hole didnt line up didn't make any differance to the car didn't leak water seamed the same to me apart from the 1 bolt hole

Cheers Peter

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I don't know about the 20 and 25 water pump, but there are differences in the blades between 26, 30 and n1 pumps.

Also there is a difference in the bolt holes between 32 and later rb26 pumps, later ones have a longer slotted hole so there must be a difference in bolt point

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Roy one on this boad runs the EWP but not for road , I really like the idea but I worry about the reliability of the plastic body . If it failed the engine could die quickly and there's too much money at stake for an RB30 . It would be entertaining to see if Davis Craig is prepared to wear the rebuild cost or only replace their bastard pump if it failed . I guess the only way to be almost safe would be to have the pump up near the highest point of the system so if it lunched itself there may be time to shut down and save the engine .

I may sound like a wuzz but I've seen expensive engines die because of plastic rad tanks failing so anything plastic in an engines cooling system I think is a risk . If and when they make an aluminium one I'm all ears . I don't suppose anyone knows pumping rates of the RB20/25/26/30 so we could fiddle pulleys to get a good/cheap solution ?

Cheers A .

PS: can the impellers be changed ie one off stuffed RB26 pump on cheap new RB30 pump or as the case may be ?

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PS: can the impellers be changed ie one off stuffed RB26 pump on cheap new RB30 pump or as the case may be ?

LOL...your a thinker :pirate: I was expecting that the shaft / pulleys ect woudl be the same. Was hoping to get my hands on an old RB20 water pump and see if i can get a new impeller and bearings for it?!?!?!?!

As for the EWP beign plastic, it is some composite, so i hadnt really worried about that

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plus i dont think EWP failure would mean instant death. as long as you watched the temp gauge you would have plenty of time to shut the engine down. i would just install and idiot light to show when coolant temp goes 93 degrees+. I mean the water is just cooling stuff. and if the pump failed at least the engine etc would all still be full of coolant (unless it just literally fell to pieces - unlikely).

I think it's a great idea, the only thing that has stopped me is the unknowns.

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  • 2 years later...

Sorry to bring up a old thread but im about to service my rb20det eccs redtop and im in need of a water pump. My local motor mate has a rb30e water pump in stock for $65, i know they fit but will the rb30e pump flow completely different to the rb20 water pump?

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i have pulled many rb's apart and there are three impeller types i have come across plus the countless after market profiles (powermax, GMB, silverline etc) i will see if i can round them up from the scrap metal pile and post them up.

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  • 3 weeks later...
i have pulled many rb's apart and there are three impeller types i have come across plus the countless after market profiles (powermax, GMB, silverline etc) i will see if i can round them up from the scrap metal pile and post them up.

Any progress on the pics :)

QUOTE from a ebay seller: Please note that RB20 water pump is not the same as the RB25/RB26 water pump due to one of hole is different size. Water will leak out if you install RB25/26 water pump on the RB20

Is this true for the rb26 aswell?

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kind of....32 needs a single hole, 33 and 34 blocks have an elongated hole. r32 part is no longer available from nissan so no matter what you buy you get the elongated hole.

You can either over use the silicone gasket sealer, or have the hole tig welded up. I did the second option on my first motor but haven't bothered since

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