22 replies to this topic

[PACINO]

Thanks for your opinion. To be honest, I no longer know which pulley is the right one for each engine. I have always thought that to cool a prepared or a little fat engine, it is the small pulley. Because it turns more times and the water pump moves all the coolant more. Now thinking that if it passes too fast through the radiator and the "cavitation" ... I could no longer say which is better.

[Northernpower]

The Minispares Evo water pump with the glass filled ceramic impeller was designed to negate the cavitation at high spindle rpm. It will safely run at up to 10,000 revs without cavitation. They built a test rig with a viewing window to confirm the lack of cavitation and while I've seen the video of it running at the York branch I can't currently find the link to it. The Evo pump will fit the smaller block but some of the earlier ones need relieving to enable the impeller to clear. It's a worthwhile purchase and they're so confident of the quality, they give a three year guarantee on it.

[PACINO]

"The high capacity water pump helps to reduce cavitation in the water jacket, particularly at high RPM, as well as circulating a greater volume of coolant. Further reduction of cavitation is achieved by using a large diameter water pump pulley CAM6408 as originally fitted to the Cooper S and reintroduced on the A-Plus engines".

Cheers man!

[imack]

"The high capacity water pump helps to reduce cavitation in the water jacket, particularly at high RPM, as well as circulating a greater volume of coolant. Further reduction of cavitation is achieved by using a large diameter water pump pulley CAM6408 as originally fitted to the Cooper S and reintroduced on the A-Plus engines".

Cheers man!

Minispares site still warns of potential clearance issues if the head or block has been skimmed

Edited by imack, 27 September 2020 - 06:04 PM.

[PACINO]

With that water pump, Minispares recomends this pulley 4.75"

[imack]

Yeah, look up the pulley on their site and read the last paragraph about potential clearance issues. Same as MED pulley.

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Edited by imack, 27 September 2020 - 06:14 PM.

[Spider]

Just as a general rule of thumb, these types of pump's optimal shaft speed is 2 000 to 3 000 RPM. The original alloy body, cast impeller type pump without the bypass, I found starts to cavitate at around 5 800 - 6 500 RPM. The pumps with a By-pass start cavitation from around 4 200 RPM. The new Mini Spares pumps I haven't tested but it does appear a very good design.

[PACINO]

Cheers Spider!