Essex rotary underdrive pullies

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350matt
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Essex rotary underdrive pullies

Post by 350matt » Sat Aug 08, 2020 2:43 pm

Hello all

I'm eyeing the the essex rotary underdrive pulley set as I need a larger crank pulley to get the pulley ratio I need for the charger

does anyone know what size the pullies are?

I've mailed essex rotary a couple of times to no avail so far

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Re: Essex rotary underdrive pullies

Post by Ryan Rotary Performance » Sat Aug 08, 2020 4:18 pm

If you need a larger crank pulley then the Essex kit is the opposite of what you need as the crank is smaller

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Re: Essex rotary underdrive pullies

Post by ChrisHolmes » Sat Aug 08, 2020 5:33 pm

Is the original Pettit Racing SC pulley the right size for your needs?
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Re: Essex rotary underdrive pullies

Post by SprintRX8 » Sat Aug 08, 2020 6:41 pm

Standard Crank petit pulley is 127mm.
I’ve bought Pensive Supercharger and Petit Pulley kit.

But I’m thinking about having a larger pulley made.
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Re: Essex rotary underdrive pullies

Post by ChrisHolmes » Sat Aug 08, 2020 7:18 pm

Is it not simpler and cheaper to machine up a smaller SC pulley
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Re: Essex rotary underdrive pullies

Post by SprintRX8 » Sat Aug 08, 2020 7:51 pm

With the Eaton to go with the smaller pulleys you need to get the nose machined down in size.
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Re: Essex rotary underdrive pullies

Post by ChrisHolmes » Sat Aug 08, 2020 7:58 pm

Not so simple then. Have you considered the Lysholm based SC with the rear entry top exit design.
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Re: Essex rotary underdrive pullies

Post by 350matt » Sat Aug 08, 2020 10:25 pm

I already have the charger (Eaton TVS R900) and Mr Sprint is correct there's only so far you can go with the SC nose pulley I'm already at 70 and can go down to 63.5 which gives me 1.81:1 and 15,000 rpm on the charger which is just a little shy of where I need to be

OK so I'll probably have to make up a new crank pulley then

cheers for the replies chaps

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Re: Essex rotary underdrive pullies

Post by warpc0il » Sun Aug 09, 2020 1:03 pm

There used to be a couple of companies based in the Midlands that would do custom pulleys with next day delivery.
They had stocks of pulleys of various diameters, widths and profiles and would just bore/mill the centre to match whatever fitment was required.

I have this link in my bookmarks but it's not working, and might not be the same guys
http://www.bearingshopuk.co.uk/belts/v-belt-pulleys/

A quick Google and I found these guys in Scotland, though they seem to be more "bespoke" and I suspect pricing to match
https://www.timingbeltpulleys.co.uk/
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Re: Essex rotary underdrive pullies

Post by ChrisHolmes » Sun Aug 09, 2020 1:21 pm

Bridge Ported 231
Light weight Flywheel
Tein MonoSports with EDFC Active
Racing Beat F&R ARBs
Racing Brake 4 Pot Front Calipers
Racing Brake two piece slotted & drilled discs
LED Rear Lights
LED 3rd Brake light with blink effect
MazdaSpeed skirts
Safety Devices Full cage
Royal Steering wheel
Short shifter
Mishimoto Catch Tank

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Re: Essex rotary underdrive pullies

Post by Essex2Visuvesi » Sun Aug 09, 2020 3:37 pm

Works on mac n Chrome as well
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Re: Essex rotary underdrive pullies

Post by 350matt » Sun Aug 09, 2020 7:04 pm

sadly the bearing shop only provides pulleys for industrial machinery
not the 5PK poly vee used on the engine
still thanks anyway

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Re: Essex rotary underdrive pullies

Post by geofftl1000r » Sun Aug 09, 2020 9:04 pm

This place has a lot of choices.

https://www.accu.co.uk/en/484-vee-pulleys

And they do custom stuff too.
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Re: Essex rotary underdrive pullies

Post by SprintRX8 » Sun Aug 09, 2020 10:56 pm

Thinking of using something like these from Summit Racing.
Having a mounting boss made that will bolt to the original RX8 pulley.
Then the charger pulley can be changed to suit.

https://www.summitracing.com/int/parts/mch-7671

7DB02403-9C53-4A2E-9346-06E7140DE3C1.png
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ChrisHolmes (Sun Aug 09, 2020 10:59 pm)
13BLT Renesis Rotary powered Dolomite Sprint in the making😏.
Balanced Lightened and Tweaked.and possibly Supercharged.

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Re: Essex rotary underdrive pullies

Post by ChrisHolmes » Tue Aug 11, 2020 11:36 am

Wrong side of the pond but these folks may be able to help you. https://pulleyboys.com
Bridge Ported 231
Light weight Flywheel
Tein MonoSports with EDFC Active
Racing Beat F&R ARBs
Racing Brake 4 Pot Front Calipers
Racing Brake two piece slotted & drilled discs
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LED 3rd Brake light with blink effect
MazdaSpeed skirts
Safety Devices Full cage
Royal Steering wheel
Short shifter
Mishimoto Catch Tank

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Re: Essex rotary underdrive pullies

Post by Ryan Rotary Performance » Sun Aug 16, 2020 6:22 pm

What are you after?

A triple crank pulley? Or a normal twin crank with the drive just made larger for the accessories?

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Re: Essex rotary underdrive pullies

Post by 350matt » Sun Aug 16, 2020 8:32 pm

I'm after a normal twin crank with a larger rear pulley to gear up the charger pulley, ideally a larger alternator pulley to go with it to prevent that being oversped
I've already converted the water pump to an R3 item which has a larger pulley than the S1

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Re: Essex rotary underdrive pullies

Post by Ryan Rotary Performance » Sun Aug 16, 2020 10:47 pm

I could probably do that, PM me of interested

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Re: Essex rotary underdrive pullies

Post by SprintRX8 » Mon Aug 17, 2020 12:10 pm

I too could be after a Crank pulley.
Rear standard for water pump and Alternater
But larger front for the charger 6 Rib.


Carl.
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13BLT Renesis Rotary powered Dolomite Sprint in the making😏.
Balanced Lightened and Tweaked.and possibly Supercharged.

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