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Discussion Starter #1 (Edited)
Everyone, to save me time from trying to measure in the dam tight engine compartment, what is the size of the stock Crankshaft pulley on our engines. Also I did a search and only noticed one option for a smaller crankshaft pulley option. Anyone have a constructive opinion on a pulley set. I saw a 4.25 inch aluminum one on ebay.

Ok i just noticed someone mentioned that our pulley is 5 inches. I found this on the forum after a hour of searching. Is this correct?
 

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The measure I have on my notes is 5.2, measure taken over the belt. I was looking to have the pitch diameter when I took te measurement, and the pitch diameter is around at the outside face of the belt. The flange of teh pulley was something like 5.3.

Reducing the diamater of this pulley can be not welcome for the cooling, the boost if you have a blower etc
 

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If you look around the inter web and search the forum you'll find that these pulleys are bad juju on the 2zz and can cause bearing damage due to the lack of a harmonic dampener. Your better off keeping the stock crank pulley and under driving the accessory pulleys.
 

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Bad idea. The replacement pulley is machined out of a single piece of metal and will not have the rubber damped inertia ring. #5 crank bearing gets worn on both edges.
 

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Discussion Starter #7
If you look around the inter web and search the forum you'll find that these pulleys are bad juju on the 2zz and can cause bearing damage due to the lack of a harmonic dampener. Your better off keeping the stock crank pulley and under driving the accessory pulleys.
Thanks, I did find that late last night. Bad idea on replacement pulleys. Still the 5.2 concerns me because i have seen notes from 4.8 to 5.2 on the pulley. The exact number is needed because i am so close to maxing out the RPM range at 8300rpm. If the pulley is 4.8 inches i can go up to about 8500rpm. If it is 5.2inches i can go to 8100 rpm.
 

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Thanks, I did find that late last night. Bad idea on replacement pulleys. Still the 5.2 concerns me because i have seen notes from 4.8 to 5.2 on the pulley. The exact number is needed because i am so close to maxing out the RPM range at 8300rpm. If the pulley is 4.8 inches i can go up to about 8500rpm. If it is 5.2inches i can go to 8100 rpm.
I'm still not clear on what you want to under or over drive. Also with out a built engine (head and block) things will start coming apart if you push the rpms. If you can gives us a few details about what it is that your trying to do maybe we can help you out. :D
 

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very strange topic. the size of the pulley don't have any effect on maximum rpm at all. the pulley is not an harmonic pulley like al in-line 4 engine.

it is like talking about a none issue thing...

i drive my car all the time at 8500, if it is ok for 2 seconds, it is ok for 2 hours.
 

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Discussion Starter #11 (Edited)
Ok let me back track. I am not trying to under or over anything. The reason i need to know what size the pully to the mm is that the size of the crankshaft pulley has a direct relationship to a supercharger RPM level. I just wanted to know what i would be pushing the supercharger to. My supercharger has a higher ratio then most supercharger do. I am doing just some simple math but need to know exactly how many mm or inches the stuipd pulley is and it is hard info to find. I thought it was 5inches (127mm). If the pulley is 123mm, that difference would mean i could rev the engine to the current fuel cut off limit. If not i have to lower the limit. Hope that explains why i just need to know what the size of the pulley is to the mm.

Example: A= B * (C/D) * SUPERCHARGER RATIO

(A) Im Peller speed max.
(B) Engine speed max.
(C) Diameter of crank shaft pully
(D) Diameter of supercharger pully
 
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