brokedown

Does anyone know if the main pulley is specific to each individual engine or if they're interchangeable through out the series and model?

If they are engine specific, could you give the reasons why each engine requires the pulley it came with from the factory.
I realise timing is an issue, but I'm wondering if stationary placement might be a causing factor or if there is no issue at all.

scathcart

Good question, and an important one.

There are two sets of stock main pulleys, and two sets of stock main hubs. The parts fiche lists the parts as different numbers for the S4's and the S5's. Without doing side-by-side comparison, the pullies cannot be directly swapped. The problem comes when attempting to time the engine, a set of mistmatched pulley-hub combo can through the timing marks off by around 10 degrees.

Your best bet is to keep the stock pulley and hub together, and replace them as a unit. If your engine is apart, you can verify the pulley hub combo being correct by comparing a rotor at TDC to the yellow timing mark. The timing should just be slightly off, by 1/3 the distance between the two timing marks. (5 degrees to the right of the yellow timing mark)
ALL REBUILDERS should verify this.

If you just have a pulley-hub combo sitting on your desk, you can check by ensuring that the yellow timing mark is just slightly less than perpendicular from the yellow timing mark (should be 85 degrees angle). If the mark is around 95 degrees, or 75 degrees, the pulley and hub are mis-matched.

Seems Mazda did the change mid-series, like they did with many other parts, as I have seen many of the 88 models with the S5 pulley-hub combo.


So, in short, never bolt a pulley to your hub if it didn't come that way from the factory unless you verify it for accuracy first.

89rx7vert

When you are putting the main pulley back on how do i time it does the main pulley have a mark?
i did my water pump i hade to take the main pulley off now when i put it back together the hole engine shakes really bad? is it the timming? help!

HAILERS

Download the Factory Service Manual from this sites FAQ thread. Just the Fuel and Emissions section will. It's a quick read and shows how to time the engine.

If you removed the pulley by removing the four small bolts that hold it on, then you could not have done anything to ruin the timing by that act alone. Now your OTHER acts might have, whatever they were. Assuming the engine ran right prior to you working on it.

JPG of the fixed timing pin on the front cover attached:

IF you took the large 19mm bolt out, then the last jpg shows how to measure to tell if the *stack* is good/bad.

lastphaseofthis

iTrader: (8)

if i remove the 19mm bolt to change a front cover gasket the timing will not be thrown off b/c the eshaft has the lock grove and pin to keep it lined up CORRECT?
anyother precautions i need to take doin this? i heard of some problems caused by inexperiance but i need to do this thanks!