Replacing the simple pulley with an overrun alternator pulley has been a hot topic among Alfisti in Taiwan. However, I found little, if not none, information of getting a proper OAP for Alfa 156 on forums in Europe. Eventually, it took me two Taiwan trips to get the right one.
According to the 2nd seller, the OAP is engine and alternator model specific. at the first time, I bought two no-brand pulleys, one for my 2.0 TS and one for my friend’s 3.2 GTA. My friend gave the shot first and his doesn’t fit. Based on his experience, I put mine on the shelf too as I don’t feel it is a quality product. Moreover, it requires a lot of labour to have it replaced on the 2.0 model. Anyway, it costed me only 20 USD. it’s not worth the effort of taking everything off then finding that it doesn’t fit.
The 2nd one is an INA OAP plus a spacer for Bosch made alternators. Because it is so labour intensive to replace it, I had it installed one year after I got it at the time my mechanic took the gear box off for final gear replacement.
After changing simple pulley to the OAP, I can easily feel the power saved from revving up the alternator. The improvement is mainly reflected in the pace of acceleration after deceleration. is it worth the cost? It very much depends on the price of the OAP and the labour cost paid. The best way to do it, my guess, is not to make it an isolated job as its own.
Reducing weight from the balance shaft pulley
Following my mechanic’s recommendation, I had removed the balance shaft belt. Since the balance shaft is not functioning, I further reduced the engine weight by reducing the size of the balance shaft pulley.
Balance shaft pulley
Shaved balance shaft pulley
About half of the weight of the pulley is gone.
My mechanic even painted the shaved pulley in black. It looks great. By disabling the counter rotating balance shaft, theoretically speaking, I should gain a few bhp in the price of a rougher running engine. I felt neither of them to be very honest. Anyway less weight should always be better.
December 2021
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