inuissus_cendi

So I have an 83 with the stock 12a and I bought a GSL-SE oil pump planning to use it as an upgrade. Now I read a thread where some said only 84-85s had the larger oil pump (like I thought) and others thought the 83s also got the larger oil pump. Does anyone know for sure? It'd be nice to know before I go remove the front cover only to find that its the same pump.

Midwest 7's

iTrader: (4)

i think the 12a pump is like 15 and the 13b is 17.

inuissus_cendi

true, but some 12a's also got the larger pump. I want to determine for sure whether or not the 83 got the larger pump like the 84 and 85s. Thanks though

Midwest 7's

iTrader: (4)

all 12a's from 76 on had the 12.5mm pump, before that they were 15mm.

Jeff20B

iTrader: (13)

'83 might have the 17.5mm pump (so called high volume). All '84-'85 12As had these. It was easier for Mazda to produce one pump size for the 12A turbo, GSL-SE, and beehive 12As. The nitrided R5 13Bs also had them, although the years those engines were produced remains a mystery. They might be the first engines to have had the 17.5mm pumps.

'83 is the crossover year. They were the first year to have the lighter rotors and the beehive oil cooler, so it's safe to assume they also had the 17.5mm oil pumps.

I won't have access to an '83 engine for a while so I can't check, but I do have access to some '79-'82 pumps. I'll measure them in a few minutes. I bet they'll all be 15mm, but I won't know until I check them.

Jeff20B

iTrader: (13)

They were all 12.5mm. One was 15mm, but I suspect it's from a '74 or '75 engine since one was torn down in the garage I got these pumps from.

inuissus_cendi

alright thanks. Well if I can't get a defenite answer on here I guess I'll just have to pull the front cover and find out.

by the way, any tips on how to remove the front cover without pulling the engine?