Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[CapriManxr2]

So I just finished rebuilding my motor not too long ago and in the first startup I noticed it was making no oil pressure. I took apart the oil pump and found that the crank was too small to spin the oil pump. So I bought a new pump thinking that would solve the problem, I bought the Melling pump off rockauto and it still does the same thing, crank is too small to spin the pump. I measured it out with a dial caliper and the flats on my crank measure 1.22” and my oil pump is 1.48”. What are your guy’s thoughts? Do I have an aftermarket crank or some sort of modified crank? See measurements below. https://imgur.com/a/JiKKkel

[greywolf27030]

If memory serves correct, the early ('91, early 92) have what's call small nose. The later ones have a large crank. I've never measured them but that may be what your are seeing.
'

[CapriManxr2]

So I just did a little bit of research and yeah, I have the small nose crank. Where do I go to get an oil pump that fits? I’ve already ordered two new ones from eBay and rockauto and neither of them fit.

[EShepherd]

So I just did a little bit of research and yeah, I have the small nose crank. Where do I go to get an oil pump that fits? I’ve already ordered two new ones from eBay and rockauto and neither of them fit.

Oh my goodness, I remember this problem from my rebuild now. So I re-used my OEM oil pump, because I was poor when I did my rebuild and the replacement pumps are expensive. As far as replacements, I was only ever able to find two options. You could go with an OEM Mazda pump from the 90-91 Miata, if you can find it. https://treasurecoastmiata.com/i-23790246-new-oem-90-91-mazda-miata-short-nose-oil-pump-b660-14-100e.html The other option is from a company called Boundary, who makes a high flow pump for the B6 w/short nose crank. https://boundarypumps.com/shop/mazda/1-8l-bp-mazda/bp-1-6l-small-nose-crank-high-flow-billet-oil-pump/

They are both expensive, the aftermarket one significantly so. The Mazda one is a large pain in the ass to find. Whichever one you go with, buy a couple of OEM Mazda front main seals. They suck ass to install properly - I need to drop my oil pan at some point because mines leaking pretty good.

[CapriManxr2]

So I ordered the oil pump for a 1990 Miata off of rockauto for $70, it comes in tomorrow and I’ll keep you guys posted if it works or not. Really hoping it works because this is all that’s left to get my capri up and running again after the motor rebuild. (Part link) https://www.rockauto.com/en/catalog/mazda,1990,mx-5+miata,1.6l+l4,1190876,engine,oil+pump,5564

[EShepherd]

They look right, but you never know for sure until you have the part in hand. Good luck

[CapriManxr2]

So the part came in today and to no one’s surprise, it didn’t fit , I’m just gonna have to keep trying oil pumps and returning them as I go or maybe source a used one from a junkyard or find someone on EBay that will measure the pump for me before I buy it.