Oil pump question
 

I'm almost done collecting parts for my 1.8l swap, but I have one question. The motor I have came out of a protege, so it has a MBSP. I have an oil pan and pickup from an 01-05 miata. I thought it would be stupid to put the old oil pump back on, so my question is this: Do I need a specific pump? I see lots on eBay, some say 94-99, others say 94-05.

There is an inspection procedure for the oil pump in the factory service manual. If it meets specifications for clearance, and the aluminum housing is not seriously scored, then it is fine.

There were two different oil pumps used in the '90-'05 production series. One was used for all B6/BP Miatas from '90-'00, and then a change was made in '01 when the VVT system was added, presumably to satisfy the extra demand for oil flow. I can't say which one your Protege motor has.

There's really only one choice in genuinely "high performance" oil pumps, and that's boundary engineering.

Actually, boundary have two choices. The first is a set of gears that are dimensionally identical to stock, meant simply to address the problem of the stock gears (which are made by a sinstering process) breaking under high HP loads / high RPM. This gearset drops into a stock '90-'00 oil pump housing.

The second is a set of slightly over-thick gears, intended to increase oil flow, and requires machining to the housing, which is done either on a new stock housing or on an exchange basis.

Boundary Engineering

Boundary gears on bottom/aka "Stock replacements", Protege on the top.

FYI protege gears are short nose cranks, well at least on the protege bottom end JasonC SBB and I had.

Attachment 203544

Before you go out and buy a new oil pump, check clearances to see if they are within tolerance and also check the size of the crank nose and gear size. Its possible you have a shortnose crank.

With that in mind, I am not sure what kind of power your looking for but you may want to consider throwing the MBSB onto a different bottom end.

I'm pretty sure the motor I have isn't a short nose, but I'll check tonight.

I'm only looking to make ~250whp. If the pump I have is in spec is it even worth it to replace it?

I wouldn't bother if its all within spec. My protege block was a 1.8, short nose. I didn't even realize that existed till i went to put in the billet gears and they were too big :o

so i checked, and my motor is a big nose. i looked at the old oil pump, i'm assuming the gears are behind the small cover on the back. where can i find the specs to make sure it's good?

the short nose/big nose change over in the protege/escort happened at the same time as the miata. 90-91.5 proteges and 91-91.5 escort GT's will have the short nose crank.

Is the later 01-05 oil pump a direct fit for the earlier Miata 1.8's?

thats my question, i dont know if the 94-00 punp will fit with the 01-05 pan

I'm pretty sure that the '01+ pan fits on <'99 motors (based upon people upgrading to MBSP) so I can't imagine why the opposite would not be true.

On the other hand, you might want to check with BE before potentially downgrading to a lower-flowing pump on your VVT motor.