timk

I've been searching through the forum to find any oil pump failure related data. It looks like most of the failures are due to or related to the pressure bypass valve getting stuck. There's also two separate threads reporting failure when the harmonic balancer is removed (replaced with an underdrive pulley) which is not suprising to say the least.

A friend of mine has also had the stuck bypass valve issue on a new build and fixed it by blocking the bypass and regulating pressure with a Peterson remote relief valve like on the bottom of this page: Peterson Fluid Systems : Pump Accessories

It might not be a bad way to go to head off these bypass valve issues? Coupled with a beefier harmonic balancer I guess...

If you have had any oil pump trouble, could you please post to this thread?

Pressure relief valve issues:

mr2daj - pressure relief valve stuck open
https://www.miataturbo.net/engine-pe...re-pics-64696/

ttmiata - pressure relief valve (unconfirmed)
Savington - pressure relief valve
https://www.miataturbo.net/engine-pe...-failed-58336/

Arkmage - pressure relief valve stuck open (unconfirmed)
left field - pressure relief valve stuck open
https://www.miataturbo.net/general-m...il-pump-14635/

petrol - pressure relief valve stuck open
https://www.miataturbo.net/general-m...rty-way-33453/

bbundy - pressure relief valve sticking partially closed when cold
https://www.miataturbo.net/engine-pe...h-56262/page2/

Underdrive pulley issues:

mazpr - shattered pump gears
https://www.miataturbo.net/general-m...-inside-45756/
https://www.miataturbo.net/engine-pe...re-*pic-46172/
1.8 96-97, aluminum crank pulley (no harmonic balancer)

paul
https://www.miataturbo.net/insert-bs...riendly-20396/
underdrive pulley

Other threads that may be of interest:

miatata - shattered gears (unconfirmed)
https://www.miataturbo.net/general-m...uestion-49958/
jap import 1.8

Blaize
https://www.miataturbo.net/diy-turbo...-c-bolt-46614/
mention of a/c bracket bolt supporting oil pump

Gt2560rMiata

iTrader: (-2)

Instead of making a thread i thought id necro this one. How common is this issue?

curly

iTrader: (25)

Grr lost my reply.

It seems semi common.

Most likely due to assembly not being done in a clean enough environment, or something in the engine grinding away a bit during break in. I don't think there was any recall for oil pumps when these cars were new, so I think all failures are rebuilt engines. Although some have happened after many miles.

I wonder if a ringed piston would survive? Or a longer piston to prevent rocking? Or a shorter piston? Or a different material?

fooger03

iTrader: (2)

Addition

Fooger03 - Incompatible pump/gears. (NA vs. NB pump + gears incompatibility)
https://www.miataturbo.net/build-thr...s-build-42652/ (Starting at post 23)

sixshooter

iTrader: (12)

Sixshooter - pressure relief valve stuck open
dipstick handle melted by exhaust heat and plastic bits in oil caused the valve to stick.
See build thread and/or a separate thread somewhere.

97montego

97Montego - pressure relief valve stuck open

Factory assembled, normaly aspirated engine - Stock.

The bore the relief valve runs in was badly eroded.

Changed the oil pump and got another 40,000 or so boosted miles out of the engine.

Savington

iTrader: (31)

I've seen two fail. My '99 pump was attributed to debris from the melted piston which carried over onto the new motor. The other was on a fresh turbo install, motor wasn't opened, but shavings from the oil pan drill got into the pump and stuck the valve open.

Gt2560rMiata

iTrader: (-2)

Thats the 2nd time ive heard of someone getting shavings stuck in the relief valve after drilling the pan with it in the car. Really thinking I should plan on dropping the pan when i go to install my drain.