need ideas about oi pressure loss

[F3BZ]

i'm asking this for a relative with a capri. the engine is a stock B6T that was torn down enough to replace pistons and rings. after start up and during the initial drive it showed a complete loss of oil pressure after 40 minutes running. so he removed the pump and bench tested with a drill and got pressure. he re-installed pump but again no pressure immediately at start up. not having seen the car or problems, my only phoned suggestions that i could think of right away was a pick up tube problem or malfunctioning oil pressure guage in the dash. i'm not intimately familiar with the turbo 1.6 so anybody have other ideas? something missed during reassembly? something even outta left field?

[shadetree]

Wrong rod bearings ?

[bhearts]

It doesn't have a gauge, you're just basing it off that plug switch in the block?

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[Movin]

Don't run the car until a hand held gauge is screwed in and tried. Once that is done you are fixing the gauge or the engine. Have him be careful the crank is the more expensive forged type I think, if he did get wrong bearings or is sucking air he could be building a mess quick. Hope all turns out well!

[F3BZ]

i'll talk to him tonight. he's very cheap so i doubt he replaced rod bearings. just piston/rings. this is a capri. i thought capris had an oil guage. i figure he had to have some kind of guage hooked up when he bench tested the pump but i'll ask to be sure. thanks.

[bravekozak]

"Proceeding from a finding that the CAPRIS is built on a 1987 Mazda 323 platform, and suspecting that the original Miata probably used, basically, the same engine, I came up with an oil pressure transmitter from Mazda (at no trivial expense). The winding in the original one was worn through by the its wipers producing the symptom of variable and very low to no oil pressure. I needed half shafts for the same vehicle. Miata half shafts were an exact fit. I needed a replacement left side window switch. The switch for an early Mazda MPV (available from Mazda) solved that problem. Thanks again for your interest and your help."

Does this have anything to do with it?

[bhazard]

Don't run the car until a hand held gauge is screwed in and tried. Once that is done you are fixing the gauge or the engine. Have him be careful the crank is the more expensive forged type I think, if he did get wrong bearings or is sucking air he could be building a mess quick. Hope all turns out well!

Only the BP got a forged crank

[Movin]

Only the BP got a forged crank

Thats good I guess, he can find a whole engine easier if he needs to. It would be ashame to needlessly ruin the crank and rods.

[WmWatt]

I've read that sometimes a replacement head gasket doesn't have all the holes in the right place and you have to compare it to the old one to make sure they are the same. I don't know if that problem would cause the symptoms reported in this case. It might be more of a coolant problem? It might help to know what problem (symptoms) lead to the pistons and rings being replaced.

[F3BZ]

ya i recently read about making sure the head gasket is facing up the correct side on a miata forum. apparently a common enough mistake but can't remember if it blocks an oil or water hole.

[F3BZ]

the end of the story is that he replaced the oil pump and problem solved but still wonders why the old one showed pressure on the bench. real good deal on new OEM ford oil pumps for small diameter crank on ebay. these are more than likely mazda japan pumps that sell for $250 through mazda.

http://www.ebay.com/itm/NEW-GENUINE-OEM-Ford-E9JY-6600-A-Oil-Pump-1989-1-1-1991-Capri-1-6L-Ford-/331622628959?fits=Make%3AFord%7CModel%3AFestiva&hash=item4d363fbe5f:g:O2QAAOSwPcVVw9Wc&vxp=mtr

[Movin]

If anything is worn in the pump they can suck a little air in as they sit on the engine running. They can lose their prime. If they are tested in a bucket of oil they will test fine.

This experience was not on a mazda engine but a chevy 6.0 liter. The design is the same. It was one we had bored, stroked and had the heads ported. When I put the oil pickup screen on I had to shim it down to clear the stroker crank. The pump starved for oil and went bad right at 1/2 hour run time. It still made pressure but was pumping air as well. I replaced the pump, it was a high volume pump too, that might have been a factor. I left the tube shimmed down but raised the screen 1/4 inch. It is an awesome engine and several years old now. With the HP tuner in a laptop and some other goodies that little small block is supposed to be 600 hp. Make sure the pump has no restrictions to it!