4agte oil pressure issues

[EVOSTi]

a friends car (chrizer) is having oil pressure issues.

i cant remember the exact numbers but at idle the oil pressure is fine, but as the revs build up the oil pressure doesnt increase.
so far we have swapped the oil pump with one off another engine, aswell as shim it but still no success.

also the car has a oil filter relocater kit and oil cooler. dissconneted both and still no love.

turbo is a GT28. so far the crank has been changed aswell as the block and head, pretty much everythings been replaced at some stage.

any ideas?

[AE71GZE]

whats the pressure at idle rpm? is your gauge working,no kinks

[EVOSTi]

dont rememberthe pressure, its a friends car.

car has a new autometer oil pressure guage, has also been tested on my workshop guage.

[terryo]

if you give me some real pressure & rpm values, I'll give you a few clues

[Cuzzo]

So have you tried disconnecting the cooler and just add a short bit of hose to bypass it.

Even though that should make f**k all difference because many 4ages are using oil coolers.

Stupid question again, is there too much oil in the motor?

Simple things first( i know your a mech, not trying to insult you)

[EVOSTi]

nah thats cool.

yeah we tried removing the remote oil filter and cooler, just disconnected them and ran an oil filter on the block but no luck. oil definately fine, been changed a few times since its had the problem.

will get the accurate reading tomorrow if i can.

[limbo]

just wondering what location are you using to tap the oil reading? Usually need to tap a point close to the stock sender unit or even a T piece on the sender unit location to get an accurate reading.

Does the engine have a blockage somewhere maybe???

P.S oil cooler will drop the PSI anywhere from 5-15PSI depending on the size of the oil cooler. My PSI dropped 10PSI when i ran the oil relocation and oil cooler

[30psi 4agte]

dont rememberthe pressure, its a friends car.

car has a new autometer oil pressure guage, has also been tested on my workshop guage.

forgive my stupidity. But i take it the workshop gauge is a mechanical gauge and not just a different gauge hooked up to the same sender ????


I guessing mechanical gauge being a mechanic

[EVOSTi]

yeah its a mechanical guage and its being tapped right at the block, think i tapped it in place of the sender which is on a t piece from the block.

didnt speak to chris today, he never came in to pick up the brand new oil pump he ordered so didnt find out the specific psi reading.

in regards to a blockage, its a very long story with this motor but it had the problem before it was rebuilt, its in a ke70 with no oil guage only light. it got a big end knock so we rebuilt it with a new crank and got is linished, all rods closed and honed. thought it would have been due to a poor tune as the top bearings in the rods were worn indicating knocking. (also some bad rep about this tuner made us suspect). drove it to wear it in before a tune, on the way to the dyno after 1000kms it got a big end knock again. changed the block and crank again, this time the owner got an oil guage. found out the pressure was ok at idle but didnt rise enough.

so anyway, im thinking next time i get my hands on the car ill tap the mechanical guage where the oil feed for the turbo went so as to eliminate the turbo. ideas?

[kingmick]

its got a sticky pressure piston or a very very worn pump! if the crank was changed it means the pickup isnt clogged-up unless someone did it and didnt know what they were doing.

[EVOSTi]

the sump, block and pickup were thoroughly cleaned and were not blocked. changed the pump with another second hand one and nothing changed.
i did the rebuild, im no rebuild expert but ive rebuilt a few engines, especially 4a's.

[kingmick]

you either have sticky pressure piston{stuffed spring,worn bore or wrong piston or missed a washer etc) in the oil pump, the wrong sized bearings or you have some shit in the capilary for the gauge.

[EVOSTi]

nah when we changed the bearings we got oversized ones, which were supplied by the engine machinist who did the crank, and i checked with plastiguage also.

coincidence that the second oil pump is the same? shimmed the second pump.

also, have used two mechanical guages.

[Joshstix]

If a reshimmed pump makes exactly the same pressure as a non shimmed pump even when you rev it then I'd have to say it is being restricted before the pump.

Without knowing how much the pressure does actually rise with revs I wouldn't like to guess any further.

One other thing that could be causeing it, but I'd expect the pressure to be too low all the time is too much clearance on the cam journals.