4A-GE/GZE Oil Pump Mods

[rolleraction]

It is of benefit in a race engine. Race engine bearing clearances are, generally speaking, larger than stocker bearing clearances, so more oil is required .(as oil can escape quicker thereby lowering oil pressure - same with worn bearings). particularly at high rpm.
A 2mm shim 'should' up the tension of oil pressure relief valve spring sufficently to enable around 10psi incease at high rpm on a 4ag / 3sg (my 3sg had over 80psi at revs as opposed to stocker pressure of about 70

[Grega]

nice one rolleraction.
theres your answer RT40...unless you're running larger than stock bearing clearances then don't bother.

+rep for u

[oldcorollas]

It is of benefit in a race engine. Race engine bearing clearances are, generally speaking, larger than stocker bearing clearances, so more oil is required .(as oil can escape quicker thereby lowering oil pressure - same with worn bearings). particularly at high rpm.
A 2mm shim 'should' up the tension of oil pressure relief valve spring sufficently to enable around 10psi incease at high rpm on a 4ag / 3sg (my 3sg had over 80psi at revs as opposed to stocker pressure of about 70

thats the thing tho.. increasing the bleed off pressure may not actually increase the oil flow... ie IF the valve is closed, then the pump is pumping all it can already..

are we saying that by increasing the pressure on the inlet side of the bearing, then even though the bearing has larger clearances, that will increase pressure on the "outlet side" (for want of a better term) of the bearing to nromal or sufficient levels?

i guess it depends on what is the rate limiting step? the oil going from gallery to the bearing.. or the oil being shed out the side of the bearings?, or.. oil in the film itself?
anyone know?

[allencr]

That special washer looks obviously dimpled to center the spring & stop it from chewing up the bore.
I would not defeat its purpose.

[oldeskewltoy]

thats the thing tho.. increasing the bleed off pressure may not actually increase the oil flow... ie IF the valve is closed, then the pump is pumping all it can already..

are we saying that by increasing the pressure on the inlet side of the bearing, then even though the bearing has larger clearances, that will increase pressure on the "outlet side" (for want of a better term) of the bearing to nromal or sufficient levels?

i guess it depends on what is the rate limiting step? the oil going from gallery to the bearing.. or the oil being shed out the side of the bearings?, or.. oil in the film itself?
anyone know?

More pressure isn't necessarily better... more VOLUME can be........ I remember all kinds of hot rodders tricks to boost pressure... all boosting pressure really does is blow oil filters apart! Boosting volume is what you are after... for boosted volume will also increase pressure where passages narrow... also boosted volume fills the larger clearences while maintaining pressure....

The oil pump I fitted to my 428 SCJ Mach 1 was 10% more volume... it achieved this by making the pump 8mm taller than the stock pump. In an old V8... where the pump hangs inside the engine.... no biggy... BUT a pump that also finishes the front of the engine.... tough to increase any dimension.

[allencr]

.... tough to increase any dimension.

Then close up the tolerances - refine the fit and finish.
Also, if you're running a mickeymouse bypass Toyota oil cooler, 'fix' its valve too.

[oldeskewltoy]

Then close up the tolerances - refine the fit and finish.
Also, if you're running a mickeymouse bypass Toyota oil cooler, 'fix' its valve too.

Hehehe.... no.. this time Mickey stays in Disney...

as of now I'm looking at Mocal's thermostatic adapter. Concerning the coolers size... I actually think the stock cooler is well located, and with the correct adapter will be more than adequate.

[TERRA Operative]

You can also 'port and polish' the oil pump. By smoothing off the edges the oil has to slip around, you will increase flow.