thugsbryan

At what oil pressure does a stock b16 oil pump relief valve start to bleed off oil pressure? I have a b16 engine an when it reaches 60psi the Guage starts to flicker and will not pass 60psi, it's a mechanical oil pressure gauge and i bought a brand new genuine oil pump about 3 months ago

PyroProblem

The FSM for a B16 Del Sol states the spec is 50 psi at 3000 rpms with an oil temp of 176*F.
Are you wanting to shim the pump for more pressure?

thugsbryan

Yes i plan to shim the pump, but i was just wondering why my oil pressure Guage won't pass 60psi at high rev, if it's the check valve in the pump causing it

PyroProblem

If the engine is in otherwise healthy condition, I would say that's exactly what is going on. At max psi, valve opens and bypasses oil.
If you shim the pump, please report back as to what size shim you used and how much it increased pressure. I haven't seen solid info as to what thickness shim equates to what maximum pressure.

thugsbryan

Oh ok, i just wanted to confirm, thanks, I plan to use a 3mm washer to shim it, I don't know what increase in psi that will give me as yet, when I do it i will let u know

civic-steve-94

I bought a brand new pump from Honda also when I built my engine. My oil pressure is higher its around 70-75psi@ 3000rpm, in vtec at high rpm its 95-100psi idle is around 20psi at operating temp.

thugsbryan

Ok, i dunno Why mine giving a lower psi then

m4xwellmurd3r

What oil weight are you using? Bearing clearance and oil weight are the two big variables that impact oil pressure.

PyroProblem

True, but I think the maximum allowed pressure would be the same regardless of oil viscosity and clearances. 60 psi is 60 psi. Perhaps oil viscosity might effect the rpm at which max pressure is reached, but I don't see how it would affect maximum allowed oil pressure (designated by the oil pressure relief valve). I could be wrong though.

PyroProblem

Where are you taking a pressure reading from?
Is it possible to try a different oil pressure gauge?
I don't know, but it does seem 60 psi might be low (max oil pressure) compared to most b series vtec engines.

PyroProblem

Is this with stock bearing clearances? What kind of oil?
I think that's good oil pressure numbers you have.

m4xwellmurd3r

Maximum oil pressure is a result of viscosity and bearing clearances. Once operating temp is reached, the resulting pressure has a maximum if it's too thin. For instance, in my car, with 5w-30, at 200F the oil peaks at like, 75PSI which it reaches at around 4000-4500rpm and holds all the way to a redline of 7000rpm (ls engine), despite having a brand new OBD2 oil pump. Cold temp it will peg at 85PSI (the relief pressure)

I have larger bearing clearances. at 3k rpm though I have 60-65psi. If I went to 10w-40 it should be able to reach 85psi at redline no problem.

civic-steve-94

I am running Lucas 20w-50 high zinc oil with around .0020 clearance on rod journals, and if I remember right around .0015 on the mains.

thugsbryan

I run 20 50 oil in car, im not sure what my bearing clearances are, I have tried 2 different oil pressure Guage and they gave the same reading

civic-steve-94

How many miles are on your engine?

thugsbryan

I put in brand new rings an bearings less dan 6 months ago

civic-steve-94

Did you measure or plastigauge your bearings?

thugsbryan

I think the mechanic did

PyroProblem

Does the flicker match any certain sounds coming from the engine? IDK if its possible to see the beginnings of rod knock/excessive rod bearing clearance with an oil pressure gauge, but it might be possible.

Aradin

3mm is going to be way too thick. .025-.035"(.635-.889mm) thick is supposedly good for a 15-20psi bump. That seems to be about the standard from my research. You may be able to go a little thicker on the washer but I wouldn't recommend going too much.

thugsbryan

No unusual sound from d engine, everyting else is normal

thugsbryan

Oh ok, noted

PyroProblem

I agree but the pressure relief valve plays a big role too, right? If the valve opens prematurely, Im pretty sure you will stop increasing in pressure regardless of bearing clearances.
The pressure relief valve hole is like what 1/2 inch or so? (too lazy to go look in the garage lol) compared to the couple thousandths of an inch in bearing clearances.

Another example is the variable displacement oil pumps used by Porsche and Im sure many other high end OEMs.

Your numbers sound nice and healthy too. Wish I could compare mine, but my car is 300 miles away..

PyroProblem

Does oil pressure drop when you hit vtec?

Aradin

Humor me. What kind of oil filter is on the car? Have you changed it recently or since the engine was built?