Too many variables from what you have asked.
What oil viscosity are you running, what outside ambient temp is the oil at when at cold start, on throttle or decel for higher rpms, oil coolers inline, ported cylinder head oil mods, stock head oil pressure regulator, etc, etc.
Good rule of thumb is 10psi per 1000 RPM.
Most unmodified balance shaft motor 4g63's will likely see 25-50 psi cold idle spring/summer, with light oils. My 4g63t (91 w/oil cooler, balance shafts, no oil port relief, 10w40 Brad Penn Racing synthetic oil (no detergents) gets these figures and my 4g61t (no coolers, 5w30 Mobil 1 synthetic oil, no balance shafts, squirters intact) also got these figures at those temperatures. Idle speed and lopy cams will affect idle pressures due to surge.
All 4G61/63/67/64 DOHC heads from 1987 (overseas) to 1994 are identical in terms of oiling, NA or turbo motor blocks they are bolted to, from what I know. Oil pressure reliefs across the different oil filter housings are considerably different in terms of length I the spring and piston combinations and the relief hole in the housing. Jafromobile does an excellent video with graphs to illustrate that on YouTube. But I digress, if your oil pressure are at any point below say 20 psi at idle, not anywhere near (10psi x per 1000 rpm) when the oil is warmed up to operating temp, then suspect a problem or a situation created by modifications that needs to rectified. These are my thought, and I'm sure many experience very high oil pressures with cold 20w50 oil, external coolers, balance shaft (4g61 block off parts), plugged squirters holes, etc.
|