Newly built 440 with low oil pressure

[Norv]

Hello, I have a 440 in my GTX that was just built by a very reputable builder.
It was broken in and runs great.
At cold stat up 70lbs of oil pressure
Took on a 25 min ride on highway at 55 oil pressure is at 30-35 lbs when you come to a stop with car in gear it’s low I attached a pic. When you get on it alittle the pressure will rise to 60lbs. I’m lost. ? In park it’s 20lbs. Any suggestions would be greatly appreciated.

View attachment 1347662

Water temp should be around 180 I think. I live in the south and I ran my 69 road runner with no thermostat. Never had a problem.

 

[Challenger340]

If you want opinions about Oil Pressure ?
Understand that Oil Pressure in any Engine is "relative" and is generally speaking affected by :
* Bearing Clearances present
* Oil/Operating Temperature
* Oil Weight
and
to some extent whether it's a Std or High Volume Oil Pump once either hits it's pressure relief setting.(~45 psi or ~70psi)

You dunno the Bearing Clearances
so it's really easy ?
if you don't like the Oil Pressure just change the Oil and go to a little thicker Oil

ie:
if using 5W anything get it the F*ck outa there
if using 10W30 then go to 10W40
if using 10W40 then go to 20W50

 

[MoparSuperBeeMe]

My great uncle had worked for Chrysler for many years and he always said that the small blocks only needed 6PSI to oil. I like to see atleast 20PSI at warm idle.

 

[dvw]

If you want opinions about Oil Pressure ?
Understand that Oil Pressure in any Engine is "relative" and is generally speaking affected by :
* Bearing Clearances present
* Oil/Operating Temperature
* Oil Weight
and
to some extent whether it's a Std or High Volume Oil Pump once either hits it's pressure relief setting.(~45 psi or ~70psi)

You dunno the Bearing Clearances
so it's really easy ?
if you don't like the Oil Pressure just change the Oil and go to a little thicker Oil

ie:
if using 5W anything get it the F*ck outa there
if using 10W30 then go to 10W40
if using 10W40 then go to 20W50

What is the issue with 5wX oil? 5w is thin when it needs to be. When it's cold. Agreed the 2nd number (X) will increase the pressure. But by reducing flow. Unless the flow is excessive due to clearance out of spec, why would swapping to thick oil be a benefit?
Doug

 

[Rusty34]

If you do in fact have .0025 on both rods and mains you are OK. That is a rather abbreviated way to state clearances during the build though. How did the engine builder determine that? Did he Mic all the journals and write down an average number? Before he installed the crankshaft did he torque each rod and main cap with new bearing shells in place and read the inside diameters with a good dial bore gage and write down those numbers, do the math and record the average rod and main clearances? I would only accept measured housing bore, rod journal and torqued bearing ID dimensions for each of all 8 rods numbered 1 through 8 and the same for all 5 mains.

Factory bearing clearances were derived at based upon using the available oil chemistry for that day and time. Today's thinner multi-viscosity oil formulas are designed to be specified for modern more efficient engines where tighter clearances are called for throughout the engine. Another point to consider is the oil pump is at the front but the tap for measuring oil pressure is at the other end of the block. If you could set up a test designed to measure oil pressure at each main bearing you would find pressure is the highest at #1 and drops progressively as you move toward #5. The Hemi oil pick-up tube is highly recommended for any big block build that might get run hard.

Another source of oil pressure loss is in the cam bearings and tappets. Roller lifters can be among the worst offenders as the manufacturers put large orifices in them to be sure the bearings in their lifters get a lot of oil. This area can be restricted as can oil to the rocker arms if need be. The oiling system should be well thought out in case some of your modifications will cause excessive oil volume to be delivered to areas that do not require that amount.

The number one goal here is to make sure you are delivering enough oil to each rod bearing because that is where starvation will end your day first.

 

[Challenger340]

What is the issue with 5wX oil? 5w is thin when it needs to be. When it's cold. Agreed the 2nd number (X) will increase the pressure. But by reducing flow. Unless the flow is excessive due to clearance out of spec, why would swapping to thick oil be a benefit?
Doug

Depends upon the Bearing 'eccentricity' now doesn't it ? and how much time does it spend and how COLD really ?
P Bearings can exhibit .0045" to sometimes as much as .0065" Clearance over closer to the parting lines depending upon the 'crush' applied during Housing Sizing.
H's and V's eccentricity are better for performance applications with less degree of change, but again depending upon crush applied by the sizing of the Housings from 'low to high' within the tolerance excesses can exist that in my experience do NOT bode well for 5W anything when speaking strictly around the 'mass' of the Oil(NOT viscosity)
just say'in....
you do whatever you want.

just me....
But I won't run a 5W anything in these old engines.... NO need.
And I would suggest that if one of these older generation engine exhibits decent Oil Pressure using a 5W anything ?
I would like to know the Oil TEMPS being exhibited over extended running time/rpm's and manifesting in water/coolant temps ?

 

[dvw]

I've personally never seen an engine with low pressure cold only due to light oil viscosity. The 5Wx oil acts the same hot as a 10Wx or 20Wx. I'd rather have flow cold. Not to mention who beats on there stuff cold before warm up? Are you saying you are worried about cold temp metal to metal contact due to lack of oil mass/film? Heck cold 5w flows way less and has greater viscosity than warm 40W. Have you seen damage from a 5Wx oil that was confirmed do to light viscosity cold? I'm curious.
Doug

 

[Geoff 2]

That is why here I can get 5W/50 or 10W/60, which is what I use, mild climate never gets below freezing in winter.

 

[Rusty34]

This engine has 360° main bearing oiling to the rod bearings now too which will lower oil pressure. 360° oiling will need a higher volume pump. He should also change to the Hemi pick-up tube to supplement the pump. This engine still has stock oiling to the tappets and rocker arms which costs some pressure. In racing applications oil is usually restricted to the upper regions so benefit of increased oiling can be directed to the rods which is the primary demand. In well dyno developed race applications the penalty for increased excess oil flow is horsepower so it is now important to know exactly how much oil is needed at full peak power RPM, full load and the oiling system is modified by installing restrictors in the path to certain areas. During development on a dyno you would install flowmeters with pressure sensors in many different places on a dyno mule and begin measuring everything everywhere in order to find out where restrictors are needed. Once the oil circuit is developed you would then begin dialing back pump output pressure and volume so you aren't wasting horsepower by pumping oil through an open bypass valve. The most important thing to know is how much pressure you actually have at each rod bearing and they will all be different. The rod bearings must survive at wide open throttle under full load with at least 2psi at the rod bearing because the hot oil coming off a fully loaded rod bearing at maximum RPM is around 400° F. This is the main driver of oil temperature.

 

[Nick Panaritis]

Nick from Nicks Garage did a video about the Melling pump partially blocking the oil hole in the block restricting oil flow from the pump to the engine.
It would pay you to check this I think.

Hi this is Nick, that pump wasn't a Melling pump as you are referring to, it was another unknown manufacturer. I have had great success with Melling pumps, they actually line up well with the block.

 

[steve340]

Thanks for clearing that up Nick.
I remembered you mentioning it and thought it may help the original poster.
Keep up the good work on the channel.
Steve

 

[Kern Dog]

It has been over 2 months since the OP started this thread and since then, he hasn't been back.
I hope he figured things out.

 

[Tony Tee]

My 70 charger 440 r/t se back in the early 80's had the nylon timing cam sprocket deteriorate and small graines of nylon somehow got by the (cheap) oil filter and embedded in all the bearings raising my oil pressure. I found this out after I tore down the engine for a rebuild. Double roller timing set was it's replacement.