oil pressure low.

[coronet69swede]

Hi guys.
Pressure is 21psi at idle and is building up to 50psi at 3500. from there it is going down. did not rev past 5000 at 43psi. cant see anything on the outside so i stripped it down. main play is 0.0043 and rod play is 0.0035. camshaft is0.0039 at 1,2 and 5 and 0.0019 at 3 and 4. Restrictors to the rockers is 0.059*2. melling HV and 3/8 tube. wrong???
Cant find anything broken.
What do i do from here.
this is the project:
http://www.forbbodiesonly.com/moparforum/showthread.php?t=30570

 

[Budnicks]

Need more info... Just spit-balling here... with out having to search another post, not knowing all the specifics of your build & complete oil system specs.... How old is the pump ??, what oil are you running ??, at what temperature are the pressure readings at ??, & is it water temp. or oil temp. ??, what type & size/capacity oil pan are you running ??, do you run a wind-age tray ??, what kind of oil filters are you running ??, & do the oil filter have a bypass ??, what kind of oil pressure guage ??, & is it mechanical or electronic ??, what pressure spring is in the oil pump ??, what kind of camshaft Hyd.or Solid ??, & is it a roller or flat tappet ??, what type of rockers push-rods & shafts are you running ??, & are they installed correctly ??, it could be a false reading from the guage &/or sending unit, it could be the type pressure spring in the pump, it could be a bad pump & needs to rebuilt or replaced, it could be lack of oil in the pan starving it at higher RPM's, it could be the viscosity of the oil, it could be the shafts are upside down not getting adequate oil, the bearing clearances don't seem to be bad enough to cause a big oil pressure drop... I see in your other thread you have modified the oil passages with restrict-or your completely changing the fluid dynamics of the original system. Also were did you get the size & restriction information from & why ???

 

[lewtot184]

if .0043 and .0035 are the bearing clearances in thousandths of an inch, thats pretty darn loose and well definitely decrease pressure. a high volume pump usually has a 75lb relief spring. i don't like restricters to the rockers but that wouldn't effect pressure. .019 side clearance is normal for stock rods. try a different pressure gauge and see if you get the same results.

 

[Stumper]

i don't like restricters to the rockers but that wouldn't effect pressure. .019 side clearance is normal for stock rods. try a different pressure gauge and see if you get the same results.

I beg to differ. Just removed my restrictors to the heads and dropped from the usual 80 psi cold (regulated) to 72 psi with warm temps effected even more.

 

[lewtot184]

I beg to differ. Just removed my restrictors to the heads and dropped from the usual 80 psi cold (regulated) to 72 psi with warm temps effected even more.

i think you have taken my reply out of context. restricters will not reduce pressure.

 

[Stumper]

Sorry if i misunderstood the comment. I thought you were indicating that restrictors don't impact oil pressures. My experience is that adding restrictors in line to the heads will increase oil pressure some. Especially noticable with high volume/pressure oil pumps.

 

[bigmanjbmopar]

my 493 idles between 20-30 and cruises at 60-70. at first start it used to go to 80 but now hovers around 60. Not loosing any oil so I think your fine.

 

[MarPar]

Wow, these are some high oil pressures (to my untrained eye) im hearing y'all are running.

what is a bone-stock 440 HP supposed to run (for a baseline anyways)?? 35 (at idle) and 55 (high RPM)??

me thinks a stroker may be higher, but im wanting to learn more. :toothy6:

 

[coronet69swede]

Thanks. Here is some more info.
Tried 1 new pump and 1 old. Put shims one the reliefspring. 7 guarts pan.
15/50 motul syntetic. Watertemp 80-85 C. Windtray. Restrictorholes from Finkbeiner book. Harland sharp full roller. Lifterholes is 0.0023. Mecanical gauge. No bypass on filter.Hydralic roller.
The pressure is fine when cold but warmer it gets the lower the pressure.

 

[Budnicks]

Go to a thicker oil...

 

[PoppaSmurf]

I concour with Budnicks everything...I guess now that you have it broken down your going to re -ring, and Re-Bearing everything, and you might find your pressure coming back up...if it were me and it's this far broken down this far...measure your Crank..rod journals and main journals, make sure it's ALL within specs, takes a an hour with a micrometer
at the least you'll know what your dealing with...
If your just going to put her back together...stick a straight 40w in her she what she does..... and :headbang: rock-on

PS if you do a freshen up....change or rebuild your oil pump...Please....lolol

 

[bigmanjbmopar]

I just changed from a non synthetic 30 weight to the Brad Penn 10-40 based on their recommendation and the pressure went up to 75 at start up. The 40 is heavier than 30 so I did expect a higher pressure.

http://www.penngrade1.com/

 

[wedge5]

The 10-40 acts like 10 weight at start up but protects like 40 weight under use. That is why you are getting higher pressure at start up.