skeet

iTrader: (18)

say chase, i was also concerned about high oil pressure, like 65 at idle, running a 30 weight oil, after changing the sending unit its still the same, i have just over 500 miles on the new 408, ive checked everything, good oiling up top, ( did change filter twice during those miles), now at hard launching at 70 to 130 the oil is around 55 psi at idle, i run a high volume pump not high pressure, nothing really changed on this build from the last one, the last one was at 45-48 psi on idle, 70 wot, but anyway i yet to find a concern.

nice to see the truck back together and running, good luck on your goals im sure youll achieve them!!!

MikeGyver

iTrader: (5)

Why in the world would you use 30 weight? That is for lawn mowers!

skeet

iTrader: (18)

200 mile break in, hence concerned about high oil pressure ! now has 20/50 and pressures are 5/10 higher than what the 30 was

CAGRacing

I have had this problem both high and low on a bunch of different trucks depending on the age of the motors. I've tried the oil sending units and mechanical oil pressure senders.

I've found that oil weight will vary psi an average of 30 psi at cold idle, more when warm.

I've first hand put 5w30 in a small block and had 2 or so psi at idle. Changed sensors and gauge, still 2 psi. Went to 10w40 and bam! 30 psi at idle.

I had a 93 step side with a brand new motor that ran at 60 psi at idle with any oil thicker than 5w30. That thing would leave the gauge at 4,000 rpm!

My current motor has 201k on the clock. Lm7 and was running at 30psi when I changed the oil. Filled with Mobil 1 full synthetic 0w30 and now swear by the stuff (first full synthetic oil change). My startup tick went away, pressure initially dropped 5 psi but has steadily increased to about 40 psi with everything the oil has trapped from cleaning out my oil.

If this is the break in oil change don't forget about all the cutting oil, shavings, assembly lube, and miscellaneous stuff that oil will pick up. That's why you run thicker oil in the first place. Your psi will drop after a few oil changes.

CAGRacing

P.s. from my experience and what I've been told high volume oil pumps will actually decrease measured oil pressure but increase the oil pressure between the bearings. this causes something negative that shortens the life of the motor by some minuscule amount in the grand scheme of things but adds piece of mind and a thicker oil cushion which is better in the short run. Also my engine builders claim high psi is no bueno for a reason I can't readily recall.

And they all lived happily ever after.

I feel like between the last two posts I wrote a novel.