Oil cooler low o/p

I have new rebuilt motor. It was running good oil p. until I installed my oil cooler setup. I?m running thermostat control oil filter sandwich, 10an lines which 2 90 fittings. Does some setups flow better than others? I have 4lbs at idle hot but climbs to 45-50 by 2500 rpms. The idle psi makes me a little nervous. Is this normal or should I be making some changes? Also, I?m running Amsoil 5w40. Thanks

Hook up a mechanical gauge and check. Mine was showing the same low ~5 psi pressure at idle but spec at 2000. Turns out it was idling at 15-20 psi no problem

I would say you are likely fine.

The question points out that his pressure dropped after installing the new cooler setup.

After I post this, lots of people will say "well mine works fine."
So... I experienced the exact same pressure drop many years ago when I installed an all new oil cooler and remote filter setup on my 2.6 stroker using -10 lines. Following a suggestion from a very experienced redblock builder, I changed to -8 lines on all setups from then on and never had that issue again. Maybe it means something, maybe not.

In 2019 I made an all new setup for my 242, remote filter and RX7 oil cooler (using -8) and I posted the full install here: https://forums.turbobricks.com/showthread.php?t=349225
Oil pressure is great on my original never opened 220k mile B21FT.

Dave B

Thanks for the link Dave, appreciate the detailed and links to find the hardware. Diffently gonna switch to 8an.

dbarton said:

The question points out that his pressure dropped after installing the new cooler setup.

After I post this, lots of people will say "well mine works fine."
So... I experienced the exact same pressure drop many years ago when I installed an all new oil cooler and remote filter setup on my 2.6 stroker using -10 lines. Following a suggestion from a very experienced redblock builder, I changed to -8 lines on all setups from then on and never had that issue again. Maybe it means something, maybe not.

In 2019 I made an all new setup for my 242 (using -8) and I posted the full install here: https://forums.turbobricks.com/showthread.php?t=349225
Oil pressure is great on my original never opened 220k mile B21FT.

Dave B

Click to expand...

Higher flow = lower pressure?

The hose size and oil pressure does not make any sense... unless you are measuring the pressure of the oil before it enters the cooler and lines, not after it. Then the smaller hose will increase oil pressure since it’s a larger restriction to flow.

I had similar issues as you did Dave, except my idle pressure is fine, higher rpm's it doesn't climb like it used to. I used the stock hardlines, replaced the rubber, but swapped to AN to fit onto the RX7 cooler I'm running. No other changes, same sandwich plate, only difference was the cooler and the fittings into it. I can also tell it's the cooler, as the pressure drop can be watched while driving, as the temp's climb into the stat opening range, consistently.

One other thing I've noted, is the pressure sender is prone to temp based changes. Different gauges, same sender. If I jump straight on the freeway when it's cool out, the pressures are actually lower than if I am in traffic for a bit before I get to the freeway, even if the temps while cruising on the freeway are the same, and the oil temps are the same. I've had a few years of driving to confirm this is a drop dead consistent pattern.

lummert said:

Higher flow = lower pressure?

Click to expand...

Redblock black magic.

Well I disconnected the oil cooler and oil pressure was still really low. So, I tried a different mechanical gauge and sure enough it shows way better oil pressure. Ill hook oil cooler back up, I might change to 8an. Anyways, thanks for the advice and help.