k24u

Built a 454 to the mercruiser 420hp engine but I am balanced bored .030 over and running ported and flowed heads. I am running the stock oil cooler and 30 weight oil the longer I run the motor say 3500 rpm cruise my oil psi slowly starts to sag from 50psi down to about 45psi If I slow down to about 3000rpm and cruise for a little bit the psi starts to come back up to about 50-52 psi. I don't know what my oil temp is but I didn't have this problem the previous years I was running a 330hp 454 before just wonder if I should install a larger oil cooler. I just figure the oil temp is up and because of all the mods. My water temps stay a steady 160 degrees. So I ready for some opinions

biginches

bought one of these,works great

oil cooler

MOP

I would check the oil temp, as long as you are running around 250 I would leave it alone. My pressure drops from 60 to 45 during a hard run but like yours comes back at cruise, I am closed cooled running at 180.

Phil

rexone

I concur, check the oil temp before spending a bunch of dough unnecessarily.

jeffswav

The 330 oil cooler is crap. The 330 cooler is much smaller than the MAG cooler. Anything other than stock engine will not work with that cooler. I just installed a EMI oil cooler from TP Performance. Talk to Don he gave me a good price. I do not have a oil temp gage but my oil pressure was dropping 20 psi or more after warm up. Now it drops less than 10 psi after warm up. Water temperature has however went up slightly. I run a 160 deg thermostat and it runs 175 to 180 on the gage. Prior to the new oil cooler it ran 160 to 170. This may have to with warmer water getting to the engine rather than cool water. One thing I did notice is that the water temp gage does not fluctuate at all. It used to bounce 10 to 15 deg. Let me know if you have any more questions about what I done.