Thread: 355 Oil pressure problem

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I have a fresh 355 (1 hr. run time). When the engine gets to operating temp the oil pressure drops and the lifters start ticking. To catch you up, after cam break in, one lifter collapsed. I pulled the intake and put new lifters in it and checked the cam. Everything looked fine, but after reassembly the oil pressure problem started. Any suggestions would be appreciated.

First off, oil pressure always drops as the oil gets warmer because it thins. All oils, all engines. So, more info is necessary unless you want folks to make a bunch of wild guesses.

First thing would be.............what viscosity rating is the oil you're using?

Oil pressure at engine start up is 70 psi. After reaching 180 deg. it drops to about 15 psi, and the lifters start ticking. I am running 10-40 Castrol.

Oil pressure changes with engine rpm too. Assuming (because you didn't state so) that it drops to 15 psi at idle, that's not too uncommon or alarming for a warm engine. I personally like 20 better, but 15 isn't bad. 10w-40 is not real uncommon, though I prefer 10w-30. I could go into a long discussion on why, and how, but I don't have time for that, and if you did a search you'd find earlier discussions on it anyway. If the lifter noise, assuming you've diagnosed that correctly, is oil caused, it could be that 20w-50 would help too. But that is a guess. It could be that there is something blocking the oil galley that supplies the lifters too. Or you don't have the rockers adjusted correctly.

You don't by chance have oil restritors in the back of the block.I have seen this happen before.