Reply With QuoteHave you thought of switching pan back to original setup and see if problem goes away. don't know if that's possible but one way to isolate the problem?
Originally posted by roostwear
I have a 460 in my Advantage with a pressure loss problem similar to yours. I have done to my boat what I suggested you do, and am positive the biggest contributor is viscocity loss due to heat. I even have a dooley pan and pickup. When I shut down for an hour or so, the pressure is fine until I'm just on plane (or faster) and it builds heat. I suspected the pickup in the beginning, but after measuring the oil level in the pan, found that the pump is partially submerged, and the pipe (that's bolted to the bottom of the windage tray) is near the oil level. The pickup pipe diameter is larger than an automotive pickup so I discounted that reason. I changed from a dyno based oil to synthetic, and the condition was much better (but still there to a degree). The more hours on the oil, the more drop I'll get.... I assume from fuel dilluting the oil in time (I run it too cold).
At idle, the oil level is not at the level on the dipstick, it's a little lower due to normal circulation. As you accelerate, the oil level will drop further as higher rpm will produce greater volume. A high volume pump will displace an even greater volume at a given rpm, with the drain back volume limited by the size of the drain holes. Easing into the throttle would cause less volume to be sent to the top end than if you stabbed it hard, but is it the basis of your problem? I don't know. It may contribute to it, but to me, loss of viscocity would seem the more logical reason.
I don't know what effect the Milodon pan is having on your situation as I've never run one. The problem is, most of the advice in this thread is theoretical, although based on reasonable logic. The only way I can narrow my condition down more is to add a cooler, and test it again.
Just another .02
Thank you very much for your input. Your idea won't hurt to try. But what if I told that it happens immediately when the oil only warm not hot? I did'nt try it yet but, I bet you it would still drop. You said your problem goes away after an hour or so after the oil cools down. You mean that you get NO oil pres drop on accelleration when the oil is warm?
Why am I having these problems since the pan upgrade? There were no oil pressure drops with the old front sump stock pan running 10w-40. So I'm not sure it's a viscosity problem.
Another thing is the pressure drop is pretty constant. Never goes below 25lbs on hard acceleration from idle only. After an hour of drive time!
I promise when I find a solution, I will post it.
Have you thought of switching pan back to original setup and see if problem goes away. don't know if that's possible but one way to isolate the problem?
Originally posted by powerplay230
Have you thought of switching pan back to original setup and see if problem goes away. don't know if that's possible but one way to isolate the problem?
Old pan is long gone. I thought of this. Would be a good test. But I'm pretty sure that the old setup would have worked ok. I did not do anything else really major to my engine to affect oiling except the pan upgrade.
Dean,
Just looked at your site, sweet job redoing the boat... that your line of work or just a personal project?
Originally posted by powerplay230
Dean,
Just looked at your site, sweet job redoing the boat... that your line of work or just a personal project?
Personal project. Thanks
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