Reply With Quotesounds like the oil pickup may be loose in the pump. As the engine starts it pulls the oil level below the loose oil pickup and the oil pressure drops.
My friend has a 572 chev in an older mantra jet.He had a major oil pressure drop and shut the engine off. After checking the sending unit and gauge connections the pressure drop happened again after restart.Initial pressure is about 50 lbs. then drops to less than 20 lbs.This engine ran great last year.The oil filter is a remotely mounted purolator and feeds into an oil cooler before returning to the engine.This remote filter assembly has an in/out cast into it, so the lines should be correct.This unit was powdercoated last fall, could some thing have melted or is it possible the oil lines are screwed up? I have yet to look at it but hope to get some opinions. One other thing, he set the valves at .022 "tight",mild solid roller and its an iron block and head motor. Thanks
sounds like the oil pickup may be loose in the pump. As the engine starts it pulls the oil level below the loose oil pickup and the oil pressure drops.
I suggested that and he said it had been welded.He cheked the oil filter and when he dumped it it felt like something was iside. I know they have some type of pressue bypass in certain filters. If he cuts the can open,should he cut near the base?
I am curious about the problem too. I had a similar (75psi@startup / 40psi once hot) oil pressure also, and am not 100% sure what the problem was and would like to keep this from ocurring again.
Is there anything that he did differently such as change oil weight or brand during the year? I there anywhere the pump could be drawing in air? Is the oil fuel contaminated (pull dipstick and smell)? Possibly the oil is getting too hot (check with infrared temp gun...aim @ oil pan)? What is the pan capacity? Does the engine have roller rockers and oil restrictors to the lifters?
Maybe we can figure this out! Mike
First isolate the O/P gauge and sender out of the picture by installing a mech guage in it with a tee fitting, run both of them. I had to do this to find out I had a flakey sending unit. If the O/P is the same when checked then you know where to look. LOL
Did he change the filter and still have the same prob? Filters do go bad. I've seen the element collapse and plug the filter. Fuel in the oil could also be the prob. If the oil lines are reversed either at the filter or engine you could get the same prob. I doubt the prob is hot oil. Sounds like the pressure is dropping pretty soon after startup?! Check, check and double check EVERYTHING. Oil pressure probs are bad juju!!
Oil lines exiting the block,where the original filter mount was, were reversed.Hopefully no damage occurred.He will test it with a mechanical gauge.The oil is 20/50 Kendall, cooler and a 10 qt pan.Thank you for the suggestions!
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