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1992 Cusader 454-oil pressure problem

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a1a82246

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Did end of season oil change. Installed Fram PH8A filters and switched from SAE 40 to 15W40. Started engine after change. Oil presure came up to 35lbs, then after 3 minutes,guage suddenly went to 20lbs and oil pressure warning light came on. Repeated and same thing happened after 3 minutes. Other engine was fine. Engines have 1100hrs on them and have been trouble free, except for occasional warning light coming on at idle.
 
Put a mechanic test gauge on the engine to rule out the sender, switch and gauge, and see what the real pressure is. See if you get the same drop after three minutes. By the way, I've had two Fram PH8A filters in a row fail.
 
Likely an un related problem but my port engine (BOTH 1992 454's) did this after warming up to operating temp and was down to about 5-10 psi at 2500 rpm while the other side was a rock solid 40. With about 750 hours, we had recently finished a top end rebuild and during the disassembly, anti-freeze had gotten into the oil pan and FROM WHAT I HAVE BEEN TOLD, antifreeze gels when it over heats and clogged our oil filters allowing the by pass to kick in.

To make a VERY long story short, it took 6 oil changes and 12 filters to "clean up" crud in the system passages and pan. Numerous cleaners and fluids to help homogenize the mix. Last year she was absolutely perfect. Rock solid 40 psi. I think we had gotten lucky FOR ONCE! Could it be you are experiencing something similiar?

FYI: We would be out fishing and when this happened each time, my brother ran down, changed the oil filter and we were back up to 40...IF ONLY for an hour or so. We kept a case of oil filters at that time on board
 
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ditto on the mechanical gauge.

The low pressure light should not be on if there's 20 psi in the galley.
 
a followup to Knuckle's comments - I'm investigating coolant filters for the diesel truck. With a few remote oil filter heads around, I figured why not use one instead of springing for the $100 kit? Checked with WIX and Honeywell and the consistent response was NOT to use an oil filter as a coolant filter. Turns out the water will "clog" the media and nothing will flow thru it. So, now there's another reason to change the oil and filter if you get coolant in the crankcase.
 
What should I use to clean out the water in my oil? Is there a magic additive that will flush out the oil system??
 
Kevin; if your sure that no more water is getting into the crank, and your running on a fresh oil change, I'd run it at cruise for a couple of hours. Look at the breather outlets and oil fill cap for signs of water. You can't get all the water out with drainings, but heat will drive out the water. Heat is that magic additive. Make sure oil pressure is maintained thru this exercise, and run it at cruise power, not wide open, like about 3200 for a few hours. That will get the oil temp close to the boiling point of water and drive the vapor out the breathers. The sooner this is done, the less corrosion that will occur.
 
Ditto DD's advice - heat is the preferred approach.

If you have access to a vacuum pump, that's another approach (cheaper because you don't need the fuel) but will require some fabrication to get the connections to the engine.
 
Well then....unknowingly, it is what eventually solved our problem.... I think it was LineSix Rick that actually had mentioned this to me a few years back
 
dont use fram filter ever on a marine motor!!!

they have the wrong pressure valves inside of them
they use tin metal, which will corrode
 
When you say the wrong pressure valves, can you be more specific. I had a simaler issue with my engine where I would start with good pressure but once she warmed up it dropped down to nothing. I have the engine out to work on but have yet to start on it. The engine is a chevy 350.
 
missnancy said:
I would start with good pressure but once she warmed up it dropped down to nothing.
Click to expand...

Sounds like main bearing high clearance. Either increase the oil viscosity, or if its already at 40w, likely time for engine work. Lower on the list is cam bearings and oil pump.
 
Dave is right. Recent;ly helped a friend rebuild his 1991 big blocks with very low oil pressure. lots of hours (nearly 1800) and several other issues. With the engines finally complete, his oil pressure is near 60 at startup and levels out to around 45 after warmup. Frankly, I'm impressed enough with all the other elements of the rebuild to consider a rebuild on mine next winter
 
If an oil filter plugs and buypasses you will still have psi going to the bearings it just will not be filterd but were your sender is geting is reading from in your case is also geting buypassed like the other guys said find a different place for a mech gage look for an 8th inch plug fitting going into the oil galory not alway ez to find but thay are thare do to casting and drilling the block in tha manufacturing of the block and put the gage in it that way it can't lie t you also I would pull my vavle covers off and. See if you don't have a lot of sluge build up cuz this can slow down the draining of oil back to the pan and starve it of oil temperarily also don't use a high detergent oil in a old engine wich thay sell a lot of now days thay disloge and plug filters and even the pick up screen and make more fome and always use a thermostat a lot of people take them out the engine runs to cold and makes more sluge. The cleaners don't remove sluge thay just loosen it and plug filters just something for you to think about.
 
Ah filters don't have valves in them and almost all are made of tin except some of tha cartridge types the psi valve is in the pump and the buy pass valve in the filter houseing .fyi
 
I would look in the pan for the pick up to be partly pluged up psi will drop a bit when hot also but not much since its out replace the oil pump or to save money open up the pump and replace the relef valve and or spring you can also get different psi springs to bring up your oil psi if you would like and spend the saved money for new parts or gas.
 
FYI...this situation did not simply clean up with 1 oil filter change... we kept 4-6 extras on board and used 2 on one trip alone. It took about 3 months of frequent boat use and maybe 10 filters to actually eliminate that issue. Last season (2010) we had no trouble at all with good pressure
 
Hard to believe that an oil filter makes that big a difference, but I just remanufactured my 1988 454s and installed Fram PH8A filters.

Using Shell Rotella T 15W40, my cold pressure registers 40 PSI, but when fully warmed up, can drop to as low as 20 PSI at idle, momentarily triggering the warning flasher. The oil then cools somewhat and the pressure rises to 25-30 PSI.

My engine rebuilder says 20 PSI is more than adequate, so I should not worry. But I curious about the claim that changing to K&N (or perhaps another marine grade) could make such a difference, so I'll give it a try.

Another reason for lower oil pressure is that new bearings and pristine oil galleries should allow the oil to flow easier. Higher volumetric flow is accompanied by lower oil pressure (less restriction).

I’ll be back with the results of the oil filter test soon.

PS. Fram PH8A oil filters do have a bypass valve. I know—I opened them up after the break in period to look for signs of metal.
 
According to the old (and conservative) rule, you need only 10 psi oil pressure per 1,000 rpms.

I run Wix filters sold by NAPA that are good for 100 psi plus and are highly rated in filter tests.

Jeff
 
It is really hard to beat the NAPA Gold filter (made by Wix). Well built, relatively inexpensive and readily available in many sizes. I've used them for years in everything from big block Crusaders to old 1600cc Porsche engines and have never had a problem.
 
Ok for what it worth 10 psi per 100 rpm is enofe to keep a stock or near stock engine of eney make alive as long as its in good condishion as far as filters I like remote one like old fram canister types or the same type. Thay are baced on old lube a finder type truck filters but smaller but without getting into all that the more filtration the better.
 
I use the NAPA / WIX filters and there are two that fit my 1985 454's. One is longer and holds/ filters/ cools more oil.
- Oil Filter: WIX Long 51773 = NAPA FIL1773. WIX Short 51515 = NAPA FIL1515
 
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