Oil Pressure on a 454 Hot & Cold

[TeamNutz]

I was just wonder what types of pressure other people are having on there boats.

I have a Gen 6 454 that today had about:

40lbs at 2500rpm (cold)
25lbs at 900rpm idle (cold)

The other day my pressure got really low in the poker run obviously because it was running alot hotter then usual. When hot we were at:

40lbs at 2500rpm (hot)
<10lbs at 900rpm idle (hot)


I read on other forums this is normal. Supposedly Mercruiser states in manual #23 minimum required is 4lbs at idle, 30lbs at 2000rpm.

Just looking for other peoples gauge readings????

[Grantz]

My Formula has 420 Mercs (454 Block). They both drop to 30 when they are hot and I am at idle. They run about 65 when hot and over 2500 RPM.

[hllywd692]

I had the exact same concern last year... eventually it kept dropping to as low as 8... when at idle hot....then it spun the main bearings. Turned out the bearing were worn causing the low oil pressure when the oil was thin (hot) I know of many people who have the same concerns/ issues - but in my opinion its a ticking time bomb... eventually you're going to have issues.

[hllywd692]

Guess to answer the question, since the rebuild i run at 30 at idle hot and 70 at 3000rpm hot now...

[N'Mocean]

my 454/496 runs 58lb hot oil temps are 195 after a decent run; at idle they which is 750-800rpm 30lbs. Cold temps it will carry 75-80 lbs but it is not good to carry high psi with low temps that is bad too. I always let the engine warm up until I show some temps on the oil temp gauge. Not until then do I put the power on to it. High psi and low temps can spin bearings

[www.stvowners.com]

Sounds maybe it maybe low. You could use an mechanical gauge to check the pressure as sometimes electrical ones could be flaky and could just be the sender. Also what weight oil are you using? Back when I had an I/O I think the Merc oil was 25w-40

[BobbyB]

Try changing your oil. Sometimes it will raise the pressure again. And run 25-40 in it.

[Mofun21]

My newly rebuilt Gen 6 (502) is at 30, hot, idle and 60-70 hot WOT

[TeamNutz]

We changed the oil - no difference
changed out to a mechanical oil gauge - read the same as electronic.

So we decided to pull the motor - to find copper metal shavings in the bottom of the oil pan.

Sent the motor back to ATK-Engines where it came from. Barrings are shot. They are claiming that I must of had air leaks in my oil pick up and the pickup was at an 1" from the bottom of the oil pan and that it is not close enough. The bottom of the oil pan is supposed to have a wall to keep oil on the pickup during movement.

I was not able to remove the pickup from the oil pump without a rubber mallet and the oil pan had 8 qtrs of oil in it. Oil pressure never fluctuated, it was strong from the start until 5 hours in it all of a sudden lost pressure about 25lbs across the board hot or cold.

Not sure what to do now. My concern is that if I have this ATK rebuild it and the excuses that they listed me is not the real problem this may happen again.

[Mofun21]

If you are looking for a new engine builder or just someone to ask about marine engines, Ashcraft Speed and Marine in Butler does a great job, anywhere from stock to wild. Did ATK build it as a marine motor, I don't know them so I'm just asking? The oil pump pick-up location and a good marine oil pan with trap doors are very important. 1 inch was way too high, 1/4" to 3/8" off the floor.

[TeamNutz]

Definitely looking for someone to trust. ATK builds engines for Advanced Auto. It definitely was a marine motor.

Bottom line they are claiming the oil pickup must be 1/2" from the bottom. Because it was an 1" that was my issue. Crank is distroyed and most of the barrings were shot.

[hllywd692]

I had mine rebuilt at Broughers in West Mifflin - I had the exact same problem, spun a couple and bearings and the crank was junk. They never did find out what was the exact cause - but the re-builder didn't like the small oil lines runing to/from the remote oil filter, so I eliminated it and put it on the block. Cost me about 1400, which included a Dyno run since I wanted to make sure it had ample oil pressure before leaving their shop... Purrs like a kitten now.

[Mofun21]

Ashcraft Speed and Marine then to Cygan speed engineering for the dyno work. Both places were great, both in the Butler area. If I had to do it again I would not hesitate going back to these guys.

[www.stvowners.com]

Can't imagine having the pickup 1/2in to high in an 8qt pan would make a difference. Is the pan for a marine appilication?

[Mofun21]

On extended runs at higher rpms all the oil ends up getting pumped up into the block and valve covers. It doesn't return fast enough to the pan plus a 1/2 high and no oil to the crank. Because marine motors do run at higher rpms for extended periods you have to put some oil control measures in place. A 10 quart pan is a good place to start and in the case of the 502 we also went to a different size push rod to control the oil running up thru to the lifters.

[N'Mocean]

You also have to make sure you have a windage tray in the oil pan. The marine engines that I have done have all had a windage tray mounted to the crankshaft bolts. I did try an experiment on a small block chevy in a boat by removing and windage tray to see what would happen. They oil psi was fine running in s straight line but any kind of waves or turns it would drop down to almost nothing. I pulled the motor and installed the tray back on the motor and that was with the oil pump pick-up 1/4 inch off of the bottom of the pan.

As to the size of stock oil lines to the remote filter and cooler. They are way too small, throw them away, there are many articles about this on many of the marine boards. I lost a 454 due to the size of my lines. On the rebuild, every line was replaced with aero-quip hoses and fittings -12. I am even running the large racing filter K&N 5001. The stock fittings are junk and so are the hoses they restrict flow.