Oil Pressure Problem

[Roostertail]

I recently replaced the gauges in my boat. On the first ride out I noticed that I had great oil preassure at idle(60psi)and it increased up to 70-80 as RPMs increased. After I really cranked it up to around 4000-4500 the oil pressure started dropping. It would go down to about 25psi. So I thought it could be the sending unit, I installed a mechanical guage and it is doing the same thing. I pulled the motor and dropped the pan off expecting to find the pickup in the bottom of the pan. Well I cannot find anything that would couse this. I checked the bearings, the pump and anything else I thought would cause it. I have not found anything so I put the motor back together and changed the filter to a Wix. I still have the same problem and I cannot figure it out. I do not know if it was doing it prior to the new gauges because the old gauge was slow to react and I am not sure if it was picking it up.
Any help would be appreciated.
Terry

[MudPumper]

What kind of pan and oil pump are you running, and how much oil????

[seho]

Maybe check the by-pass (if you have one) on the filter adapter?

[celeb1]

You are most likely sucking the pan dry, foaming up your oil or overheating your oil.
You need to make sure you don't have too much oil which would cause it to foam up by getting whipped up by the crank.
Do you have an oil cooler? If not you can be overheating the oil at higher RPM which would thin it out.
I get the best oil pressure with straight 40 weight and a huge STP Oil filter that looks like it holds about 1.5 quarts. The oil filter alone gave me almost 10 extra PSI.

[Roostertail]

I am running a 10 Qt milodon marine pan. It has a windage tray and all the baffles. I have 10 qts plus filter oil. I have been running a 30 wt havoline oil.
Terry

[HammerDown]

I have been running a 30 wt havoline oil.
Terry [/B]
My bet is that 30 wt oil is getting thin after extended RPM runs...try some straight 40 or 50 wt.
My Kendall 40 will drop down some psi after extended RPM's...then it comes back during some idle time.
Some like and use Lucas HD Oil stabilizer.
PS. it's not uncomon for oil temps to rise 100 degrees higher than water temps guring a long hard run.

[Morg]

I am going with Hammer on this one.
I ran a BBF in my old boat 60-75 psi when cold, 20-25psi after 6000 rpm passes. with 50wt.
You are simply warming up the oil.
I would recomend a straight 40wt or even 50wt. You need to consider your main bearing clearances.
Good luck

[Oldsquirt]

Another thought would be insufficient clearance between the oil pickup and the bottom of the pan. Good enough for low rpm flow, but not for the higher rpm flow needs.

[Rexone]

The above is excellent advice on things to consider. If you're running a Fram Filter by any chance we've had lots of reports of them collapsing and causing pressure drop. That would be the first thing to shitcan if you happen to have one in favor of Baldwin, Wix, or K&N. IMO of course :)

[GofastRacer]

Sounds like a stock pump, wanna solve the problem, take the pump apart and set the clearance to .0025 and sand the cover flat and smoothe for a good seal against the housing, put a .060 SAE washer in the bypass, you're good to go!..BTW, make sure you have at least 3/8" clearance pan to pickup!...

[Fiat48]

Originally posted by GofastRacer
Sounds like a stock pump, wanna solve the problem, take the pump apart and set the clearance to .0025 and sand the cover flat and smoothe for a good seal against the housing, put a .060 SAE washer in the bypass, you're good to go!..BTW, make sure you have at least 3/8" clearance pan to pickup!...
And then no Havoline. Havoline always was thin stuff.

[396_WAYS_TO_SPIT]

All of the above are are great tips. I had the same problem so I pulled the pan and checked the pump. My "new" pump was shot. I hand turned the new pump before I swapped it out. I actually had to go through 6 pumps before any of them sounded smooth. That should be the first test ;) now my oil pressure is 80lbs at idle and when the oil is hot I have 45lbs all day long and my motor is very loose(.0025 rods and .0035 mains). Oh yeah and I run straight valvoline 60 wt oil. I also stretched my sping a little(by hand).
And i agree with rexone on what he said. Those damn fram filters pulled my oil pressure down to 25lbs :mad: When I put the mobile 1 filter on it she went back to 45(hot);)
396

[Little Wood Boat]

Roostertail, how many hours were on the engine with the "old" gauge? Did you have the engine rebuilt and don't have a baseline for oil press. before you changed the gauges? I have heard of this problem before..but my answer will depend on if you just had the motor gone through. LWB

[Big Boys Toy PE857]

I just had my second run in with the Fram oil filter problem. Those things should be banned from the market. Lost oil pressure and assumed the worst, just changed the filter to an AC and went back to normal.

[Just Tool'n]

Stay away from Fram, put one of there high perf on last year, started the boat.
WTF? No oil pressure what so ever! Start to scratch my head.
I took that piece of shit of & put another Baldwin HP filter on it.
I now do not buy anything Fram!

[cruser]

Oil breaking down at high temp is what made me switch from Havoline (sp?) to Castrol. I had the pressure in my tow vehicle drop to 0 after driving in second for about 5 miles when I forgot the shift back up after a long down hill. After the oil cooled down the pressure came back but that was the last batch I used. I have had no problems with Castrol.
cruzer

[MAXIMUS]

Try using a straight 50 wt like Kendal or I use Torco. Also a good reason to consider an oil cooler! I have been using a systems 1 oil filter & have been very happy with the results, not to mention being able to clean & inspect! Lets you see all the shit you don't want to see...lol:)

[Roostertail]

The engine was rebuilt last year. It has a full season of runs on it. I really do not know how accurate the old gauge was. This problem just showed up with the new gauges. I did verify that it was not a gauge problem by putting a mechanical gauge on it to verify that is was actuall y a pressure problem.

[GofastRacer]

Originally posted by Fiat48
And then no Havoline. Havoline always was thin stuff.
Yep!..

[LakesOnly]

Roost,
Oil Level: Are you sure your capacity is correct? Milodon says to fill their pan this way:
"Fill the Empty Pan with the Number of Quarts Listed in this Catalog. Listed Capacities Are For the Oil Pan ONLY and DO NOT Include the Filter. Before Starting the Engine, Check the Dipstick and Scribe the New "Full" Level Where the Oil Mark Is. The Original Full Mark Has No Bearing on Where Your New Milodon Pan Full Level Will Be."
Filter: Get the tallest quality filter that will fit in your boat. The greater the pleat area, the lower the required oil pressure to pass a given volume of oil. Incidentally, if you run a dual remote filter set-up make sure the filters are plumbed in parallel (not series) for this very reason. (Also, if one filter should clog for some reason, the second filter--in parallel--will allow oil flow to continue.)
Oil: Let me tell ya something, Roost: The ONLY reason Mario Andretti ran Havoline in his Indy car was because they paid him about a MILLION DOLLARS to do so. There is no other reason to run Havoline. If you engine was built last season and has, say, twenty five hours of good run time on it, then it's time to switch to a synthetic. Among other great attributes, sythetic oils maintain their viscosity over very extreme temperatures--such as those that jet boats subject their motor oil to. Get some Mobil 1 or Royal Purple or Amsoil, etc.
Incidentally, for the first ten hours of run time on my new motor, I was running a petroleum-based motor oil and after several hard passes, my oil (hot) pressure went from 40/70 (idle/5000rpm) to 20/50. After switching to a synthetic, oil pressure stayed at 40/70.
If you are still experiencing unusual oil pressurre characteristics after doing all of the above, shut the motor down and get back on the boards.:)
LO

[Fiat48]

But lakes, My Dad's 1951 GMC 228 spent it's whole life on Havoline and stayed together till his son tried to go 80 mph with it. The smell of burning Havoline is all by itself. :p

[LakesOnly]

Originally posted by Fiat48
But lakes, My Dad's 1951 GMC 228 spent it's whole life on Havoline and stayed together... :p
I'm sure that back in the 1950's, Havoline was a great oil :D
Originally posted by Fiat48
But lakes, My Dad's 1951 GMC 228...stayed together till his son tried to go 80 mph with it.
:D :D :D
LO

[Roostertail]

The oil pressure drop is instant. It goes from 70 psi to 25 psi instantly.

[GofastRacer]

That sounds like a pickup to pan clearance, you don't have enough, you're sucking up the bottom of the pan and not getting enough oil, I've seen that happen many times!..

[LakesOnly]

Originally posted by GofastRacer
That sounds like a pickup to pan clearance, you don't have enough, you're sucking up the bottom of the pan and not getting enough oil, I've seen that happen many times!..
True that...I'd like to add:
Measure your pan-to-pickup clearance. Check depth of pan and then check height of screen above the pan mounting surface area.
I know there may be differences in opinion on this, but I suggest a pan-to-pickup clearance of 3/8-inch.
Did your check oil level yet? How many quarts did you add once the motor was back in? Should be more than 10 (with the Milodon 10 qt pan). How long are you at a sustained rpm before pressure drops?
LO

[GofastRacer]

Originally posted by LakesOnly
I know there may be differences in opinion on this, but I suggest a pan-to-pickup clearance of 3/8-inch.
LO [/B]
That is the minimum!..;)

[Little Wood Boat]

Believe it or not...a friend paid big bucks to pretty well known engine guy in SoCal...he put the cam bearings in incorrectly where the oiling holes didn't line-up. Awesome low RPM oil press. then the same thing you have 20-10psi at anything higher than 3500 RPM. Feel like tearing your motor down and letting us know...BTW, if you've already pulled the motor once so far, just pull it again and go through it and save the money 'cause in the long run when an engine grenades, a decent engine builder won't want any "used" parts in the next motor. Again, I said DECENT, this obviously excludes a budget backyard rebuild. LWB

[Roostertail]

I filled the filter with oil before I installed it. I then put 10 quarts in the pan. I am using a long Wix filter on it. I will try to pull it back out this week to measure the pan to pick up clearance. It does not appear that the motor has actually benn starved for oil. It still looks great on the inside. I am measuring the oil preassure at the port above the oil filter.

[GofastRacer]

Originally posted by Little Wood Boat
Believe it or not...a friend paid big bucks to pretty well known engine guy in SoCal...he put the cam bearings in incorrectly where the oiling holes didn't line-up.
Oh I believe it, that's why I do all my own shit!..:D

[ONAROLL]

Before you pull it again, pull your valve covers and look for a busted spring and/or bent push rod, this occured in my fresh BBF and I went through the same thing , Filter, oil pump, oil pickup tube , bypass valve, all to find out that when the valve spring let go and the push rod got bent it allowed the lifter to jump off the cam and into the intake valley, you would think I could have heard the miss in the engine but standing next to open headers is not a good place to hear any miss, my oil pan was spotless too, at idle I had enough oil pressure to save my bearings, .02

[Stab-n-Steer]

Originally posted by Rexone
The above is excellent advice on things to consider. If you're running a Fram Filter by any chance we've had lots of reports of them collapsing and causing pressure drop. That would be the first thing to shitcan if you happen to have one in favor of Baldwin, Wix, or K&N. IMO of course :)
I wouldn't recommend a Baldwin. We had one "explode" last weekend in a crackerbox while racing in Laughlin spraying hot oil on driver and rider!:mad: Fortunately, they were not burned badly... My pick would be Wix or K&N. As most racers know, Fram's are crap.
S&S

[adsala]

RosterTail,
Did you ever figure out your problem. Could you share it with us when you do. I'm having the exact same problem. Look at the long winded thread I got going. My problem started when I upgraded my old front sump pan to the Milodon rear sump running a stock oil pump. I think it needs a better oil pump to compensate for the longer pickup tube. I might try it.