Fresh 427 s/o 40psi oil pressure drop
 

Does any one have any other Ideas One of those once in a life time things! Ive Checked Oil pump ,gauages ,oil filters,oil filter adpter plate,oil galley plugs, main &rod berrings relief valve . what am I missing? Could it just been a fluke? a piece of trash in the reileif valve that disloged afterwards. it has a 428crank so theres no plug there. I guess Ill put it back together an light it up see what happens! Is there any one place a galley could get a crack? Have .003 clearances. ANYONE???? Thanks again.

some questions.
 

When and how does this oil pressure drop occur?
Have you checked the oil pan to oil pump pickup clearance...too small and it will cavitate and lose pressure, or simply lose suction all together.
Also, are you running a high volume pump with an otherwise stock oil pan and oil system? The HV pump can, and often does, pump the pan dry at high rpms because the oil either does not drain back quick enough or the oil pan just does not have the capacity required for an HV pump (FE's are finicky with this much more than almost all other motors)
Lastly, what oil filter ar you running? Frams are know to have anti drainback valves that fail and clog the way.

Check jimmymac's initial thread on this problem...

http://www.clubcobra.com/forums/fe-talk/71441-new-so-lost-some-oil-pressure-40psi.html

trw hv oil pump from keith. 7.5qt. t cobra oil pan windage tray. oil cooler two frams that were prefectly intact when cut apart. oil pressure builds to 40 just off idle tries to climb 44+- back to 40 to red line 7000. I used to turn my t/o 8000 no problems.

Do you have the oil hoses connected to the filter heads correctly?

I checked that I dont think I could have had good oil pressure the first 2-3 hours. also run prelube test oil test with oil pan off. what did i see about the right main berrings witdh a solid cam and a service block???

I know this is going to sound crazy buy my Dad would not run Fram oil filters on a Ford. Told me to run Motorcraft FL-1A. I have always done this except with my new engine and never had a oil pressure problem. With my current 427 I am running a System One re-useable oil filter. I maintain 50 psi all the time after start up which is usually about 60 psi. As I rev it up around 6000 RPM my oil pressure doesn't climb significantly only 60 - 65 psi max.


Clois

I just went back and read your original post and at one point you mention how you can easily move the oil pressure relief valve with a screwdriver.
I am assuming you are speaking of the relief valve in the back of the block and not the one on the oil pump, I am assuming that speedpro has a pressure relief outlet .
On my sideoiler I eliminated the pressure relief valve/spring in the block and shimmed the oil pump pressure relief valve spring to achieve a higher and sustainable oil pressure, I'm using a Melling HV57 oil pump.
This leaves me an idle pressure of about 70 -75psi and a "heavy +" oil pressure of 100psi @ higher revs, 2500 up through 6200 rpms.
I don't believe that the pressure relief spring that you moved with a screwdriver is supposed to be that "soft", my understanding is that you should be realising a lot more resistance out of that relief spring than you describe, it should be worth a look, possibly a spring pressure test before you put it all back together...good luck.

Well, It's back together. I haven't changed the oil pressure relief spring. Thats next. It did move with a small screwdriver with minimal effort. My top oiler spring may have had a bit more resistance, but not a big difference. Guess I'll find a new spring , pull the trans,clutch flywheel. Hope that Lakewood comes off with headers on? Lineslinger; What kind of clearances are you running on rods and mains. 100psi hot oil? How hard do you rev it? My top oiler rounded a Milodon oil pump shaft at 80psi. New ARP is fine. My mains clearance is .003 rods are .0033 . Does anyone have similar or larger clearances. If so what oil pressure do you have? What oil? I find it hard to believe these clearances are killing my oil pressure. If my machinist is correct .I checked with plastic gauge you know how that is upside down. I did put some pressure (upward) on the crank .003 ANY IDEAS OR INFO ON PRESSURE AND CLEARANCES. THANK ALL jimmymac

Check the clearances with a mike and indicater

We quite often will get someone in the shop that has checked there clearances with plastic guage and say they don't have any or enough
usually a mike and inside dial indictor will prove that they are about 002 off

If you add 002 to your plastic guage 3 your clearances are out to lunch

Jerry

Jerry Thanks for the advice. Heres the problem. The engine is in the car. I absolutely know the crank is standard,standard , chromed an mallory balanced by CSC. the berrings are std. Main bore is max. If the rods had .005 I think Ray Charles could feel that. I feel it's premature to pull the motor. Before changing a little spring that could be the problem, Not saying It couldn't be but i'm trying to be systematic about this. Paul Vanderley of Gulfport did all the Machine work!!! Good or bad? As I rev the motor above4000 I believe the pressure drops a little more. Could the spring be opening fully with more volume an pressure on it? I do Appreciate the help jimmymac

I took a quick look at the posts so far and do recall anyone suggesting installing "oil restrictors" in rocker oil galley in the heads (if you have restrictors check that they are still installed and possibly change to smaller ones). This should increase pressure in the system. Another place to check is the oil pick-up to make sure it is sealing to the pump and that it doesn't have any cracks or leaks.

Just more long shots.........good luck,
Mike

Oil restictors made from brass screws and drilled with the smallest bit Ace had still get ok rocker oiling. Do ANY of you have build specs on your motors?????????? S/O's type oil and pressure hot? at what rpm???

I have a side oiler ...just rebuilt and my car runs at around 100 psi till its gets hot then drops down but at any kind of RPM will run around 80-90 psi and down to around 40 at a idle..I do have restricters installed in my heads also running 20/50 motor oil .....Odd that your oil pressure drops when reved? got me

just a hunch; are you using a crossdrilled crank??

steve

Ok, here is the problems.Thanks to Neil At Guessford's he made me look at this differently. Oil restictors are important but won't hurt oil pressure like i'm experiencing. Check your build sheets clearances. All under .003 I'll bet there's a reason for that. My Engine builder didn't care to pass on. My engine moves so much oil I believe it would suck the pan dry at wide open throttle in less than a minute. But oil pressure takes horsepower. To generate volume at lower pressure takes less power,more oil moving. I asked for less clearance but he didn't listen. Chev man. So a few extra 10th's cost pressure. I'll bet money no one can tell me oil pressure at the rod berring oil pressure at 70psi engine at 7000rpm. there other force's at work there ,centrifugal slinging the oil from the main to the rod journal. Sooo with the extra clearances i'm using a lot more volume. With my filters an oil cooler an ONE BRASS fitting that I even opened up inside just wasn't big enough anymore. RESTRISTING my oil flow at higher rpm (volume) What I'll have to do is run an 10 to my filters sn 8 to my cooler an8 from cooler to a block (three way) an8 from filters to block then an10 back to engine. sort of a bypass. that much oil can't be cooled going through the cooler that fast. It (the cooler) will still restrict the flow some. so the by pass line So I hope this will efectivly cut resistance and Increase oil flow. Later I'll put a set of .001 under berrings in it so I won't use the volume i'm using now. Look for new post Fe-85 fuel soon as i get some down here. Stennis Space center is closest I've found . THANKS TO ALL FOR HELP.jimmymac427

I just had a experiance similar to Jimmy with my fresh built 406. I had 80-90PSI at start then 55-60 @3500RPM 35-40 at idle when warm. While setting my dist curve I went out on a road test and the oil pressure dropped to 40@ 3000 and 20 at idle. I found this post by SFfiredog http://www.erareplicas.com/427man/engine/oilpress.htm and my gasket appeared to have a hole so I installed the fix. Now my oil pressure has returned to the previous 80-90PSI at start then 65-70 @3500RPM 40-45 at idle. I'm not sure if s/o's have this same by-pass but it's an easy thing to check.

Mike

Mike
Thanks for the info, I found my problem. Guess you missed my other post. It was a oil line restriction. brass fitting 1/2 inch pipe I even opened it up with a die grinder. Still not enough volume. -an10 here I come.LOL

I'm confused! Wouldn't a restriction make the pressure go up?

Bob

guess it would depend on which side of the restriction you were measuring....