RED86Z28

I have a 355" with a Melling standard oil pump and a Miloden 5qt pan. Oil pressure at idle is about 20 psi and is at least 40 psi at 2000 rpm. When you get on it the pressure starts to drop rapidly around 3300 rpm until it hits 0 psi. I know the guages are correct because I have both a mechanical and an electrical one. The oil level is correct. Any ideas what would cause the pressure to drop?

sofakingdom

iTrader: (1)

Pickup fallen out of the pump

Put an extra quart of oil into it; if it improves, then that's probably the problem.

ross

Or the pick up is to close to the floor of the oil pan.

Air_Adam

Sofa's method seems like the easiest place to start. What guage are you using? Factory dash guage? How old is the sender?

RED86Z28

Ill try the extra quart but the pickup was welded to the pump and is was at the proper hight. I really doubt it came loose. I dont have the factory gauge cluster. One gauge is a Sunpro mechanical gauge and the other is a Nordskog digital gauge.

RED86Z28

An extra quart did not change anything.

sofakingdom

iTrader: (1)

Then it's probably the next most common possibility, the one ross suggested; the pickup is too low (close to the pan), and the pump therefore pulls a vacuum in the screen at high RPM because the hole for the oil to come into is covered by the pan.

F-BIRD'88

I had this problem come up on my 400. Changed the oil filter and the problem went away.

RED86Z28

I found the problem. There was cork cloging the oil filter inlets. I dont know where it came from but It probibly came from the cam change a few months ago. Im usually very careful but I guess sometimes things happen.

F-BIRD'88

thats nasty

Sonix

iTrader: (1)

Wouldn't you still get oil pressure via the bypass?

sofakingdom

iTrader: (1)

That would do it....
Not if the bypass was plugged, like the ancient McDonalds parking lot hot-rod folklore wisdom maintains is the only way to go.... (not me)

Glad it didn't require a tear-down!! Maybe the moral of the story (besides unplugging the bypass) is, check the simple stuff first before panicking.

ljnowell

I think the worst part of this story is that awful picture of the fram filter and the harsh reality that a fram filter was actually on his engine.

Sonix

iTrader: (1)

Something is wrong with fram filters? That's basically all that's stocked nearby, are you saying pretty much the most popular filter in existence is crummy? What's next, the most popular oils here (pennzoil and quaker state) are bad?!?

Toehead

There is a website that tore down all the filters. They did find some problems with the basic design of the fram filters.


I usually use AC Delco.

RED86Z28

The bypass was clogged too. I got lucky on this one. The car was running fine tonight.

The filter I tossed on today was a Fram too. I run whatever the store has and I dont worry about it.

F-BIRD'88

[QUOTE

I usually use AC Delco.[/QUOTE]

me too.

EvilCartman

iTrader: (1)

I use the Napa Gold filter which is made by Wix last I heard.

RBob

iTrader: (1)

That is unfortunate. This is an area that the King of Sofa's and I disagree on. With an active bypass I would venture to say that some of those pieces of cork are now in the engine oil passages.

RBob.

RED86Z28

I would hope that very little if any cork made it through the screen on the bypass valve. This is one of those situations where having no bypass valve might have helped since it got plugged up anyway. On the other hand this incident was outside the relm of normal operation for the bypass valve and filter. It was never ment to keep oil flowing in situations where there were big chunks of cork in the filter aerea.

sofakingdom

iTrader: (1)

Right; enormous chunkies like that should NEVER have made it past the pickup screen.

Since pickups all have screens in them to prevent this sort of thing, that pretty much renders this moot as an argument against using the bypass.

Which brings us back to, maybe the pickup DID fall off; or maybe it just fell apart? Not good in either case.

And yeah, DEFINITELY get rid of the Fram filter. That has got to be the lowest quality of ANY of the major brands out there. Whatever they built whenever they got whatever reputation they had at one time as a "high performance" product, has long since been abandoned. Every "study" that people do, with whatever degree of scientific rigor, puts them at the bottom of the heap in filtering efficiency, durability, and alot of other measureable properties. For example, Fram is the ONLY brand of oil filter I know of, where the filter medium has been known to disintegrate and get flushed INTO the motor. I cannot envision a situation where this would be good.

Meanwhile, you've got a motor that's been spun up however high however many times, with no oil. Your bearings are probably not in the best of shape any more.

T-rick'srod

Hey Ya'll, just my two cents - I use AC/Delco filters ( oil,fuel,air ) because they are manufactured to GM specs - not Fram specs. AC/Delco stuff is
priced competitively if not lower in some cases with Fram products. I use
AC/Delco and I don't worry - Bada Bing!



" The secret of life is honesty and fair dealing....
If you can fake that,you've got it made. "
Groucho Marx

impaled

i always use mobil 1 filters with mobile 1 synthetic. that is what i have used in my mustang for a long time and i have no problems with it. i might not be going synthetic with the chevy though. i am not sure.

RED86Z28

I think the cork broke up and it went through the screen because all the chunks were small enough to make it through the pickup screen. Im sure that this incident was not good for the bearings but as long as I have oil pressure and no other problems all is well for now.

You can buy the best filter and oil in the world but one mistake like not noticing a chunk of cork fell in the engine can ruin it all.

sofakingdom

iTrader: (1)

Ummm... no.... that's exactly my point.

The holes in the screen are about the size of a large grain of sand, maybe .060" square. You've got boulders there that are 10 times that size and more. IMPOSSIBLE for that stuff to get past a screen.

RBob

iTrader: (1)

I've never seen a bypass with a screen on it. Doesn't mean that they aren't ones like that. But it does make a difference in how one feels about filter bypasses on modified engines. This old timer has blocked the bypass on every engine that is higher performance then stock.

Then again, when those bypasses were stock it was nothing more then a big hole with a disk and a light spring behind it.

RBob.

P.S. I agree with Sofa on the filter, ditch the Fram's.

MPNolin

I've seen some nasty stuff in oil pans while tearing down for a rebuild.
One customers' car had about 20 of the little foam seals Quaker State used to put on their quart bottles.
I found a dipstick tip once, looked like it had rusted off and fell in.
Many had RTV and silicone chunks.

I'd be worried your oil passages are contaminated with those cork chunks.
It will likely cause problems in time. If any passage gets clogged in the
future there will be engine damage.

I'd as least pull the pan and see what's in there that the pump didn't
or couldn't pick up.

Worse case;
Pull the engine, dissasemble, hot tank it, run brushes though all the oil passages.

antman89iroc

Oil flows through the screen, pick up, pump, straight to the filter, then the bearings. The mistery is where did the pieces come from and how'd they get there? I can not imagine any way except the pump screen is missing or loose. They look sort of like valve cover or oil pan type gaskets. But it seems to me the pump would have chewed them up. I suppose they MIGHT get through since they're somewhat compressable. Regardless, I would expect to have debris in the oiling system downstream. That's the bearings, lifters and beond. I'd at least pull the pan and inspect the bearings. Unless it's a high mile engine and your planning a stroker soon!

RED86Z28

I looked at one of the pictures taken when I built the engine and you can see that the pickup holes are smaller than I remembered. Maybe the suction pulled the flexible chunks through the screen or maybe they broke the screen. I’m not going to pull the pan and take a look. Right now is not a good time to tear down the engine.

danandamy

I was thinking the same thing, wondering how pieces came out that big after going through the pump, also wondering how the heck it got through the pick up screen. I'm wondering if there were cork end piece gaskets that got dropped down in the valley during the intake swap.

sofakingdom

iTrader: (1)

Not to be the bearer of bad omens; but, instinct and experience tell me that at some point in the not-too-distant future, you will lose the choice of whether it's a good time or not. Engines have a way of making that decision for you, and for some reason when they decide it's time, it's never at a good time for the owner.

Best to be making plans to deal with it, now, while the situation is still somewhat under your control.

Sonix

iTrader: (1)

I'll have to post a picture of my picture screen, I could easily fit a 1/8" drill bit through the holes in mine, and i'm sure it's the stock pickup and screen.
Either way, those are bigger than the pickup screen (even mine). It may very well have fallen off.

If you tear it down now you might be lucky and just be replacing the oil pump. If you wait, and lets say you're unlucky (murphys law) and a chunk gets stuck in an oil feed hole in the crankshaft, it starves the front, you're now replacing the crank, some rods, need a new balance job most likely, all new bearings, maybe a line hone.... yuck, that's much more money.
No alternate vehicle to drive in the meantime? Bus doesn't have good routes?

RED86Z28

I simply don’t have time to tear into the engine. I’m going to let it go and see what happens. Even If I had the time I don’t want to sink a few hundred dollars into seeing if anything was in there. This was the first engine I built and it is around five years old now. Someday I’ll build a better one.

Should disaster strike atleast its not my only car.