Welcome to the Corvette Forums at the Corvette Action Center!

Hugh Oil Problem - I Really Need Help.

C

CAJUN C4

Guest

Would you mind giving me your opinion on a problem I’m having with my 84’ Vette (87’ Engine).

About 4 months ago I went to start it up one Sunday morning and when it fired up about 2 quarts of oil shot out of the oil filter gasket. I let her sit filled up the oil and all was well..well after that ,I sometimes get lifter clatter when first started but it goes away after a few minutes even with 60 psi oil pressure at idle. (I put new lifters in right after this occurance) Well,yesterday I went for a ride approx 30 miles and when I returned home I noticed the oil pressure was 9-10 psi and the check engine light was on (because of the low pressure it cuts off the fuel pump)
I then stopped it and tried to re-start and it naturally it wouldn’t. I looked under the car and oil was seeping out around the Oil Filter gasket.I tried to tighten it but it only turned about a ¼” max.I let it sit a couple hours and I started it and it was OK with 50- 60 psi pressure. I drove it home after work and when I got in my drive way again was low oil pressure.I looked under the car and a little oil was leaking out from the filter again. I called my local mechanic and he suggested it could be the Oil filter By-Pass valve sticking.
I called my engine builder and he dis-agrees and said it sounds like the oil pump relief valve sticking partially open when it gets hot. I Remind you it , is fine when driven 15 -30 minutes. Now my lifters have been quite for over a week now but this morning they clattered for a few minutes.Grump,I’m really perplexed. Can you suggest what might be wrong.????

Thanx for your help.

Dennis

Mandeville,La
 
theres NO WAY the oil filter ADAPTER or the OIL FILTER GASKET should leak REGUARDLESS of the oil pressure the pump supplies, check by removing , carefully inspecting,and re-installing the oil filter adapter and/or oil coolant adapter and gaskets and filter, and use a quality oil filter
http://minimopar.knizefamily.net/oilfilterstudy.html

IF you feel the oil pump needs replacing thats fine but ID bet that theres no problem that can,t be fixed fairly easily by removal,/testing/replacing the oil filter and oil coolant adapter, the oil pump can only pump oil that the oil pump pick-up can access, your problem appears to be oil control and leakage vs pressure, now that of course assumes youve not yet damaged the engine clearances
 
I don't have an oil cooler.How do you explain the low oil pressure and Oil leaking out of the filter gasket?Could it be a bad Oil Pump relief valve?

I'm really at wits end.

Thanx
 
If the filter or gasket is releasing pressure then your system will read lower. I would first try installing a quality filter and gasket. As Grumpy said, there should be no leak regardless of how much pressure your pump is supplying.
 
there are two areas that are cronic oil leak sources, first the oil filter gasket can be seperated on the oil filter or not correctly seated or the mounting adapter can be loose.
Ive seen those gaskets remain stuck to the adapter and not come off with the filter, then guys install a second filter , you now have two o-rings trying to seal against each other (NO $%^^ WAY)
Id also check the oil pressure sending unit near the distributor base as those tend to leak when they fail and oil runs down both/ether side of the bell houseing

low oil pressure is usually the result of low oil volume OR the pump or oil pump pick-up coming loose, OR in rarer cases excessive bearing clearances due to improper installation or excessive wear if the oil temp was excessive or volume low

If you were closer ID say, just bring it BY and well find the problem in a hour or less
 
Thanx Grump for the kind offer...I don't know...Sending unit not leaking,I have only one Filter gasket on it.Remember,it doesn't leak all the time.when first started it's fine good oil pressure no leaks it only did it yesterday after a long drive. This morning it was dry & good pressure.Very Wierd.You don't think getting a new filter adapter would help? I'll get a new good filter and try that.Might be worth a trip to Florida.
Thanx Guys and keep thinking.
 
Cracked oil filter adaptor might act this way ? Opening up with higher temps

Glenn
:w
 
Cracked oil filter adaptor might act this way ? Opening up with higher temps

Glenn
:w

If you replace the oil filter adaptor make sure you have the correct O ring. I just had my LT4 rebuilt and there are two different O rings, one has a square and the other is a standard round O ring.I think this was a LT1 vs a LT4.

I would remove the adaptor and check for cracks. Try a pan of water on the stove and get the adaptor Hot and use a light to find a small crack while it is warm. Just a thought. Good Luck.
Louis
 
BTW all this conjecture is based on the assumption that your useing the correct matching part number oil filter, for your application and its not deffective,you might want to cross check and verify that little potential problem area, and get a new filter while your at it! you would hardly be the first guy to get the wrong parts from a local chain store and I sure would NOT use a cheap filter, try to read thru that oil filter link and sellect a good one......the cheap ones are CRAP! and fail far more frequently

http://minimopar.knizefamily.net/oilfilterstudy.html
 
Thanx Grump...I've changed 4 filters so far...........BUT !!!!!

No on can explain how ,when I started it up months ago, how 2 quarts of oil spewed out in my driveway aftyer running flawlessly for 3 years.!!
 
damn, I wish you were accross the street, this stuffs fun to diagnose and correct, but your an easy 13 hours from here!.... BUMMER!
 
damn, I wish you were accross the street, this stuffs fun to diagnose and correct, but your an easy 13 hours from here!.... BUMMER!
Grurmp..What should I do...I've asked at least 50 people and no one can figure it out. At first I thought something may have broken off in the filter or something and went downstream to plug an oil galley causing tremendous head pressure thus out the filter it went.What should I do? Change the Filter adapter and / or Oil Pump? This morning it was fine...great pressure and no leaks.Did have a little valve clatter as it does every so often more when it's below 50F or so. (like oil being restricted to the lifters? They are new by the way.)
Go Figure
 
well if it was my vette ID pull the oil filter,& oil filter adapter out and at a minimum replace those and check the bolts and threads they seat in, as a cheap and easy precaution, while they were out Id check the passages for crud, if the problem continues Id pull the pan and replace the oil pump with a new high volume one with a matched pick-up and check those block passages but thats NOT likely from what youve said.
Id bet its something simple, but if you can,t find it don,t gety crazy, think it thru and logically track down the cause, look at it this way, its a good excuse to install a new performance engine oif youve got the time and cash....(like you needed an excuse)

http://data.melling.com/TECHtips.php
 
well if it was my vette ID pull the oil filter,& oil filter adapter out and at a minimum replace those and check the bolts and threads they seat in, as a cheap and easy precaution, while they were out Id check the passages for crud, if the problem continues Id pull the pan and replace the oil pump with a new high volume one with a matched pick-up and check those block passages but thats NOT likely from what youve said

That's what I'll do Grump.I'll keep you posted on how I make out.

Thanx a Bunch

Dennis

PS You think a High Volume pump is the way to go over a stock one?
 
high volume pumps are SUPPOSED to be used with a HIGH CAPACITY BAFFLED OIL PAN, but they are not 100% mandatory, but youll be well advised yto go that route

http://www.midwestmotorsportsinc.com/order_part.php?item=31504&line=MIL

http://www.midwestmotorsportsinc.com/order_sub.php?id=33&make=1&sort=0&mfgr=0

7.5" deep is max, and make sure the dipstick side and seal depth match the application


I had a Melling High Volume standard Pressure pump installed last month when I had my LT4 comlpetely redone. I noticed Melling has a new pump that has a thinner casting( make sure you order the old style Melling that has the thicker casting) that the Drag Racers are breaking. But my Vette will Never see slicks or a Drag Strip. One of the members on Corvette Forum was posting I had made a Big mistake buy going with the melling High Volume pump that it for the wrong application ( a street engine). I said he was wrong as I saw a post where you had said the OEM pumps were designed for a 265 CI :) I have used the High Volume Melling standard pressure pumps for 20 years and Never had a problem.
 
Ive used both high volume sbc and STANDARD volume BBC oil pumps for over 35 years and never had a problem, if they are correctly installed with matched components.
the standard volume pump gears are about 1.2" long the high volume pump gears are about 1.5 inches long (depends on manufacturer)
heres the discriptions right from chevy

12555884
SBC Oil Pump, High Pressure Z28/LT1. Production high-pressure oil pump with 1.20" gears.Will produce 60-70 psi oil pressure. Does not include screen. The pickup tube dia. is 5/8" for this pump.
62.17

14044872
SBC Oil Pump, High-Volume. This high-volume pump has1.50" long gears.It has approximately 25% more capacity than a production pump at standard pressure. Does not include screen.

and yes I comonly build small blocks useing bbc oil pumps like the ls7 pump, it has 1.3" gears but they are bigger in dia. and have 12 not 7 teethlike the small block pumps (many standard sbc pickups use 5/8" dia. pickups) (the ls7 pump is best used on 8qt-9qt road racing oilpans as the larger 3/4" pickup flows lots of oil for extreme high rpm engines with a multi baffled pan useing windage screens, scrappers and cut outs for extreme (G) loads where a dry sump can,t be used or cost makes you stick to a wet sump pan. these LS7 pumps dont fit most sbc oil pans so your stuck using the high volume sbc oil pump if your not using a true racing 8-9 qt style oil pan in some cases


read this over carefully
IVE POSTED MOST OF THIS BEFORE BUT IT FITS HERE AS A SOURCE OF INFO FOR THE NEWER GUYS

ok lets look at a few things, pressure is the result of a resistance to flow , no matter how much oil is put out by the oil pump there is almost no pressure unless there is a resistance to that oil flow and the main resistance is from oil trying to flow through the bearing surface clearances and once the pumps output pressure exceeds the engines ability to accept the oilflow at the max pressure the oil return system/bypass spring allows the oil circles back through the pump ,now the amount of oil flow necessary to reach the furthest parts in the engine from the oil pump does not go up in direct relation to rpm, but it instead increases with rpm at a steadly increaseing rate that increases faster than the engine rpm due to centrifugal force draining the oil from the rods as they swing faster and faster since energy increases with the square of the velocity the rate of oil use goes up quite a bit faster due to the greatly increased (G-FORCES) pulling oil from the rod bearings over 5000rpm going to 8000rpm than the rate of oil flow increases from 2000 rpm to 5000rpm (the same 3000rpm spread) and remember the often stated (10 lbs per 1000rpm)needs to be measured at the furthest rod and main bearing from the pump not at the pump itself, next lets look at the oil flow itself, you have about 5-6 quarts in an average small block now the valve covers never get and hold more than about 1/3 to 2/3 of a quart each even at 8000 rpm (high speed photography by SMOKEY YUNICK doing stock car engine research with clear plastic valve covers prove that from what Ive read) theres about 1 quart in the lifter gallery at max and theres about 1 quart in the filter and in the oil passages in the block, that leaves at least 2 quarts in the pan at all times and for those that want to tell me about oil wrapped around the crankshaft at high rpms try squirting oil on a spinning surface doing even 2000rpm (yes thats right its thrown off as fast as it hits by centrifugal force, yes its possiable for the crankshaft WITHOUT A WINDAGE SCREEN to keep acting like a propeler and pulling oil around with it in the crank case but thats what the wrap around style milodon type windage screen is designed to stop)the only way to run out of oil is to start with less than 4 quarts or to plug the oil return passages in the lifter gallery with sludge or gasket material! now add a good windage tray and a crank scrapper and almost all the oil is returned to the sump as it enters the area of the spinning crankshaft! forming a more or less endless supply to the oil pump, BTW almost all pro teams now use DRY SUMP SYSTEMS WITH POSITIVE DISPLACEMENT GERATOR PUMPS that are 3,4,or 5 stage pumps each section of which has more voluum than a standard voluum oil pump because its been found total oil control is necessary at high rpms to keep bearings cool and lubed

NOW I POSTED THIS BEFORE BUT IT NEEDs REPEATING
ok look at it this way,what your trying to do here is keep an pressureized oil film on the surface of all the bearings to lube and cool them and have enough oil spraying from the rod and main bearing clearances to lube the cam and cylinder walls/rings. now a standard pump does a good job up to 5000rpm and 400 hp but above 6000rpm and 400hp the bearings are under more stress and need more oilflow to cool and because the pressure on the bearings is greater you need higher pressures to maintain that oilfilm.lets look at the flow verus pressure curve. [color:"red"] since oil is a liquid its non-compressable and flow will increase with rpm up to the point where the bypass circuit starts to re-route the excess flow at the point were the pressure exceeds the bypass spring pressure. but the voluum will be equal to the pumps sweep voluum times the rpm of the pump, since the high voluum pump has a sweep voluum 1.3-1.5 times the standard pump voluum it will push 1.3-1.5 times the voluum of oil up to the bypass cicuit cut in point,that means that since the engine bearings leakage rate increases faster as the rpms increase because the clearances don,t change but the bleed off rate does that the amount of oil and the pressure that it is under will increase faster and reach the bypass circuit pressure faster with the high voluum pump. the advantage here is that the metal parts MUST be floated on that oil film to keep the metal parts from touching/wearing and the more leakage points the oil flows by the less the voluum of oil thats available for each leakage point beyond it and as the oil heats up it becomes easier to push through the clearences.now as the rpms and cylinder preasures increase in your goal to add power the loads trying to squeeze that oil out of those clearances also increase. ALL mods that increase power either increase rpms,cylinder preasures or reduce friction or mechanical losses. there are many oil leakage points(100) in a standard chevy engine.
16 lifter to push rod points
16 pushrod to rocker arm points
32 lifter bores 16 x 2 ends
10 main bearing edges
9 cam bearing edges
16 rod bearing edges
2 distributor shaft leaks
1 distributor shaft to shim above the cam gear(some engines [/color] that have an oil pressure feed distributor shaft bearing.)
so the more oil voluum the better,(AS LONG AS ITS TOTALLY UNDER CONTROL ON BOTH THE PRESSURE AND RETURN/SCAVAGEING SIDES OF THE SYSTEM
chevy did an excelent job in the design but as the stresses increase the cooling voluum of the extra oil available from the larger pump helps to prevent lubracation delivery failure, do you need a better pump below 5000rpm or 400hp (no) above that level the extra oil will definitely help possiable deficient oil flow and bearing cooling and a simple increase in pressure does not provide a big increase in voluum that may be necessary to keep that oil film in the correct places at the correct voluum at all times.the stock system was designed for a 265cid engine in a passenger car turning a max of about 6000 rpm but only haveing the stress of under 300hp transmitted to the bearings, Im sure the orriginal designers never thought that the sbc or bbc would someday be asked to on occasion hold up to 450-800hp and 6000-8000 rpm.nore did they forsee valvesprings that placed 500lbs and up loads on the lifters and the use of over 9 to 1 compression ratios in the original design so the oil voluums and pressures necessary to cool those valve springs and bearings at those stress levels were never taken into account for that either.

Continued (oil Pan/pump)
the oil pump can only pump as much oil as the engine clearances allow at the max pressure that the oil pump bye -pass circuit will allow, and no more. for your idea to be correct (which it could be under some conditions)the oil flow through the engine clearances would need to be so great that the pump turning at 3500rpm,7000rpm engine speed(remember the pump spins 1/2 the speed the crank does)and most likely pumping at max pressure could lower the oil level to the point that the pick-up becomes uncovered or a vortex as you call it forms and the pump starts sucking air.


now under hard acceleration it is very possiable for the pickup on ANY oil pump to to become uncovered in a oil pan that has less than 5qt capacity and with no oil control baffles as the oil rushes to the rear of the oil pan if the pick-up is located in mid pan or under hard brakeing if the pick-up is located at the rear of the pan on a non- oil baffle controlled pan.

I will grant you that it is possiable for ANY oil pump to pump a good amount of oil into the lifter gallery at high rpms IF THE OIL RETURN PASSAGES IN THE HEADS AND LIFTER GALLERY ARE BLOCKED, preventing its normal return to the crankcase

, but running a high volume oil pump will have little or nothing to do with how much oil is in the pan if the engines drain back holes are clear and your useing a milodon style windage screen. I have several times had that same complaint about lack of oil pressure under acceleration but it is caused by a non-baffled pan or the pickup mounted so close to the pan bottom that the pump cant get a good intake flow, if you carefully check youll find that on a dyno runs it seldom happens,because the oil is constantly removed by the windage screen is returned to the sump, most of the oil pumped into the system exits at the rod and main bearing clearances or at the cam bearings and from the lifter bores lower ends, its not the constant oil flow or lack of oil into the rocker arms that has the big effect on total oil flow as SMOKEY YUNICKS PHOTOGRAPIC RESEARCH PROVED YEARS AGO,its the oil flowing from the bearings and lifters and that oil flow is quickly returned to the sump by a windage screen scrapeing it off the spinning crank and rods as the spinning assembly passes over the windage screen. in effect most of the oil in an engine works like your timeing chain in that it constantly cycles top to botton and back never getting higher than the cam bearing lifter area.

[color:"red"] now what does quite frequently happen [/color] is that the guys installing a high volume oil pump just swap out the standard pump, reinstall the stock or simular pick-up and bolt on the pan with the pick-up in the stock possition on the oil pump. the stock pick-up is mounted about 3/8" off the pan bottom,the high volume pump is normally equiped with impeller gears about .3 inches longer than stock, the high volume pump body is that much lower in the pan, resultting in the pick-up being only about 1/8" from the pan bottom. the result is that on a normal chevy oil pump pick-up this leave a space of about 1/8" x 2.5" for oil to flow into the pump. at low rpms this works but as the rpms climb the pick-up that can,t get any oil to pump cavitates as it spins and fails to pump oil, result oil pressure drops untill rpms are lowered no matter how much oil is over the pick-up. simply checking to make sure that anout 1/2" of space is under the pick-up when the pan is installed cures that problem (a simple trick is to weld a 1/2" thick nut to the oil pump Pick-up base and test fitting the pan BEFORE WELDING THE PICK-UP TO THE PUMP BODY)

what it comes down too in every case that Ive looked into so far is a improperly positioned pick-up or a non- baffled oil pan without a windage screen or less than 5 qts of oil in the system, not a problem of all available oil being pumped into the lifter gallery and valve covers like some people would like you to think.

the MELLING COMPANY HAS THIS TO SAY

Most of the stock automobile engines are designed to operate from idle to 4500 RPM. The original volume and pressure oil pump will work fine in this type of application. As the demands on the engine increase so does the demands on the oiling system and pump.
The oil pump's most difficult task is to supply oil to the connecting rod bearing that is the farthest from the pump. To reach this bearing, the oil travels from three to four feet, turns numerous square corners thru small holes in the crankshaft to the rod bearing. The rod bearing doesn't help matters. It is traveling in a circle which means centrifugal force is pulling the oil out of the bearing.

A 350 Chevy has a 3.4811 stroke and a 2.111 rod journal. The outer edge of the journal travels 17.5311 every revolution. At 1000 RPM, the outer edge is traveling at 16.6 MPH and 74.7 MPH at 4500 RPM. If we take this engine to 6500 the outer edge is up to 107.9 and at 8500 it is 141.1 MPH. Now imagine driving a car around a curve at those speeds and you can feel the centrifugal force. Now imagine doing it around a circle with a 5.581, diameter.

The size of the gears or rotors determines the amount of oil a pump can move at any given RPM. Resistance to this movement creates the pressure. If a pump is not large enough to meet the demands of the engine, there will not be any pressure. Or if the demands of the engine are increased beyond the pumps capabilities there will be a loss of oil pressure. This is where high volume pumps come in; they take care of any increased demands of the engine.

Increases in the engine's oil requirements come from higher RPM, being able to rev faster, increased bearing clearances, remote oil cooler and/or filter and any combination of these. Most high volume pumps also have a increase in pressure to help get the oil out to the bearings faster.

That is what a high volume pump will do. Now let Is consider what it will not do.

It will not replace a rebuild in a worn-out engine. It may increase pressure but the engine is still worn-out.

It will not pump the oil pan dry. Both solid and hydraulic lifters have metering valves to limit flow of the oil to the top of the engine. If a pan is pumped dry, it is because the holes that drain oil back to the pan are plugged. If the high volume pump is also higher pressure, there will be a slight increase in flow to the top.

[/color] let me point out this chart
clearances1.jpg


clearances2.jpg


clearances3.jpg

http://www.diabolicalperformance.com/clearances.html
heres other info,
http://www.babcox.com/editorial/ar/ar10180.htm

http://www.thirskauto.net/BearingPics.html

http://www.waynesgarage.com/docs/oil.htm

http://www.jimcookperformance.com/TechNotes/TN%2023.html




http://www.cryoeng.com/images/EngineDurabilitySecrets.htm

http://www.melling.com/engoil.html

http://members.aol.com/carleyware/library/engine2t.htm
 
BTW

oil restrictors a a band-aid approach to a problem that rarely exists and can be TOTALLY avoided, the concept is that a limited oil supply in a 4-5 qt oil pan,needs to be rationed,to low cost parts to save high cost parts and dirrecting the majority of the flow to high value components at a far greater rate than easily replaced and less expensive components is necessary.
the flaw in that thinking is that a properly designed PERFORMANCE oil system has more than enought volume to supply and cool all components, unlike a pass car system that is rarely expected to operate at over 5500rpm,for more than a few seconds,and still retain several quarts in the sump and that oil is the major coolant of the valve train and bearing surfaces and its pressurized flow is what keeps moving parts from touching and galling and seizing up.
the key is that PROPERLY SET UP HIGH VOLUME PERFORMANCE OIL SYSTEM, which in the case of a comon wet sump,requires some thought and differant components designed for that application, and at least a 7-8 qt baffled oil pan with windage screen.
 
Thanks Grumpy, some good information. I will look for a larger oil pan for my 96 LT4 Vette. Does my stock LT4 have a windage screen that will work as I did not see my engine while it was being rebuilt. I will ask the machine shop that built and balanced my Long Block for the Melling part# and pick up tube# and is it 1/2 inch up from the oil pan. This shop builds a lot of HP Chevy's and has a good reputation.

Edit

I have 1200 miles on the new engine so I changed the oil and filter non Synthetic (again, every 500 miles) to Mobil 1 Synthetic 5/30 and a Mobil 1 filter and ran the engine until the oil temp was 220 and for the First time I pushed it to 5900 RPM 2nd thru 4th gears and my oil pressure stayed at about 60 PSI and at Idle about 30 PSI. So that tells me my Melling Oil Pump and pick up was installed correctly (1/2 inch up from bottom of oil pan) New LT4 runs good :)
 
Another Option

Thanx Grump...I've changed 4 filters so far...........BUT !!!!!

No on can explain how ,when I started it up months ago, how 2 quarts of oil spewed out in my driveway aftyer running flawlessly for 3 years.!!

Okay lets go to the basics. Did you run the same filter for 3 years or had you changed the filter just before this all started? Do you change your own filter or do you have someone do it for you? This may sound silly but my dad and I ran a 1960 250K with three different engines. The original 283 then a 327 and finally a 350. When we would go to have the oil changed usually the mechanic looked at the age of the car and tried to put a 1960 filter on it. Like Grump says I think your problem is a simply one. Sometimes we get so focused on a part of the problem, that we lose sight of every thing else that might contribute to the problem.
 

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors

Dealers:

MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Back
Top Bottom