oil pump bad, different oil pan?

The oil pump can be replaced without pulling the engine, I have done it. But it is not any easier than pulling the engine to replace the pump. All the same stuff has to be loosened/removed, and it is a major headache to get everything scraped clean. The only thing that you don't need is the engine hoist. The engine hoist is a loaner/rental item at most of the better auto parts stores.

Disconnect the battery at the battery ground terminal, remove the fan and fan shroud. Both motor mounts will need to have the large nuts that secure them to the frame removed. The trans mount will also have to be loosened, and it is a good idea to remove the drive shaft.

I also had to disconnect the cat pipes at the headers to get the engine high enough to remove the oil pan. Be prepared to have to drop the steering rack and disconnect the steering shaft. Jack up the engine with a wood block under the oil pan and watch for things that bind or hoses/electrical wiring that may need to be disconnected. I put a couple of wood blocks between the headers and the frame to support the engine. You will likely need to jack up the rear of the transmission as well to get the required clearance.

Scrape the pan mating surfaces clean as possible - old gasket stuck to the surfaces are a source of leaks.

Get a high volume/heavy duty pump, and a replacement HD pump shaft. FMS makes one, and ARP does too. When you install the pump, the funny looking washer thingy goes on the part of the shaft that fits into the hex socket in the distributor shaft. It keeps the shaft in place when you remove the distributor, which you will have to do to prime the pump. Forget to put it on, and the pump shaft can come loose and fall down in the bottom of the oil pan.

There is a one piece oil pan gasket which will help re-assembly if you can find it. If you can't get this gasket, use weather strip adhesive to secure the cork gasket to the pan rails and the rubber strips to the bearing caps. Read the instructions on the adhesive carefully to make sure the gaskets are permanently stuck in place and won't move when you slide the pan in place. Use lots of blue silicone sealer on top of the front and rear rubber seals where they mate with the pan.

Fill with oil, replace the filter. Reconnect the battery, switch the ignition on to enable the gages, but DON'T crank the car. Remove the distributor and use a 1/4" hex socket to turn the pump counter clock wise (same direction as distributor rotation) until you see oil pressure (an external gage is a great help long about now). And keep turning for about 30 sec after you see the pressure come up. A reversible drill is the best tool to use to turn the 1/4" socket. The pressure should come up to about 50-80psi with cold oil. Once you see good pressure, check for obvious leaks, and then and only then, lower everything back into place and bolt down the mounts and anything else you had to take loose.

Re-install the distributor and set the timing with the engine running using timing light (don't forget to disconnect the SPOUT plug and reconnect it when finished) 12-14 degrees BDC is good. Start up and check for leaks, let it warm up and look again for leaks. It took me 2 days plus, but I am old and slow, maybe your granny is faster.

The oil pump resides in the front part of the sump, but the pickup is in the rear of the sump.

Why an HV pump? wouldn't you be worried he sucks the pan dry if he ever goes near 1/2 a quart low on oil? or if he's Fing around on some twisties?

89white50 said:

Why an HV pump? wouldn't you be worried he sucks the pan dry if he ever goes near 1/2 a quart low on oil? or if he's Fing around on some twisties?

Click to expand...

This myth is just like the engine won't run because the distributor is one tooth off myth - it just won't die...

Thanks to bubba-dough for helping to educate all of us...

http://data.melling.com/Tech pdfs/HIGHVOLUMEPUMPS.pdf
You will need the Adobe Acrobat viewer which is also a free download – http://www.adobe.com/products/acrobat/readstep2.html

From the Melling site, for those who didn't follow the link & read the tech note...



High Volume Pumps: Advantages, Myths & Fables

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.

It will not wear out distributor gears. The load on the gear is directly related to the resistance to flow. Oil pressure is the measure of resistance to flow. The Ford 427 FE "side oiler" used a pump with relief valve set at 125 psi and it used a standard distributor gear. Distributor gear failures are usually caused by a worn gear on a new cam gear and/or worn bearings allowing misalignment.

It will not cause foaming of the oil. With any oil pump, the excess oil not needed by the engine is recirculated within the pump. Any additional foaming is usually created by revving the engine higher. The oil thrown from the rod bearings is going faster and causes the foaming. This is why high performance engines use a windage tray.

It will not cause spark scatter. Because of the pump pressure there is a load on the distributor gear. The number of teeth on the oil pump gears determine the number of impulses per revolution of the pump. In a SB Chevy there are seven teeth on each gear giving 14 impulses per revolution. At 6000 RPM the oil pump is turning 3000 RPM or 50 revolutions per second. To have an effect on the distributor, these impulses would have to vibrate the distributor gear through an intermediate shaft that has loose connections at both ends. Spark scatter is usually caused by weak springs in the points or dust inside the distributor cap.

High volume pumps can be a big advantage if used where needed. If installed in an engine that does not need the additional volume, they will not create a problem. The additional flow will be recirculated within the pump.

I dented my oil pan, then noticed a loss of pressure, so, being the crafty mechanic that I am, I rented an engine hoist for the day ($35) and bought a new oil pan and pickup. After pulling the manifold and attaching the hoist, and removing the engine mount bolts (24mm?) I just got under the car and removed the 6 bellhousing-to-engine bolts, then the exhaust and lifted the motor up. No need to remove the driveshaft??! And transmission mount?!? Pulled the pan, swapped it and dropped it into place. Only tricky part was getting the trans imput shaft lined up...took like 10 min. to do it...But it's actually very easy, whole procidure only took about 4 hours...Good Luck!