The Stovebolt Site Forums The Shop Area Engine Shop Bleeding oil pump

Hello,
I've bought a new high pressure oil pump. If I started my 235 cui engine and I saw the following process. If the engine is standing a few day, it lost it oil pressure. If I start the engine the oil pressure is in the idle by zero. So I have to kick down the accelerator and as now the oil pressure is coming and the engine gets now oil pressure in the idle.
I've been to my garage this time and I opened the oil canister. Its empty! Is there a check valve anywhere that doesn't works? I mount the oil filter container at the inner fender (see on the photo).
http://s66.photobucket.com/albums/h242/wokri/?action=view&current=lfilter.jpg
Its on the level from the valve cover, is this to high?
What can be wrong?
Ask
Wolfgang

The bypass oil filter needs a flow-restricting orifice in its supply fitting to prevent too much oil to flow through the filter, which would reduce the oil pressure. I believe that the orifice diameter is about 1/16". There could be no harm in simply disconnecting the bypass oil filter to see if that helps the oil pressure.

I do not recall, back when I worked on Stovebolts fifty years ago with bypass filters, if the canister would have oil in it when the cover was removed. As the outlet is higher than the return hole in the block, there is no reason why the oil should not all drain into the oil pan.

This question has come up before, and I am sure that are members more current experience with bypass filters. I have converted my 1954 261 from no filter to full flow filter.

The restricting orfice is actually in the outlet protion fo the filter housing, but you are correct in that it is located farily high up in the housing. The filter should have oil in it, about 1 quart. If thw filter is empty, I would suspect a possible plugged supply line. On the pump, I'm concerned that perhaps the pickup isn't attached properly, or perhaps there's something amok internally in the pump itself. You chouldn't have to rev it to get pressure, it should come up pretty much right away, especially when cold.

Different oil filter canisters fill and drain differently. Assuming you have an AC filter: where does the hose from the bottom of the canister enter the block and where does the hose higher up on the side of the canister enter the block?

Here are the inlet and outlet holes on the 235 block. Hose to inlet is on the upper side of the canister and the outlet hole is on the bottom of the canister.

Here is a diagram of AC oil filter plumbing compliments of Denny Graham.

On the 3 engines with bypass filters that are in my shop right now, all of them have the return line at the bottom of the filter canister, with pressurized oil going into the side of the housing. If the engine sits for several days without being run, practically all the oil should drain back into the pan. A very badly clogged filter would keep some oil in the canister, but a clean filter element should let the oil drain back pretty quickly. The restrictor for a spin-on filter should be about 1/16" in diameter, and it can go into either the pressure or return line.
Jerry

I should have mentioned, most of the filters's I've dealt with on these are Frams, which don't drain down. The outlet for them has the metering hole about 3/4 of the way up the center tube. The do plumb the same as the AC, with the pressure comming in the side, return out the bottom.

The oil does not drain to bottom of the reservoir in my AC filters because there is a tube from the bottom hole that goes up 4-5 inches (I'll post photos later today). The oil has to drain out by going into/over the top of the tube or into a hole near the top of the tube (similar to LONGBOX55's description of his Fram filters).

However, "Different oil filter canisters fill and drain differently.

A sludge siphon was a handy device for getting oil out of the bottom of canister that did nor drain to the bottom and did not have a drain plug near the bottom of the canister.

wokri,

You have looked inside your filter canister. When you take out the filter element, is there a tube in the center of the canister?

A restrictor on the feed side will slightly improve oil pressure on start-up since it delays filling the filter up.
It also protects the engine if the filter or housing leaks - which would otherwise drop system pressure if the restriction was in the return line to the pan.
If your housing drains out, you can cure that by simply making a new longer return line that loops up higher than the filter and back down to the block drain. A simple piece of brake line will do.

Hello,
so I was today evening in my garage and I looked after the oil filter canister and after the oil pump.
In the canister was a small rest of oil on the bottom about 5mm strong.
Then I started the engine, it came suddenly and I gave it a short kick down. But the oil gauge shows no oil pressure.
After I jack up the truck I disamble the oil pan and take a look after the oil pump. I opened the pump and oil came out of the pump. I turned the rear wheels to turn the engine and look if the pump is turning, the pumps wheels are turning.
So what could be wrong?
Were is the mistake that let the pump have no oil pressure if the engine is tuned off for a day or longer? I check this if I disamble the distributor and spin the pump with a boring machine. It takes a half minute or longer if the pump gets pressure. The pump is new!
Has someone a idea?

Air leak between the oil level, pick-up head, pick-up tube or pump body.
Any one of these will break suction.

Where does the hose from the bottom of the filter canister enter the block and where does the hose higher up on the side of the filter canister enter the block?

You could try removing the oil filter assembly/lines. Plug the forward hole in the block; and, adapt the fitting for the oil pressure line (at the hole nearer the rear of the block). If you get good pressure, the problem is related to the oil filter assembly.

Hi Tim,
the hose from the oil canister goes to the hole nearer the front of engine (fan side No.1)the hose from the top of the canister comes from the hole to the back side (gear side No.2).
See the photo:
http://s66.photobucket.com/albums/h242/wokri/?action=view&current=Motorblockteilsaufgebaut1.jpg
On No.2 is also connected the oil gauge.
Wolfgang

Hello Wolfgang,

Is there a metal tube inside the canister that runs from the hole in the base to the hole in the cover? If yes, is there a hole in the side of that tube (if yes, how high up the tube is the hole)?

Hi Tim, no there isn't one. There is only one tube where the screw is to fix the cap of the canister. I'll try to make a photo tomorrow.
Wolfgang

Hello everbody,
I found today the reason why the oil pump couldn't made enough pressure the pressure got lost if the engine was standing still for a day. :-((
The oil pump has a valvet that must work if the pressure gets to high. This valve has a small steel ball, a spring and a pin to fix all. I take pressure air and blow it into the oil pump. Normally I think the valve should open about 6 or hight bar. I had a pressure under 1 bar and the air was coming out of the valve. :-((
So I remove the oil pump and take a look what ccan be wrong. I push out the pin, take the spring and have a look after the ball. But there was no ball. :-((
I meassure the borehole take another ball from a bearing and put it into the hole. Fix the spring over the ball with the pin and blow air into the pump. And great pleasure the valve works. :-))
I think some of the workers how build the pump had lost the ball and put only the spring into the pump and said okay thats all for today. What a fool!
Happy Wolfgang

I've heard that some engines, the reverse is true, the checkvalve makes sure that oil stays in the engine after you shut it down, but I don't know.