No oil pressure after reconnecting oil cooler lines

Goopie 18 · #1 (**permalink**) 07-31-2012, 11:00 AM

I have a Roush 427R (351 W). Had to replace mechanical fuel pump. In order to get at it, had to remove oil cooler lines from block adapter. After replacing pump, I replaced the oil cooler lines to the block. I made sure the outlet line was connected to the outlet port of the adapter(turned engine and saw which port pumped oil). The outgoing line then was connected to the oil filter housing(paid attention to the direction arrow on filter housing). From the oil filter housing the return line goes through the cooler then back to the engine. I now have no oil pressure showing on my gauge. I turned the engine over several times (coil disconnected) to fill the lines. Then I connected the coil. Engine started and I ran it for about 10 seconds. No oil pressure showing on gauge. Does it take a long time for the oil pressure gauge tube to fill with oil to get a reading? Did I do something wrong? Don't want to run the engine for a long period of time If I messed up on the above work.

Blas · #2 (**permalink**) 07-31-2012, 11:17 AM

Did you reconnect the small pressure tube to feed the oil pressure gauge? It's usually directly above the oil filter adapter block. If stock, it;s a small white plasric tube. Maybe you kinked it and no pressure is reaching the gauge? FYI..it is not desireable to have oil in this small tube actually reach the gauge. It's the air trapped in the tube, being compressed by a small plug of oil in the line that makes the gauge work... You can contact me directly and I'll give you my phone number to call with any questions tonight... See below

strictlypersonl · #3 (**permalink**) 07-31-2012, 11:48 AM

Quote:

Originally Posted by Blas

Did you reconnect the small pressure tube to feed the oil pressure gauge? It's usually directly above the oil filter adapter block. If stock, it;s a small white plasric tube. Maybe you kinked it and no pressure is reaching the gauge? FYI..it is not desireable to have oil in this small tube actually reach the gauge. It's the air trapped in the tube, being compressed by a small plug of oil in the line that makes the gauge work... You can contact me directly and I'll give you my phone number to call with any questions tonight... See below

I disagree. The more air you have in the system, the slower the gauge will react to any pressure change at the engine. Air compresses. Oil (in a practical sense) does not, so the oil transfers the pressure to the gauge quicker.

Goopie 18 · #4 (**permalink**) 07-31-2012, 11:53 AM

The tube runs between the exit/entry ports. I never touched it.

jhv48 · #5 (**permalink**) 07-31-2012, 12:11 PM

That tube is very easy to knock loose when replacing the fuel pump. Remove the fitting and check the tube fitting in the hold down fitting.

To be sure, you can always hook up a cheap aftermarket gauge to verify you do in fact have oil pressure. You probably do.

Once you are through, you will probably want to replace that nylon tube with a braided metal tube that will never break or leak. There is a parts store that sells these lines custom made for our cars. Wwwbatinc.net. They will custom make you a braided line with the proper fittings to attach to a British gauge and an American engine.

Blas · #6 (**permalink**) 07-31-2012, 12:45 PM

The problem is not so much knocking the tube loose, it's cracking the tube at the ridgid insert in the tubes end. Perhaps look for a bit of oil at the block fitting.

Goopie 18 · #7 (**permalink**) 07-31-2012, 12:58 PM

tube does look fragile. I must have knocked it loose. I like the idea of upgrading from the plastic. The place that has been recommended above is only 1/2 hr. away. Simple job to replace? If I remove the oil filter and crank the engine with the coil disconnected oil should pump out of filter housing if I have oil pressure?

jhv48 · #8 (**permalink**) 07-31-2012, 01:25 PM

I would buy a cheap oil pressure gauge at your local parts store (less than $15) and hook it up to the oil pressure outlet on the block. A local mechanic might even lend you one. Then crank the engine. If no oil pressure shows on the new gauge, you have other problems. my bet is you cracked or knocked the stock tube loose.

Dangerous Doug · #9 (**permalink**) 07-31-2012, 01:38 PM

You need to check and see if your oil pump is working before you do anything else!

Remove the distributor and you'll see deep down in the distributor hole a hexagonal shaft. (Mmm, if it's NOT there you forgot something on your oil pump replacement). Procure an oil pump primer shaft from a friend or the local auto parts place, put it on your drill and spin that oil pump shaft (verify direction, but I believe it is counterclockwise). Your oil pressure should rise with this priming. If not, you'll need to start all over with your oil pump replacement.

Also, careful with the oil line that goes into your cockpit to the guage---if that is loose at the gauge you'll have oil under your dash with all of that live wiring and may have a fire on your hands. Actually, I'd feel around under the dash under the oil pressure gauge first, to make sure there was no leak and THEN pull the distributor and prime the oil pump.

Cheers,
DD

Goopie 18 · #10 (**permalink**) 07-31-2012, 02:03 PM

Doug, I replaced the mechanical fuel pump, not the oil pump. In replacing the fuel pump could I have damaged the oil pump?

Gaz64 · #11 (**permalink**) 07-31-2012, 02:12 PM

The owner has replaced the mechanical fuel pump, not the oil pump.

The system will stay self primed if the oil cooler hoses run down hill to the cooler. If may have difficulty self priming if they run uphill.

Crank the engine with the gauge line off, then you'll know which direction you're heading.

DAVID GAGNARD · #12 (**permalink**) 07-31-2012, 03:38 PM

After cranking the engine and 10 seconds of running, things should be primed up and you should see oil pressure.......
I would try another gauge and pull the distributor and spin the shaft with a drill to verify you do actually have oil pressure before doing anything else......

David

Rick Parker · #13 (**permalink**) 07-31-2012, 05:16 PM

Were the lines and cooler full when reattached? Was the filter filled with oil?

Goopie 18 · #14 (**permalink**) 07-31-2012, 06:16 PM

cooler and filter were filled, lines were not

madmaxx · #15 (**permalink**) 07-31-2012, 06:17 PM

The pos yellow covered plastic oil line with the fked up push pin connector has failed. Replace with braided stainless steel, drive.

bobcowan · #16 (**permalink**) 07-31-2012, 06:47 PM

The first question is, do you have oil pressure or not? DO NOT run the engine for a while to see what happens. Bad things can happen - really bad things.

Remove the distributor and a valve cover and run the pump with a drill motor. You should be able to see oil come up through the valve train to the top of the rockers.

If you have oil at the rockers, and the gauge shows Zero pressure, the gauge has a problem.

That cheap plastic tube is easily damaged and pinched off, or start to leak. There should be some oil in the tube, but there should also be some air. Air is compressable, and will buffer down the oil pump pulses. Without the air, the gauge needle will be buzzing. Too much air, of course, and the gauge will be inaccurate and slow to respond.

If you spin the pump with a drill motor and don't get any oil to the rocker arms, you probably got the hoses switched at the block adapter. A very common error. Remember, center to center, outside to outside.

vatdevil · #17 (**permalink**) 07-31-2012, 07:11 PM

Once you have oil pressure sorted out, consider installing an oil pressure switch and dash light. A big light that you can see in daylight. Good insurance.

Bill Bess · #18 (**permalink**) 07-31-2012, 08:07 PM

Perhaps it's a simple thing....1) re-verify that you have the oil cooler and filter lines routed correctly ( you can find a print out on the Club Cobra).
2) Disconnect or loosen the oil gauge tube where it connects to the filter mount, start the motor..if it blast oil, look for a line problem.
I've run a copper line with plenty of coils and had no problems for year.
Good Luck, Bill

DAVID GAGNARD · #19 (**permalink**) 07-31-2012, 08:55 PM

Quote:

Originally Posted by Goopie 18

cooler and filter were filled, lines were not

Like Bob said, don't start the engine without finding the problem........right now the easiest and surest method is like Bob said, spin the oil pump with a drill, pull a valve cover and see if your getting oil to the top of the engine.........

When I changed the oil cooler on my race car, I filled the cooler the best I could,still took what seemed forever to get oil pressure when spinning the pump with a drill, took a lot longer than I though it would considering everything else was full of oil..........

Do not start the engine without seeing oil flowing and oil pressure on your gauge.....

David

Rick Parker · #20 (**permalink**) 07-31-2012, 10:18 PM

If you are using a remote filter mount, the hose from the block adapter marked "OUT" should be connected to the one marked "IN" on the filter adapter, the one from the filter marked "OUT" goes to the cooler (either side) and the other hose from the cooler goes to the "IN" port at the block adapter. You probably have the hoses at the block reversed, attempting to force oil backwards through the filter. Easy to do. If you use a drill to spin the pump it must be set to Reverse.