No oil pressure after reinstalling motor

Discussion of 4-Cam Type 547 engines (and all the Fuhrmann racing variants) and cars that powered them.
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Bill Sargent
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Tag: Faux-Cam
Location: Seattle, Washington

No oil pressure after reinstalling motor

#1 Post by Bill Sargent »

I have had the 587 motor out of the 59A for several months to fabricate and install a street exhaust system. After reinstalling the motor today I encountered a new to me problem. No oil pressure when cranking or with a 2 second startup!

I finally traced the problem to the oil pump not being primed. I had the motor upside down so long installing the street exhaust the oil pump went dry. Then the anti backflow valve in the oil suction line from the oil tank to the motor did what it was supposed to and even when started (for 2 seconds) the oil pump did not generate enough suction in air to open the valve.

This would not happen on a stock car as there is not a backflow valve in the suction line from the oil tank to the motor. But on a stock car after a week or two of sitting oil will migrate from the tank (with about 8” head above the bottom of the motor) through the oil pump into the engine case. If enough oil migrates into the case it can cause problems. So I use a valve similar to those used on the 962 and available for 911s to keep oil in the tank when not running. There is a small cone in the valve that stops static flow with light spring pressure. If the oil pump is primed it easily opens the valve when the motor is cranked and the motor gets oil.

My fix was to lightly pressurize the oil tank with the oil suction line fitting at the motor loosened. This opened the valve and allowed oil to fill the suction line downstream of the valve, with a little dripping into the pan under the fitting.

There is a vent on the filler neck which I plugged. I took the other tank vent hose off the cows udder breather box on the firewall. I then Loosened the suction line fitting at the motor and blew compressed air in the vent hose to lightly pressurize the oil tank by holding a rag around the vent hose with the air gun. That was enough to open the anti back flow valve and fill the oil pump and suction hose downstream of the valve. After putting everything back together I cranked the motor without ignition and got 30 psi fairly quickly.
Regards,

Bill Sargent
#151489 59A Cab - Faux Cam
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Alan Klingen 2
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Re: No oil pressure after reinstalling motor

#2 Post by Alan Klingen 2 »

You might want to try to prime the oil pump by flooding it with oil you can also try pressuring the crank case with air pressure and then turniover the motor. Alan The Stable.

Alan Klingen 2
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Re: No oil pressure after reinstalling motor

#3 Post by Alan Klingen 2 »

Are you sure the pump is installed correctly? So al the oil passages in the pump align with the case correctly? Alan The Stable.

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Martin Benade
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Re: No oil pressure after reinstalling motor

#4 Post by Martin Benade »

Both the problem and the solution were in post #1.
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Harlan Halsey
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Re: No oil pressure after reinstalling motor

#5 Post by Harlan Halsey »

Bill, I "always" pre oil any new installation, 356 or Carrera (or English Ford or Climax for that matter.) I have an old oiler off some truck with a sight glass, but I have seen a 356 oil filter canister used too. I put 40 lbs on the pre oiler until pressure shows on the car or stand oil pressure gage. I then start the engine and let the engine oil pump push excess oil back into the oiler. (Dry oil pumps are the problem because they don't prime well. In the old days we sometimes used to grease the oil pump gears to get it to prime.)

Carrera oil pumps sometimes don't leak oil from the tank, mine don't much, but Chuck Forges did. Chuck pointed out that the oil level in the tank is above the intake cam drive bearings. That means that with the tank at the full level even when sitting the cam bearings remain fully lubricated. Your anti drain back valve may keep the tank full but it will allow the oil to drain from the upper part of the engine. Maybe better to monitor the oil level in the tank and start the engine when the level is down a couple of quarts. In your case as so often happens, your solution was the problem. Absent that valve-I've always wondered how a valve inn that direction could work-Carrera oil pumps have no problem priming because they are under the oil tank head.)

Alan Klingen 2
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Re: No oil pressure after reinstalling motor

#6 Post by Alan Klingen 2 »

Try priming the pump with some oil you also can try trilting the motor a few degrees one way or the other. Alan The Stable.

Alan Klingen 2
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Re: No oil pressure after reinstalling motor

#7 Post by Alan Klingen 2 »

you can also pressurize the case slightly. Alan The Stable.

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