First Startup - No Oil Pressure?

[GaTechPorsche]

Hopefully some experts can help me out with this one. Car is a 1978 911 SC.

I disassembled the engine down to the cylinders to replace some studs. Replaced the timing chains and re-timed the cams. Replaced some other CIS components and gave her a good cleaning. I've gotten everything back together and installed.

The next step is to run the starter to build oil pressure. I've disconnected the CDI box and the fuel pump relay. I've turned the car over with the starter 10 or so times for 10 to 30 seconds at a time and it doesn't seem that any pressure shows on the gauge.

I did a quick test of the gauge and wiring, it pegs at 5 bar when the spade connector for the oil pressure sender is hanging out in the air, sits at 0 when the spade is grounded.

I tested the sender out of the vehicle with an air compressor and an ohm meter. Reads 9 ohms at 0 psig, 37 ohms at 20 psig and was around 80 ohms at 40 psig. I put it all back together and hoped that it would work, but the gauge in the dash still sits at 0 bar when cranking the engine over for 10 or 15 seconds.

The gauge does flick up from the rest position to 0 when the ignition is switched on.

With an ohm meter on the sender when installed on the car and cranking the engine, there is no change in the reading. Meter leads were touching the spade and grounding to the engine. The engine/transmission ground strap is good to go.

Lastly, with the gauge out of the car and clear tube in the crankcase port for the sender, oil does steadily pump out when cranking the car.

[Flat6pac]

Does the idiot light go out?
As long as you didnt open the center case, nothing should change from before.
Bruce

[dtw]

Put a mechanical gauge on it and fire it up, should be fine. No plugs left in oil lines? You put enough oil in?

Replace "some" studs? Have you got mixed dilivar and steel head studs on the exhaust side? You'll be back in there soon. Just had a 3.0 where the PO did that. Half the remaining dilivars broke when I put a wrench on the nuts.

[GaTechPorsche]

The idiot light should be a good check of the oil pressure, but I don't think there is anything behind the lens. I will check that out.

Is there any place locally where I can find the fittings to plumb in a mechanical gauge? I measured the threads on the fitting that fastens the sender to the case. It appears to be 12mm x .75. This doesn't sound right to me. Where can I find this?


Thanks for your help!

[MBruns]

crack the oil line loose at the cam feed hose banjo bolt and have someone spin it over til it shows you oil there, one side will do.

Mike Bruns

[GaTechPorsche]

Well I found where the idiot light had fallen behind the dash. It works and turns off as it should after a few seconds of cranking.

I've gone ahead and tried cranking the engine with fuel and spark. No luck so far.

I check with a strobe that one of the cylinders is getting spark and it is.

I purged the fuel lines by running the fuel pump until is made a steady sound.

After a few tries cranking, fuel can be smelled near the back of the car.

Any clues on why it won't just start right up? Could I have gotten some wires reversed?

Thanks again!

[Flat6pac]

You might be 180 out or wired the plug wires clockwise.
Bruce

[GaTechPorsche]

Bruce,

You are exactly correct. I must have somehow timed the cams 180 degrees off. I switched the plug wires around and she started right up.

I noticed this on my own when I went to check the valve lash and for some reason (even though I recall doing the valves with the engine out) every single valve was "off" by the same amount.

I went a "fixed" them all. Then I actually watched the valves while rotating the engine over. It all made sense after that. I had to go set all of the valves over again.

Could have saved myself a little time if I had checked back here a little sooner... or if I had set the cams right to begin with. Well next time I drop the engine, I know what I have to do.

Thanks for your help!

[jpnovak]

Cams are fine.

Its the relationship of the distributor to the cam that is the problem. 10 minute fix.

Just pull the distributor When at #4 TDC and re-index it to #1 TDC.