Help - 216 no oil pressure!

[harrygrey382]

Just started my C15A up after doing the valves and I'm not getting any oil pressure. This is the first valve adjustment after rebuild (pump was good and all bearings/shafts measured well in tolerances). It had 25-30psi cold at idle and 5-10 hot when idling.

I pulled the valve gear off to retighten the head and it all went back on fine. After starting it and running for 15 seconds twice, still no pressure. I pulled the valve cover off to check if I'd put the rocker oil delivery pipe on properly and that's fine, but oviously no oil being delivered up there. I started it for a couple more seconds with that pipe off and nothing's coming out.

Could it be when I took the rocker gear off all oil drained back and it needs to be pumped back up and this takes time? Would've thought two bursts of running for 15 seconds would do this though. How long can I run safely with no pressure in a 216?

[Grant Bowker]

Just curious, did you at any time try the trick of chucking a flat screwdriver bit in a drill, removing the distributor and driving the oil pump with the drill to spread oil around? Also, is it possible that the distributor isn't seated quite deep enough in the block for the tang on the distributor shaft to engage the oil pump shaft? Since the engine ran, the distributor is engaging the camshaft but this doesn't guarantee that it is also driving the oil pump. Oil pressure should be visible when turning the motor over with the starter (particularly if the system has been primed at some time with a drill).
I would be reluctant to run any more without knowing you have oil pressure but is the gauge "known good". You could check with air if you turn the regulator on the compressor down, start at near zero and work up (looking more for a progression of pressure than absolute values).

[rob love]

The screwdriver on the drill is the answer. I wouldn't run the engine again until you verify oil pressure. When you turn the pump, you will feel the resistance when it starts pumping. With the valve cover off, you will see oil coming out the rockers and the drain tube.

It is possible that the relief valve in the pump is stuck open, or that the relief valve spring has broken. Not common on a chevy, but I saw it many times on the perkins diesels.

[harrygrey382]

Thanks guys. When I first reassembled it I did the screw driver trick. It actually took quite a long time to get oil pressure like that but it did in the end. So could this be it - opening that pipe opened the system and it needs repriming? I actually just tried to remove the dizzy but seemed like something was holding the shaft in - had about 2mm of up/down then stops (yes I removed the clamp bolt!), is there a trick? I was in a rush so didn't keep pursuing it, should read the manual really...

The thing is I've run it quite a bit, probably about 2-3 hours overall. Oil pressure has always been good so the shaft is obiously mating well and the gauge is good (it's a manual one out of a dodge d5n).

So drill/screwdriver it is.

[Lynn Eades]

Harry, As Grant has stated, about the dizzy.
When you drop in the dizzy, the gear on the bottom meshes with the cam shaft, but the dog teeth on the bottom don't always line up with the pump slot. You have to turn the pump with a screw driver to line up with the dog, which doesn't happen easily, because the gear on the dizzy turns going in. It might take a few goes to get it in.
You shouldn't need a drill to turn the pump as it will only take a couple of turns of a suitable screwdriver to feel the resistance of the oil pressure(you had pressure before?)when you turn the pump in the correct direction.
Your oil pressure to the valve gear is only low pressure, and low volume. It is fed from a cam bearing and regulated by machined cuts in the camshaft, so this is not the reason for the sudden loss of all your oil pressure.
Good luck!

[Lang]

Harry,

You have a seriously good 216 oil pressure with 5-10psi at hot idle. With 14 psi as the book running pressure and "indicating" as the book idle pressure your jigger looks in top condition. Most people would not stress if the needle dropped to zero on hot idle.

Lang

[rob love]

I doubt very much that opening the tube to the top would lose the prime. Not unless it was over a very long time.

The distributor should come straight up. You may be on to something there. Perhaps there is some problem in the belly of the beast.

The reason why I suggested the drill over simply turning the screwdriver is so that you can see the oil run up to the top end. If the system is dumping the oil somewhere else it is better to figure that out with the drill than with the engine running.