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A friend's son has a Brock Commodore and it hadn't been started in 18 months. When he started it the other day he left it run for some time only to find on his return it had no oil pressure and some serious bearing noises. Do these engines have a common problem or did the pump dry up by sitting so long? I suggested he take the pump off and fill it with oil and see what happens but I have concerns with how much engine damage he has done.

The pumps are a problem to prime initially, but I have never had one loose it's prime from sitting too long. But that's exactly what it sounds like here.
Can try re-priming it but I'd have to agree with you that the damage is already done. How long was it running? Rocker gear would have been dry too. Or is there any oil up in the heads still?

If you get oil pressure back, maybe an oil sample afterwards will confirm engine condition. For a $30 sample could save you pulling down the engine if it's still ok.

I have had this happen with a few engines before other than Holden from sitting around too long. The oil film goes away with enough time that the gears/rotors can't seal against air and bleed out the vac quicker than overcoming the draw of the oil and thus fail to ever prime. I had this happen on a VP v6 engine that sat for some 12 years the seller told me, this was quite a few years back now but multiple restarts I could not get oil pressure and it was very noisy.

I ended up using a funnel and filled the oil pressure switch bung in order to wet the rotors enough to pull a better vac, then discarded the prefilled oil filter as I learned is a mistake on a dry first start engine as the oil resistance of a wet filter prevents the dry pump from pushing the oil out and never primes. Soon as I installed a dry filter and put a few mL of oil down the pressure switch bung it primed up and got pressure fine, but until I did those 2 things together I spent about half a day of cranking/starting attempts all in vain.

That engine did 400k and the bearings were still almost like new when I tore it down many years later. So hopefully it will be ok.

Thanks for the tips guys. I'll be seing him tonight and tell him to try filling the pump via the switch hole and if that don't work to pull the pump off and pack it with molly grease, vaseline or similar grease that will mix with the oil. I'll let you know the outcome.

Well the good news is they got oil pressure. The bad news is he ran it for 10 minutes and it now has some serious knocking noises.

Shame.
What sort of Brock was it? VK?

Charlescrown wrote:Well the good news is they got oil pressure. The bad news is he ran it for 10 minutes and it now has some serious knocking noises.

Oh shit

On the subject I had a work mate with a 304 at my last job who had oil pressure issues. His was loosing pressure after a few min but would start up ok if you left it for a while.

He ended up finding that the oil disappear if you ran it too long or drove it, the issue was the carbon build up in the heads weren't allowing the rocker covers and heads to drain oil back to the sump so all the oil would end up in the top end emptying the sump.

So that's another thing to watch out for on these engines. Had a similar thing with my nephew's Buick toyota 4 runner, while it didn't empty the sump, filling the engine during service was a pain as the oil took ages to go down in the rocker cover. The engine died anyway due to newspaper in the sump blocking the oil pickup and the negative input shaft end float that destroyed No2 thrust face and crank. Conversions done dodgy It still ran and drove but the engine was not happy.

It's a VL and still has the polariser fitted. Not having seen it I can't tell you anymore. It's owner is a mates son inlaw.