Hi all, I have a real head scratcher on my hands.

I purchased a "20k mile" HE V12 that allegedly has been sat for 26 years in the back of a local shop after being pulled from a wrecked car. Could not verify the story or mileage but it does look the part. I pulled the spark plugs, added a little oil to each cylinder and turned the engine over by hand a few times; no issues yet. Using a borescope I inspected the cylinders and the crosshatching certainly suggests very low mileage. The timing chain and guides also look brand new.

I wanted to perform a compression test on the engine so I plumbed in the oil cooler, filled the engine with oil, replaced the filter, and wired up the starter- this is where everything went sideways.

I replaced the oil pressure sending unit with a mechanical gauge and after a few bursts on the starter I was seeing zero oil pressure. I pulled the oil cooler line off of the sump inlet and I had fresh oil pouring out of the inlet which would suggest the oil is making it to the pump, no oil in the cooler however. So I pulled the cam oil feed banjo bolt off the main gallery and no oil came out when cranked. I replaced the banjo bolt and pulled the new oil filter off, and not a drop of oil came out of the filter housing when cranked. Verified oil level on the dipstick.

I am stumped. Any suggestions?

 

Pulled the sump- oil pickup is spotless, as is the inside of the engine.

Current hypothesis is that the system is failing to prime. Tomorrow I will try to rig up something to pump oil into the oil pump through the forward sump inlet and possibly also into the gallery on the side of the engine. Barring some bizarre issue like the woodruff key on the pump drive gear being broken, this should restore oil pressure.

I just hope no damage has been done by cranking the engine with no oil pressure.

 

Remove the idiot light switch, place a suitable fitting in the hole with a spigot.
Attach a hose to that spigot, then using a large syringe, pump oil into the beast.

Some use fancy pumps etc, but I am old, and the old ways are always the most reliable.

A dry, yours, engine will take a bout 2 ltrs to prime, IF you have prefilled the filter, if not, then about 3ltrs.

It will take time, and much patience, but thats how I have done it for too many years.

Any engine, not just these things.

 

Forgot, welcome to my world.

Sitting that long, the o/rings on the oil pump suction and supply pipes will be knackered.
Sandwich plate off, and replace them with Viton from any seal supply mob near you, nothing special at all.

 

Have you checked the oil lines to and from the coioler for blockages. Also unbolt the filter head and make sure there are no blockages there and that the pressure relief valve is working.

 

Thanks for the help Gents,

I pumped about 2.5 liters of oil into the top of the engine per Grant's instruction, and double checked that the oil cooler was not obstructed and now I'm getting a stable 70psi (4.8 bar) when cranking over the engine.

I'll add Viton orings for the oil suction and supply pipes to the parts list for this engine along with all new hoses and gaskets.

Up to this point I didn't know the V12's required priming when dry; you learn something new every day.

Attached are a few photos from when I picked it up last week.

 

That looks so clean for an engine from a wrecked car and that has been sitting for years! Sooo much better than I thought it would be!

Well done!

Paul

 

Well done.

I say it once more.

SIMPLE engines these V12's.

ANY engine needs priming after sitting that long, or having serious long term internal work done, even the beloved US Cast Iron things, its just common sense.

I remember the Road Train engine, took 5ltrs and 3 hours to prime that sucker, many beers consumed during that process.

Maybe a tad rough there Grant, but really, Old age has its advantages, so dont take it weong please.

 

While it is out, ditch the air injection system!

 

You're the one who got to it first. it looked real nice.