[outrider02]

I'm wrapping up the full rebuild of my engine after spun main bearings. Everything's been torn down, rebuilt/replaced, cleaned, and reassembled with fresh bearings, rings, and gaskets. I've replaced everything, every o-ring, copper washer, etc.

I'm not getting any oil pressure cranking the engine over. I have the turbo oil feed line just running to a can where I'd expect to see oil flowing. I've cranked probably 3-4 min or so, on and off, 15 seconds at a time.

All the glow plugs are out, and both the intake and exhaust manifolds are off. I poured oil in the filter housing which I believe should've helped the pump catch a prime. I tested the pump before I put it in, pumping cleaning solution through it turning it by hand. I put some assembly oil in it as well for good measure. I know I replaced the oring on the pickup, the chain is attached, etc.

Any ideas what could be going on? I feel so defeated, I really don't want to have to pull the pan back off. I'm so sick of working on this car at this point, but I just have too much time and money into it to quit. Hoping maybe there's some dumbass thing I need to do and just overlooked it.

Thank you!

[zachattach12]

Hey outrider, I know it can be frustrating (especially after you invested all that time into the rebuild).

I was just in a similar situation. I spun main bearing #1 and just rebuilt a donor engine and installed it last week. I also replaced everything short of the rotating assembly. At every step that made sense I added assembly lube (cam bearings, timing chain, roller rockers, etc..). For the turbos I just took a medicine syringe full of oil and squirted it into the distribution block connected to the HP turbo. I soaked the oil filter prior to installing. Then I pulled all the electrical connectors on the injectors and ran the starter for about 30 seconds, 3 times and said that was probably good enough to at least get some oil into the oil pump. Well it fired up and I have no problems.

The thing is, the engine will not be spinning fast enough with the starter to build oil pressure to distribute it through the engine. When I used to build Subaru engines, they also didn't spin fast enough to build oil pressure to circulate through the whole engine. So when doing the rebuild I would just add assembly lube liberally and fill the oil filter (they have canister style filters) and then call it good.

Assembly lube is designed to dissolve into the oil but also provide that protection to the engine during the first startup.

FWIW I think you are fine to just fire it up. I certainly understand the anxiety and frustration though.

[Andystobbs]

I'd have to say the opposite. I'd always expect to see oil from cranking. Especially after 3 minutes.
Oil pumps are positive displacement they pump regardless of speed and a rebuilt engine should be getting oil pressure to the turbo very quickly.

Neither of these should be necessary but
Last resorts would be:

Over fill oil
Pressurise crankcase

You don't mention it but I'm guessing the crank was in good order?
And the pickup was cleaned/new? Sorry for asking elementary questions

[outrider02]

Appreciate both of the replies.

Yes the crankshaft went to the machine shop as well and was polished. I also checked the clearances during assembly on every bearing, they were all very close to one another and within spec.

I also cleaned the pickup thoroughly, and replaced the o-ring. It was the original pickup (and pump) however.

I've rebuilt many engines and have always cranked them over to prime. I did have an issue on my 260Z where I have to pull the pump back off and fill with motor oil before it would catch, this was on a brand new pump however. With that in mind I had poured some assembly oil in the pump and turned it over before installing it to coat the internals just in case.

I thought about just sending it, but I think if I killed my new motor on the first startup I'd want to push the car out back and torch it. So I hoped posting on here maybe someone would say "they never prime until they're started" or "stop being a meathead and pour oil in hole xyz".

I have the heat on warming the shop up. I'll see if I can find an easy way to pressurize the crankcase.

[Tomnavigator]

Outrider2 I agree with you on being extra careful. I agree with zachattach12 that the oil pump may not build pressure with the starter only. I also agree with you, the oil pump is positive displacement and therefore will pump oil at any speed.
The oil pump has to pump enough oil faster than it drains back to the sump to build pressure. If it is not turning fast enough, no pressure will be built. You can be getting flow without building pressure. I suggest putting something that will absorb oil (like a paper towel or sponge) in the oil filter canister. Turn the engine over for about 30 seconds. Then check the oil filter canister to see if the absorbent material is soaked in oil. If it is soaked in oil, you know the oil pump is working. Remove the absorbent material and start your engine. DO NOT REV THE ENGINE! If the oil light does not go out within 10 seconds, shut the engine down and replace the oil pump.

[outrider02]

Is there any reason I couldn't just crank it over with the filter out and the cap off, and look down inside the housing to see if it's pushing oil up? Or does it need to be a sealed system in order to work.

[Tomnavigator]

The system does not have to be sealed. The oil will drain down quickly so you should get someone else to crank it while you look or it could be drained by the time you get out of your car and look. The only reason I suggested a paper towel is because once soaked in oil it will be obvious.

[outrider02]

Roger that, thank you Tom.

I was actually using one of those push button switches with alligator clips just jumpering the solenoid to the battery terminal, so I could look right down in the housing while I cranked. There's no activity, not even in the slightest.

I drained the oil back out but lost motivation to go any further last night. I'm gonna pull the pan and just double check everything. Maybe there's a hairline crack in the pickup somewhere I didn't notice, or maybe I forgot to tighten the oil pump gear or something stupid like that.

I'll post an update if I find anything. Thank you everyone for your help!

[outrider02]

Final update. I should've just sent it, there was nothing wrong. I think probably just sitting on the stand for a year while I waited for parts and time the oil I pre-lubed the pump with must have ran out. I couldn't find anything wrong, pulled the pump out and poured a little 90 weight gear oil in it while spinning by hand to coat everything again, re-assembled, and had oil within probably 10 seconds of cranking.

So hopefully I didn't hurt pan gasket taking it back apart. Unfortunately I accidentally pinched the trans cooler line right at the cooler while jacking the sub-frame back up, and now that appears to be leaking. I love this car...