Should I pre lube or let er rip?

Sorry for another Miata thread. Getting ready to start the car this week. 

I did gaskets and pumps (water & oil) on my engine. Did not touch the head gasket, or bearings as I would have gone crazy with the rebuild that already was a year in the making.

My issue is I forgot to prime the oil pump, so I installed it bone dry.

Am I screwed? Do I need to get a pre-luber? Or can I just crank it like normal? Pull the CAS and plugs? TIA

It's a 1994 Spec Miata, and I have an aftermarket oil pressure gauge so not relying on the on/off light.

I built a preluber for my LS swap out of a garden sprayer, something like this. 

https://youtu.be/16h6vIUvvrg?si=j5PVkMLVzuJeWdYg

I'm not sure if there's a port to force oil though, but at the minimum you should crank with the injectors disconnected and see if it builds any pressure.

My engine builder was not a believer in prelube or greasing the oil pump in my suby.  Needless to say he won't do another motor for me! Anyway I used a funnel and tried to fill the system via the oil pressure sender to no avail.  After a minute or 2 of cranking, plugs out and fuel pump off red lite still on.  Finally I removed the filter, put a tray underneath and cranked for like 10 seconds.  Instant pressure to the filter.  Put it back on, prefilled of course and the red light went off very quickly.  10K miles later no issues but I never want to go thru that again.

+1 for the DIY pre-luber. Definitely don't just let 'er rip. You might be able to build pressure by cranking with plugs out and injectors disconnected but it's not the safest solution.

Crank to build oil pressure then start it up

I'm pretty sure the factory didn't prelube cars when they came off the assembly line - some guy would jump in, start it up and drive it off to the parking lot.

That said, prelubing the car isn't a bad idea, or at least crank it without spark until the oil pressure comes up.

In reply to stuart in mn :

Wouldn't the factory fill the pump with assembly lube?

GameboyRMH said:

Wouldn't the factory fill the pump with assembly lube?

I really doubt it.

I have never pre-filled any of the oil pumps on the motors I've built.  I do pull the fuse for the computer and crank it on the starter until I get oil out of the turbo supply line, though.

You also have to keep in mind that the engine should have been assembled using assembly lube so you aren't really starting it "dry".

stuart in mn said:

I'm pretty sure the factory didn't prelube cars when they came off the assembly line - some guy would jump in, start it up and drive it off to the parking lot.

That said, prelubing the car isn't a bad idea, or at least crank it without spark until the oil pressure comes up.

I wouldn't doubt that they do pressure check the oiling system of every engine, though.  It's not difficult, especially for an assembly line.

I have always believed you do more damage cranking the engine over for an extended period of time, than you do by filling the oil filter and lighting it up as quickly as possible.  

Pushrod engines lube their camshafts by oil splash, which does not happen on the starter motor.

Further to that, when I'm starting a car that has been sitting for an extended period, I change the fuel, fire it up, and zap the throttle until all the cylinders are firing and most of the lifters stop rattling.  If it's gonna blow up, it's gonna blow up.  Ain't got no time for  timidity.

In reply to Streetwiseguy :

Ever change the oil pump on a Buick 231?  Nothing short of 2000rpm for far longer than feels comfortable will get the pump to prime if you don't pack it with grease.  Starter motor isn't going to do squat.

I'm with you on just starting the sucker, after doing what you can to make sure it will start as quickly as practical.

Use a good quality (and quantity) assembly lube and go for it. It'll come up to pressure in a few seconds. 

Dry cranking it trying to come up to pressure that way only risks washing/pushing out all the assembly lube.

amg_rx7 (Forum Supporter) said:

Crank to build oil pressure then start it up

I see this a lot and (at least with old school V8s) it is not recommended.  You can disable injectors and take plugs out, but there is still pressure generated and the big thing is there is still motion.  It doesn't matter that you've removed much of the restriction, it's still spinning bearings.

Is it apocalyptic?  Not likely, but the problem is that you are trying to get lube in there BEFORE things move.  The bearings don't just get oil to lube things, they get oil pressure to suspend the surfaces and prevent them from touching.  It makes a pillow.  A properly-spaced bearing and journal don't touch each other when oil pressure is in there.

In reply to Curtis73 (Forum Supporter) :

A properly spaced bearing generates its own hydrodynamic pressure. Lots of engines don't have positive oil pressure or even oil pumps, even today. The oil pressure is mainly for cooling, as far as the bearings go anyway.

If the journals are wet with oil, it'll be fine.

For what it's worth, on a chevy performance LS crate motors you void the warranty if you don't prelube it first. and to me, cranking and confirming oil pressure is more about knowing it's going to work period without the engine spinning at 1000's of rpm vs a few hundred.

That's what I like about race cars - just hit the switch for the accusump and you get fast pressure in the gallery before you hit the starter!

stuart in mn said:

I'm pretty sure the factory didn't prelube cars when they came off the assembly line - some guy would jump in, start it up and drive it off to the parking lot.

That said, prelubing the car isn't a bad idea, or at least crank it without spark until the oil pressure comes up.

Motors are usually run/bench tested after they are assembled before going into cars.  

Guys, the OP is asking about Miata engines and oil pumps. Don't know why people are talking about v8 s of various flavors...  There is no pre lube capability on Miata engines and oil pumps.
 

If the person who assembled the engine used assembly lube as specified, crank to build pressure is the way to do this. Once you have pressure, reconnect whatever you disconnected so that combustion didn't occur and start it up. 

amg_rx7 (Forum Supporter) said:

Guys, the OP is asking about Miata engines and oil pumps. Don't know why people are talking about v8 s of various flavors...  There is no pre lube capability on Miata engines and oil pumps.
 

If the person who assembled the engine used assembly lube as specified, crank to build pressure is the way to do this. Once you have pressure, reconnect whatever you disconnected so that combustion didn't occur and start it up. 

I'm not sure what you mean there is "no prelube capability" there is more than one oil port on the passenger side of the motor to force oil through to get them to the bearings (and hopefully pack the oil pump a bit). The "prelube" port on an LS is past the oil pump as well, it's not some bespoke port.

And I'm only mentioning what I have experience with - I've just started rebuilt BP's after cranking until oil pressure. Just stating the options.

wspohn said:

That's what I like about race cars - just hit the switch for the accusump and you get fast pressure in the gallery before you hit the starter!

I have an accusump on my race car, but you can't really pre-lube the accusump, can you? Haha - I guess you could build an accusump pre-lube'r as well!

All engines can be prelubed, even if it's just rigging a pressurized tank of oil and using a rubber tipped blow gun on its outlet hose to blow it in to the oil filter fitting before you screw a filter on.  Threaded port is always the way in to the engine.

This won't help the oil pump, but it does ensure that the galleries and everything are full.

If you go in through an oil passage plug, this WILL get oil into the pump, through the filter.  I used to do Subaru engines this way, right on top of the engine at the pressure switch port.

Pete. (l33t FS) said:

All engines can be prelubed, even if it's just rigging a pressurized tank of oil and using a rubber tipped blow gun on its outlet hose to blow it in to the oil filter fitting before you screw a filter on.  Threaded port is always the way in to the engine.

This won't help the oil pump, but it does ensure that the galleries and everything are full.

 

If you go in through an oil passage plug, this WILL get oil into the pump, through the filter.  I used to do Subaru engines this way, right on top of the engine at the pressure switch port.

Could I possibly still go through the oil filter to pressureize the system and get into the oil pump? Looking at this picture, its might be possible but idk?

I also saw that there is a screw in the back of the head under the CAS (shown below) that people use as a turbo oil feed line. Could I potentially use that too to pressureize the oil pump?

Or possibly this bolt, can I remove it and pre lube the system from here?

I don't think any of that will pressurize the oil system. It will add some oil to those passages (one of which goes to the oil pump) and maybe aid in getting the system pressurized faster when you start cranking it.