Establishing pre start oil pressure

[Chuey]

I've got my project bike ready to try starting it. The engine hasn't been run in years so I'd like to establish oil pressure before I start it.

I have taken the spark plugs out so it will crank very easily and not start. Do I have to do anything so I don't stress the electrical system? I mean something like putting the plugs back into the wires and have them lying on the engine. Is that what I need to do or can I crank it for a few minutes and then reinsert the plugs and start it up?

Chuey

[dougie]

My understanding is that the plugs must be hooked up and grounded if it is electronic ignition.
That's what I do with my '87.
I don't just lay them on the cylinders, I use wires with alligator clips to connect them to one of the fins.

[Major Softie]

I'm pretty sure that the ideal of establishing pre start oil pressure is a hopeless concept. Prestart oil pressure is always going to be zero.


You haven't identified anything about this "project bike" (i.e. model/year). If it has a kick start, then all you have to do is pretend that you are doing the brainless "why won't this damn thing start?" episode that we all have experienced sometime in our misspent youth, and kick it quite a few times with the key off or the kill switch on.

[Chuey]

You haven't identified anything about this "project bike" (i.e. model/year).

Oops, I'm sorry. I know better. It's an R100 - 1983 vintage. And I guess it's not oil pressure, but having oil all through the engine that I'm trying to accomplish. Thanks for the clarification.

Chuey

[wirewrkr]

Wrong-o
It's always a good idea to spin the engine until the oil light goes out.
This fills all the passages and the oil filter cavity etc.
It's the same reason I used to hand fill my customers oil filters before screwing them onto the engine when just doing an oil change.
The same reason I built dummy distributors for spinning the oil pumps on certain engines before starting them.
It can also let you know ahead of time if there's a problem brewing.
ie, if the light won't go out etc, those kind of things.
I would rather know BEFORE the engine is actually running!
We had a bad oil Pressure switch that we found out was bad BEFORE the engine was started for the first time.
Saved some hassle and head scratching.
As far as the ignition is concerned, you can also just disconnect the neg or pos lead from the coil(s) and not have a problem. Or as was mentioned, ground the plugs.
I like doing the former so I don't have to worry about spark jumping around outside the engine and finding an fuel to ignite.

[Chuey]

Wrong-o

What's "Wrong-o"? Everybody here has been talking about the same thing. Major Softie pointed out a detail in the language I used which was not quite accurate. Everything else is right in line with what you posted. And thanks for that.

Chuey

Edit: corrected typo

[mattcfish]

My understanding is that the plugs must be hooked up and grounded if it is electronic ignition.
That's what I do with my '87.
I don't just lay them on the cylinders, I use wires with alligator clips to connect them to one of the fins.

I think you can just ground the sparkplug wires without the plugs if you want. That's what you do on VW's with electronic ignition.

[Major Softie]

Wrong-o

What's "Wrong-o"? Everybody here has been talking about the same thing. Major Softie pointed out a detail in the language I used which was not quite accurate. Everything else is right in line with what you posted. And thanks for that.

Chuey

Edit: corrected typo

No, I see how his point is different than mine (regardless of whether or not I completely agree). He's talking about getting the light to go out when using the starter - which would be best done with the plugs out and grounded as you first asked about. Just using the kick-start to fill the passages does not give the feedback that his technique would give. I can see the value of doing that test, although I would still be satisfied with just knowing that I'd filled the passages. After all, before we had electric starters, we still started all our new and rebuilt engines for the first time.

[barryh]

Another reason it might be considered prudent to prime an engine with oil after a rebuild or an oil change is to reduce the potential for hydraulic shock on the filter when the engine starts. I'm not saying failure to prime did this but you get a little cautious after one of these.

[robtg]

To pre-oil a new motor I made a pressure tank (old fire extinguisher) and pump a quart of oil in through a fitting
in place of the sending unit. Oil light goes out instantly when you hit the starter.