Paulryan

I just recently started my built motor for the first time. I used copious amounts of assembly lube during the build process. It was a little nerve racking to turn the key for the first time but I took the advice of all the smarter people around here and just fired it up, watched to make sure oil pressure registered, got out looked for leaks real quick than jumped in and took it out and followed thr FM break in procedures. As long as you assembled everything properly, checked clearances and torqued everything correctly you should be fine.

Savington

iTrader: (31)

In the worst case scenario, it's no different than what happens in the first few seconds after start-up. All the assembly lube is scraped away as the motor spins over without oil pressure.

I assure you it does. You can build 30+psi of oil pressure cranking the motor over at 300rpm.

Logically, it should take a specific number of rotations for the oil pump to draw oil from the pan, fill the pickup tube, fill the pump body, and fill the block passages. At that point, the gauge will start to register pressure in the system. Those rotations can happen at 300rpm on the starter motor or at 1500rpm idling, the oil will get there in either case. The big difference between the two is that at 1500rpm, the engine is running, and the bearings need oil pressure ASAP in order to support the combustion loads being produced by the motor (even at idle). At 300rpm while cranking, there are virtually no loads on the engine bearings or cam journals. Since I have to turn the motor over 100-150 times or so for the oil pump to push oil into all the passages, I'd rather do it with virtually no load on the bearings/journals. I pull the spark plugs to further reduce the compressive loads on the bearings (and to give the starter motor a fighting chance).

Furthermore, if you fire the motor on the assembly lube, and for some reason you don't develop oil pressure, you might be inclined to wait a little too long in the hope that it will "eventually build pressure". Doing it while cranking prevents you from doing that.

AndrewG

That makes sense thank for you patience with me lol. I will use your approach on my new build.
My biggest scare now is starting of the motor with ITBs on, so I will probably use standard closed intake for the first start and break in.

curly

iTrader: (25)

Yes, try not to do anything beyond the motor, for Don's motor I had to test an alignment on new suspension, break in the engine, and street tune it all at the same time. MegaSquirt's test mode came in handy to make sure it all worked properly on first start up.

Something that hat hasn't been mentioned, a few hours before cranking the engine over, throw a charger on the battery if you have one, it's always a big pain diagnosising a problem or even just cranking for oil pressure on an old battery.

ninerwfo

So, not trying to deliberately get everyone to jump down my throat, but - IF - you can be bothered to organise an external oil primer of some sort, then would this the "optimum", lowest risk way to do a first start? I know everyone will say "you don't need it", but what if I my paranoia drives me to do it, surely pre-pressurising the engine with oil is the safest of all?

curly

iTrader: (25)

Yes, that's called an Accusump. Many race cars use it. Key on, open valve, wait for 10+ PSI on your AiM dash, start engine. More beneficial if you do it every time vs only the first start. AKA, if you're not going to do it every start, don't bother.