James88

Thanks Kevin

Macster

There is oil pressure in the plain bearings.

As the crankshaft (or cam shafts) begin to spin the residual oil forms a hydrodynamic bearing oil film. Then the oil from the oil pump arrives real quick and as the engine fires and rpms pick up there is plenty of oil pressure. Way too much actually. I mean if approx. 1.5 bar is plenty for a hot engine at idle 5+ bar for a cold engine at idle is overkill.

Cranking the engine at slow (approx. 75 IIRC) RPMs using just the starter may be more harmful than just letting the engine crank and fire normally.

With the starter the engine spins much slower and it spins at this slower speed for a longer period of time. This can have a negative impact on the formation of the hydrodynamic bearing oil film and the sustaining of same. Speed of the rotating bearing surfaces is needed. There's a reason that all engines crank and then when they begin to run do so at RPMs above even their cold idle speed.

There's absolutely no evidence any engines are wearing out from lack of oil at cold start even those that sit sometimes months unused.

Even for a rebuilt engine removing the fuse and cranking the engine is a poor substitute for lubing a rebuilt engine. During assembly proper assembly lubing should be done. Then if the oil pump can't be driven independently of the engine spinning I would explore a way to supply oil under some pressure into the engine oil galleys from outside the engine using perhaps the oil pressure gage fitting to plump in an oil line and an external pump connected to an oil reservoir.

This would supply the engine with oil under pressure (how much depends upon the pump used) and fill all oil galleys and put oil in all bearings.

One could perhaps hand spin the engine -- with its plugs removed -- to help feed oil to the various lifters as these have their oil feed holes blocked when they are not in the right position.

Thus the assembled engine has its oil passages full of oil fed there under some pressure and the lifters have had their cavities recharged with oil to replace any oil forced out by (some of them) sitting stationary with their valve open so when the engine is cranked and fired for the first time it does so under conditions almost identical to that of a recently run engine.

ltc

Run a simple experiment.

Let the car sit for a few weeks/months, jump in and start it. Time how long you hear a very unsettling noise coming from the engine and watch the oil pressure gauge.

Now, pull the fuse, crank until full oil pressure is built up, replace the fuse, fire up the car and listen for the unsettling sound.

I have a 2001 with 6000 miles, I've done the experiment (taking one for the team).
As per usual, Kevin is correct. If you've been around this forum long enough, you should have figured it out by now.

Kevin

http://www.stealth316.com/misc/clevi...ng-fund-p2.pdf

TurboTodd

My car is used very infrequently, most times it sits for weeks or more.
I always pull the c4 fuse and pre oil before stating.

When I do start it with this method I get no bad sounds and instant oil pressure.

Its my car,, it makes me feel better , my car loves me for it and I will continue to do so.

nick49

If it's really important to you install a primer pump between the tank and a main oil galley. Power up the pump before starting your motor to establish pressure.

It would be pretty simple and very inexpensive to do. No more anxiety over whether or not you had damaged anything with a "dry" start.

Quadcammer

i swear threads like these make me embarrassed to be a porsche owner. Firstly, its not a fabrege egg. Secondly, perhaps you aren't hearing funny noises while cranking because the bloody starter is running. Thirdly, for people who drive it once every 2 weeks, you probably won't put enough miles on it to have to worry in the least bit about the tiny extra bearing wear you may get from just cranking the bloody thing.

I really wonder if you all realize how ****, nerdy, and just plain scared you sound when you ask stuff like this?

Dock

Great post!

"02996ttx50

lol.. again! faberge egg! priceless

rmc1148

I have owned more cars then I can remember and am very concerned with maintenance, but the starting of my car after an oil change has never been a worry. I have driven some of them hard up to 200k and with preventive maintenance they held up well. My car sat for seven months and when started this spring it sounded fine= no noises.

cburke996

Whoa...a bit heated in here for just asking a simple question. Normally I wouldn't think twice about it...but my car was basically sitting with its *** end 2 feet in the air and front wheels on the ground for a week....just simply thought one end of the engine might be a bit...more dry...than usual?

My appologies to Quadcammer for embarassing him as a Porsche owner

James88

neanicu

That's because you don't know Quad,he's funny like that...don't take him all too seriously.

James88

I know who's car on here l would prefer to buy.