Re: Oil Pressure at Start up
[Re: moparniac]
#310739
05/07/09 03:26 PM
05/07/09 03:26 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
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Re: Oil Pressure at Start up
[Re: HemiDart68]
#310740
05/07/09 03:39 PM
05/07/09 03:39 PM
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Joined: Oct 2005
Posts: 46 Macomb Michigan
65 Belv A990
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Posts: 46
Macomb Michigan
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Quote:
I don't really see the benefit of cranking an engine with the ignition off to build oil pressure. It’s still going to move around the same number of dry revolutions to build oil pressure. My use a preoiler if your concerned, or just start it. I don't see how 30 seconds of cranking to build pressure is any better then starting it for a second to build it.
I agree plus the residual oil that is sitting on the bearings after an ignition off cranking session is not what protects them or the journals from damage. It is the crank getting up off the bearings on its oil wedge that protects these parts, and that is a function of oil feed pressure AND sufficient continuous rpm to sustain the wedge. Now if you are trying to suck up some heavy viscosity oil out of the pan in the dead of winter, or an engine that sits for extended periods of time, then a pre-oiling accumulator system like Matt suggested would be a smart idea. I also agree that pre oiling a new motor with an oil pump priming shaft is mandatory. My motor has an instantaneous 80-85 psi cold at fire up at a 1400 rpm idle with 20w 50 synthetic oil, and settles down to about 45-50 psi once it warms up.
Ed.
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Re: Oil Pressure at Start up
[Re: emarine01]
#310743
05/09/09 01:02 AM
05/09/09 01:02 AM
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Joined: Aug 2003
Posts: 43,185 Bend,OR USA
Cab_Burge
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Bend,OR USA
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Quote:
Hey Cab , How come you dont like to crank to build press?
Sorry for not responding sooner, I've been out of town for two days. I don't like cranking the motor over for any longer than it takes to get the motor started because most BB Mopars take to long on the starter to make oil pressure with the spark plugs in I have seen SB Chevys get oil pressure in two revolutions on the starter but not any Mopars I have ever owned As already mentioned several times, the crank and rod bearings and crankshaft surfaces have residual (SP?)oil on them, no matter how long the motor sits unless the oil was real hot, above 260 F and the motor sits for several months between starts, like in the winter months I have had drag race motors sit for several months in the Mojave desert where the outside air temps reach 100+F and the rods and main bearings oil look like I had just shut the motor off right before pulling the oil pan and rod and main caps off
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Post deleted by Defbob
[Re: Cab_Burge]
#310744
05/09/09 04:22 AM
05/09/09 04:22 AM
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Re: Oil Pressure at Start up
#310745
05/09/09 07:33 AM
05/09/09 07:33 AM
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Joined: Jul 2004
Posts: 1,770 Pa
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Quote:
Accusump
X2
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Re: Oil Pressure at Start up
[Re: emarine01]
#310747
05/09/09 08:08 AM
05/09/09 08:08 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Romeo MI
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To me its just a matter of X revolutions to get the pressure up no matter if its on the starter or if it fires, but in my opinion its easier on the engine if its cranking without the ignition(less pressure on the bearings). Of course the Accusump would be the best way
Last edited by MR_P_BODY; 05/09/09 08:10 AM.
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