I have a 351W and have a pretty big oil pressure drop from when it is cold to when it is hot. When cold it is between 60 to 50 then once hot and idling at stop sign (700 rpm) it drops to about 10. Once I start moving the pressure goes up with the rpms. I am just concerned by the low oil pressure at idle. Should I be concerned if so what can I do to improve the oil pressure?
Update: after reviewing other threads I noticed some advice and some questions other threads were asking. I actually have a mechanical gauge under hood and an electric gauge inside. It seems like a different oil might help. I can't remember what weight I put in last but I know I was told to put performance oil with zinc added. I have been messing with adjusting carb. Perhaps flooding could add to the problem. The engine was rebuilt about 5000 miles ago.
"What is the hot pressure if you turn the idle up to 800-850 or so?"
Answer: I is normally about 15. If I turn it up above 900 it gets run on. The bad part is that the idle will very day to day by about 100 to 200 rpm. So I have to set it close to 700 to allow for the days (or times of the day) when it wants to run a little faster. If I turn it up to 850 or so and it steps up to about 1000 (when idle and not in gear) then I have to leave it in gear so it bogs the engine down to below 900. Don't know if this helps. Perhaps the idle is a whole other thread issue. I would prefer for it to idle closer to 800. pressure is better, voltage is better. Currently there is about a 150 rpm drop when put in gear. So it is idle in park @ 750-800 then drops to 600-750 in gear.When I drive at 1500 rpmI can get around 25-30 psi. Temp normally runs around 180 f.
I don't think that's too bad for pressure. They say 10 PSI per 1000 RPMs I think. Too bad it runs on when you turn it up more. 600-750 seems a little on the low side in gear but I'm not that familiar with autos.
Been a long time since I had a vehicle with a Windsor and an oil pressure gauge...
Used to have a 65 Mustang with a well worn 289 and if I recall... it ran maybe 10-12 psi at idle hot.
I still don't think 10 psi at hot idle is bad.
There is very little load on the engine at idle,
and he says the pressure comes up with rpm, as you would expect, so I still don't think it's a concern.
Now if the pressure stayed low, then I would worry.
Edit; for the record... I have had numerous "other brand" engines that had hot idle pressure ~ 10 psi and never a problem.
How has this situation changed over time since the rebuild? I concur that 10 PSI at hot idle is not a real problem as long as it has not been a rapid change, or a significant change over a short time.
I had the run on problem with my 408W so I installed an AC Solenoid that held the idle up to 850 RPM's at idle but dropped to ZERO with primary butterflies completely closed when I turned the ignition OFF.....worked GREAT!!:wink2:
Give that a whirl if the low OP at idle is bothersome!!:smile2:
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