Date: Fri, 10 Jul 2015 08:44:24 -0700
Reply-To: Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject: Re: Oil pressure
In-Reply-To: <CA+az7_4HieWOanzbdbrraUqGnndnKgkPyrXWfdHOqiqyvpwgRg@mail.gmail.com>
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Well, the oil enters the gallery at full pressure out of the filter, but loses pressure as it gets to the far end of the gallery because it is leaking out of the bearings all along the way. For a tight engine the cam and filter measuring points will be very close, but as the engine ages the cam port at mid-gallery will be lower, essentially an average of the two ends of the gallery. Again, it's the trend in pressure drop you want to monitor, so either one works for that.
Stuart
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of John Rodgers
Sent: Thursday, July 09, 2015 10:07 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Oil pressure
So ..... oil pressure is oil pressure?
John
On Jul 9, 2015 5:57 PM, "Jeff Schwaia" <vw.doka@gmail.com> wrote:
> Actually, the only difference between the two oil pressure locations
> is that one is before the oil filter, and the other is after the oil filter.
>
> Cheers,
>
> Jeff
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> Behalf Of Stuart MacMillan
> Sent: Thursday, July 09, 2015 3:50 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Oil pressure
>
> I prefer the cam location simply because knowing the pressure there is
> the most critical. Oil pressure leaks down at the bearings, and this
> measures it at the bearings.
>
> Full oil pump pressure is delivered to the filter/sandwich plate, so
> you will likely see a somewhat higher pressure there as the engine
> wears, as compared to the bearings, but probably not much higher.
>
> The important thing is to watch the long term trend of the pressure
> drop, which is inevitable. When you get below 8 psi at hot idle and
> 20 at 3000, start saving for a new engine. Six psi at idle and you
> are on borrowed time. BTDT-my experience with a used 2.1 engine:
>
> OIL PRESSURE: 8 psi at idle, 24 psi cruising when installed. Over the
> next
> 10,000 miles pressure steadily dropped to 4 psi idle, 12-15 psi cruising.
> At the end of the 3000 mile trip idle pressure was zero (red light
> came on), cruising 8 psi. Blew up at 65 mph just 65 miles from home,
> still running strong!
>
> I'm hoping for one more year from my current 1.9 with the same initial
> oil pressure.
>
> Stuart
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> Behalf Of John Rodgers
> Sent: Thursday, July 09, 2015 2:25 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Oil pressure
>
> I've got two oil pressure guage setups. One takes pressure from the
> pressure switch that monitors oil pressure at the cam. No oil temps.
> It has a pressure guage only. The other is a sandwich device that
> takes oil pressure and temperature between the oil filter and oil
> cooler. Of these two, which would be best. Opinions? Why?
>
> Thanks,
>
> John
>
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