Craig and Derek,
I tend to agree with your analysis. Had not considered the pressure
drop
through the hoses, filter and cooler. Thanks.
At 06:00 PM 1/5/2002 -0800, you wrote:
>Hello James,
>
>My guess is:
>
>Your oil pump has an internal pressure relief that is set to probably
around 70-80
>psi. They all do. So, it sounds like due to the higher volume pump, is
exceeding the
>pressure relief, maybe all of the time. This means that you have, say, 75
psi coming
>out of the pump, hot or cold, because you are lifting the relief. It is
then pump
>through the block to the filter adapter, through the lines to the remote
filter and
>then back to the filter adapter, where you are measuring the pressure. Due
to the
>head loss through the lines and filter, you will indicate something less
than the
>pressure out of the pump. When the oil is REALLY cold, like 30 degrees (I
live in
>California), the pressure out of the pump is the same, because the relief
is still
>lifting at 75 psi, but the head loss of pumping that thick cold oil is
higher, in
>you case 10 psi higher. I see this same issue in my 289 Shelby and 427
Cobra with
>high volume pumps. It isn't a problem at all.
>
>Craig WRight
AND:
>Reply-To: "Derek White" <derekw@sltnet.lk>
>
>Hi James,
>
>
>The pressure out of the pump is regulated by the bypass valve but it harder
>to push thicker oil through the pipes, filter, cooler. Usually the thicker
>oil means higher pressure since it can't push past the bearing clearances so
>easily-- in this case the drag of the thicker oil before it reaches the
>gallery could be greater than the positive effect of the thicker oil at the
>bearings. cheers, derek
>
>James Barrett wrote:
>
>> Folks,
>> Just had a cold wave hit Florida, got down to below 40 degrees.
>> (For you Northern folks, remember that "cold" is a relative to what one
>> is used to.)
>> I presently park my Tiger outside the garage under a car cover so
>> The Tiger
>> was cold at startup. (Working on an Alpine in the Garage).
>> Now the wierd part: I normally have 65 psi indicated on my oil gauge
>> when in normal running or idleing at 1000 RPM. When I get in traffic for a
>> long time, It may drop to 60 psi if water temp start to get above 90
degrees C.
>> Today (in the cold) the oil pressure came up to 50 PSI and stayed
>> that way
>> until the motor warmed up to 80 to 85 C. At warm up, the oil pressure
returned
>> to 65 psi. I was driving around 2000 to 2500 RPM in town. I use Valvoline
>> 20W-50 oil due to the normally hot temperatures here in Florida. I have a
>> remote Oil Filter inside the fender under the driver's side headlight and
>> 1/2" ID hoses connected to the original Tiger II fittings (both at the block
>> and at the oil filter). I also have the original two tube Tiger II oil cooler
>> in the circuit.
>>
>> My previous experience has been that when the oil is cold, one has
>> higher oil pressures than when the oil is hot.
>>
>> I use a high volume TRW oil pump in my 351C. The pump is less than
>> a year
>> old. I also use a modified oil pan that holds 12 quarts of oil without
>> hitting the
>> oil hitting the crankshaft.
>>
>> Any one have an idea of what is going on with the oil pressure
>> during the "cold".
>> Note that this "problem" is presently not serious enought to warrent
pulling the
>> oil pan. Would just like some ideas.
>>
>> James Barrett Tiger II 351C and others
>
James Barrett Tiger II 351C and others
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