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danweb
08-20-2005, 06:41 PM
HI To all, I have a question on oil pressure. When i start my hawk (62 GT Hawk) in the mornings it reads about 80 psi, as the motor warms up it drops to 40 psi now comes the part I don`t understand. When I`m crusing on the freeway it stays at 40 psi when I get off the freeway and stop at the end of the offramp it drops to about 10 to 20 psi. Is this normal? Its got about 65,000 original miles on it and I was told the motor had been rebuilt at 30,000 just to freshen it up and to replace seals since it had been in storage for several years. It doesn`t burn or use oil and she runs like a top, so what gives? Any help would be appreciated. since this is my daily driver I want to keep her running good. Thanks Dan

raprice
08-20-2005, 08:15 PM
If your pressure is holding at 40 psi while underway, as far as I know, that's normal. It's always higher when the engine is cold.
If it drops to 20 psi while idling, that's ok as long as the pressure rises back to 40 when you speed up again.
I'd be interested is what others say on this issue.
Rog

Transtar60
08-20-2005, 08:19 PM
Yeah thats normal. Part of it is the oil is still trying to return to the oil pan after your high speed run. Rule of thumb I've been told is 10 psi per 1000rpm.

Roscomacaw
08-20-2005, 09:27 PM
Sounds to me like your Hawks doin' just fine.;)

Miscreant at large.

1957 Transtar 1/2ton
1960 Larkvertible V8
1958 Provincial wagon
1953 Commander coupe
1957 President 2-dr
1955 President State
1951 Champion Biz cpe
1963 Daytona project FS

danweb
08-20-2005, 09:52 PM
Thanks for the info guys. It reallt helps to have people out there like you to help us along.[8D]

curt
08-20-2005, 10:03 PM
Sounds like mine. Get 60psi on start up idle. It takes a while for the engine to warm up and then the psi settles in around 50 to 56 on interstate. Idle 10 to 12psi in gear ( automatic).

N8N
08-21-2005, 06:55 AM
Like everyone has said, that's perfectly normal. ISTR that the pressure relief valve opens at 50 PSI so you really shouldn't see much over that at any time except on cold startup (where the oil is so thick that even an open OPRV is seen as a restriction.)

Personally I'd be a "little" (as in very little) concerned if my oil pressure at cruise was only 40 PSI, but a) gauges can be inaccurate and you might actually be seeing a normal 50-55 PSI and b) I have heard tell of Stude engines running for many, many miles with less oil pressure so if it runs good don't worry about it. What you may want to do is pull the OPRV and clean it, to make sure that it is working freely in its bore and not sticking partially open. Probably not your problem, but it's worth checking just because it's so easy.

Low oil pressure at idle is nothing at all to worry about, unless there is none at all. Perfectly normal. Studes used solid lifters, so extrapolating from my experience with brand-X cars, they don't require as much oil volume as an engine with hydraulics, and therefore the oil pump is sized accordingly (and pressure is allowed to drop more at low RPM as high pressure is not needed)

good luck

nate

--
55 Commander Starlight
62 Daytona hardtop
http://home.comcast.net/~njnagel

Tom B
08-21-2005, 08:56 PM
My (53) shop manual specifies 40 lbs. oil pressure in a hot engine at 40 mph in high gear. When at idle, as long as there is pressure, it shouldn't matter, there is no load on the bearings.

My coupe, when cold pins the pressure gage, (10W 40 Rotella T) and at 40 mph hot only shows about 18 lbs. It's been that way for the last forever, as far as I can remember,and I've had it since 1959. When I had it checked at 80,000 miles the bearings were good enough to be left alone.

Keep it full of oil, and some pressure and worry about something else.

Tom Bredehoft
'53 Commander Coupe
'60 Lark VI