| Author |
Message |
Jeff K (Jbk)
| | Posted on Tuesday, May 01, 2001 - 6:39 pm: | |
Good advice, I'll try that first. Thanks for the reality check. |
Steve Magnusson (91tr)
| | Posted on Tuesday, May 01, 2001 - 10:08 am: | |
HEG is right to doubt the gauge/sensor first -- I picked up about +20 psi on the gauge at both idle and high RPM after replacing the sending unit on my ex-'78. |
Herbert E. Gault (Irfgt)
| | Posted on Monday, April 30, 2001 - 9:18 pm: | |
Before you go fixing something that may not be broken, have the actual oil pressure checked with a known accurate mechanical gauge. These electric gauges are very inaccurate and your pressure may well be already correct. Changing the pressure is simple, you just unscrew the big nut and add shims or washers to add more tension to the spring. Keep in mind that it will still not change the pressure at idle because the engine is not turning fast enough to develop enough pressure needed to overcome the pressure relief spring. Oil pressure is probably the most dependable part of a Ferrari and I believe we are creating too big of a concern over it. |
Jeff K (Jbk)
| | Posted on Monday, April 30, 2001 - 7:59 pm: | |
Reading everyones posts made me think the pressure in my 77 308GTB is a little low. I'm running castrol syntec 5W-50 and the pressure stays around 60 from just off idle to redline. Looking in the owners manual, it says normal pressure should be 78 - 92.5 @ 6000 rpm, and if it's low it can be adjusted by the valve on the front cover of the crankcase.
Looking at the cross-section diagram of the engine, the valve seems to be a spring loaded pressure bypass. If this is adjusted too loose, it would account for the constant lower pressure over the rev range.
Before I go and start turning the knob, has anyone tried to adjust this valve? Did it work, or were there any expensive problems? |
Craig Dewey (Craigfl)
| | Posted on Monday, April 30, 2001 - 6:28 pm: | |
1986 328GTS ---
45psi Hot idle
90psi Cold Idle |
Michael A. Niles (Man90tr)
| | Posted on Sunday, April 29, 2001 - 7:56 pm: | |
I need to revise my numbers. I just got my car back from Florida today and drove 80 Plus miles. Great!! I did not realize the first hatch mark was around forty pounds. At idle warm -- 40- 42 psi Oil pressure and at 6000 rpms -- 90 psi OP. |
Kurt Kjelgaard (Kurtk328)
| | Posted on Sunday, April 29, 2001 - 11:32 am: | |
Just a point for info - pumps (oil, fuel, whatever) do not produce pressure. Only volume.
Restrictions, intentional or unintentional, produce pressure, i. e. decreased restriction (worn bearings, leaks and the like) and unchanged volume equals less pressure.
brgds Kurt |
Jorma Johansson (Jjfinland)
| | Posted on Sunday, April 29, 2001 - 10:56 am: | |
It also debends where you messure the oil pressure. I you messure the pressure in the end of the circulation and you still have 4 lbs, it could be ok, BUT if the messuring poin is like in 308 before the crank and cams how much you think will be the pressure in the last bearing? |
Michael A. Niles (Man90tr)
| | Posted on Saturday, April 28, 2001 - 3:05 pm: | |
Thank you, Herbert. |
Herbert E. Gault (Irfgt)
| | Posted on Saturday, April 28, 2001 - 12:58 pm: | |
My experience with oil pressore on engines in general is that as long as there is oil being provided to the bearings and they are not starved then there is no advantage to a lot of pressure versus minimal pressure. Most cars will operate just fine with as little as 4 lbs pressure. In a stock unmodified engine, oil pressure at idle is an indication of the clearance of the bearings throughout the engine. The more wear the bearings have the lower the oil pressure will be. Increasing the viscosity of oil will increase pressure but will not necessarily help the engine and in fact will slow down the engine since thicker oil is harder to pump throughout the engine. At idle speed the pump is moving so slowly that the relief valve is seated and full pressure is being transfered to the bearings. As speed increases the pump pumps faster and if the bearings are tight the oil pressure will exceed the pressure relief spring and will bypass the galleries and the excess will return to the pan. Changing to a higher viscosity oil to raise the pressure will only mask a bearing problem. An average car will run about 10-12lbs at idle with no problems. |
Michael A. Niles (Man90tr)
| | Posted on Saturday, April 28, 2001 - 11:48 am: | |
What's the difference/advantage? Is 40 lbs at idle any better than 20 lbs? I do not know much about oil pressure effects at idle -- can someone explain which number is better or worse and why? |
Jorma Johansson (Jjfinland)
| | Posted on Saturday, April 28, 2001 - 11:28 am: | |
I changed the oil to PENZOIL 20W 50 and allso like Steve got idle 1000 rpm / 40lbs and driving 3500 rpm / 85 lbs. Before it was like Jeff`s around 20.
J.J |
Jorma Johansson (Jjfinland)
| | Posted on Thursday, April 26, 2001 - 12:55 am: | |
Thank you all, seems to be quite interesting issue when you look at the different answers. |
'75 308 GT4 (Peter)
| | Posted on Wednesday, April 25, 2001 - 11:34 pm: | |
I'd get 80-90psi driving normally (warm engine, 3500+ RPM) and about 30-35psi standing at a light after that long (and good) drive... that was when my engine was still in the car. |
Steve (Steve)
| | Posted on Wednesday, April 25, 2001 - 9:06 pm: | |
77 308 GTB with Valvoline 20W-50W and a warm engine (normal temp)and 75 degree day it runs at 82 psi +/- 3 psi @ 3500 rpm. At idle it is about 35-40psi (1st hash mark) @ 1000 rpm. Steve |
Jeff K (Jbk)
| | Posted on Wednesday, April 25, 2001 - 7:55 pm: | |
77 308GTB. Cold engine at idle, around 65. Hot engine at idle, under 20. |
Frederick Thomas (Fred)
| | Posted on Wednesday, April 25, 2001 - 4:18 pm: | |
I have an 83 308. My manual says that with the
engine warm at idle, an oil pressure of less than
64 psi is considered normal. |
Michael A. Niles (Man90tr)
| | Posted on Wednesday, April 25, 2001 - 1:52 pm: | |
I do not know that one. I have a TR and its sits around 25 at idle and 85 at 6750. You will know in a bit -- a lot of us on this site have 308s. |
Jorma Johansson (Jjfinland)
| | Posted on Wednesday, April 25, 2001 - 1:37 pm: | |
Sorry, 308 GTSi 1980 |
Michael A. Niles (Man90tr)
| | Posted on Wednesday, April 25, 2001 - 1:35 pm: | |
Which model are you talking about 308,328,TR, 355,348 ??? |
Jorma Johansson (Jjfinland)
| | Posted on Wednesday, April 25, 2001 - 1:32 pm: | |
Please look at your oil pressure gauges and let me know. The owners manual only tell what it should be at 6000 rpm.
J.J |