oil pressure change

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Jun 27, 2005
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San Jose CA
My newly installed used-but-ran-great F engine has a few problems. There are oil leaks which I'm methodically fixing and odd noises associated with the tranny or xfer. The real problem I think is the oil pressure. With a full load of oil the pressure is 40-40 lbs at start. After a casual drive down the hil I hit the freeway, about 15 minutes. The pressure remains god for about 5-10 minuites of freeway at 55-65 mph. Then the pressure drops to 30, with a drop to 10 when idling at a turnout. If the engine is shutoff for awhile, the pressure comes up some, maybe to 35-40.

Any ideas? The leaks do drop the oil amount, but very minimally. What should I check/replace/blow-up?????

1970 FJ-40 w/ 'new' '71 engine, 4 spd, manual xfer
 

Poser

Oh...Durka Durka Durka.
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Sounds normal for a used engine...


What weight oil are you using?


If it is light, 10-30, I would get 15-40 or even 20-50 if you are in a warmer area...


I run 15-40 year round in my 2F


Good luck!


-Steve
 

phishtaco

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fcgadget said:
My newly installed used-but-ran-great F engine has a few problems. There are oil leaks which I'm methodically fixing and odd noises associated with the tranny or xfer. The real problem I think is the oil pressure. With a full load of oil the pressure is 40-40 lbs at start. After a casual drive down the hil I hit the freeway, about 15 minutes. The pressure remains god for about 5-10 minuites of freeway at 55-65 mph. Then the pressure drops to 30, with a drop to 10 when idling at a turnout. If the engine is shutoff for awhile, the pressure comes up some, maybe to 35-40.

Any ideas? The leaks do drop the oil amount, but very minimally. What should I check/replace/blow-up?????

1970 FJ-40 w/ 'new' '71 engine, 4 spd, manual xfer

Sounds like what my F did......Then it started knocking....Now there is a 2f in it's place almost running good luck :frown:
 
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I'm running 5-30, the temp is in the 50-60 range. My pressure just seems way too low 10 at idle and 30 at freeway speed!
 
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It's nice to know that there are other V8's out there that do this. I'm wondering if on my next oil change, I should try some 15-40. I usually only drive it in the warmer weather.
 
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fcgadget said:
I'm running 5-30, the temp is in the 50-60 range. My pressure just seems way too low 10 at idle and 30 at freeway speed!
That's way too light for your engine, IMHO
 

brian

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fcgadget said:
I'm running 5-30, the temp is in the 50-60 range. My pressure just seems way too low 10 at idle and 30 at freeway speed!
1. these are not race engines.
2. these are closer to tractor engines.
3. these use engine tech that was old, when these engines were new.....
4. 10psi per 1000rpm is reguarded as fine, give or take a few rpms.
5. step it up to 15w-40...yes that's dessiel oil...yes, lots of us use it.
 
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I have not seen mine go below 25 even at the hottest temps, the old girl has 270 000kms, but then again she is a diesel
 
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With a plain bearing engine like we have in the F and 2Fs you can run as low as 5psi when idiling. No biggie. 30-40 on the open road sounds fine to me.
 

Pin_Head

 
 
 
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I don't get too excited about what numbers the oil pressure gauge says as long as it is not zero. Think of it as an idiot light. The stock guage is a notorious liar and I have driven a few engines that had low oil pressure for many years. As long as all the bearings are geting oiled it is good.
 
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fcgadget said:
I'm running 5-30, the temp is in the 50-60 range. My pressure just seems way too low 10 at idle and 30 at freeway speed!
I'm guessing that this is degrees C. Dino oil will start breaking down in the 210-220F range (~100C). So if this is your cruising temps/presure it doesn't seem seriously amiss for a used engine.

I do agree with the other suggestions to use a heavier oil. 5-30 is great for Fairbanks in January, but kinda thin for the rest of the country.
 
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