Oil Pressure - Rebuild?
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Freshman User
Joined: Jul 2003
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From: Colorado
Oil Pressure - Rebuild?
I have a 84 F250 with a carbureted 460. The engine has 150,000 miles and runs like a champ! I use it mainly as a plow truck so it doesn't get much run time.
Anyway, I've been having problems with oil pressure lately. I noticed the guage dropping rather low and made a bee-line for home. When I pulled in to my driveway the engine started tapping and the oil pressure bottomed out.
After running some tests I found that the engine has normal oil pressure when started cold, and for about 10 minutes after reaching operating temperature. It then heads south from there. The engine does not knock or make any other sounds from within.
Am I looking at a rebuild? Cam bearings? Oil pump? Its odd that it has normal oil pressure when cold, or even throughout the warm up. It only drops when it reaches operating temperature.
Any ideas?
Thanks!
CJ
Anyway, I've been having problems with oil pressure lately. I noticed the guage dropping rather low and made a bee-line for home. When I pulled in to my driveway the engine started tapping and the oil pressure bottomed out.
After running some tests I found that the engine has normal oil pressure when started cold, and for about 10 minutes after reaching operating temperature. It then heads south from there. The engine does not knock or make any other sounds from within.
Am I looking at a rebuild? Cam bearings? Oil pump? Its odd that it has normal oil pressure when cold, or even throughout the warm up. It only drops when it reaches operating temperature.
Any ideas?
Thanks!
CJ
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Joined: Sep 1999
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From: Indiana
ColoradoJon
Its getting time for a rebuild. Its sounds like your bearing clearances are getting excessive. When its cold the parts fit tighter, then when its hot the metal swells and the clearances open up, which equals loss of oil pressure.
Or if you want to patch it up, turn the crank and put some new rod and main bearings in it.
Its getting time for a rebuild. Its sounds like your bearing clearances are getting excessive. When its cold the parts fit tighter, then when its hot the metal swells and the clearances open up, which equals loss of oil pressure.
Or if you want to patch it up, turn the crank and put some new rod and main bearings in it.
Postmaster
Joined: Nov 2003
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From: Cab of a truck
I am gonna tell you the same thing. I have a 84 460 in my 77. After about 20 minutes of driving the oil pressure would go down to about 5 lbs when at a idle. I replaced the rod and main bearings and that restored oil pressure, it wont go below 20 lbs now no matter what. The motor had 180,000 miles on it, and when I got the old bearings out they were showing a lot of copper, pretty bad.
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Freshman User
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From: Colorado
Hey, thanks guys! I assumed a rebuild or at the very least main bearings. Glad to get some confirmation on this...
I figure if I'm going to tear it apart I might as well do a good job and check out everything in there.
CJ
I figure if I'm going to tear it apart I might as well do a good job and check out everything in there.
CJ
Posting Guru
Joined: Sep 1999
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From: Indiana
ColoradoJon
If its not using a lot of oil, and it seems not to be a daily driver, you could buy some more time with it anyway, by replacing the bearings.
Look for scoring on the crank, bearing journals.
If its not using a lot of oil, and it seems not to be a daily driver, you could buy some more time with it anyway, by replacing the bearings.
Look for scoring on the crank, bearing journals.
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Freshman User
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From: Colorado
I could just do the mains, but I think I will just pull the engine and do the mains, main seals, timing chain, cam bearings, and piston rings. I might do the clutch as well. I'm not going to mess with rebuilding the heads unless we find a problem while we are in there.
I was hoping to find a band-aid fix to get me through the winter plowing season here in Colorado, but looks like I'm out for the rest of the winter!
CJ
I was hoping to find a band-aid fix to get me through the winter plowing season here in Colorado, but looks like I'm out for the rest of the winter!
CJ
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From: Indiana
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Elder User
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CJ, just try using heavier oil until spring. No need to tear that thing apart now. If you can hold 5 lbs. at hot idle, that's enough.
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Posting Guru
Joined: Sep 1999
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From: Indiana
ColoradoJon
Are you tight on time or no place to work?
You could pull the engine, tear down the bottom end, send the crank out, new timing chain and gears, oil pump, stick some new rod and main bearings in it and go.
Couple - three weeks at the most, down time.
Are you tight on time or no place to work?
You could pull the engine, tear down the bottom end, send the crank out, new timing chain and gears, oil pump, stick some new rod and main bearings in it and go.
Couple - three weeks at the most, down time.
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Freshman User
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From: Colorado
Its not my daily vehicile so I have plenty of time and a workplace. I may just turn the crank and slip in new rod bearings to get me through the plow season and then do a more thorough rebuild over the summer.
I've put together a list of parts and have found a decent machine shop to do the crank. I'll probably get started next weekend.
Thanks for all the help!
CJ
I've put together a list of parts and have found a decent machine shop to do the crank. I'll probably get started next weekend.
Thanks for all the help!
CJ