low oil pressure
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low oil pressure
i have a 1981 bronco custimized with squeezing a 460 into it the engine was rebuilt about 10,000 miles and 10 years ago. the truck had been sitting for maybe 8 years, due to a broken axle. Anyway it was fixed and i drove it for a couple of months and it ran great. Then one day i started it heard a sharp noies, kinda like a when u start a engine thats already started, then the engine died. i restarted seemed fine then realized it had very low oil pressure(mechanical guage). pulled the distributer that was all good. Any ideas before i pull it. Hoping it may be something simple. I can't even drop the pan unless i pull the engine.
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I have an '82 Bronco with a 460 and the same situation, pulling the pan means pulling the engine.
About three engines ago I had a situation with low oil pressure. I pulled the distributor and valve covers and used an electric drill to spin the oil pump. Very little oil came out the valve train assembly.
In that case I was able to jack the engine up (the firewall tunnel is the limiting factor) just enough to to drop the pan where I could get my hand in with a socket to R&R the oil pump and clean the bottom of the pan. Proper replacement of the pan gasket was out of the question, so I used commercial liquid gasket, the black gunk as used by many commercial rebuilders. A giant PIA, but better than pulling the engine.
About three engines ago I had a situation with low oil pressure. I pulled the distributor and valve covers and used an electric drill to spin the oil pump. Very little oil came out the valve train assembly.
In that case I was able to jack the engine up (the firewall tunnel is the limiting factor) just enough to to drop the pan where I could get my hand in with a socket to R&R the oil pump and clean the bottom of the pan. Proper replacement of the pan gasket was out of the question, so I used commercial liquid gasket, the black gunk as used by many commercial rebuilders. A giant PIA, but better than pulling the engine.
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Could have also spun a main bearing. I had a 351C do this. I drove it hard for 2 years like this and it would not blow up. When I finally tore it down, It had overlapped a main bearing 3/4". It only held 3lbs of pressure at an idle and 20 reved up hot on a good day.
Jimmy
Jimmy
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RICEBIRD WAS RIGHT
THANK YOU, I checked the rockers and had a broken valve spring and the push rod was bent and had fallen down. What would have caused this? Should i just replace what broke, or should i replace all the rockers and springs?
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From: Nevada
I've broken springs in different engines, including double springs, and always replace all the springs. I subscribe to what others have long said, it could be just an isolated incident OR maybe the temper, diameter or winding was below spec on a production run. 8 years is long time to sit with certain valves on open spring pressure.
As to cause, about the only thing I've seen bend pushrods that were originally correct is sticking valves or excess rpm. If it sat for 8 years you might well have corrosion on the valve stems where they're in contact with the guides.
As to cause, about the only thing I've seen bend pushrods that were originally correct is sticking valves or excess rpm. If it sat for 8 years you might well have corrosion on the valve stems where they're in contact with the guides.
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closer inspection
with closer inspection i found a crack in the valve guide. If understand correctly you can knock out the vave guide and put a new one in, is that true? But before i go through all that, is this causing the low oil presure? or do i have another problem? the valve lifter did pop out and the pushrod did fall into the cam. could that have caused something else to brake?, like a cam bearing. I am just not sure this old Bronco is worth all this hassle.
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From: Nevada
Pretty difficult to break a cam bearing. Due to the time the engine was sitting and the problems you've already encountered, you'll probably need to change all the valve guides. I'd pull the engine and go through it for peace of mind. I've R&Rd heads on my 460 while still in the Bronco and if you have any doubts about the bottom end its not that much more work to pull the engine, drop the pan and take a look at the bearings and oil pump.
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