301 low oil pressure

mshultz · Feb 25, 2011

We purchased a 301 out of an 806 from a tractor jockey who was planning to put a 361 in it. The guy didn't know much history on the tractor or the engine. It appears that the engine was recently dipped and presumably gone over, but we haven't gone inside yet. We just got it in the tractor this week and started it up, and it has less than 5 lbs of oil pressure... If it was tore down and reassembled, is there something like a plug that could have been missed when reassembled that we should look for? We checked the regulator, and all seems in check. We have another oil pump to try on it and while the pan is off we'll take a look at the bearings, but it doesn't sound like it has any bottom end knock when it runs so we're hoping that's not the problem......

Thanks for any and all replies.

El Toro · Feb 25, 2011

It may have a pipe plug missing in the oil gallery, but I doubt it since you have some pressure. A man a few days had a Super A with no oil pressure and the pipe plug behind the cam gear was missing, but he had zero pressure. The oil level should drop if the plug is missing. It could be the oil pump. Hal

mshultz · Feb 25, 2011

would there be a similar plug on the 301 anywhere? When I said less than 5 psi I mean it makes the guage barely bump off of the "0" peg, but not far enough to get close to any lines on the guage to actually estimate any type of reading.....

Janicholson · Feb 25, 2011

A plug out of a gallery is a serious possibility.
The orthe engine was very different, but many engines do have gallery access plugs in them. These are put in when rifle drilling the oil gallery to clear chips, and other reasons. They are found both internally and externally on the main block (usually cam side). The way that the CNKS (if i recall) found the missing plug was to inject air into a gallery port and listen for the escape of air through a missing plug. The plugs are routinely removed when hot tanking a block to clean the passages. Sometimes the crew leaves them out assuming they will be reinstalled by the assembler. (often) Sometimes they even give the original plugs back in a box!. If the pan is coming off, it will be pretty easy to blow air into the oil pump output hole to see where it is going. Using a mechanics stethescope with the feeler end removed can be very helpful listening to the location of an air leak. I hope this helps, or that it is a pump related issue. Jim

El Toro · Feb 25, 2011

I've never worked on that engine so I can't answer your question. It's a good possibility
if the plugs were removed during the hot tanking by the local machine shop and the owner wasn't
told of the plugs being removed. If the owner had removed them he probably would've remembered to reinstall them not aware of a plug being left out. You should see oil dripping if the rear plug was missing. You could loosen the timing gear cover to see if access oil runs out. Blow some air into the oil gallery and see if any oil flows out around the timing gear cover. If you see a lot of oil you probably need to pull the cover check for a missing pipe plug you may be able to access the plug hole through a hole in the timing gear. Hal

Owen Aaland · Feb 25, 2011

Besides having a galley plug left out there are a couple of other reasons for low oil pressure on this series engine.

Check to make sure it has the correct gasket between the oil filter base and the block. There are three (?) different gaskets that will fit the blot pattern. You need to make sure the gasket used matches the filter base.

Another common problem with the original aluminum filter base is erosion of the pressure regulator valve. The original valve is of a fiber type material and they can get a hole worn in them and allow too much oil to bypass.

El Toro · Feb 25, 2011

I 1964 my co-worker lost oil pressure on his 1962 Ford car when the oil pressure light came on.. It had the 352 engine and the valves became noisy. He pulled the oil pump the next day and found the relief valve stuck open from the sludge. I think short runs cause the sludge. He called me at work to pick up a new pump and I helped him to install it. Sure glad he had the shop manual. Hal

Too Far Gone · Feb 25, 2011

It may be wishful thinking,but Ive been worried about things I just got,or just got running that had little oil pressure and it paid me 3 different times to hook up a new guage temporarily from the parts store to see they actually had good pressure,and the oil guage was just stuck or bad

301 low oil pressure

mshultz

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El Toro

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mshultz

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Janicholson

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El Toro

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Owen Aaland

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El Toro

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Too Far Gone

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