Cub oil pressure question

Thu Nov 29, 2012 2:00 pm

The oil pressure on my '57 is very slow to come up. It only gets to 15 or 20. It runs well with no knocks or pings. What is causing this oil pressure problem?

Re: Cub oil pressure question

Thu Nov 29, 2012 2:19 pm

Without audible symptoms of low oil pressure, I would suspect the gauge is no longer reading true pressure.

Swap it with a new or known to be good gauge or check the engine with a master gauge if one is available.

Re: Cub oil pressure question

Thu Nov 29, 2012 4:33 pm

The oil pressure system in a Cub has to fill the oil filter housing before your Cub's reaches it's maximum pressure. Reason for this is that oil in the oil filter housing drains back into the crankcase when you shut off the engine.

If you watch your oil pressure gauge, immediately after engine start up you should have no oil pressure. The needle should start to move upward within perhaps 10 seconds - give or take. It may take 30 seconds to a minute to reach maximum oil pressure for your engine.

You should check the accuracy of your oil pressure gauge. If the oil pressure gauge is still showing 15 to 20 lbs pressure with a fully warmed up engine - you are good to go.

Typical loss of oil pressure is worn main and rod bearings.

Re: Cub oil pressure question

Thu Nov 29, 2012 7:37 pm

Is the oil filter housing full of sludge? Most get that way over time. Can affect the gage reading.
Are you sure you're only at 20 psi? The IH gages I have don't have numbers on them and I think they made some with different ranges.

Yes - gage takes 20 seconds or more to get to full pressure.

Re: Cub oil pressure question

Fri Nov 30, 2012 8:31 am

Even though it takes a little while to show full pressure on the gauge, not to worry, the oil galley feeding the bearings & such will have pressure almost immediately. The oil filter housing is fed oil through a small orifice so it takes a bit for the filter housing to fully pressurize. If the gauge were connected to the port on the other side of the engine, it would show a much quicker response.