Pre-purchase engine question

[Fearless Tower]

While doing some research on a potential purchase, I came across an interesting tidbit on the engine. From my discussions with one of the current owners (a partnership), the engine is low time - about 250 SMOH.

Wile doing a little searching on the net for the N-number to confirm that there was no accident history, I came across an article in a flying club newsletter that discussed the aircraft. The article was written 4 years ago by a previous owner and detailed the installation of the current engine. Basically the original engine was replaced with an overhauled Continetal O-300. The author was describing a trip within the first 100 hrs after the replacement where there was an oil pressure problem discovered on the ground. All was normal on the runup, but sometime between runup and commencing the takeoff roll, the oil pressure gauge went to zero. T/O was aborted and the engine shut down shortly thereafter. Oil temp never rose and no unusual nosies heard. Inspection of the oil filters immediately after and following the oil change and repair (apparently consisted of cleaning out the pressure spring and ball) showed nothing abnormal and no signs of metal in the oil or filter. The problem was corrected and the engine has run about 100-200 hrs since then without issue.

I consider the info in the article fairly accurate since the owner was writing to document the experience for the benefit of the flying club rather than trying to sell the aircraft. The current owner is out of town, so I have not discussed this with him yet or sat down with the logs yet.

My question is - should I be overly concerned about this engine? Is there anything I can do on the pre-purhase (aside from inspecting the current oil filter) to ensure that there was no damage done by the brief interuption of oil flow?

 

[Tom-D]

While doing some research on a potential purchase, I came across an interesting tidbit on the engine. From my discussions with one of the current owners (a partnership), the engine is low time - about 250 SMOH.

Wile doing a little searching on the net for the N-number to confirm that there was no accident history, I came across an article in a flying club newsletter that discussed the aircraft. The article was written 4 years ago by a previous owner and detailed the installation of the current engine. Basically the original engine was replaced with an overhauled Continental O-300. The author was describing a trip within the first 100 hrs after the replacement where there was an oil pressure problem discovered on the ground. All was normal on the run up, but sometime between run-up and commencing the takeoff roll, the oil pressure gauge went to zero. T/O was aborted and the engine shut down shortly thereafter. Oil temp never rose and no unusual noises heard. Inspection of the oil filters immediately after and following the oil change and repair (apparently consisted of cleaning out the pressure spring and ball) showed nothing abnormal and no signs of metal in the oil or filter. The problem was corrected and the engine has run about 100-200 hrs since then without issue.

I consider the info in the article fairly accurate since the owner was writing to document the experience for the benefit of the flying club rather than trying to sell the aircraft. The current owner is out of town, so I have not discussed this with him yet or sat down with the logs yet.

My question is - should I be overly concerned about this engine? Is there anything I can do on the pre-purhase (aside from inspecting the current oil filter) to ensure that there was no damage done by the brief interruption of oil flow?

I wouldn't worry about it after all this time.

The oil pump in the 0-0300 is driven by the cam, there is a 1/2 square bar driving the pump, I have never seen one shear. So if the engine was running there was oil flowing thru the bearings.

Just remember, pressure is a resistance to flow, So if the pressure regulator was open, at a high RPM and stuck open when the engine was reduced to idle, the pressure would drop to "0" because there was on resistance. When the big brass nut housing the spring and plunger was removed they unstuck it and it has worked normally since.

 

[Fearless Tower]

I wouldn't worry about it after all this time.

The oil pump in the 0-0300 is driven by the cam, there is a 1/2 square bar driving the pump, I have never seen one shear. So if the engine was running there was oil flowing thru the bearings.

Just remember, pressure is a resistance to flow, So if the pressure regulator was open, at a high RPM and stuck open when the engine was reduced to idle, the pressure would drop to "0" because there was on resistance. When the big brass nut housing the spring and plunger was removed they unstuck it and it has worked normally since.

Thanks Tom!

 

[Tom-D]

Thanks Tom!

YAVW, and have fun with the 172/0-300. they are better than the newer ones.