O-320 A2B Pulsating Oil pressure readings

[DRB]

Hello I have Tripacer with an O-320-A2B engine. Have about 102 hours on rebuilt engine. Not original owner. Oil pressure and temps running in green, but have a steady, pulsating oil pressure reading on cabin oil pressure/temp gage, even when found during engine run ups. ADs current on oil pump . Oil consumption not an issue that I am aware of. 1.0 litre maybe every 10 hrs at very most. Has any one had similar experience in past. Possible oil pressure bypass spring, something under ball of bypass valve, gage restrictor not so restricted? Any suggestions greatly appreciated .

[Steve Pierce]

My Super Cub oil pressure gauge has the same thing. John Wolfe Company rebuildinds them and says the pulsing is lack of some sort of lubricant inside the gauge.
http://www.johnwolfco.com/

[DRB]

Tanks Steve. At least I now know to where to start looking for the cause. i.e. instrument or engine. Thanks again. Anyone know of good instrument repair/rebuild shop in Edmonton area?

[akt]

Mine does the same thing. It was recently rebuilt by John Wolfe Co. I have the Piper oil pressure line with the orifice.

[Steve Pierce]

You might call them. I don't remember the specifics but they explained what it was and supposedly remedied it when they repair the units.

[Glen Geller]

Is it possible there is an air bubble in the oil line near the gauge and it compresses with each pulse of the pump?

GG

[DRB]

Glen, I presented this problem to my mechanic. He followed along your idea, but he suggested rather than air been the problem, it could be 1 or combination the following; (1) a small particulate caught in the small restrictor orifice located in the oil sense line to the gage (2) weak oil bypass valve (3) again particulate caught under the ball of the oil l bypass valve. Guess, like all trouble shooting, process of elimination. Thanks

[N2803P]

I have about 4 hours since major, same problem. I am putting a call into the folks that did my case to see if they machined the seat where the relief ball rides. There is a "new" style relief valve that is not compatible with the old style.
i will let you know. Never an issue with my high time engine prior to the overhaul. BTW, love that Casper Labs oil filter adapter, kept my steel lines. Also added the Niagra oil cooler and Bracket air filter.

[DRB]

Hello N2803P. Sounds very interesting. As part of my trouble shooting, my mechanic has suggested to check the oil pressure gauge in line restrictor. Will be a week or 2 before I get back with finding/results. Have to shingle a cabin roof this weekend. Cool fall temperatures are on the way in our neck of woods in Alberta. Sounds like restrictor may be located on back of gauge. Thanks

[Steve Pierce]

Piper used a restrictor in the end of the hose going into the engine.