Oil pressure

[Moosebuddy5769]

Hi all
The reason I posted earlier about engine swap was because I've been having oil pressure issues on my Big dog chopper with S&S sidewinder 117 right side drive. Long and Short of it is about 6 month ago the oil light came on, I did all the typical, sending unit,ground,fuse, everything. same thing fire it up no problem get 3 or 4 miles down the road oil light on. I did a oil pump refresh,new gaskets,new key on shaft. Put oil gage same thing fire up 12 lbs or more pressure no problem get 4 or 5 miles down road pressure on gage drops to 0 maybe 1 lb pressure.

I'm totally confused I've changed oil filter oil lines everything. When it drops no engine knock or tick from lifters. Thoughts everyone?
Thanks Moose

 

[knothead]

Sounds like the oil holes in the head are dirty and restricting the oil flowing back to the tank thus causing the oil light to come on...sounds like its time to pull the rocker boxes and look in the valleys at the return holes in the heads... the tappet screen doesnt sound like its dirty because if it was restricting flow then you would have a tick in the rocker boxs that you could noticeably hear...im leaning toward oil holes in the heads being the issue

 

[Moosebuddy5769]

That's next

 

[Mikeinjersey]

Assuming you have a clean tappet screen, correct oil and filter ( Evo has a different filter than twin cam). At what rpm does the light go out and the pressure raise above 0? My understanding is that the accuracy of oil pressure gauges can be poor depending on which one you have. If your idle speed is set too low you can get a flicker of the light when the oil gets hot.
Double check the filter you put in because the EVO requires a high flow filter. The twin cam uses a much finer filter which would restrict your oil flow.