Some concerns after porting and clipping OFH

[turboglenn]

Well,Iported and clipped my OFH relief to make the pressures suitable for the holset turbo ( i was seeing 100psi+ by redline) but now that the oil I changed in after the new ported and clipped OFH and SPring i am seeing that i only get 40psi cold, then when warmabout 30psi at idle and lower RPM cruise, but when i get on it and get towards redline i'm only getting about 48 - 50psi oil pressure. some places I've read this is OK and very acceptable on SBC's but being that i'mrunning a built 4g63 I can't afford to mess up i'dlove some feed back

thanks

 

[Yamahaulin]

My general rule of thumb is 7psi per thousand rpms. Worked on every car I've ever owned.

 

[BeatupVR4]

I get the porting part but what do you clip? The mistake I always see people make on the internet is you have to make sure you don't mess with the top part of the hole. By top I mean the part that would first get exposed when it opens. If you move that "higher" it will lower what pressure oil starts getting relieved at. You need to radius the "sides" and hog open the "bottom". It seems like everyone just take a drill bit to the thing.

Zero G to the rescue again. This is from a RWD but you get the point.

Don't mind the poopy paint skillz.

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This is how I ported mine. I went with a D shape with the flat of the D being the "highest" point that was already there and opening and radiusing the sides and bottom. I prefer to go wider than lower so as not to ever be able to see the bottom of the piston when it's in it's fully seated position. I kept the top sharp.

 

[HIGHPSI4]

I have the 4GCS engine and no BS. I ported my OFH like jim there is showing and I still had 100psi cold and 100psi plus over 5K rpm. I have pulled the OFH off again and I really laid into it this time. I have not put it back on but I ported almost up to the top of the relief piston (stopped at the shoulder) and squared it up some. Hopefully this summer I will take some time and get my car back on the road.