No.2 & No.3 main jurnals drilled

[HGturboT]

Has anyone done this to there blocks upon rebuild and if so how does it help oil psi ? I see those two are the smallest of the 4 and read about it being done but that was it, so if anyone has done this could you give me some input please. Oh it's not a stock rebuild

Thanks, Danny

 

[ThikStik]

I had it done on mine and it caused the cam bearing to have precious little area to fit in on one side of the bore. The hole may have been off center from Buick to begin with. I wouldnt do it again. But then the machine shop messed up most other facets of my motor.
Nick Micale does not recommend it.

 

[Red Regal T]

I drilled out and chamfered, just the upper main bearing shells to 9/32" on 1, 2, & 3........same size, 9/32", as #2 & #3 main oiling passages. I like it!

 

[m233roller]

Drilled Mains?

I did this on a new motor a few years ago and at about 2000 miles had it apart and actually saw no difference in anything compared to a couple of other motors Iv'e had apart at about the same mileage. (That were not drilled bigger). My machinist, that I would put up against any out there, recommends NOT doing it.
Mike.

 

[ThikStik]

I suppose that if it has been done and you want to reverse it, you can just put a new bearing in without drilling it out thereby letting its lube hole act to slow oil supply to regular spec. My motor now has 300 miles on it. I have 12 lbs at idle and 40 at speed and worse yet a small tap of a rod bearing . I spent more time with mics on this motor than any other. Never have i had a misbuild- So this mod can go to hell because it has added a cause for alarm as my cam bearing could be an issue here.

 

[Lee Thompson]

oil holes

I believe this was a mod recomended back in the early 80/s by Jim Ruggles for engs seeing extended periods of high rpm such as his Busch eng. Since then Buick has made improvements in the oiling system such as 5/8 in. pickup tube instead of 1/2 in. Just read a book on V-6 Buick and their suggestion was that it was no longer necessary on street and strip eng.

 

[Russ Merritt]

I don't do it either. Once you do it, they say to run a big oil pump. Have a blast.

 

[Red Regal T]

Originally posted by ThikStik
I suppose that if it has been done and you want to reverse it, you can just put a new bearing in without drilling it out thereby letting its lube hole act to slow oil supply to regular spec. My motor now has 300 miles on it. I have 12 lbs at idle and 40 at speed and worse yet a small tap of a rod bearing . I spent more time with mics on this motor than any other. Never have i had a misbuild- So this mod can go to hell because it has added a cause for alarm as my cam bearing could be an issue here.

I think if I was in your position, rather than letting all that work go to waste, I'd install a hi volume oil pump. Should help the situation. I have the same HV pump in my car for 155,000 miles. If I ever have an oil pressure issue, I know it's not because of the pump.

 

[Russ Merritt]

Sounds like someone didn't size one of the rods correctly.