Porting in the block - there's two spots that are easy to reach:
- where the oil comes into the block from the timing cover, next to the oil pressure sender/turbo oil supply hole. Port the turn it has to make.
Unported:
http://pages.prodigy.net/buickv6/CarStuff/oil to block unported1.JPG
http://pages.prodigy.net/buickv6/CarStuff/oil to block unported2.JPG
Ported:
http://pages.prodigy.net/buickv6/CarStuff/oil to block ported1.JPG
http://pages.prodigy.net/buickv6/CarStuff/oil to block ported2.JPG
- on the passenger side of the #1 cam bearing, behind the plug, the oil has to come up and make 2 90 deg turns to go to the gallery that feeds #2-#4 mains, and there's a step change where the passage diameter is reduced. Port the turns and smooth out the step change.
Unported:
http://pages.prodigy.net/buickv6/CarStuff/behind plug unported1.JPG
http://pages.prodigy.net/buickv6/CarStuff/behind plug unported2.JPG
Ported:
http://pages.prodigy.net/buickv6/CarStuff/behind plug ported1.JPG
http://pages.prodigy.net/buickv6/CarStuff/behind plug ported2.jpg
I had my #2 and #3 main feed holes drilled out, but not quite as big as what the Power Source said. I think 3/8" was in the PS, but I went with 5/16" maybe. Bigger than stock, but not quite as big as the max PS recommendation. I seem to remember that the PS has that recommendation in two spots, one place says 3/8", the other place says 3/8" or 5/16". I went with the smaller of the two.
Porting any other passages in the block takes a lot of effort, more effort than I wanted to put forth, so I haven't tried anything else other than what I just listed.
Cam bearing discussion that follows assumes you have a '86/'87 block with the groove under the #1 cam bearing. Older blocks might need something a little different.
- cam bearings - I don't like the smaller hole trick any more. To do it right you have to fill the groove in the block that is underneath the #1 cam bearing, like this:
http://pages.prodigy.net/buickv6/CarStuff/cam brg bore 1.jpg
otherwise the smaller holes don't do a dang thing.
I think the best #1 cam bearing setup is essentially the same as the stock '87 setup: let oil flow around the groove between the block and cam bearing and use a cam that does NOT have a groove on the #1 journal. Because of the groove under the cam bearing you can orient the oil feed hole any which way you like, set the oil feed hole at about 4 o'clock, so the oil is fed to the bearing right at the spot where the high load begins. You can see the typical wear pattern here:
http://pages.prodigy.net/buickv6/CarStuff/cam brg wear 1.jpg
Note the wear pattern due to the groove in the #1 cam journal. You can get a Comp Cams hydraulic roller without the groove. Minimizing #1 cam bearing wear should really help long term oil pressure, since this is the first spot oil gets to as it comes into the engine. Excessive clearance and leakage here really takes oil away from everything else.
Personally I like the TA Perf cam bearings with the grooves on the backside. Not cheap, but worth it. With those you can also orient the oil feed holes on the other 3 bearings in the 4 o'clock position, and so get the maximum oil wedge between the cam journal and bearing where it does the most good.
John
