enlarging main oil feed holes

[buickturbot]

is enlarging the two center main oil feed holes good or bad idea?

 

[turbobose13]

make sure you use a HV oil pump or you will have low oil pressure, and drill out the front cover to, 1/2"

 

[Blown&Injected]

What about the main bearings?

The stock passages are bigger than the oil hole in the upper shell so does it make any difference if it (the passage in the block) is opened up without modifying the bearing?

 

[turbobose13]

you need to drill the bearing to the same size whole, so the oil flow's smooth.

 

[turbobose13]

my oil pressure is 75 cold & 45 at cruise and 25 hot, if you do it right you will have great oil pressue.

 

[Louie L.]

my oil pressure is 75 cold & 45 at cruise and 25 hot, if you do it right you will have great oil pressue.

Those numbers are easily attained with out drilling out the main feed holes. In my opinion its not neccessary.

But i do believe that drilling smaller holes in the cam bearings and reclocking them prior to install is a more worth while procedure. Ive had this done in every one of my motors(2 109s n Stage 2) and never have had any oiling problems.

 

[Blown&Injected]

you need to drill the bearing to the same size whole, so the oil flow's smooth.

This is not the article I thought it was:
Buick Power Part 2 -- GM High-Tech Performance Magazine
But they do make mention of the oil passages.

The one I was looking for talked about using the HV oil pump IF the passages ARE modified. Do not recall if they commented on the use of the HV pump if the passages to the mains are NOT modded???

It makes sense to open up the bearings. I wonder what affect the opening up of the hole in the upper shell of the main bearing to match the stock oil passage which is much bigger than the hole in the bearings I have seen. It seems like a HV pump might be needed in such a situation ???

 

[Red Regal T]

You'll find the main bearing oiling passages are 9/32". The main bearing oiling holes are smaller. You can drill and chamfer the bearing oiling holes to match the passages. This will increase oiling somewhat, without getting into drilling the block oil passages.

 

[Blown&Injected]

You'll find the main bearing oiling passages are 9/32". The main bearing oiling holes are smaller. You can drill and chamfer the bearing oiling holes to match the passages. This will increase oiling somewhat, without getting into drilling the block oil passages.

Is it the opinion of the engine builders that just enlarging that hole in the bearing is enough that a HV pump should be used?

 

[turbobose13]

mine are not drilled, my oil system is stock and i think my oil pressure is good.

 

[Blown&Injected]

I was thinking about the OP'ers idea to drill the block and was thinking about an alternative for increasing oil flow to the crank.

Also thinking about how one may open up the main feed but do no good because of the restriction the hole in the bearing causes.

 

[Blown&Injected]

ALSO:
Enlarging the holes does not increase oil pressure but it sounds like it can hurt it if the passages are opened and a HV pump is not used. And wondering if just the bearing mod would require the bigger pump - that alone seems like it is evidence of more oil flow.

 

[Lee Thompson]

Imo

Only a small amount of oil will pass by the main and rod bearings. If you have so much clearance that a 1/8 in. hole won't keep up---you have MAJOR problems. Bearing clearance is a controlled oil leak.

 

[Blown&Injected]

It seems like opening up the hole in the bearing and or the block passages to the mains would serve to increase the flow to the "controlled leak" thus requiring the HV pump. I KNOW there is a debate about the need for the big pump, but considering the question of opening the passages and or bearing hole....then the HV pump?

 

[Turbo6Smackdown]

Louis L.
But i do believe that drilling smaller holes in the cam bearings and reclocking them prior to install is a more worth while procedure. Ive had this done in every one of my motors(2 109s n Stage 2) and never have had any oiling problems.

I'm lost. (not trying to be smart) but, how does one drill smaller holes? if you drill an existing hole its going to get bigger. or, if you meant drilling a new hole, drill it bigger...than what diameter? (im trying to learn)

 

[Blown&Injected]

Lmao!!!!!!!!!!!

 

[Blown&Injected]

How to drill a smaller hole:

1: I have not done this but I believe I understand it.

2: I never realized how funny this procedure sounds.

3: Cam bearings have oil holes that must be "clocked" properly to line up with the oil galley so the oil can get to the cam. The oil that flows to the cam also flows to the crank so smaller holes that feed the cam should send more oil to the bottom end.

Since the bearings must be clocked to match up the oil holes it is then possible to drill a smaller hole than the hole that is already in the bearing, and then clock the smaller hole to the galley that feeds the cam.

Of course there are other things going on, always is, such as any groove in the block or bearing that may serve as another oil passage and flow to the top of the engine...but i believe the above is the main idea.

4: there is no four.

 

[Louie L.]

Louis L.
But i do believe that drilling smaller holes in the cam bearings and reclocking them prior to install is a more worth while procedure. Ive had this done in every one of my motors(2 109s n Stage 2) and never have had any oiling problems.

I'm lost. (not trying to be smart) but, how does one drill smaller holes? if you drill an existing hole its going to get bigger. or, if you meant drilling a new hole, drill it bigger...than what diameter? (im trying to learn)

LOL I guess I should have been more specific. I thought that you may have been familiar with the procedure.
It is well known that the front cam bearing in these motors has a huge hole which hemmorages oil that is absolutely un neccesary. This bearing is in the main path to the top of the motor. The way to fix this is to redrill the all of cam bearing in a spot 180 deg from the original hole in the bearing with a much smaller hole.

I cant tell you the size because the last time i did it was 3 years ago and ive lost my notes somewhere in the house. You will then intall the cam bearing with the new smaller hole lined up with the oil feed in the block. Again Ive either done this myself or had the machine shop do it to all my motors.

This procedure is covered in the Buick Power source book. Im sure if you do a search this has been covered in the past.

 

[Turbo6Smackdown]

ahh ok. yet one more thing i will store in my head, for a rebuild. thank you.

 

[VadersV6]

With the plugs removed from the galleys, look through the hole with a flashlight, and look to see how misaligned the holes are. They drill from the front and from the back, and they usually dont meet together concentrically. Thats pretty much the main reason for doing this. If the alignment is good, I wouldnt really worry about it.