6bolt block oiling system

[97gsxIA]

I'm creating this thread in an effort to increase my basic knowledge of the 6bolt oiling system and to help me decide on what kind of oil clearances and modifications I should do (such as elongating/widening of oil chamfers on the crank, porting oil galleys and deciding how loose I can run my main and rod bearing clearances)

What I'd like to know are any major differences from the 6bolt oiling system to the 7 bolt oiling system (just in the block) as well as opinions on modifying chamfer sizes (trailing edge/leading edge) and oil galley porting and what kind of oil pressure change I can see from porting these areas.

Also, this assumes a BSE is performed and B/S bearings turned.

 

[Blurred Talon]

Check out Jafromobile's channel on Youtube, he's posted lots of info on the Oiling of the 4G63.
https://www.youtube.com/channel/UCyGT_yinKL7uRiZmTjC17RQ

 

[97gsxIA]

Check out Jafromobile's channel on Youtube, he's posted lots of info on the Oiling of the 4G63.
https://www.youtube.com/channel/UCyGT_yinKL7uRiZmTjC17RQ

I've seen most of all his videos, but he talks very vaguely on how it effects his oil pressure (saying his oil pressure will be high if I do this.. or low if I do this..)

I'm looking for a little more raw data. Specifically what kind of changes in oil flow are seen after performing these modifications.

For instance:
If I took my motor out, just ported the front oil galleys, and put it back in what part of the oiling system are effected and what can I look for in pressure changes.

My bearing clearances are looser than spec for racing purposes, so theyre much less forgiving to change in the oiling system. Which is why I'm asking these questions.

another instance:

If I create larger oil chamfers on the rod journals, will that effect the amount of oil pressure across my mains?... if I do, should I port my OFH a little to relieve higher oil pressure at the bearings on the crank?

Specifically to me, I have A BSE..without porting the OFH at all because I wanted a little higher oil pressure with the looser bearing clearances...

How will these modifications affect my motor's oiling setup specifically.

 

[craig4g63]

I've seen most of all his videos, but he talks very vaguely on how it effects his oil pressure (saying his oil pressure will be high if I do this.. or low if I do this..)

I'm looking for a little more raw data. Specifically what kind of changes in oil flow are seen after performing these modifications.

For instance:
If I took my motor out, just ported the front oil galleys, and put it back in what part of the oiling system are effected and what can I look for in pressure changes.

My bearing clearances are looser than spec for racing purposes, so theyre much less forgiving to change in the oiling system. Which is why I'm asking these questions.

another instance:

If I create larger oil chamfers on the rod journals, will that effect the amount of oil pressure across my mains?... if I do, should I port my OFH a little to relieve higher oil pressure at the bearings on the crank?

Specifically to me, I have A BSE..without porting the OFH at all because I wanted a little higher oil pressure with the looser bearing clearances...

How will these modifications affect my motor's oiling setup specifically.

The answer to your questions requires a thorough understanding of thermodynamics and fluid dynamics including the venturi effect and bernoulli's equation. This isn't something that can be spoon fed. Each change will require analysis.

 

[BogusSVO]

Oil weight and brand will also effect it.

But oil mods like oil port mod 1 and porting the front oil galleys is more about oil flow than pressure.

Now mods like OFH porting, and cut spring mod will effect pressure

 

[97gsxIA]

Ok, oil pressure aside, what are the oil flow benefits of porting the front oil galleys?

Could you say that with higher oil pressure, you would want more oil flow (or are oil flow mods done no matter what because of design flaws?) especially in the troublesome spots? Is there any correlation?

I do oil port mod #1 on every head I've worked on just on the sheer fact that oil flow to the head is particularly troublesome (lifter tick/inadequate oil flow to turbo in certain cases, etc.).

Why doesnt everyone increase chamfer on the trailing end of rod journal oiling holes, and in my case of looser clearances, would increased flow promote longer life of the bearings? How about if clearances we'rent on the loose side? (i.e tighter side of spec)

 

[BogusSVO]

Ok, keep in mind that presser is a measure of restriction.

I port the front oil galleys of the block on every block, the reason is there is just casting trash in them, and that will just slow the flow of oil in that part of the oil galley, but it should be kept at the same oil pressure as before the porting because of the the oil bypass valve in the OFH.

Now, thinking of the Garden hose and drinking straw.
You would think, that porting the the front oil galleys would lower oil pressure due to the larger cross section of the galleys, and it would if the bypass was locked shut, but not by much.
The reason the oil pressure gauge dose not show that is the oil pump is still moving more oil (GPH) than the galley will flow.

Now the oil pump is not working as hard to push oil through that segment of the oil galley

Now, for chamfering the the trailing ends of the oil ports in the rod throws in a 4g crank, It is not really needed, but will not hurt, the reason why? The 4g crank is cross drilled in the rod throws, so there are 2 oiling points for the rod bearings, Not one oil port like on a domestic V8 crank.
Also check a Domestic V8 crank from Eagle, Scat, you will see the oil port has a larger than stock chamfer than stock, but not the tear drop shape. It holds more oil on the bearing face.

 

[97gsxIA]

Looking at the 6bolt oiling system...

Is it safe to assume porting the front galleys will increase flow to the oil squirters then #1 main, #1 rod tapering down through the mains/rods sequentially? Or would it increase flow to the entire oiling system?

Also bogus, is there a write up on how much porting to do on the front galleys, and is it just on the block side, or front case as well?

 

[BogusSVO]

Look down the main oil galley of the block, it is about .600 Dia.

The main oil feeds are about .300

So there is more oil than needed in the main oil galley to keep the mains fed and the squirters too, they are what about a .010 hole??

Porting will increase flow to the main oil galley, since the rest of the oil galleys have not been touched, they will be the same.

As far as a write up, yes I have one posted. Click the link in my sig line and enjoy reading.