options for oil pressure/flow balance lines

dave brode

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All,

We've talked about the option.

Repeat from other thread: It appears to some of us that the mains in the rear of the engine do not see as much flow as those in the front. I believe that the big problem is the pass side header that feeds a much greater number of leaks. However, although it may be a lesser problem, but I also believe that flow in the driver's side header is also not even, and number 5 main sees less than #1.

It would be fairly simple to connect the front port above the pump to the rear of the pass side header. If one wanted to connect to both headers, the effort becomes more complicated. The boss on the dr side header protrudes more.

It looks to me that the sloped/angled part of the block's rear bulkhead would be the easy place to come through.

Anyone care to stare at a block and give input as far as fittings and such? Clearance at the cam plug boss is limited.

Dave
 

dave brode

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Member 3508

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Why is it not as simple?

Maybe the 3/8NPT to the pass side, and a much smaller one to the Driver side?
 

dave brode

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frankenregal84 said:
Why is it not as simple?

Maybe the 3/8NPT to the pass side, and a much smaller one to the Driver side?

Yes, but unlike the buick where the bosses are even with the back of the cam plug boss, ours are closer, and one side is way in, one out. Have a look at a block. I'll do same.
 

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10-4.

In the meantime. I was reading the oil-mod sticky on V8Buick and noticed a few more things.

1) He says the balance line is only recommended at 600+hp or 5500+RPM. It wont hurt below that, but on the buicks you dont see a benefit below that RPM. Any ideas on how the Caddy would react?

2) He says to accomodate most fittings, you have to RE-TAP the hole to fully seat the fitting. If thats the case, I cant do it, because my block is ready to go together, and I REALLY dont want to have it jetwashed again for the 15th time.


Im in assembly mode now, so ill take a look when im there and maybe post up some pictures.
 

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Another method if the 90* elbow doesnt work.
Look at the second last picture. The buick guys install their gauges this way to get a more accurate reading.

http://home.roadrunner.com/~tooloose/70buick455.html

P.S.
What if we enlarged the oil pressure sending hole and fed the balance line to there? I dont know where this port goes though.

P.P.S.
Are his pistons upsidedown?
 

dave brode

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member 3508,

It sure looks like his pistons are upside down.

At what power level and rpm does our oil system become a problem? Good question. A number of issues hacve been discussed in the bearing thread.

Back to topic, our pressure gauge port is tapped to 1/4" pipe, and comes off of the driver's side header. I'll have a look at our block to see if we have any options like the buick.

DB
 

dave brode

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Looking at the block, the gauge pressure port looks to be the easiest way to feed the back of the dr side header. It's plenty big. It's a 90 junction at the header in the block, but there is only an inch of so room between the boss and the flex plate, so if that header if fed from the back of the block, a sharp 90 would have to be used there. So, there is going to be a sharp 90 somewhere.

On the pass side header, there's way more room between the pass side plug and the flex plate.

One could plumb it a number of ways.

1. Along the block, through the lower part of the block, tee/wye out at the top to the pressure port.

2. Tee/wye outside, seperate lines through block to pass side header, the other branch running outside the block to the gauge port on top to the dr side header.

3. Another option would be to run the feed line run over the top of the engine, away from exh heat. Tee/wye at the rear of the intake, and drill the block right near the pressure port in the top to feed the pass side header behind the flex plate.

member 3508, regardless of the plumbing route, if a short fitting is used behind the flex plate on the pass side header, I bet that you would not need to chase/deepen the threads there.

Dave
 

dave brode

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More silly thoughts;

Looking at the flow from the pump;

9/16" hole in the pump mounting area up a bit. The flow turns apx 30* and heads to the pass side header, via the drilling at the port on the block.

So, flow potential is greatest between the pump and the turn at the port. Bringing the oil out at the port means the oil has to make an apx 120* turn to get out of the port.

It may distort the pump body, but one could drill/tap the pump body in the bulge that contains the outlet port. Doing so back near the downstream end of the bulge might minimize distrortion.

Silly?

Dave
 

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Excessive.

The buick balance line has basically the same port and I dont think anybody does that. I believe they DO enlarge the port though to 1/2" if it isnt already.
 

dave brode

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member 3508,

By excessive, you mean don't worry about the sharp turn to the port, ot of the block in the front? I can't disagree. Our port there is plenty big for a -6 line imo. The drilling between the header and gauge port at the rear also appears to me to be plenty big.

Nick,

I believe that one could fashion a manifold under the vallvey and drill into the headers. However, imo, an external line from the main drilling at the pump outlet passage to such a manifold would still be needed to add any pressure/flow to the rear of the headers. Taking the oil in at the rear of the headers seems to be the easiest option to "even out" the pressure in the headers.

DB
 

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Thats exactly what I mean.

I rather like the idea of plumbing into the oil pressure port since it IS smaller than the galley plug at the back. So a larger amount of oil should go to the Psgr side and slightly less to the Driver side. Seems like a sound plan to me.


Nick, im sure you could. There was a guy that converted his block to "priority main" oiling this way.Under his intake was just a spaghetti of braided stainless hoses. Worked like a charm, but its alot of work.
 

dave brode

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frankenregal84 said:
I rather like the idea of plumbing into the oil pressure port since it IS smaller than the galley plug at the back. So a larger amount of oil should go to the Psgr side and slightly less to the Driver side. Seems like a sound plan to me.
Yes, 1/4" npt vs 3/8" npt at the rear of the headers. Fwiw, I don't see the size being a big issue, but it does look like the easiest way to feed the dr side header. The question is, how to tee/wye off for the pass side header. Drill through bell area at top, or drill at the sloped area at the bottom rear of the block, then drill again out of the top to feed to the gauge port?

On the size of the feeds to the rear of headers, imo, a -6 to one header, or split to both with even -4 would do what we need. Coming off of the port at the front of the block means we are coming out of the system before any leaks, where the pressure has to be highest [even if only slightly higher].

As I see it, as long as we have a line big enough to flow well enough to make the pressure the same at the rear of the header as the front, we will balance the pressure in the headers, and therefore balance the flow to the main bearings.

Now, with all of that said: Remember, we feed the pass side header first, and oil goes from that header to the other side over main #2.

Let's say we feed oil from the port at the front, to ONLY the dr side header at the gauge port. Doing so, we would potentially stop, or at least greatly reduce the flow from the pass side header through the cross-over to the dr side header. That would mean less oil leaving the pass side header = more oil to the 2, 3 and 4 mains.

In other words, feeding to only the gauge port on the rear, from the pressure port on the front might well balance the system well enough, via the dr side header. Then again, a small jumper line between the headers at the rear of the valley should fully balance flow and might be easier than teeing the external feed line etc.

Dave
 

Nick Campagna

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[/quote]

In other words, feeding to only the gauge port on the rear, from the pressure port on the front might well balance the system well enough, via the dr side header. Then again, a small jumper line between the headers at the rear of the valley should fully balance flow and might be easier than teeing the external feed line etc.

Dave[/quote]
That was what I was trying to say Dave, Can we repeat the crossover at the back, and maybe in the middle ? A block blueprint would be invaluable here.
 

dave brode

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Nick,

It looks to be a fairly simple job to connect the rear of the headers in the valley just forward of the last lifter on each side. Go into the gauge port on dr side, and connect there should balance the headers pretty well imo. Simpler that a tee/wye outside to each header? Dunno, probably a little.

Dave
 

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I have a diagram just like the the Buick one in one of the other threads. Not a blueprint but might be good for a visual. Its from a 70's Motors repair manual. I can post later tonight if it would help.
 

dave brode

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Those drawing aren't really clear, or for that matter, accurate. Most inaccurate is what it shows for "valve lifter supply". There is no passage at all, but just an opening at each lifter bore where the lifter bore and the header drilling intesect. There also is no angle in the passage from the left header to the port for the oil pressure switch.

It does show how main #1 and 5 oil from the left header and #2, 3 and 4 from the right header. It also shows how oil for each cam bearing comes right out of the main bearing oil groove below it.

The plug on the front of the block above the pump ["angular passage"] is there due to the drilling up to the right header that intesects the drilling from the pump mounting flange.

If you look at a block, it is very simple and clear.

If one wanted to feed "pump" oil from the port on the front of the block above the pump to only the rear of the left header, and join the headers at the rear under the intake, rather than plumbing to both headers at the rear:

You can clearly see the header's location if you look at a block. One could easily drill into the top of the headers in the valley, and connect them with fittings/line etc. There is room between each lifter bore for at least 1/4" npt imo.

That said, I agree with member 3508, running to both headers at the rear of the block would be better. Probably no more work in the end.

Dave

p.s. if your manual shows an "engine transverse section" drawing, you can see how the lifter bores intersect the header drillings.
 
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