Oil pressure vs volume

[Steve.k]

So you had to do those mods to get the pressure?

[tuffxf]

G,day Steve,
do you know cam bearing and lifter - bore clearances?
What i did when going to a roller cam was to have the have the engine on the engine stand with pan, rocker covers and intake off.
put the pan on floor or box, level so you have access to see what is going on , take the pickup tube out of the pump and put a npt - -12 jic nipple in its place and make up a -12 hose as a temp pick up and place in the pan at correct height off the floor.
You will have a priming tool you can run with a decent drill
to make it real, you need to work out what the viscosity of your oil of choice is at the operating temp you are running, easy to work out.
Then buy some lighter weight oil that matches that viscosity at room temp, it will be real light, i used thinner oil plus my pan heater to achieve what i wanted.
jam a mechanical gauge on it
Next step is important!
crack a beer or make a rum, preferred! you will need it.
Run the thing on the drill and be prepared to make a bit of a mess, you will be able to see any obvious pouring of oil or volume loss issues,
pay attention to what is coming out above and below the lifter bores, out the lifter axle lube,front of the cam / cam gear area, take note of what the gauge is telling you.
Then for an interesting experiment for yourself, rip the roller lifters out of it and drop a set of flat tappet lifters into the bores and repeat.
Then make another rum when you see the difference!
Huge difference in oiling and sizing between different lifters.
It is really only a small amount of work but it will answer a lot of questions and point you in the directions that need addressing.
Cheers
Paul

[Mark O'Neal]

How is the bypassed oil being handled?

That depends on the pump. Some pumps will dump the bypassed oil back to pan, others will redirect it back to the inlet....

Or...as mentioned earlier.....it shoots the filter across the shop and dumps 5 quarts on the floor.

To my never ending amusement.

[tenxal]

How is the bypassed oil being handled?

That depends on the pump. Some pumps will dump the bypassed oil back to pan, others will redirect it back to the inlet....

Yeah...I know.

I don't see where the O.P. has discussed it, other than to state what pump is on it.

[Steve.k]

Melling dumps back to inlet side I believe.

[Kevin Johnson]

Melling dumps back to inlet side I believe.

Yes, you can see a series of pictures of the basic pump body here -- no external relief opening so an internal bypass:

https://www.jegs.com/i/Melling/689/M84AHV/10002/-1#

Aside: If you are using the stock pickup head then it is a poor design with respect to anti-vortexing. It is better than a free standing hemispherical bulb, yes. Look to the Nissan VG30DETT pickup tube head.

mel-84-as1_w.jpg

VG30DETT

VG30DETT.jpg

[blykins]

Where were you measuring the oil pressure? It makes a difference if it's at the front of the block near the pump or at the rear of the block.

FWIW, here's the bearings from my 354C, which had a standard pressure/volume pump on it. Were seeing about 60 psi at the rear of the block, pulling to 8500 rpm. Standard main bearings, coated rod bearings, can still see my mic tracks. 620 hp.

[Steve.k]

Oil pressure feed is standard location. Its a custom kevko piickup to fit pan. Last dyno session before this our bearings looked the same.

[blykins]

I think you're in good shape.

[Steve.k]

B9C095C3-7AB8-4718-83EF-2A80DCE284A9.jpeg

4975EAB2-D27B-4897-9CEE-7B6114E5CF8E.jpeg

Melling dumps back to inlet side I believe.

Yes, you can see a series of pictures of the basic pump body here -- no external relief opening so an internal bypass:

https://www.jegs.com/i/Melling/689/M84AHV/10002/-1#
Theres pickup tube.
Aside: If you are using the stock pickup head then it is a poor design with respect to anti-vortexing. It is better than a free standing hemispherical bulb, yes. Look to the Nissan VG30DETT pickup tube head.

mel-84-as1_w.jpg






VG30DETT
VG30DETT.jpg

[Kevin Johnson]

Thank you!

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Edit 2: Other interesting flow is set up beneath tray but the above seems to be an issue in my 'noggin. The leading edge of the tray directs flow smack down the smooth pan wall. The louvers there immediately adjacent reinforce this.

[piston guy]

So you had to do those mods to get the pressure?

It was standard practice in the late 70's and was already done when I bought the complete engine. I did not build it , I only rebuilt/maintained it after I got it.

[Steve.k]

Thank you!

Steve.gif

Steve 2.gif


Edit 2: Other interesting flow is set up beneath tray but the above seems to be an issue in my 'noggin. The leading edge of the tray directs flow smack down the smooth pan wall. The louvers there immediately adjacent reinforce this.

So Kevin you think there could be some ariation issues set up this way? Maybe im better off without windage tray.

[Kevin Johnson]

You just need to put some fine directional screening over that area. If you measure the box and approx. size of the sump well I will make you something (no charge).

A few years back, Yves had a similar issue.

PM me the measurements and your address.

[Steve.k]

Ok thanks Kevin I’ll get measurements later today. Im more than happy to pay you for your help and expertise.