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XRV8 Gremlin

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amcenthusiast View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Nov/09/2019 at 9:49am
Yes; I considered knife edging, but for the amount of work done -just to obtain balance- the sides of this crank are simply rounded off.

In this case, because it was so labor intense, the primary concentration was to complete the work  and make a running model, in hopes of taking this crank to a billet crank manufacturer.

And yes; and I plan to try at least two types of custom made crank scrapers in the future.


Edited by amcenthusiast - Nov/14/2019 at 2:47am
Link to XRV8 Race Parts website: www.amcramblermarlin.1colony.com
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Nov/09/2019 at 10:05am
XRV8 Race Parts anti-vortex oil pump pickup tube and oil pan assembly for Rambler V8 engine:





Above, showing former custom oil pan made to fit Gremlin chassis. Now internally painted to improve oil quality by reduction of corrosion induced contaminants.

-The preparation prior to paint application is critical; scoured clean, wire brushed, treated with phosphoric acid, then final rinse liquid soap and water, compressed air dry, then spray paint -very light coat -just enough to seal the metal & help prevent rust.

The paint is not there to make it look pretty. A bright color will make it easier to see it's cleanliness, where a dark color will make it more difficult to see dirt.



Below, showing prototype anti-vortex suction tube device for Rambler V8 oil pump:



This configuration is made to fit down inside the oil reservoir of the Gremlin oil pan -'car guys' always call it a 'sump' using automotive jargon like 'deep sump' oil pan etc.

We can hardly imagine a worse case scenario for an oil system reservoir environment than automotive application:

-limited depth, for ground clearance

-limited space, for everything else that belongs underneath the engine

-exposure to air, for oil cooling, is close proximity to hot header pipes instead

-oil exposed to time, inside oil pan, to allow air bubbles to escape, is rather exposed to extreme 'wind' caused by the undersides of the pistons which move at mind boggling speeds (each, ten times per second at only 600 rpm)

-movement of reservoir, causing 'oil slosh', creates strong potential for 'gulping air'

Basically, all the environmental attributes are wrong!



Edited by amcenthusiast - Nov/10/2019 at 9:20am
Link to XRV8 Race Parts website: www.amcramblermarlin.1colony.com
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Nov/09/2019 at 10:12am
Moreover, even people who don't  study hydraulics, oil pumps and reservoirs probably know something about 'vortex formation'.

Open the drain on a bathtub full of water and see what happens... notice, at some point, it will form a vortex (an empty tornado shape, full of air going down into the drain)

The attributes of a typical automotive oil pump suction tube poking down into a typical automotive oil pan is ripe for intense vortex formation action!

By simple hydraulics textbook definition, the depth is WRONG from the get-go; too shallow and it will create vortex induced cavitation and aeration.

In the field of hydraulics, vortex formation is elementary (widely known scientific phenomena)

So... this poses the question:

WHY? ...is there no talk about vortex formation in any automotive oil pan discussion?

Can't see it, so it does not exist?

OK... enough ranting.

On this unit, the top horizontal plate is to avoid giving a vortex formation above the suction tube an outlet to air space. The vertical plates are to thwart or inhibit rotating oil in the pan. -it's all based on pre-existing scientific studies of vortex formation in hydraulic system oil pumps submerged in oil reservoirs.

Basically all I've done here is to simply incorporate hydraulic system solutions into an automotive application. It's not 'genius', rather it is 'common sense'...in any non-automotive application (!)
 



The stock suction bell's opening is made full width and doubled in size. This reduces local oil flow velocity at the opening itself, -where a smaller opening creates more oil speed into the suction bell and more chance for vortex formation (especially if the suction bell intake opening is offset to one side)



Below, the oil pump's high pressure bypass tube is turned around 180 degrees to dump oil into the corner of the pan where it's blocked by walls on three sides not to induce swirl to the suction bell.



The top anti-vortex plate(s) double as 'wind breakers' to prevent 'wind' induced aeration and/or cavitation caused by the pistons. aka 'windage tray'

During original assembly of the engine, the front portion of the pan had to be dimpled for clearance with the longer stroke crankshaft: measuring the clearance between the rods and top surface of the windage tray -there's only about 1/4" clearance... adding more oil to the pan only creates instant aeration as soon as the engine is started and the connecting rods begin to violently strike the oil.



will come back and add more critical info, time and space permitting...


Edited by amcenthusiast - Nov/14/2019 at 2:52am
Link to XRV8 Race Parts website: www.amcramblermarlin.1colony.com
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