Oil pressure dropping on right turns

bettlesr

bettlesr

Senior Member
Last year I had an engine rebuilt with all the "good stuff", balanced, full pressure, insert bearings, etc... About a week ago I added an oil pressure gauge and tach under the speedometer. I've noticed that on a sharp right turn, the oil pressure drops from 35 psi to under 10 psi. Has anyone had a similar problem and how did you get around it? On my Lotus, I had to make a baffled trap door pan and run a quart over. Seems a little overkill on a Model A. I don't have to be going fast for this to happen. As soom as the oil sloshes to the left side the pressure goes away.
Thanks
Dick
 
Is the oil on the full mark of the dipstick? Maybe you are turning too quickly, Elliot Ness wasn't after you was he?
 
when you turn right, the momentum would carry the oil to the left side of the oil pan. The oil pump is on the right side. So it would make sense. I don't think it's anything to worry about. Your engine won't starve of oil if you make a right turn.
 
That is normal, and is only noticed if you have a guage. The pump starves for a while during the turn. Since the engine is not a pressure oil system, it does no harm. There is still oil in the valve chamber for the mains, and oil in the dip trays for the rods. Now if you were going down a spiral staircase kind of road, that might be a problem.
 
Thanks, I am going to add another quart first. This is a full pressure system so there is no oil in the chamber to run down into the mains. I don't have to make a fast turn at all. If that doesn't work I will probably make a hinged baffled pan as I did on my other car. AND three positives don't make a negative? Yea, yea, yea.
Thanks
Dick
 
Yes, It has a new high capacity pump with a built in 35 psi relief valve. I wonder if I would still need the original tray or if that may be keeping the oil from returning as quickly as possible? Anybody have plans for a road race pan?
Thanks
Dick
 
i have had the same problem . my motor has a "v8" pump . on rt turns it will lose most of the oil pressure . i have installed one way gates (as in race cars) but still does it . the problem with mine is the v8 pump is higher than the stock pump was . next time i drop the pan , i am going to build a lower pick-up . for now i just go a lil slower on rt turns ... hope this helps .............
 
Dick,
I have built pans on and off since the mid 70s, not hard just time consuming for a
proper job. Look on line/ebay at road race pans for images inside the pans. The
gates, trap doors, are made from piano hinge(light weight, 20 gauge), with welding rod for the hinge rods. The gate opens no more than 45 degrees, and move very freely.
Dudley
 
I think that Urb Stair went in to this in detail in the secrets of speed journal in the ninties. On a sharp right turn the oil is pulled away from the pump. He constructed a baffle around the pump and recommended running seven quarts of oil. I tried running seven quarts of oil in an unmodified engine. Without special rear main seal it doesn't work well. The coupe left a trail of oil when run with seven quarts. I figured I was better off running five quarts and not having to appologize for the leaks.
 
bettlesr said:
Thanks, I am going to add another quart first. This is a full pressure system so there is no oil in the chamber to run down into the mains. I don't have to make a fast turn at all. If that doesn't work I will probably make a hinged baffled pan as I did on my other car. AND three positives don't make a negative? Yea, yea, yea.
Thanks
Dick
Click to expand...

The chamber is dry? Who built this pressure system? No pinhole nozzles to squirt oil on the valve stems and lifter contacts? No bleed hole to keep the chamber full with wet felt feed wicks running oil up to the top of the valve stems? No road draft vent hole in the upper rear of the cover to draw crankcase mist across the valves? Anything? What cools and lubes the valves? I'd worry more about that than 10psi to inserts that will run all day with near zero pressure in an A.
 
Is this the baffle that is being described?
 

Attachments

  • A6631-4737.jpg
    A6631-4737.jpg
    19.1 KB · Views: 442
  • A6631withoilpan-4738.gif
    A6631withoilpan-4738.gif
    8.9 KB · Views: 28
CarlG said:
Is this the baffle that is being described?
Click to expand...

That '31 baffle keeps the dipper tray full on hard lefts, necessary if you do not have a cross-drilled crank. It does nothing to address the problem described. You need a lower baffle in the sump, a relocated pickup point, or a pivoting pickup to keep the pump fed constantly.
 
MikeK:
I'm not sure what is in there, I was only saying the chamber is not full like a regular "A" engine. The bulk of the oil has to come from the pressure system.
Dick
 
L-head ngines that are not designed for hydraulic lifters generally have no organized oiling system for the valves. Cam/lifter area is continually splashed by oil departing the reciprocating and rotating parts, upstairs gets some splash and lots of oil fog.
In a Ford flathead V8, leaving out a minor baffle in the valley floor will generally cause oil burning...suggesting that stock non-system is feeding the stems all they can handle.
 
MikeK said:
The chamber is dry? Who built this pressure system? No pinhole nozzles to squirt oil on the valve stems and lifter contacts? No bleed hole to keep the chamber full with wet felt feed wicks running oil up to the top of the valve stems? No road draft vent hole in the upper rear of the cover to draw crankcase mist across the valves? Anything? What cools and lubes the valves? I'd worry more about that than 10psi to inserts that will run all day with near zero pressure in an A.
Click to expand...

Look at a "B". Two quarter size holes in the chamber floor..
 
d.j. moordigian said:
Look at a "B". Two quarter size holes in the chamber floor..
Click to expand...

Yes! That would permit oil mist from the crankcase to flood the chamber. Something that is NOT happening on an A that has been converted to pressure. Adding those large holes would be an excellent idea.
 
You must log in or register to reply here.
Back
Top