Pinto Diagnosis - Oiling puzzle.

[BeerBudgetRacing]

I hate to say it, but if this were my engine I would find out who made the oil pan, and return the windage tray back to the factory geometry. I've seen way too many intuitively good ideas for oiling and breathing take a sh*t when tested on a dyno with plexiglass oil pans and high speed video recordings and strobe lights. As you mentioned in another thread, it's a 300 mph hurricane in the crankcase, and nothing behaves the way you think it will. If your mods have resulted in too much air windage/velocity under the tray, you may in effect be blowing the oil out of the trough.

The washers were the recommendation of TDC - the manufacturer. Prior to that change the windage tray was screwed directly to the edge with NO gap for oil to run through. Only 1 place for sitting oil to go - toward the rear there was a gap.

I see your point, but does it explain my tests with the engine off? Test 1?

[tlracer]

Compared to air, the oil has an insanely 'thicker' viscosity. If there is a chance for air to "sneak" into the scavenge hose (due to say a loose hose clamp), the air will instantly start to flow when a vacuum is pulled on the scavenge line, whereas the thick viscosity of the oil makes it really lazy. More than once in my engine dyno development experience, I have encountered leaks in the scavenge line components that were so small they did not drip a drop of oil overnight with the engine off, but then sumped horribly once the engine fired up.

This is where I was coming from with my thoughts about the scavenge pulling in air: The pressure side of the pump will have an inlet head from the oil in the tank, where the scavenge relies on the trough being at a level where it can pull oil rather than dragging mainly the less-viscous air, so 'stalling' the flow of returning oil.

My question about oil grade also came from this - typical advice for Pintos here in the UK is 20W50. Whether the lower 10W30 you're using means the internal flow patterns are altered is a difficult one to examine though!

Finally, my experience in another industry (brewing!) confirms that tiny leaks can allow pumps to pull in air but have no sign at all of liquid escaping ( in this case it causes high dissolved oxygen levels in the beer, damaging the flavour ).

[xmazdatracy]

Give it a leak down test. Couldn't hurt... We all make mistakes. Might have messed up one ring, and that is all it takes to have crank case pressures pushing oil out every where.

[BeerBudgetRacing]

Give it a leak down test. Couldn't hurt... We all make mistakes. Might have messed up one ring, and that is all it takes to have crank case pressures pushing oil out every where.

Would the rings be seated after only a few minutes of running? I hate to come to the wrong conclusion.

[DaveW]

Would the rings be seated after only a few minutes of running? I hate to come to the wrong conclusion.

If you have one bad ring, the leakdown on that one will be a lot worse than the rest - it's not the absolute value that counts in your case, since you're looking for an issue on one cylinder.

[Jon Jeffords]

I see your point, but does it explain my tests with the engine off? Test 1?

Two considerations to take into account:

1) For accuracy during Test 1, don't start the stop watch when you start spinning the pump. Instead, start the stopwatch when oil starts coming out the scavenge hose. Actually, for all the tests the stopwatch should be started when the bucket initially starts to fill with oil, but I see the Test 1 configuration as having the longest delay time to deaerate the system.

2) The output (gallons per minute) at the feed pump port may be less during Test 1 (oil flowing through restrictive engine) than it is during Test 2 (oil flowing through short non-restrictive hose), as the pressure relief valve MIGHT be opening during Test 1 if the pump rpm is high enough and the oil is cold enough.

[BeerBudgetRacing]

If you have one bad ring, the leakdown on that one will be a lot worse than the rest - it's not the absolute value that counts in your case, since you're looking for an issue on one cylinder.

Hopefuly not. Had an experienced builder do the bottom end work and assemble it.
At least with the pan off I can heard the air below.

[tlracer]

Gone right back to your initial post on this:

Am I right that you had a total of 8 quarts of oil in the system? That is surely too much...depending on who you talk to, it should be around 5 to 5 1/2 quarts (I use 5 litres of 20w/50 semi on a full change, which works out at 5.3 quarts).

Over time there is always going to be a certain amount of 'run back' into the engine through pump clearances and the scavenge isn't going to completely clear the engine of oil and return it all to the tank, so the tank level will be rather lower than when first filled.

[Rick Kirchner]

if he opened up the volume of the internal catch tank it will be at least a quart more

[cleaver racecar engineering]

if he opened up the volume of the internal catch tank it will be at least a quart more

On our S2 pinto we run 5 liters total fill when we service and change oil there is at least 1 to 1 1/2 liters in the sump , so I belive you are over filling.

[DaveW]

Any resolution to this issue?

[BeerBudgetRacing]

Any resolution to this issue?

Nothing conclusive but the thought is simply too much oil. Probably my own fear.

I've had to write-off my remaining schedule for the year and haven't had time to work on it.
The plan is to re-seal the pan and re-test with only 5qts onboard - no more.