Rotella T4 oil, dirty oil

[Jeff/Illinois]

Originally Posted by 30 Closed Cab PU

Do you run any filters?

No. I used to run the Air Maze airfilter on the Tudor but one day it fell off somewhere out on the highway, and the car ran better after that anyway so I never bothered to replace it.

That was on a Tillotson carb, the air inlet opening had scrunched down a bit from the set screw.

Naw, a Model A is about the easiest thing to ever change oil on so every 500 miles or end-of-season I change the oil. Never had a problem.

[30 Closed Cab PU]

Originally Posted by kimlinh

Your oil is not getting dark because it is the wrong oil. The air and oil filters also have little to do with it. It gets dark because of the incomplete and inefficient combustion of the Model A engine. Unburned fuel and water are the biggest culprits. Your modern car stays cleaner-looking longer because it is much more efficient. Raise the temperature of your engine with a thermostat, use a higher compression head, run leaner and advance your timing as much as you can without preignition will all help you burn your fuel cleaner, however, a Model A engine will never be as efficient and clean as a modern engine. Don,t worry about it, It's normal. Just enjoy your car, and if you don't use an oil filter, Keep changing your oil at 500 miles.

I agree and understand most of this. I do like what you wrote, summarizes things very well.


I am trying to understand why some others say there their oil is not a deep black at 500 miles like mine is doing. I do not expect my oil to remain fresh/new looking like a modern car, and do understand the Model A motor is not as efficient and is dirtier.


I do not have a high compression head. Decided for my style driving, do not need the extra power. I do not do multi day tours, do not feel the need to run above 45 mph, most enjoyment for me is running 30- 40 mph max. on back roads.

I do run a thermostat year round with additional holes drilled in to provide better coolant (Antifreeze) bypass. With Tan cruising/high speed plug reads I assume Carburation is correct, and I do not have to add coolant.


I run the GAV at 1/3rd turn open, because at less than that I get a little engine cough at cruising speeds when letting off the gas, and also when shifting. I usually keep my spark advance at least 1/2 down. I adjust it when at cruising/high speed to where the lever is just below (advanced) where further retarding causes reduced motor performance. I retard it a little to avoid possible knock going up longer/steeper hills. It idles well down to 450 rpm at full retard, GAV set just above completely closed.


"The air and oil filters also have little to do with it." - Am not sure about this. Would not an oil filter filter out the contaminates in the oil, keeping it looking cleaner longer, and extending the life of the oil?

[johnneilson]

So, a couple comments, worth exactly what you paid for them, not more.

Temperature, oil doesn't start to work until it is approx 140 degs f. The symptom of sludge in the bottom sump is an indicator that it is not run long enough at proper temps.

The oil filter back in the 50's was found to extend the life of the motor in a full flow system, meaning the oil is filtered and fed directly to the bearings. Yes, it will help but not keep the oil clean.

There is a ton of debate on modern oil and synthetics on this forum, personally, I use full synthetic oil. Modern oils are many times better than what was available in the 40's.

The only way to diagnose the oil is to have it analyzed for metals and contaminants by a lab. Having several tests done over time will indicate the wear points in the motor.

Enjoy your car or pickup, that's why we have them.

J

[30 Closed Cab PU]

Originally Posted by johnneilson

So, a couple comments, worth exactly what you paid for them, not more.

Temperature, oil doesn't start to work until it is approx 140 degs f. The symptom of sludge in the bottom sump is an indicator that it is not run long enough at proper temps. This is a possibility, with a fresh Bergs radiator and a cleaned out fresh motor and with a 160 degree thermostat with the outside temps in the 70s, coolant temps would only get up to 140 - 150 degrees. And when below 70s coolant was 100 - 120 degrees. May have to start blocking the radiator. If coolant is that cold, oil probably is not getting up to 140. I did not know 140 oil temp was a # for proper oil function.

The oil filter back in the 50's was found to extend the life of the motor in a full flow system, meaning the oil is filtered and fed directly to the bearings.
I believe this is recommended if converting to Insert Bearings.
Yes, it will help but not keep the oil clean.

There is a ton of debate on modern oil and synthetics on this forum, personally, I use full synthetic oil. Modern oils are many times better than what was available in the 40's.

The only way to diagnose the oil is to have it analyzed for metals and contaminants by a lab. Having several tests done over time will indicate the wear points in the motor.

Enjoy your car or pickup, that's why we have them.

J

Thanks John, really appreciate your comments. - you supplied another piece to the puzzle. See my added comments above.


I agree with the other points you made. I just prefer frequent oil changes to keep an eye on how the motor is doing, especially since it was rebuilt last winter. Otherwise would probably go synthetic too.


Plus seems you are not supposed to use synthetic on a fresh engine, causes break in issues. You probably are already aware of this.

[johnneilson]

30CCPU,
Glad to hear you are open to suggestions, I run a 190 thermostat all the time, even when 100+ degs here in Cali.

I am not sure about the babbit being any different than inserted motor, I do hear some talking about washing out the babbit under pressure. Never seen any evidence of it.

As for the break in on synthetic, I do not subscribe to that. But, I do not run conventional ring package in these motors, never had a problem. I was working in the lubrication (oil industry) years ago. What sold me on the synthetic oil was the fact that it passed every test the first attempt (API criteria). Conventional oil only had to pass 4 out of 10 attempts, some batches of oil were junked due to failure of cert test.

Enjoy your vehicle(s), working on them is half the fun, driving them the other.

Happy Thanksgiving, J

[eagle]

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A quick test would be to switch oil brands. Some oils definitely turn dark sooner than others. Take a few drops of oil and put it on a coffee filter. You’ll see right away if you have sediment. Dark oil isn’t necessarily the same as dirty.

[30 Closed Cab PU]

Thanks eagle, will have to try that on next oil change.


Thanks to all who have posted so far, a lot of great info/ideas. Am open to more.


After Searching here previous to 1st post, I was hoping there would be additional info, and there has been a lot of great additional info. Hopefully I can find and up date this post as to results next year.


Hope you all U.S. folks had a good Turkey Day.

[Werner]

Kimlinhn ha described it exactly and correctly. Oil always gets dark because it gets residues from combustion in the cylinder. Every combustion that does not run 1: >1 stoichiometry produces a lot of soot.

You see that well in the back of the black exhaust or if you have started the engine with exhaust end in front of a wall.

Soot is oil-soluble, but is only partially filtered out by special filters in the sidestream. This is only available in modern injection engines, as well as the exhaust remains clean.

But there are oils that make more or less residue from your own combustion! Transmission oils, ATF, Rhicinous, etc, leave a lot of residue, two-stroke oils very few. It depends on the additivation.

Synthetic oils leave very little combustion residue, but they are very hard. Simple mineral oil leaves more combustion residues that are soft for it.

Much more important than the type of oil is the regular change to remove the many soot residues out from the motor. These are oils above API "B". A filter retains coarse residue that is sucked in or chipped off hard oil crust. The oil filter prevents wear, but can not really keep an oil "clean". Personally, I would change the oil every 1000 miles / 1 time a year with the filter. Without filters every 500 miles. The few rinsed short distances, the more gerunger is the soot entry.

[rotorwrench]

To add to Werner's post, if you think of oil as a solvent with the calcium based ashless dispersants in there then comparison is similar. A naphtha based solvent starts out almost clear but after you clean a bunch of parts it continues to get darker. All the large particulate is filtered and settled out but it never gets back to a clear fluid. The fine particulate just stays in suspension until you change it out.

Modern cars have government mandated efficiency built onto the fuel delivery systems so they have a much more efficient burn than any of the old carbureted engines could ever attain. The full flow filtration systems are as good as it gets. With all this, the lubricating oil will still stay relatively clean by comparison and therefore last a lot longer.

Limitations of modern engine lubricants are more with the plastic polymers that they add in for multi viscosity function. I doubt if they will last much more than 3,500 to 4,000 miles but modern engines have such tight tolerances and run so clean that the oil is still functional for some time after the polymers are worn out.