Got the results back from my oil analysis. I'm not too familiar with what all of the numbers mean, some of you who are more knowledgeable can help out interpreting the results.

Sample was taken on 8/26/01 with 13451 miles. The previous change was on 6/16/01, with 3135 miles between changes. Oil was Amsoil 5W-30, filter was Amsoil. Oil level dropped 1 qt between changes, and wasn't topped off at any time between changes.

Here's the results:

Physical properties:

Glycol: neg
% water: <0.05
% fuel: 1.26
Viscosity 40 deg C: NA
Viscosity 100 deg C: 12.0
% solids: TR

Oil degradation:

Soot: NA
% OXD: 14.4
% NOX: 28.6
TBN: 12.0
TAN: NA

Spectrographic Analysis (PPM):

Iron: 7
Chromium: 1
Lead: 3
Copper: 79
Tin: 1
Aluminum: 5
Nickel: 0
Silver: 0
Manganese: 1
Silicon: 9
Boron: 12
Sodium: 2
Magnesium: 376
Calcium: 3148
Barium: 0
Phosphorous: 1280
Zinc: 1567
Molybdenum: 0
Titanium: 0
Vanadium: 0
Cadmium: 0

Results of tests performed indicate:
Fuel dilution elevated:
fuel present in oil – fuel leak, excessive idling, or incomplete combustion
Oil is suitable for continued use
Resample at next regular interval


I'm not sure what caused the fuel number, but it doesn't appear to be a sympton of oil degradation, or related to the PCV. I did run a large bottle of Techron fuel system cleaner in between oil changes...it's possible that caused it.

The fact that the oil is "suitable for continued use" after 3135 miles leads me to believe the reduced PCV airflow isn't causing any problems with oil quality. The back of the results sheet gives a description of what each item above would indicate, but it doesn't give a range of values that would be expected. I'm assuming that if any one of them fell out of the "normal" range, it would have been mentioned in the results section.

 

I don't know how a gas cleaner can get directly in the oil unless it was from blowby which would be via the PVC system ?

Here is another oil sample test you can use to compare, you see some of your are much hgher then mine

http://teamzr1.com/blackstone.html

John

 

That second analysis appears to be tranny oil and not engine oil. I don't think the two are comparable.

As for the analysis, if it pointed to an increase in fuel in the oil with the PCV mod installed, it most likely is because there is some fuel in blowby gasses and more of that fuel is "recycling" into the oil because there is less flow through the PCV system. If the oil is still deemed suitable for use though, you're probably OK with respect to engine lubrication.

One thing the analysis can't tell you though, and the thing I'm most worried about, is what effect the extra "trapped" oil/fuel fumes are having on the inside of the crankcase. The thing that causes sludge in the crankcase is not liquid oil (the oil that gets mixed back into your oil supply) but rather the atomized fumes that "condense" on surfaces that should normally be dry. The oil saturated air settles on normally dry surfaces and creates a film there. Over time, this film gets thicker and thicker, causing sludge. I would think that reduced flow throught the PCV system may be a bad thing since the entire purpose of the PCV system is to remove trapped/atomized oil saturated air.

Some part of that oil saturated air is obviously turning back into liquid form and re-entering your oil. I'd be less concerned about the part that re-enters the oil if your oil analysis is OK. I'd be more concerned with the (apparent) fact that you are leaving more oil saturated air floating around in your crankcase. It may in fact be better for the engine to burn that in a recycled combustion process than to leave it in the crankcase.

Mike

 

John - I didn't think that fuel directly entered the crankcase. I thought that the high dose of Techron could have caused a period of slightly incomplete combustion. I have no idea whether this is feasible, I'm just guessing. Since someone thinks your analysis is tranny fluid, I haven't looked at it. But some of the higher numbers on the analysis are good rather than bad, since they indicate an anti-wear additive in the oil, which would make sense with Amsoil.

Mike - If sludge were building in the crankcase, I think this would show up in the analysis via sludge in the sample. Also keep in mind that the PCV mod doesn't prevent flow, it only reduces it. Fumes are being removed.

I'm going to play around with the Jaz catch can this afternoon. If that works out well, I'll be able to remove some of the restrictions in the system, and this shouldn't even be an issue. If it doesn't work out well...I'd still rather be wondering if there's a possibility of a sludge problem later, than to hear the top of my pistons taking a detonation beating right now. Continual detonation, which is what I get without the mod with ambient temp in the 50's or greater, would lead to worse results in an oil analysis, I think.

 

I wanted to run one idea by you that popped into my head that may help the catch can idea work better. What if, before routing the air into the catch can, you ran it through a small coil of metal fuel line hose and used the centrifuge effect of the coil to try to condense the oil on the metal hose before it entered the can?

If you had a small diameter fuel line (or some bendable hose that is compatible with oil/fuel) that was wrapped in a tight coil, say by taking 1/8 inch ID metal hose that is maybe 3-6 feet long and wrapping it around a baseball bat or something of similar diameter to form a tight coil. As the air/vaporized oil mixture moved through the coil, the oil may turn back into a liquid as the heavier-than-air oil particles get flung up against the sides of the cool metalic tubing. Once liquified it will probably stay a liquid and you could have the output of that tubing enter the catch can. The whole setup would work with almost no restriction in the normal flow.

Just an idea...

Mike

 

Sorry guys have way too many things on my website, here is one in using Mobil 1. Keep in mind my engine has a lot of Molly 4340 parts which shows up in the oil



John

 

1.26% of the lubricant is gasoline. I think that is significant. While is is possible that it is caused by a misfire condition, it is likely caused by inadequate PCV flow. The fuel vapor (from our decidedly poor ring sealing and blow-by) needs to be evacuated by the PCV flow. As you reduce the flow, the vapor residence time increases resulting in greater absorption by the oil. Reduced flow also hampers contaminant "burn off" that occurs at elevated oil temperatures in the presence of adequate ventilation.

It is important to recognize that there is a proportional relationship between PCV flow and oil contamination. You cannot simply say that if there is flow, it is OK. I would be very interested to install a flow meter in series with/without the various mods.

I second mchaney's comments (separate thread) about the octane vs. deposition theory.

I appreciate the spirit behind the SMH modification, but Fuel filters are grossly inappropriate for this application. The media and physical configuration do not lend themselves to effective demisting, flow, or drainage. A thick coalescing media should be used in an orientation where the resulting liquid is captured away from the bulk of the flow and without restricting the media. Look at a good quality air compressor demister for some good design ideas (but I think they would be too restrictive for this application).

So I am not providing criticism without suggestion:

I guess we have to define our design goals - do we wish to remove the majority of the vapor, or just the droplets and liquid? I am using a sealed Jaz can with no media to capture the liquid flow in the line as well as the larger droplets. It meets my goals by capturing a significant volume of oil with little or no restriction.

If you want to capture the majority of the vapor as well, you have to go a step further. A free-flowing media is required in the catch can to demist and coalesce. Media could be squeezed into the Jaz can, but the inlet and outlet are not well positioned for greatest media vapor exposure (flow across the top rather than forcing it through the majority of the volume). The same goes for the artful Greddy can. Ideally, the inlet needs to be near the bottom, but above the liquid level. The exit needs to be at the top. This forces flow across most of the media while benefiting from gravity to pull resulting liquid away from the outlet.

It may be possible to fashion a little tube on the inside of either can to force the flow inlet to the bottom of the filter, but the challenge is to do so without reducing the tube diameter. I guess you could relocate the inlet as an alternative.

While I am sure that we can find a commercial coalescing media that would be ideal, lightly packed stainless or plastic "scrubbie pads" could be used. (no soap coating of course)

As an alternative to modifying either of the catch cans and adding coalescing media, experimenters (or the budget minded) may want to experiment with fabrication from PVC pipe. Try a 3" x 8" PVC pipe, lightly packed with media and capped at both ends. Insert a barb at the top for the outlet and a barb about 2" from the bottom for the inlet. A petcock in the bottom can be used for drainage. You probably will not find one in my engine compartment, but I think this will give very good results for the experimenter or budget minded. And you don't even have to name it after me. ;)

OK Jaz and Greddy, can you build us something appropriate for this application? I think I will email this thread to them and hope they realize how many of use are seeking a solution like this.



[Modified by C5 Tweaker, 3:13 PM 9/8/2001]

 

stevenmh,

While you're checking things out you may as well consider the following:

1. Are the injectors throwing a poor pattern, resulting in incomplete combustion.

2. Is the ECT sensor within specs? If not, it may be causing an overly rich condition on "cold starts".

3. Is the car "short tripped" a lot? If so, I'd take it for a 30 minute "work out" ocassionally in order get it hot enough to evaporate the gasoline in the crankcase. I would guess that you do that already. :D :D

I think that any of the above may be causing a condition wherby the cylinder walls are being "washed down" with gasoline.

I don't think the Techron is contributing to the condition....however there is an 800# on the bottle if you want to kick it around with one of their techies.

Let us know what you find out.

Good luck.
Mark




[Modified by MDT, 5:15 PM 9/8/2001]

 

I just installed the Jaz can this afternoon, as well as a clean set of downstream filters. If they stay clean, I'll start removing restrictions. If not, I'll play around with the media idea.

The car is short tripped alot. It's my wife's daily driver, to and from work, 13 miles each way. I'll take some EASE data at the track next weekend to look for a rich condition, misfires, etc, that could be contributing.

What's ETC?

 

Cstevenmh,

ECT=Engine Coolant Temperature. This is a sensor with a 2 wire connector, not to be confused with the Temp Sending unit which is a 1 wire connector.

It does what the automatic choke did in the days of carburetors;provides enrichment fot a cold start. It's a thermistor as I recall; resistance varies inversely as the temperature. Anyway, if it has drifted off spec it could be causing the fuel mixture to be too rich at start up.

Good luck.
Mark

 

I think all of our cars that see regular high-rpm driving have blowby. Wouldn't ring blow-by be the more likely leak of fuel into the oil?

Would an overly rich condition of the engine's tuning be more likely to result in this condition? Steve, what kind of O2 #'s are you running at WOT??

 

When the engine coolant temperature is below 68*, the fuel delivery system will operate in open loop.
The PCM ignores the O2 signal and calculates the A/F ratio based on inputs from these devices: ECT, MAP and TP sensors.

OBD-II regulations require the the ECT sensor be monitored for performance deterioration thus if it was out of specs PCM errors P0128 or PO125,
so I would doubt that it is the problem in this case.

You could start a Ease recording with key on, then start and see what happens before and after 68 degrees, when it goes to closed loop
and monitor all 4 O2s and compare downstream O2s to their upstream partner before going closed loop to see if there is a cold start richness problem.

I doubt that would cause the high percentage of fuel seen in that oil test esp in the heat of the summer.


John

 

Also, on the issue where you get knock as soon as you disconnect the mod, I bet that is a side effect. Try putting everything back the way it was (without the mod) but pull the PCV's out of the intake so they suck clean air instead of oily air. I guess you could put some type of non-restrictive filter element over the end so it doesn't suck any dirt in or something. Just make sure the PCV hose is still able to pull the "normal" amount of air, i.e. it has no restriction but it is now sucking clean air. I bet you'd still get knock on the clean air, indicating that the oil fumes are not what is causing the knock.

My theory of why you get knock with your PCV connected is that your car is running right on the edge of knock *with* the mod, i.e. just barely rich enough to eliminate knock. When you hook the PCV back up, you pull a little more air into the intake that is not metered by the MAF. You therefore will get a slightly leaner mixture with the PCV system connected because the PCV basically is sucking unmetered air into the engine that bypasses the MAF. The "normal" setup may account for this but if you are a bit too lean to begin with due to mods or something else, restricting the amount of air going through the PCV system may be doing nothing but richening the mixture just enough so that you don't get knock.

If the above turns out to be true, the "real" fix to your knock would be to use a MAFT to tune your fuel mixture properly.

Of course, this is only a theory, but logically it seems to me that the amount of air passing through the PCV system versus the total amount of air entering the engine is a larger ratio than the amount of fuel being sprayed versus the amount of atomized oil fumes coming through the PCV... so, I just think it's more likely that the amount of air passing through the PCV system has a greater affect on your air/fuel ratio which is what causes the knock.

On the other hand... what seems logical is not always what works in life. ;) I think it would be worth the effort though to see if your knock returns with a totally unrestricted PCV system that is sucking clean air. If so, the oil fumes are not your problem and you just need a richer mixture to compensate for the extra air getting pulled through the PCV system.

Mike

 

Mike,

I think you make a lot of sense, bro.

Good luck.
Mark

 

Your argument makes sense, but I already considered that a long time ago. The pinging started when the car was bone stock. The first "mod" I bought was a laptop and EASE software to see what was going on. Like you, I figured the car was running lean. I was hoping for an easy diagnosis like a bum O2 sensor. But the O2's were at 0.89 at WOT, so that looked OK. Also, it wasn't just on the "edge" of pinging...it was so loud I could hear it over the stereo and I was pulling up to 9 deg of KR. It was happening under all acceleration conditions...both part throttle and WOT. The only time it DIDN'T ping was when traveling at a constant speed. This all started when the ambient temp got into the 50's (I picked the car up at the end of October). My theory is that during that first winter, the cold air was counteracting the tendency to pre-detonate. Had I picked the car up in the summer, I believe it would have been doing it off the dealer's lot.

Also, I had noticed on several dyno days that I was getting a lot of dark grey/black smoke at WOT. From a fuel standpoint, that would indicate rich, not lean. After doing the PCV mod, no more smokescreen. I think the smoke was carbon buildup being blown out, and cleaning the engine and getting rid of the source of the buildup explains why it's now gone.

When I get a chance, I'll likely try your idea of sucking non-oily air through the PCV just for the sake of being thorough. However, we really don't know whether the PCV air is unmetered or not. Granted, it's downstream of the MAF sensor. But if I were the engineer on the LS1, I'd have the computer add fuel appropriate for the sum of MAF measured air plus PCV air. Also, I would think that the amount of PCV air as a percentage of overall air is so small, that even if fuel is based soley on MAF measured air, the computer would learn to adjust via LTRIMS. I dealt with the pinging for about a month before playing with the PCV system, which was plenty of time for the computer to get the mixture right. I believe it couldn't adjust for it because the mixture wasn't the cause of the problem. It saw the pinging, but didn't know what to do about it, and just reduced timing.

MelloYellow - that's probably part of it. I still think there's a number of other things that are more likely to contribute to the number than the PCV mod.

Besides that, let's assume for the sake of argument that it IS the PCV mod causing it. The point of my taking the sample was to determine if the PCV mod was "safe" in terms of maintaining oil quality. I think the results show that it is. The overall determination is that, even with the 1.26% fuel, the oil is suitable for continued use. That means that the oil I'm dumping into the recycle drum at AutoZone is still good oil. Perhaps if I were aiming for an extended change interval, the fuel number would eventually rise to a value that's not acceptable. But I'm not interested in an extended change interval, and I expect that the vast majority of LS1 owners feel the same way. As long the oil that we're throwing away as "dirty" is still considered "clean" by lab standards, I don't think there's an issue. It probably WOULD be an issue if I had elevated metal in my oil instead, as a result of the tops of my pistons slowly making their way into my crankcase via pre-detonation damage.

Someone mentioned that the fuel filters are "grossly inappropriate for this application." I think it's all relative. In my opinion, it's grossly inappropriate for GM to let this problem go ignored. It's grossly inappropriate for us to have to fix it ourselves. I don't own a manufacturing plant, and I don't do this for a living. It's a weekend hobby. I came up with something that solves the problem, and that people can build themselves. They can build it quickly and easily, using parts readily available to them. I get emails from people who have built their own kit and had it solve their pinging problem. They're thankful that their pinging is gone, and they don't think the filters are the slightest bit inappropriate. I don't either. They may not be the best solution, but they're not an inappropriate solution. They're just one solution among many. After the results of the oil analysis, I feel confident that I'm not posting information that will lead to any kind of oil quality issues. I've indicated on my webpage that extended drain intervals are a no-no if you want to use the mod.

The SMH PCV Mod is not at it's final point, it's a work in progress. I put the Jaz can on yesterday, with a clean set of downstream filters, and will see how it does. If all goes well, I'll start removing restrictions to get the flow back closer to stock. If you've ever tried blowing through one of the downstream filters, you'll realize they present almost no restriction at all. The restriction is deliberately introduced through the universal elbow and universal connector, which isn't trimmed for the 3/8" tubing. These are the areas where I'd like to open the flow up.

 

FWIW, I think you are rich and this is unrelated to the PCV Mod.
In any case, with my MAFT I have no problems tuning my A/F ratio. I am not running rich.

I'll do an oil analysis to someday. I'm not worried about your analysis results.

 

Just as another point of reference, my car will knock like crazy if I set it so that the O2's are .89. For my car, .89 on the O2's is *way* too lean. I can hear the knock only slightly but when tuning my car with the MAFT and Ease, I get 9 degrees of knock or more at .89. At about .91 the knock has gone away completely, but if anywhere during the run one of my O2's went down to .90, I get about 1-3 degrees of knock. I have therefore set my MAFT so that the knock just barely disappeared. For me, that turned out to O2 readings that never drop below .91. They briefly touch on .93 on a very short piece of the run but they mostly stay at about .91. At that reading, I get no knock retard at all and the car runs like a scalded ape. I get no black smoke or any signs of running rich either, but then again, my car is one of the lucky ones that doesn't burn any oil either.

Just wanted to mention that because I really don't think tuning to an O2 reading of .89 is the answer (for everyone)... at least by itself. It certainly didn't work for me anyway. I don't know whether the O2's are just not accurate enough or whether certain setups might need a little richer mixture, but .89 certainly caused knock for me and I seem to have very little oil consumption.

Just a little more info to throw into the stew. ;)

Mike

 

The issue about excessive oil burning I think is limited to some C5s and is being blamed way too much for ping/knock issues.
I PCM scanned 15 c5s on the same day on a chassie dyno and what became clear was the '01 and '02s had zero knock whereas '99/'98s had a bunch of knock.
I think some of the knock is due to piston slap and the newer model uses a teflon coated piston with a tighter spec'd rings to match the honing.

I have published several times scans showing I could totally remove ping by tuning and thus showed in my case it was not some oil burning issue.
In fact I have taken out PCV mod and get the same results with or without that mod.

Here is a perfect example of tuning to remove all knock at WOT.

http://teamzr1.com/greatwot.html

To do that I had to change the ATF so that at the time of WOT upstream O2s reporting just over .900 mVolts, and if leaner then had knock.
Also adjusting ATF for a WOT timing around 28 degrees also helped remove ping/knock issue.
It would be helpful if those doing PCM scan to inform us if they are getting multi-misfires and if so which pistons ( esp if they are next to each other)

Lastly the grade and type of fuel is a big issue esp in the hot weather.
I now use 5 gallons 100 octane to a tank of this 91 octance crapgas.

John

 

John,
I'm a little confused at this data. What part of a run are we looking at? All the data seems to be between 3400 and 3700 RPM and the frame numbers don't seem to line up with increasing RPM which you would expect at WOT???

Also, if you are getting frames that fast, how are you doing it? The Ease only captures maybe 4 or 5 frames for me during a WOT blast in second from about 1500 RPM to 6000 RPM. Actually, I get more frames than that but the values don't seem to update but about once a second, indicating that the PCM is not outputting the data any faster than that.

Mike

 

I've been thinking about this a bit more. Air going through the PCV system is definitely unmetered. As you say though, the PCM *may* be accounting for it because it knows it should be there. The fact that nothing is metering it though means that either way, if you restrict the PCV system, you *will* get a different mixture than with it connected with no restrictions whether the PCM is accounting for it or not because there is now more air going through the MAF.

Second, the PCM probably will not be able to learn the change (properly) using LTFT's. At part throttle, where your LTFT's update, the PCV system is sucking a lot more air than at full throttle because the throttle plates are partly closed. At full throttle, the plates are open and you should have less flow through the PCV. So... by restricting the PCV, you are forcing your PCM to have to compensate differently at part throttle. Whether it will compensate lean or rich would depend on whether the PCM tries to take into account the PCV flow that it thinks should be there. In any case, I would think that restricting the PCV flow will force your LTFT's one way or the other and would affect WOT operation as a result. It could therefore be the fact that you are forcing your LTFT's around that ultimately reduces knock.

Mike