Help me decide on a long-term UOA plan

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As my RX-8 approaches the end of its engine warranty, I'm working on a plan to use oil analysis in an ongoing, long-term way. Would love some feedback on how best to do this.

I shouldn't need to worry about the condition of the oil because OCIs will be short (3k-4k).

Wear would be good to know about for obvious reasons.

But the best thing to know about would be anything related to combustion quality -- fuel dilution, byproducts, etc. Those might point to problems with fueling, ignition, etc., most of which is much easier to fix than mechanical wear from any other source. Also, because the RX-8 consumes oil by design, it'll be important to gather any available evidence of how it's burning.

Unfortunately, nothing short of a $150 UOA provides good info on all of the above. That’s more than I’d like to spend on a whole year’s worth of oil analysis. So, it might be best to focus on a few things and use that info to make inferences about the rest.

As far as I can tell, assuming a yearly budget of $100 or so, there are three options:

A. A bare-bones UOA package at every OCI. All I'd look for would be elemental analysis and flash point. If I could skip other tests (FTIR, TBN/TAN, etc.) to save money, I would.

B. A slightly more comprehensive test package at every other or every third OCI. This might include viscosity (to back up flash point as an indication of fuel dilution), direct-read ferrography or particle quantifier, some FTIR tests to look at combustion byproducts and such, etc.

C. A Dyson Tuner analysis 1-2 times per year. Terry Dyson is tight-lipped about what this test contains, but it’s supposed to focus on “combustion dynamic and efficiency”.

Option A would yield the best trending. Flash point, maybe combined with viscosity, would allow me to infer fuel dilution; that could provide at least some insight into how the engine is running.

Option B gives more information but worse trending (fewer samples and more time/miles between them).

Option C promises to provide the most actionable info, as described above. It’d also give me access to Terry Dyson’s expertise.

I've also considered a different barebones UOA package, with just FTIR stuff and maybe GC. Doesn't seem like a good option though, just because I wouldn't know what to make of the results.

Thoughts? Anything else I should consider?
 
Get the NAPA one for $16.00 (includes TBN) and then do a UOA then skip an OCI, then a second, then every year or two.

What are you looking to learn from a UOA? For most vehicles doing 7500 mile OCI with a 5qt oil pan they are a waste. Trying to extend OCI and or many gallons of oil in the pan then they start to make some sense.

The Blackstone comments are pretty useless in my mind.
 
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Understood. The UOA you are interested in is the expensive kind because you are looking for combustion by-products. Wear metals are not your primary concern.

I'd be more tempted to find a shop that will let you use their SMOG sniffer on the exhaust and get a print-out of the conditions of the exhaust, plus a regular old NAPA UOA. Between the two, you can build a baseline on nominal good running engine. Then be on the lookout for changes.

It will always show up first and easiest in the exhaust gasses
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Originally Posted By: BrocLuno
Understood. The UOA you are interested in is the expensive kind because you are looking for combustion by-products. Wear metals are not your primary concern.

I'd be more tempted to find a shop that will let you use their SMOG sniffer on the exhaust and get a print-out of the conditions of the exhaust, plus a regular old NAPA UOA. Between the two, you can build a baseline on nominal good running engine. Then be on the lookout for changes.

It will always show up first and easiest in the exhaust gasses
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The sniffer is an interesting idea. Seems like a bit of a job to be doing multiple times per year, though. And I'm not sure what I'd do with the numbers. Any thoughts on that?

Also, is there a link to what the NAPA UOA includes? My quick Googling isn't finding anything but the test kits.
 
d00d, explain to me what your goal is with the UOA plan? Trying to monitor engine health?

I daily an 04 RX-8 with 130k miles on it (original engine replaced by original owner at Mazda @ 96k due to a failed apex seal causing sudden loss of compression / idle outta the blue (according to work order comments)

Knowing that these engines can fail suddenly, I personally think it would be a waste for you to try to gather any info from extensive UOA testing into 2018.

From personal experience, I feel a Rotary Compression Tester is your best friend. This tool instantly tells you the health of the rotors. Nothing else really matters with these engines in regards to longevity / durability.

My 04 obviously still has the first gen [censored] oil design, so I'm not surprised the original block failed but 96k is still pretty good in the Rotary world.

I'd love nothing more then to keep an engine going for 200-300k miles but I feel lots of modification is needed to achieve this such as the stand alone oil injection system (forgot what it's called) a nice thick 15w40 oil, a bypass oil filteration system and most of all, frequent oil changes to flush out the fuel contaminated Lube.

I personally dump my conventional oil every 1,000 miles. A quick drain n fill of 4 quarts takes me a few mins and the block is happy with 50% of the old oil replaced this often. I can't imagine going longer. My oil smells terrible by this point.

I replace the oil filter every 4th oil dump.

My engine is stock for now but I plan to add oil bypass and oil injection system to keep this block alive at 9,000rpm.

Again, a compression tester will tell you 10x more info about how healthy your engine is and how much longer it will spin before you start having starting issues / poor idle / low power. I can loan you my $350 kit if you want.
 
Originally Posted By: Artem
d00d, explain to me what your goal is with the UOA plan? Trying to monitor engine health?

I appreciate your interest and would love to trade some tales sometime. I don't want to do that here because I don't want to turn the thread into a referendum on my maintenance habits or plans for the car. Maybe we can PM.
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Good call on the compression tester, and thanks for the offer. Hadn't occurred to me that an RCT would pay for itself after 3 compression tests, which isn't outside the realm of possibility.

For oil analysis, as I said, it would be nice to monitor the health of the engine. But if possible, I'd also like to use it to keep tabs on things like injectors, ignition, and how the oil is burning. Those are particularly important for this engine, and I've seen oil analysis catch problems with them long before they got serious enough to throw a CEL or cause other symptoms.
 
Oh I agree about using the UOA to catch things like too much fuel in the oil diluting it to where the oil is no longer adequate to protect the engine.

My quick conversation with a rotary engine rebuilder convinced me to start using 15w40 to help protect the bearings and the crankshaft. Even the 15w40 comes out thinner then the 5w20 I sometimes use in my Mazda 3. It's scary. I don't understand how a 5w20 would handle my particular engine.

I'd be interested in seeing your results, so I'm subscribed for more...
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I would do the test prior to the warranty ending. You could do the Dyson thing. But why are you changing so often? its 100% not necessary. My subaru has averaged 7500+ miles between and three 10,000 mile ones.

The fact that you brought up the money thing..you are throwing $$$ away (IMHO)

In either case, I would not do more than 1 per year. Don't waste $$$ on TBN
 
Originally Posted By: Al
But why are you changing so often? its 100% not necessary. My subaru has averaged 7500+ miles between and three 10,000 mile ones.

Can always tell when someone either isn't familiar with the RX-8 or hasn't realized we're talking about it.
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Heavy fuel dilution, lots of blow-by, and about a third of the oil remains in the system when you drain the sump. Not a recipe for long OCIs.


Originally Posted By: Al
In either case, I would not do more than 1 per year.

Because?
 
VOA of Honda oil or any FF oil is paramount and the one I saw said TBN was only half usitlized in a 4800 mile time-span OCI with that oil so this leads me to believe 500 ppm of moly is good for the engine to break-in with. Now what becomes the pinnacle of paramount is what oil to you use subsequent to the ff and does it also have a high or above avg moly or is it. oOr is it some other concoctioon that the oil engineers and car manufacturers deem even more important (less Calcium for LSPI for example) or lets just say moly is not the end all and its the magicc of the addy pack in comebo of base oil with good density. I think there are many ways to skin a cat and no, I never understood the analogy nor metaphor.
 
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RX8 with the 13B-MSP cannot be compared to a Subaru. That's like comparing apples to oranges.

Since you are doing short OCI's I would have a used oil analysis done every other or every 3rd change. This way you can monitor viscosity, wear metals, and fuel dilution. Is your RX8 mostly stock? I have worked on a few rotaries and many of the die hard enthusiasts run 2 cycle oil premix in the fuel to prevent wear at the apex seals while disabling the oil metering pump. RX8's are pretty high maintenance cars if you want them to last a while.
 
Comparing the Rotary engine to ANY other internal combustion engine is
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I use the IDEMITSU Rotary specific Pre-Lube @ 0.5 OZ per gallon to HELP the factory oil metering pump with Apex Seal lubrication in an effort to extend their life. In my experience, the engine seems to run better and smoother with the Pre-Lube added. It also acts as a fuel system cleaner along the way and obviously helps remove carbon buildup.
 
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