Oil Analysis - ?? Meaning ?

blimpy

blimpy

New member
Got the results of the first oil analysis for my franklin 150.

Company had no "normal" reference values to compare my numbers to.
And of course I did it to establish base line values.

Their comments indicate that the measured level of IRON at 158.6 ppm " appears high".
after 23 hours on the oil ( plus plenty of added quarts ! ).

Followed by a boilerplate explanation ( no pun intended) regarding cylinders, shafts, valves, and corrosion.

Does anybody here do oil analysis on their Franklin... and have any wisdom to share regarding this
value for Iron in the oil ?

other values in parts per million measured were:

copper 13.7
nickel 1.7
Alumi 11.1
Silicon 11.6
Mag 1.2

I am assuming the above are bearing and valve guide materials.. and are "normal" values
comparable to other similar A/C engines.

After the loose intake manifold / fuel starvation event, and given that I have one low cyl, I'm
not very surprised.

But as to real significance, well I just don't know.

Wait and see I guess.

I will take another sample at the annual, but that will only be with about 5 hours flying time.
Maybe too soon ? :?: :)
 
Larry,
Did you mention before what the low cylinder details were?

Did it sound more like valve or cylinder leakage? A broken ring will make iron. Like you though, I don't know what a normal expected value should be, but ~160ppm does seem significant.

I just googled "typical oil analysis readings" and got among others :
http://www.bobistheoilguy.com/used-oil-analysis-how-to-decide-what-is-normal/
From the numbers there, 160ppm is very high.

I am looking into < $50 Ebay Chinese borescope video cams that will work through the 14mm plug holes. One has a 7mm dia., another 5mm dia. head. It might help with diagnosing these sorts of things.
r
 
Generally speaking (and you know what it's like when Generals are speaking), high-ish iron numbers are typical with engines that are not run regularly, comes from light surface corrosion on standard cylinder walls getting polished-off.
Chrome cylinders usually don't see it, one of the big advantages to running chrome on lightly-flown engines. But I've never seen a Frank chromed.
Using oil analysis to monitor engine health is more art than science. I have a couple of owners who use it religiously - but don't know how to interpret the results. They'll see one number drift up a little (lead is the most common one) and sink into an aviation hypochondria of woe and gloom - until I ask them if they've been leaning their engine... Fuel has lead :) They think there's lead coming off their bearings. Sure enough, they get back into the habit of monitoring their mixture and the lead numbers go back down.
Oil analysis is good additional info, but it wont tell you everything. Cutting open and examining the contents of the oil filter (if you have one) yields info much clearer and sooner.
 
ronm said:
Larry,
Did you mention before what the low cylinder details were?

Did it sound more like valve or cylinder leakage? A broken ring will make iron. Like you though, I don't know what a normal expected value should be, but ~160ppm does seem significant.

I just googled "typical oil analysis readings" and got among others :
http://www.bobistheoilguy.com/used-oil-analysis-how-to-decide-what-is-normal/
From the numbers there, 160ppm is very high.

I am looking into < $50 Ebay Chinese borescope video cams that will work through the 14mm plug holes. One has a 7mm dia., another 5mm dia. head. It might help with diagnosing these sorts of things.
r
Click to expand...

Honestly, you'll get most of what you need to know about top engine health from compression test, plug health, and borescope examination of the cylinder(s). Oil analysis is good additional info but don't get too wound up about it. I had an O-470 bought to me once (on a Skylane) that had an awful sound coming from the starter, customer asked me to replace the motor. Motor was fine but the starter adapter was toast - I found almost 2 tables spoon of metal shavings in the oil filter!! but the oil analysis was normal. see, oil analysis can only show you what is dissolved in the oil (and to some extent what is in suspension). Metal shavings aren't dissolved :)

About Chinese bore cameras...
They usually have one trait that makes them useless for checking cylinders.. they only can see strait ahead. It's impossible to see the valves at all, and often do a poor job at seeing the cylinder walls, especially near the top. They're fine if you're trying to figure out where a wire goes or looking for a dropped nut.
The one I use is a Lenox 6600K "Autoscope". It has a 9" long 8mm dia probe with the camera situation at 70 degrees and a super-bright light. With it you can see both the tops of the valves AND most of the face and seats. It's pricey, I know, but it's the only tool that can really "scope" a cylinder. I've had it for years, it's always been great and I've never regretting spending that money at all - imagine my delight when I discovered Continental calls it out specifically is their SB03-3 service bulletin for checking engines.

by the way.. SB03-3 is published specifically for continental engines BUT, IMHO it should be the bible for checking *any* piston engine. Now that TCM also owns Lycoming too, I have no doubt they'll revise it to include them. It's prefect on Franks also. I'd love to see that old "if it's below 60 it's junk" tribal tale be banished from the universe in my life time.
 
I have been using oil analysis on my airplane for a few years and find it helps as a way to track engine trends. There was a good webinar (EAA, I believe) about two or three months ago about using it. By itself it's not much of a tool but it helps get a better idea what's happening inside the engine if you have a baseline established.

The comments about iron (in a Franklin) are what I've heard over the years and what I see on mine too. The previous lab I used didn't track lead but the current lab does. Considering the fuel we burn I'd agree that you'll have to be consistant with your leaning practices to have that number mean much at all.

A filter, or "pancake" style screen, is good at stopping big pieces of stuff that can do damage if allowed to circulate, analysis tell you about the really small stuff suspended in the oil that is continuously circulating. The better trend info you have for your own engine and operator practices the more useful that data.

Scott
 
Thanks guys !.

I wanted to establish a baseline - albeit one that starts at 1000 SMOH.

I knew that lead was gonna be due to fuel, and not important.

The plane only flew 23 hours last year, and the one low cylinder is 55.
Previous 2 annuals it has been 65, then up to 70 ( warm) last year when I flew it 40+ hours
in 6 months, and this last time ( during a repair) when it came up 55 ( warm).

there is very little actual blow by.. so I'm guessing valve leak.

Maybe Dan T. can do a proper bore scope in 2 weeks.

I'm not worrying, but not adverse to OH'ing a jug either.

If it gets sold at annual... then the new owner can do what he wants.

I have a spare cylinder, I could send out for OH, and save the down time,
if/when it's necessary.

---

I'm starting to think seriously about Larry L's advice to get a means of looking at all 6 EGT's
and CHT's. The EI scanner is about the cheapest ( discounting the 6 position EGT switch).
Not quite sure how it displays in practice. Other things topping $1200-1800 out of my reach.
 
If you get a digital egt, you will need to hire a secretary to fly with you to record the numbers...unless you can remember 6 four digit numbers and how they change when you lean. You might want to look at KS Avionics mixture mizer (sp?) with a switch. It shows a single cylinder that you use a pilot movable pointer, then switch to the next cyl, lean to see if the EGT goes up or down, and so on. Check their web site. If you find a great deal on a digital, I guess...I just found them hard to use. You might check ebay and Vans Airforce for good deals.
 
This is what I have - UBG-16, SC5A and FP-5L, all from EI
The UBG comes with data collection (look to the left of the clock)

http://youtu.be/aC6ndH2vLDI
 
what I need is somebody to buy this thing.

I feel like the sorcerer's apprentice.. except what my bucket can't keep up
with is the outflow of money.
 
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