Will switching from Synthetic to Dyno oil harm my engine?

2. you go ahead & change your oil anyway - you just send a sample of the >
old oil at change time. the resulting report tells you whether you're

I dont really want to know if I'm about to encounter a problem lol. Looking
at the things it can diagnose, I can diagnose most of them shortly before
they go critically wrong anyway by ear/feel etc. If they take out something
else when they go, they were probably wearing it excessively anyway and so
I'd replace that while i was changing it. If I were to know about it I'd
worry about when was the best time to change whatever was failing etc I
guess that since I do all my own work im less worried about the costs of
labour if things go wrong.

But a)I'm not too worried about environmental issues regarding a couple of
gallons of oil, b) I know 3K miles is a nice short interval on top Q synth
oil, c) my differing driving habits from one month to the next would mean I
couldnt really use one change's analysis results to predict the rest - which
nullifies the point of doing the test.

TBH it is just too much faffing to be bothered with, and with the fact that
the vehicle is sometimes thrashed, sometimes pampered, the cost of repeated
analyses would vastly outweigh the benefit. The oil testing companies *are*
out to sell you stuff - the next analysis - they dont do it for fun. I can
see its a great idea for a normal vehicle under fleet use conditions, and if
I were to be running 10 cars I'd consider it to reduce oil change costs, but
really its over-analysis for the normal user when all thats required is a
safety buffer of maybe 1 extra oil change.

Due to its long term racing/drag/street history the 3Sgte engine is well
documented, and the known 'good' change interval is accepted as 3K as per
the manufacturer specs, unless the car is track-abused.

I'm not saying its a bad idea, just that it doesnt suit all cases, and
really in my case its a waste of cash and simply serves to scare the hell
out of me warning me of the next failure - why worry about things you cant
alter. .

As I say, since its not a daily driver, and is sometimes abused, sometimes
mollycoddled, it couldnt be used to predict extending/shortening the
schedule. Horses for courses.

J

 

personally, i'd rather know what's coming and have a chance to budget
both time & money for a fix that's convenient rather than be stuck in
the middle of 6 lanes of stop-go holday traffic waiting for a tow truck.

but they're not out to sell you more oil! and if they recommend a
longer change interval, they're not exactly forcing you into the next
analysis either.

^^^^^

and there it is. personally, i think it's like using radar when flying
in fog vs. flying low & hoping i see the mountain in time.

prevention better than cure...

 

You only can't alter them when you don't know about them. You're a
bit keen on the "i'm SO good i can tell by ear if somethings wrong -
oblivious to the point that it's already a fair bit broken if you can
hear it.

My father used to rally, (was a road legal escort mexico iirc) and he
used to get the analysis done. A place up by the whats now the Jag
plant in halewood used to do ti. He managed to catch a head gaskett
just in time, before a race, thanks to analysis, would ahve cost him a
race, and thus the championship.

However, he also does it on his daily drivers. he had an a-reg
cavalier he bought about 15 years back, and the first thing he did was
take a sample of the oil, for analysis. unfortunatly, on the day the
results came back, he was on his way back from work in runcorn, and
the engine siezed right on the runcorn bridge (and that was before it
was widened) The results waiting for him at home told him that was
likely to happen. Engine SOUNDED fine, FELT fine (it wasn't his first
cavalier) and had he gotten the results back a day earlier, he'd have
taken my 340, and made sure te engine didnt sieze. 5 months I think it
took him to fix that engine. He even did one on my last 340, and its
now at 20,000 miles between changes, and the oil's still pretty good.
(its running synthetic, and is mainly a motorway cruiser for me, when
i'm in the UK)

As i've tried to explain, the analysis CAN make it worth your while.
You, however, seem to be the sort of person that never checks their
hoses and belts. You can't hear a cambelt thats about to snap, you can
often SEE it though, but if it's oing to go, and takes out some
valves, well "they were probably wearing it excessively anyway and so
I'd replace that while i was changing it" Do you even use your
dipstick(s) at all, or can you tell if you're low on oil by feel/ear
too?

 

I can suggest a reason for this. The concentration of fine carbon (fine
enough to go through the filter) when the oil is changed is far more than is
needed to make the oil opaque black. When you change the oil, there is
sufficient soot left behind in the oil stuck to the engine surfaces to turn
the new oil black. It isn't the oil getting by the rings in the first few
minutes of running that does that, but the residual oil and soot left behind
after draining.

In any case, soot that fine won't cause any harm. In fact, a couple of
decades ago one company sold oil that was loaded with graphite that came out
of the can jet black. Nasty stuff.

George

 

No, but if they happen to tell you you need to worry about something you are
bound to get more tests done next time. I trust no-one - i trust my own
knowledge more than 99.99% of other people, being a design/research
engineer, having worked in most aspects of the industry and having
experienced the other areas first hand i know i trust me more than anyone
else in these areas - everyone has an ulterior motive but yourself,

But the point is - at what point do you decide to fix whatever is wrong from
the results? Also, when its not a daily driver and covers no more than 8K
miles a year, what difference does it make? If it goes breasts up I call
breakdown and get carried home - who cares? And then i know whats gone
wrong, what needs repairing and how to do it myself.

J

 

Yes George, we know this to be the case. After an oil change, the oil
delivery galleries are still full of oil ... which might account for 10-20
ounces of oil (guessing). Certainly that amount would discolor new oil.

I recall well ARCO Graphic and a similar Kendall product. Lost a camshaft
to ARCO graphite back in 1978. Too bad that stuff was not pulled from the
market sooner.

 

That is a good point. The last engine I was involved with that failed
internally was in my #2 son's '82 Corolla. The oil light started coming on
at idle, and we brainstormed a course of action. The upshot was that the car
wasn't worth any of the investigations or potential repairs (like oil pump
replacement) that would have made a difference. Eventually a rod threw - big
surprise - and the matter was settled. Oil analysis probably would have
shown the problem earlier, but it still would have required a prohibitive
amount of work to investigate further.

The same could probably be said about any car that is more than a couple
years old. For a car that is under some sort of warranty... the report
within the warranty period would support a claim if the engine failed after
the warranty expired, but you can be sure the warranty won't support any
action be taken on the basis of an oil analysis.

I used to work in general aviation, and oil analysis is very common there.
With such expensive engines and scary prospects in case of internal failure
it is a sure winner. For most cars I don't see a path forward if the
analysis shows a problem, unless you count selling the car without notifying
the buyer.

Mike

 

No shit Sherlock!

Huw

 

I'm in the UK and can assure you that most oil companies provide the service
as well as some engine and equipment manufacturers.



It really is cheaper and less time consuming to change

This type of oil analysis not cost effective for light duty cars and vans.
The more vehicles you own, the bigger they are, the higher their utilisation
ratio and the higher the cost of their downtime then the economics of true
analysis for oil changing and early detection of potential overhaul or
preventative maintenance becomes more attractive.
Latest technology allows the car's internal systems to appraise and advise
the service intervals and this is now routinely fitted even to fleet cars in
Europe e.g. VW and Opel/Vauxhall. This effectively makes a long [optimised]
flexible service interval based on driving cycles and crude oil condition
analysis become economically viable for almost everyone.

Huw

 

two things:

1. how does an engineer/researcher have no interest in science-based
decisions???

2. inability to qualify those you need to trust is a function of your
upbringing, not your education. the day you get over that is the day
you'll start getting more from others as well as yourself.

K'Tetch gave you the perfect example - analysis could have prevented an
expensive time consuming siezure. who willingly flys blind when they
can hit the 'on' switch on their radar?

 

What do you do when your education compromises your ability to "qualify"
those who one might trust?

 

Simply re-read what I wrote, quoted below. Don't worry, I'll explain it
again when we get down there....

I for one never said or implied a word about NOx.

Ring sealing technology has improved since 1960, but only very slightly
compared to improvements in other areas, such as fuel delivery
management and forced induction pressures. Combustion pressures tend to
be much higher with direct injection, hence there's a bit more blow-by.
So even though the combustion gasses may be cleaner, more volume (albeit
of cleaner gas) passes through the crankcase. Also, the higher pressures
result in higher piston underside temperatures, and that too stresses a
lubricating oil.

 

Nissan SD22 (debuted in 1964), indirect injection, advertised compression
21:1, non turbo. and oil cooled pistons
Ford and Dodge Cummins of late ... direct injection, advertised comp 17.5:1
with turbo, 21.5:1 without, and oil cooled pistons.

From these stats, your claim of "Combustion pressures tend to be much higher
with direct injection" is not supported. Perhaps you'll clarify.

In the case of the SD22, there are pistons with three compression rings and
those with two compression rings. Depends on application.

It is known that indirect injection while quieter, does result in more soot
production.

AS I see it, less soot production due to chamber design and better fuel
management ... MORE than off sets your claim of greater oil contamination
due to compression ring blow-by so far as oil service life is concerned. Is
there disagreement?

 

from
http://www.chevron.com/prodserv/fuels/bulletin/diesel/L2_6_3_rf.htm

"Since rapid fuel autoignition requires a certain air temperature, an
IDI engine needs a higher compression ratio to achieve the desired air
temperature in the prechamber. IDI engines operate at compression ratios
of about 20:1 to 24:1; while DI engines operate at ratios of about 15:1
to 18:1. The heat losses that necessitate these higher compression
ratios have another, more important effect: they decrease the efficiency
of the engine. IDI engines typically achieve fuel efficiencies that are
10% to 20% lower, on a relative basis, than comparable DI engines."

this text appears to be from the bosch automotive handbook - a superb
publication.

 

1. how does an engineer/researcher have no interest in science-based

I do have interest in them, but as I repeat - at what point would I take the
decision to do something about it? Thats a decision I'd not make by oil
analysis but by my own pretty capable decision making processes.

The day you stop trusting everyone who is supposedly qualified is the day
you free yourself from the stinging tail of trust. I have NEVER met anyone I
trust to make a decision about my car. I also know how easy it is to screw
up this kind of test proceedure, contaminate things etc and how sloppy labs
can get, and how it makes no difference to the guy who is doing the testing
whereas it does to me.
Other fields, yes, I've met plenty I trust and respect more than my own, but
having seen dealers, 'specialists' and many others making totally stupid
mistakes and assumptions costing friends and family large sums of money for
no reason, at least I know if something goes wrong I only have myself to
blame, and being pretty good at this stuff things dont generally go wrong.

I'd never have let it get to that stage, the moment the oil light flickered
I'd have had all *my* test equipment on the car and sorted the problem
myself. But I pretty much guarantee I'd have spotted a change in engine note
before the light started flickering - and would have had it out to inspect.

J

 

I'm in the UK and can assure you that most oil companies provide the
service

Kindly point me to one then, because I have been looked at very strangely by
many people in the auto industry when asking about it.

My point precisely.

J

 

i'm not saying you should trust everybody, i'm saying that it's possible
to differentiate the good from the bad if you learn how to qualify them.
if you withdraw from the qualification process, you can't complain
about lack of candidates.

and some people you /have/ to trust, whether you like it or not. you're
in the emergency operating theater after a crash. you going to worry
about the competency of the blood group testing that was done on you
before the transfusion? how about the last time you flew? did you
worry about the competency of the person that signed off on the wing
root bolt torque certificates? admittedly, the car world has very low
barriers to entry, but that doesn't mean everyone is a fool. qualify them!

if siezure was simply a function of oil pressure, life would be simple.

 

Caterpillar were worldwide pioneers of oil analysis and service schedule
prediction. I have had my oil analysed be Shell and even small blenders like
Ovolene do it.
One analysis is not representative of anything. A particular engine needs a
series of analysis for a meaningful interpretation.


This is now a well established procedure and interpretation of long drain
interval oil is reliable. Mobil can provide information IIRC.

Huw

 

No, I believe your point was that it is not appropriate to *you*, which
obviously I can't comment on.
It may well be cost effective and a useful management tool for others. In
fact a form of analysis and optimised flexible servicing is now so cost
effective that it is built-in to many fleet and private cars, i.e. family
hatchbacks and saloons, as standard fit.

Huw

 

INdeed. I've read a fair number of Bosch SAE, and Cummins publications on
the subject. I have opined that IDI diesels are more soot prone. Is there a
particular point that you are supporting or disagreeing with? For
comparisons of IDI vs. DI diesel, the presence (or absence) of a
turbocharger must be consistant.