Will switching from Synthetic to Dyno oil harm my engine?

Michael Pardee wrote:
> ".Philip." > wrote in message
> ink.net...
>
>>jim beam wrote:
>>EVERYBODY is reluctant to qualify THEMSELVES first. Sure it's easy to
>>call the other guy who makes errors an idiot but ... are you better
>>qualified or better experienced? Be honest. Why did you sublet the
>>repair in the first place?
>>
>>--
>>
>> - Philip
>>
>
> I know this is getting far afield, but the question is a good one.
>
> I had started subletting larger part replacements because sometimes the time
> and frustration are more important than the money, and I lacked air tools.
> Now that I have air tools, there are more I do at home - although a lift
> would be nice :-)
>
> I have let out exactly one diagnostic since about 1987. I had an '84 Dodge
> with a Mitsubishi power train (live and learn). It failed emissions on
> cruise CO, and I didn't feel up to troubleshooting that new-fangled feedback
> carburetor so I took it to the dealer. The dealer said it needed a new
> carburetor - $660, please - but couldn't say what was wrong with the
> carburetor. I took the car back and determined the problem was the
> mechanical fuel pump - it couldn't keep up with demand and when it caught up
> the carb was still trying to enrich the mixture. $20 and an hour and a half
> later the problem was solved.
>
> Since then I once had to take my turbo Volvo to the dealer because it ran
> like a dog after I replaced the injectors (longer story, but that's the gist
> of it.) The mechanic spent most of the day swapping parts, and was baffled
> until he put in new injectors (although the flow rates on the ones I put in
> were on the money). Problem solved. But the engine still wouldn't run in
> turbo boost, and he blamed the $500 ignition control module. I had to find
> the problem in a sensor connector myself.
>
> The question is one of batting average - nobody bats 1000, but I like my
> average (with the help of my friends, local and on-line) better than any
> shop I've found.
>
> In addition, professional and DIY approaches are necessarily different. When
> I find an electric motor misbehaving, I always tear it down to see if
> brushes, lube or cleaning will take care of the problem - it usually does. A
> pro can't afford to do that, because if it fails the cost falls on him, not
> the customer. If the part has to be replaced, he is out the labor for
> trying. Ditto with the time the A/C clutch failed in the Volvo - no pro
> would replace the clutch because the compressor lifetime was about the same
> as the clutch. I replaced my own clutch and sure enough, a year later the
> compressor failed. Didn't cost me any more that way, but a pro couldn't do
> business like that.
>
> Mike
>

good points mike! i've had similar experiences to yours, and often do
stuff myself if i have the time or inclination. but, like you, there's
stuff i can't do because i don't have the tools or won't do because i
don't have the time. i don't do alignment or crank regrinds for
instance. while it can be apita, and if you call enough people, you can
find people that know their business.

as for replacement vs. repair, replacement makes perfect economic sense
/if/ and only if the diagnosis is good. just bought a car from someone
after they'd spent a fortune on trying to get it to start properly. it
still wouldn't so they gave up. new distributor, new plug leads, new
injectors, new starter, new battery, the works. turns out, incredibly,
that the morons at the garage had not bothered to change the plugs for
what looked like over 100k, so of course, absent electrodes, the plugs
weren't much good! if it /had/ been a distributor problem, as you say,
the labor of repair vs. replace with the uncertainty of subsequent
reliability means that replacement is definitely the way to go. all
about the quality of the diagnosis.

Steve wrote:
> .Philip. wrote:
>
>
>>
>> "We" know that turbochargers increase air density within the
>> cylinder and therefor ... dynamic compression. This readily evident
>> to everyone but you that turbo charged engines running significant
>> boost pressures will always have different pistons to reduce
>> cranking compression. "We" also know that all else being equal,
>> having brake mean effective pressure close to TDC will result in
>> higher combustion chamber pressures than with BMEP further from TDC.
>
> And that has precisely WHAT to do with the static CR of a Nissan SD22
> vice a Cummins B5.9 and their comparative peak chamber pressures? And
> why are you seemingly using the term "BMEP" to represent a pressure
> at a single point in the cycle, when in fact the "mean" in the term
> "brake mean effective pressure" makes the measurement at a single point in
> time nonsensical?

BMEP is the highest pressure attained during combustion. This is affected
by numerous factors, not the least of which is the mechancial compression
ratio and boost pressure. All else being equal and with natural aspiration,
do you disagree that BMEP with 24:1 is going to be higher than BMEP with
17:1?

--

- Philip

Steve wrote:
> .Philip. wrote:
>
>>
>> To append: The lower compression pistons fitted to a turbocharged
>> engine also help prevent excessive peak dynamic compression levels,
>> Steve. Known fact that higher cranking compression reduces the
>> amount of boost you can safely run ... gasoline or diesel.
>
snipped material regarding gasoline since my dialog is regarding diesel.

> A diesel, on the other hand, has no such mechanical limit except the
> mechanical strength of the
> connecting rods, bearings, and crankshaft- and these effects are WAY
> beyond consideration in most purpose-built engines (although they're a
> real issue in some gasoline engine conversions like Powerstroke and
> Duramax). In practical terms, NOX production is the real limiting
> factor when you have to meet emissions requirements.

We should agree here because detonation is combustion starting before
scheduled ignition, which in the diesel arena begins when fuel first exits
the injector.

> And as for the obvious effects of higher combustion pressures on oil
> contamination, I really have to wonder how much real-world experience
> you have... have you EVER observed an engine operating under high load
> and high boost? Gasoline or diesel? In either case, the typical thing
> you can see is a shocking amount of vapor blowing out the crankcase
> breather (way beyond what can be handled by positive crankcase
> ventilation). And that's on a brand-new just-broken-in engine on a
> dynomometer, not some 400,000 mile tired-out rig, either.

Spent 12 years driving line haul, some of that as O/O. Being that road
draft tubes are illegal since about 1990, one does not see blow-by belching
forth under the cab. I recall well the days when you'd see a turbo glowing
dull red on a long pull. Obviously the driver wasn't paying attention to
the pyrometer limit of 1100 degrees. The company I retired from kept OTR
trucks to 600k miles typically. The engines were fine for the most part.
Turbos however were considered expendable items.

> The REAL reason that there is such a difference between the engines in
> your example (SD22, Cummins, and Navistar/Powerstroke) is because one
> is an IDI and the other two are DI, which demand less compression for
> starting (when the turbo isn't operating anyway).

I recall making that distinction some time ago regarding soot production.
ID injection diesel does not have the flame front dampening that IDI
combustion chambers provide. Of course, there are trade-offs but emissions
and 'greeness" rule so .... IDI.

--

- Philip

jim beam wrote:
> Michael Pardee wrote:
>> "Steve" > wrote in message
>> ...
>>
>>> All together, class: "What does static compression ratio have to do
>>> with the peak pressure achieved during combustion?"
>>>
>>> NOTHING!
>>>
>>> Post again if you can't figure out why.
>>
>>
>> I can't figure out why. By your logic, mechanical compression ratio
>> would be meaningless.
>>
>> Ignition timing (injection timing for a conventional diesel) and
>> induction charge affect the combustion chamber temperature/pressure,
>> but so does mechanical compression ratio. For gasoline engines, that
>> is why compression ratios were reduced when NOx limits were imposed
>> - to reduce peak combustion temperatures. EGR (to reduce effective
>> induction charge) and changes in ignition timing were part of the
>> solution, but mechanical compression ratio was an important key.
>>
>> Recall that the pressure is the result of the addition of heat
>
> PV = nRT. heating is adiabaic. the above sounds like constant volume
> which clearly is not the case.

Rapidly rising pressure results in heat. You can have pressure but without
heat ... no ignition.

--

- Philip

> EVERYBODY is reluctant to qualify THEMSELVES first. Sure it's easy to
call
> the other guy who makes errors an idiot but ... are you better qualified
or
> better experienced? Be honest. Why did you sublet the repair in the
first
> place?


Maybe I'm just big headed, but in actual fact I trust my own diagnosis
first, then i ask around for advice and filter out the crap, which is almost
always from dealers and 'specialists' and people I know have no idea. As far
as I can remember I've not been wrong yet, except for in the hunt for a
knock on the rear susp of a pug 306, which i dont thing was ever found lol.

Jim Beam Wrote:
> if you withdraw from the qualification process, you can't complain
> about lack of candidates.

I never complained about lack of candidates?

>and some people you /have/ to trust, whether you like it or not.

And believe it or not, I know enough people in medical areas to know the
number of mistakes (that are generally covered up) are actually scarily
high, and YES I do worry about the guy checking the bolts on the wings -
being an engineer has instilled into me a complete lack of trust of anyone i
dont *know* personally and know the quality of their work.

I know an aircraft technician, and I know the quality of his work is good,
I've seen it with my own eyes. I'd have him help me on my car, but I'd be
double checking everything myself.

>admittedly, the car world has very low
>barriers to entry, but that doesn't mean everyone is a fool. qualify them!

I DO qualify them myself, and I've yet to meet someone i trust to do a
better job than me. I know that i may take longer, I may have to buy an
extra tool, but I know what im doing and i know i do it right - im not
leaving it to whether or not someone forgot to torque something up when the
finished for their coffee break. I'm also not trusting someone who gets paid
more for the more work they fit into a day. Or for finding more things to
replace - tis a totally backwards thing to do in my view. Why trust someone
to do something I can do myself. And when i have to, say i needed a block
honing or turbo rebuild, yes i am very untrusting and dislike being put in
that position.

I've seen a lot of these places, and worked in a few. Worked in a few
scientific labs, seen the shortcuts people make. Unless I can see the work
being done, or know the person who is doing it personally it aint being
done.

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

The vast majority of main/little/big end seizures are oil starvation
related. There are few other things capable of causing it, but if i had
symptoms of low pressure I'd have the bottom off the engine to check the
lot. Job done properly, not either a)guessed at or b)replaced sequentially
like a dealer would.
Couple of my mates have worked as spanner monkeys in dealerships, ive seen
how they work, and I've also seen how they take fast cars like mine and rag
the crackers off it while its left there. Main dealers, more so specialists.
Trust yourself, if you dont know - learn.

J

".Philip." > wrote in message
ink.net...
> Steve wrote:
>> .Philip. wrote:
>>
>>
>>>
>>> "We" know that turbochargers increase air density within the
>>> cylinder and therefor ... dynamic compression. This readily evident
>>> to everyone but you that turbo charged engines running significant
>>> boost pressures will always have different pistons to reduce
>>> cranking compression. "We" also know that all else being equal,
>>> having brake mean effective pressure close to TDC will result in
>>> higher combustion chamber pressures than with BMEP further from TDC.
>>
>> And that has precisely WHAT to do with the static CR of a Nissan SD22
>> vice a Cummins B5.9 and their comparative peak chamber pressures? And
>> why are you seemingly using the term "BMEP" to represent a pressure
>> at a single point in the cycle, when in fact the "mean" in the term
>> "brake mean effective pressure" makes the measurement at a single point
>> in
>> time nonsensical?
>
> BMEP is the highest pressure attained during combustion. This is affected
> by numerous factors, not the least of which is the mechancial compression
> ratio and boost pressure. All else being equal and with natural
> aspiration, do you disagree that BMEP with 24:1 is going to be higher than
> BMEP with 17:1?
>

Since a 17:1 is likely to be direct injection and the over-twenty to one
will be indirect, then it is likely that the 17: 1 will have the higher peak
pressure, not least because the pressure rises so suddenly to the peak. This
is why direct injection engines are more noisy. Of course technology
advances and it is now possible to limit the peak pressure by injecting
sequentially in up to five stages for each power stroke and each cylinder
can be adjusted dynamically in real time using individual knock sensors to
adjust the fuel volume for each injector. Modern fuel injectors of the
piezzo controlled type each have a bar code which is read by a laptop which
informs the ECU which setting to apply to match it to each other injector in
the system. With this constant then everything can be controlled with
unbelievable accuracy.

Huw

".Philip." > wrote in message
link.net...
> Steve wrote:
>> .Philip. wrote:
>
> I recall making that distinction some time ago regarding soot production.
> ID injection diesel does not have the flame front dampening that IDI
> combustion chambers provide. Of course, there are trade-offs but
> emissions and 'greeness" rule so .... IDI.
>

I don't understand what you are implying here. Are you implying that IDI
engines are greener or the other way around?

Huw

Huw wrote:
> ".Philip." > wrote in message
> ink.net...
>> Steve wrote:
>>> .Philip. wrote:
>>>
>>>
>>>>
>>>> "We" know that turbochargers increase air density within the
>>>> cylinder and therefor ... dynamic compression. This readily
>>>> evident to everyone but you that turbo charged engines running
>>>> significant
>>>> boost pressures will always have different pistons to reduce
>>>> cranking compression. "We" also know that all else being equal,
>>>> having brake mean effective pressure close to TDC will result in
>>>> higher combustion chamber pressures than with BMEP further from
>>>> TDC.
>>>
>>> And that has precisely WHAT to do with the static CR of a Nissan
>>> SD22 vice a Cummins B5.9 and their comparative peak chamber
>>> pressures? And why are you seemingly using the term "BMEP" to represent
>>> a pressure
>>> at a single point in the cycle, when in fact the "mean" in the term
>>> "brake mean effective pressure" makes the measurement at a single
>>> point in
>>> time nonsensical?
>>
>> BMEP is the highest pressure attained during combustion. This is
>> affected by numerous factors, not the least of which is the
>> mechancial compression ratio and boost pressure. All else being
>> equal and with natural aspiration, do you disagree that BMEP with
>> 24:1 is going to be higher than BMEP with 17:1?
>>
>
> Since a 17:1 is likely to be direct injection and the over-twenty to
> one will be indirect, then it is likely that the 17: 1 will have the
> higher peak pressure, not least because the pressure rises so
> suddenly to the peak.

Sorry Huw. You do not get to rewrite the question via your answer. The
passage "All else being equal" is germane.

> This is why direct injection engines are more
> noisy. Of course technology advances and it is now possible to limit
> the peak pressure by injecting sequentially in up to five stages for
> each power stroke and each cylinder can be adjusted dynamically in
> real time using individual knock sensors to adjust the fuel volume
> for each injector. Modern fuel injectors of the piezzo controlled
> type each have a bar code which is read by a laptop which informs the
> ECU which setting to apply to match it to each other injector in the
> system. With this constant then everything can be controlled with
> unbelievable accuracy.
> Huw

Agreed. But this gracious contribution of yours is beyond the current scope.
But we'll get to it soon! LOL You know how these threads evolve.
--

- Philip

Huw wrote:
> ".Philip." > wrote in message
> hlink.net...
>> Huw wrote:
>>> ".Philip." > wrote in message
>>> ink.net...
>
>
>>> I think it is not important. My Nissan IDI turbo engines deposit far
>>> less soot in the oil per mile than my NA Land Rover diesel ever did.
>>> In fact I don't see much difference between the Nissan turbo's and
>>> the small Ishikawajima NA indirect.
>>> My Toyota direct injection turbo keeps oil very clean for a diesel.
>>>
>>> Huw
>>
>> Huw. Are you saying the presence of a turbo is not relevant to soot
>> production? All else being equal, Cummins and Caterpillar would
>> laugh you off into the liquid abyss that surrounds your island.
>
>
> It is hardly relevant in the simple way I think you mean.

You inferred on the simple level. I know my audience. :-)

> Today's road
> diesel engines produce less exhaust soot, which is representative of
> total soot production, than ever before and I cannot think of one car
> diesel that is not turbocharged offhand. It is interesting that in
> parallel to the dominance of turbo diesels the service intervals have
> also increased substantially and so have power output verses swept
> volume and specific fuel efficiency.

Yes Huw, all this is appreciated but a dodge from the question I posed to
you.

> You have shown a disturbing trend towards a lack of understanding on
> this topic Philip. Nothing is black and white, but are mostly shades
> of grey. That is, all systems interact in a complex way and no
> particular is fixed because technology in all areas advance
> continuously but is applied in steps as is convenient for each
> manufacturing process.
> Huw

See the comment I made just moments ago. Shades of gray represent the
superficial understanding. ;-) From a very qualified Cummins source, I've
been told I a good grasp of the interdependent variables. How the fuel
delivery basics can be electronically manipulated is an ongoing education.
--

- Philip

".Philip." > wrote in message
hlink.net...
> Huw wrote:
>> ".Philip." > wrote in message
>> ink.net...
>>> Steve wrote:
>>>> .Philip. wrote:
>>>>
>>>>
>>>>>
>>>>> "We" know that turbochargers increase air density within the
>>>>> cylinder and therefor ... dynamic compression. This readily
>>>>> evident to everyone but you that turbo charged engines running
>>>>> significant
>>>>> boost pressures will always have different pistons to reduce
>>>>> cranking compression. "We" also know that all else being equal,
>>>>> having brake mean effective pressure close to TDC will result in
>>>>> higher combustion chamber pressures than with BMEP further from
>>>>> TDC.
>>>>
>>>> And that has precisely WHAT to do with the static CR of a Nissan
>>>> SD22 vice a Cummins B5.9 and their comparative peak chamber
>>>> pressures? And why are you seemingly using the term "BMEP" to represent
>>>> a pressure
>>>> at a single point in the cycle, when in fact the "mean" in the term
>>>> "brake mean effective pressure" makes the measurement at a single
>>>> point in
>>>> time nonsensical?
>>>
>>> BMEP is the highest pressure attained during combustion. This is
>>> affected by numerous factors, not the least of which is the
>>> mechancial compression ratio and boost pressure. All else being
>>> equal and with natural aspiration, do you disagree that BMEP with
>>> 24:1 is going to be higher than BMEP with 17:1?
>>>
>>
>> Since a 17:1 is likely to be direct injection and the over-twenty to
>> one will be indirect, then it is likely that the 17: 1 will have the
>> higher peak pressure, not least because the pressure rises so
>> suddenly to the peak.
>
> Sorry Huw. You do not get to rewrite the question via your answer. The
> passage "All else being equal" is germane.
>

But they cannot be equal because there are no IDI engines running 17:1 and
no DI running remotely near to 24:1. You may know that IDI engines do not
incorporate the combustion chamber, as such, within a recess in the piston
crown which is the case with all DI diesels.

Huw