Digest for sci.electronics.repair@googlegroups.com - 10 updates in 2 topics

The Real Bev <bashley101@gmail.com>: Nov 06 07:58AM -0800

On 11/05/2017 08:05 PM, Frank wrote:
>> never done?
 
> I've never painted a car. I suppose some day I'll give rebuilding an
> automatic transmission a shot, but I've been lucky so far.
 
After an unfortunate shifting incident in Arkansas, we hobbled in to a
local repair shop in Fort Smith and had the pleasure of watching the guy
rebuild the motorhome trans by hand. He had Parkinson's, but it
disappeared while he was working. I swear he looked like a machine
programmed to pick gears up and put them down in exactly the right place.
 
> I've done things ring and bearing jobs but everything is holding up
> better nowadays.
 
In life there are always tradeoffs :-(
 
 
--
Cheers, Bev
"Qui custodiet ipsos custodes?" --Juvenal
The Real Bev <bashley101@gmail.com>: Nov 06 08:02AM -0800

On 11/05/2017 05:27 PM, Frank wrote:
> could be partially starved for oil even if it was full of clean, clear
> oil.
 
> The heat riser could be designed out of EFI engines.
 
It's amazing how far one can be thrown when it's discovered that its
stuckness is the cause of the engine overheating.
 
 
--
Cheers, Bev
"Qui custodiet ipsos custodes?" --Juvenal
Ed Pawlowski <esp@snet.net>: Nov 06 11:24AM -0500

> Not to denigrate the GOOD engineers out there - but he sure thinks
> like a typical engineer - - - One with no practical experience and a
> "god complex" only exceded by orthopedic surgeons.
 
Intelligent people question
Arrogant people think the know everything.
The Real Bev <bashley101@gmail.com>: Nov 06 08:25AM -0800

On 11/05/2017 08:48 PM, RS Wood wrote:
> grow over time. I don't really understand why, but it does. It gets almost
> imeasurably larger over time, until you finally feel it while braking at
> speed.
 
My mom had a heavy foot, but I don't think she was given to braking
hard. My mom drove the car to work (7 mile round trip) on surface
streets. I first noticed it at around 50K miles.
 
She had the car "serviced" (as in "screwed") by the dealer 4x/year. He
replaced all the rubber at 20K. Would he have removed brake deposits too?
 
>> lady on the phone who told me the time.
 
> I have a few Rolex watches (most received as gifts).
> They suck at keeping time.
 
Friends in Santa Rosa had one in their half-refrigerator-size safe. The
fire popped it open and everything inside burned/melted, including what
might have been a Rolex; why else would you keep a watch in a safe?
 
 
> Life is one thing but the *primary* factor in brake pads is friction.
 
> I buy $35 PBR pads with FF or GG friction ratings which last 30K miles or
> so and the dust isn't objectionable.
 
I'm a lousy housekeeper. I regard dust as a protective coating. What
kind of people find brake pad dust objectionable? What kind of people
even notice it?
 
> c. Decent life (the only way to know is to ask owners)
 
> Friction Coefficient Identification System for Brake Linings
> <http://standards.sae.org/j866_200204/>
 
TMI here!
 
 
--
Cheers, Bev
"Qui custodiet ipsos custodes?" --Juvenal
RS Wood <rswood@is.invalid>: Nov 06 04:34PM

> Not to denigrate the GOOD engineers out there - but he sure thinks
> like a typical engineer - - - One with no practical experience and a
> "god complex" only exceded by orthopedic surgeons.
 
On page 10 of that example the Master's Thesis covers the set of piston
rings, where nothing said is the least bit complex.
 
The author talks about the compression and oil ring, and that each has its
purpose. He talks about the location of the piston ring. And that the first
ring takes 75% of the pressure.
 
The paper suffers enormously from lack of English language skills, which is
to be expected in a paper from Europe, where, for example this is a
verbatim sentence:
"The choice of the number of rings should be the result of careful
analysis, with one hand, depends on to the gas that passes into the
crankcase should be the minimum, on the other, the number of rings
determines the mass of the piston, engine height and friction losses."
 
But that's as "technical" as the paper gets with respect to piston rings,
which makes the paper essentially a summary of piston rings that anyone who
isn't even an engineer could easily do.
 
Then the guy shows a diagram of piston rings in action, with a few typos
(so the paper isn't all that well reviewed), and then he talks about how
bad it is to have burnt oil.
 
The only slightly technical thing in the paper is a chart of clearances for
the sealing and scraper rings that he clearly crobbed off the net somewhere
and where he doesn't discuss any of the engineering tradeoffs involved.
 
On page 34 he defines a temperature for each of three rings (finally
spelling the word "scraping" correctly) and then he shows a trivially
simple picture showing, essentially the same thing (so why does he do it?).
 
That's it for page 34, so we move on to page 49 and page 50 for the last
discussion of the piston rings.
 
On page 49, he seems to be covering the same thing, in effect, as he did on
page 34, starting with the verbatim sentence "The piston rings take a very
important place when cooling the piston." Um. OK. Tell us something we
didn't know before we read the paper please.
 
He then chooses a heat for the piston crown that is high, saying the rings
won't work at that temperature based on his simulations, but that they work
at a lower temperature. Um. OK. (This is basic high-school level stuff.)
 
Lastly, on page 50, he tells us "Increase the high of the scrap ring in
order to adjust to reality". He doubled the height from 3mm to 6mm and lo
and behold, it worked where it didn't work at 3mm! (Notice the tolerances
here ... we're talking *huge*.) He also added channels to the rings which
is, again, high-school stuff.
 
In summary, while I am not going to fault the guy for his poor English, I
will fault someone for not reviewing the poor English - because it just
means that this paper is not a reliable paper because it was clearly not
reviewed.
 
Worse ... this paper didn't say *anything* that any high-school student
doesn't know, about piston rings. The changes he made were enormous, where
all he simulated was that it didn't work before he made the enormous
changes, and then it did work when he did.
 
Let's get back to reality, shall we.
I never said that the design of *anything* is super complex at the stage of
designing the perfect system. I even said that a spark plug is complex at
that level.
 
But at the level of using the thing in fixing a car, you already have very
limited choices since all you're doing is fixing a car. To say that fixing
a car by replacing piston rings is scientifically complex is just pure
bullshit.
 
And it's even worse that you backed up that claim with a high-school level
paper (yes, I know it's a thesis but that doesn't change the sophomoric
level of the paper).
 
As an engineer, I'd be embarrassed if I claimed that paper said anything
that is even remotely related to proving that, in practice, the selection
of replacement rings for repairing an engine in your driveway is in the
least bit complex.
 
I give up if anyone thinks that paper proved otherwise because I'm only
using very basic logic here because that's all I do.
RS Wood <rswood@is.invalid>: Nov 06 04:34PM

Ed Pawlowski wrote:
 
> Dealer may be 1 hour at $75
 
That's a joke, right?
 
I realize in *some* parts of the US, the dealer may be more than half what
they are here, but it's closer to $200 and even an Indy is at $100 an hour
here.
 
In a sense, it makes even more sense to DIY here than wherever you are,
since the price difference between you and me for the shop rate is
enormous.
RS Wood <rswood@is.invalid>: Nov 06 04:37PM

rbowman wrote:
 
> Cheaper? No, you're wrong on that one.
 
Let's give up on the FWD.
If you think they're made for handling in the snow, then they'd come with
snow plows on the front.
 
OK. I'm joking, but they're not made for handling.
They're just not.
 
No logical person on this planet can argue that with another logical
person.
 
Since at least one of us isn't thinking logically, and since you think it's
me and I think it's you, let's just give up, because both of us can be
right on that but given that, we'll get nowhere.
 
You think it's all about handling.
OK. You keep believing that.
The Real Bev <bashley101@gmail.com>: Nov 06 08:37AM -0800

On 11/05/2017 08:48 PM, RS Wood wrote:
 
>>>What doesn't last longer on a car nowadays?
>> Sometimes things like power lock actuators and some electrical
>> connections
 
88 Caddy driver's window/door controls stopped working long ago. Stupid
motor-driven passenger-side mirror just unstuck itself from the mirror
and would have required removing the entire dashboard and AC to replace.
Whoever thought of the stupid electrical trunk-lid grabbing latch
should have been flayed alive. Engine ran fine up to the 90K end, it
was just the rest of the stuff that died.
 
> I was watching a video by the MythBusters on how to get out of a car that
> is sinking in a pond (pool in their case) where someone mentions to roll
> down the windows ... heh heh ...
 
They claimed that power windows would work long enough to allow them to
be rolled down. Do they assume it would take minutes for the electrical
system to short out? Is that reasonable?
 
> When's the last time you saw a roll-down window?
 
Our 70 Dodge pickup has them. What you can't get is the stuff that
keeps the windows from rattling.
 
For a while I thought I wanted a car intended for third-world repair
capabilities -- everything possible manual, etc. And then I
discovered the joy of pushing the tiny button on the key that unlocks
the doors :-(
 
--
Cheers, Bev
"Qui custodiet ipsos custodes?" --Juvenal
RS Wood <rswood@is.invalid>: Nov 06 04:40PM

rbowman wrote:
 
>> When's the last time you saw a roll-down window?
 
> About 12 hours ago when I parked the car.
 
That made me laugh!
Thanks.
 
I think I'm only going to respond though, to the posts that aren't already
in the dirt (the fwd is in the dirt, the warp is in the dirt, the piston
rings is in the dirt, and the drilled rotors are in the dirt).
 
But there was a lot more in this thread than those few topics.
 
I learned a LOT from you all.
Thanks.
Wond <gboot.phil@gmx.com>: Nov 06 03:52PM

On Sun, 05 Nov 2017 22:00:52 -0800, David Farber wrote:
 
 
> http://webpages.charter.net/mrfixiter/images/Electronics/Rickenbacker/Flakey-terminals.jpg
 
> http://webpages.charter.net/mrfixiter/images/Electronics/Rickenbacker/Filter-caps.jpg
 
> Thanks for your reply.
 
Looks like the filter cap lead in the middle of the pic may not be
soldered properly!
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