What are some car-repair jobs you always wished you could do but have never done?

Xeno wrote:

>> Hrm.+AKA- I thought that was done to lighten them -- bicyclists are
>> sometimes also called gram-shavers.+AKA- It provides better cooling too?
>>
> Removing mass reduces heat holding ability. The material removed does
> not provide a gain in surface exposure. The real gain is providing a
> path for the gasses coming off the pad surfaces to escape from between
> the pad and rotor. Reduces the hovercraft effect.

I can spout marketing bull**** as well as anyone can.
I just choose not to.

If you can find a scientific study that proves for street cars that a
drilled/slotted rotor makes *any* difference over a solid rotor in braking
performance, let me know.

I'm all about logic.

Xeno wrote:

> Pads, under extremes of heat, give off gases. It is the presence of
> those gases *between* the pads and the disc that prevents the friction
> from happening. The gases make the pads operate more like a hovercraft.
> The slots provide a means by which the gases can quickly escape.
> In a road going car, slotted rotors are probably overkill. Not so on
> high performance vehicles.

I've heard it all.
Marketing bull**** is wonderful bull****.

We're talking street cars here.
Racing cars are nothing like street cars.

They drive on bald tires for heaven's sake!

Sometimes applying what works for racing to the street is good.
But most of the time it's marketing bull****.

As it is with drilled and slotted rotors.
Besides, braking in cars is not happening due to the rotors anyway.

The friction coefficient of steel sucks.
You need pads which have better friction ratings than the rotors have.

So pads are what matters.
For fade, on street vehicles, mass is what matters.

If you can find a scientific study that proves for street cars that a
drilled/slotted rotor makes *any* difference over a solid rotor in braking
performance, let me know.

I'm all about logic.

On 6/11/2017 3:48 PM, RS Wood wrote:
> wrote:
>
>> Some of the best rotors out there are Chinese - but also some of the
>> worst. Consistency is the problem
>
> I can't argue but my point is that I've heard everything.
> The problem is that the advice has to be both logical and actionable.
>
> Saying "buy only Brembo or Meyle" is actionable, but not logical.
> Saying "don't buy Chinese crap" is logical but not actionable.
>
> For advice to be useful, it has to be both actionable and logical.
> I've never heard that in rotors other than buy solid and don't buy
> drilled/slotted rotors.
>
> Other than that, there's no way for a person to tell if one rotor is gonna
> be better than another.
>
> Hence pragmatically ... a rotor is a rotor is a rotor is a rotor.
>
>> In some instances (virtually never normal street use) grooved and
>> slotted rotors DO provide better braking. We are talking competition
>> use, where the rotors are glowing red hot half the time, and the pads
>> are off-gassing like crazy - where even 100% dry DOT4 brake fluid
>> boils in the calipers. Under those conditions, rotors can warp - and
>> even fracture (in Rallye use I've seen red hot rotors hit an icy
>> puddle and totally fracture)
>
> I'm never talking racing.
> They drive on bald tires for heaven's sake in racing!
>

Yep, far better coefficient of friction - in dry conditions.

>
>> Actually, on SOME cases you can. Look at the consistancy of the fins
>> in the rotors, and the even-ness of the thickness of the braking
>> surfaces on both sides of the fins.
>
> I'm not gonna disagree that we all can see the mark of good quality on some
> things when we have two to compare in our hand, but it's too late if you
> order on the net.
>
>>> How are you gonna know the metallurgy?
>>
>> You don't - that's the hard part - but when you are in the business
>> you get to know which suppliers stand up, and which don't. If you
>> know the suppliers well, they will tell you which ones they have
>> trouble with, and which ones they don't.
>
> Yup. I have nothing against good suppliers. I use Brembo and Meyle but if
> someone else gave me a rotor at a better price, I'd consider them too.
>
>> And some rotors DO WARP. Not many - but I've had at least a bushel
>> basket full of genuinely warped rotors in my 25 year carreer. Most
>> "warped" rotors are not warped - but some are. Some DRASTICALLY - to
>> the point the caliper moves visibly when the wheel is turned - and if
>> the sliders stick the pedal jumps and the steering wheel twitches.
>
> That's not the measure of warp.
> Warp is measured on a flat bench.
> Just like head warp is measured.

Or with a dial indicator - on both sides - for comparison.
>
>> More often than not though, they are either pitted or have deposit
>> buildup, ot they have "hard spots" due to metalurgical inclusions
>
> The only person who says their rotors warped that I will ever trust is one
> who measured the warp just like you'd measure head warp.

Use to check for warp every time.
>
> If they haven't measured it, it's not happening.
> And nobody measures it.
> So it didn't happen.

Some do. I did. I also taught apprentices to measure for it.
>
> It "could" happen. But it doesn't (on street cars).
> The problem is the temperature never gets hot enough.

It can under specific circumstances. See it most often on autos in very
hilly country.
>
> Now they can be "warped" from the factory; but that's different (and rare).
>
>> Wrong tool. The one I'm talking about has tabs that fit into the
>> notches on the piston face to "thread" it in as you squeese. Can
>> sometimes get away with the $17 "cube" but the kit you KNOW is going
>> to work starts at about $35 for one of questionable quality, and goes
>> up very quickly from there (and IT won't turn back Mazda rear calipers
>> - they use a different system
>
> I think we're talking about two different kinds of disc brake systems.
> I had the Nissan 300Z which had the rear disc also as the rear parking
> brake, but my bimmer has the rear disc and a separate rear parking brake.
>
> The piston arrangement is different as is the way to retract them.
>
> You don't *twist* pistons in disc brakes that I own that don't have the
> parking brake as part of the disc brake itself.
>
> At least I don't.
>
>
>>> Never once in my life have I found a single person who has *measured* the
>>> warp.
>>
>> I have. many times.
> How?
>
>>> You know why?
>>> They don't even know *how* to measure rotor warp.
>>> They don't have the tools to measure rotor warp
>> A somple dial indicator tells the tale
>
> Nope.
> How you gonna tell runut from warp with a dial gauge?

Measure disc thickness at various points around the disc. If the
thickness doesn't vary, then any runout measured on the dial indicator
is warp. Verified by back and front runout comparisons.

By the way, thickness variation checks are part of a standard disc
inspection process.

>
>> - and sometimes one side is
>> straight, and the other side is not - parallelism warpage - where some
>> fins collapse and one side of the rotor "caves in" - 1 inch thick on
>> one "side" of the rotor, and .875 or something like that diametrically
>> across the rotor. - and sometimes virtually deead flat on both
>> surfaces - other times with about hald paralel and the other half
>> "sloped"
>
> Now you're straining credularity.
>
>>> (Hint: It requires a flat benchtop and feeler gauges and it's not hard -
>>> but they don't know that because they didn't measure a single thing.)
>>
>> That won't necessarilly tell you anything. The only way to KNOW is to
>> use a dial indicator properly.
>
> How you gonna tell runut from warp with a dial gauge?

Compare measurements.
>
>> And that is where YOU are WRONG.
>> Many technicians measure brake rotors virtually every day of their
>> working lives.
>
> On the entire freaking Internet, find *one* picture (just one) of a
> technician actually properly measuring brake rotor *warp*.
>
> Just find a *single* picture please. Just one.
> On the entire freakin' Internet.
>
> Find one.
>
>> Dealerships were then REQUIRED to buy an "on-the-car lathe" to true
>> up rotors.
>
> That's not warp.
> Nothing on this planet is going to fix warp.
> There's not enough metal to remove.

Depends on the warp severity.
>
>> A wize man learns from the mistakes of others - a fool never learns
>> because he "never makes mistakes"
>
> Which is why I wish I had done these half-dozen jobs:
> 1. Alignment
> 2. Transmission
> 3. Engine
> 4. Tires
> 5. paint

Done all, taught 1 thru 4 at a technical college.
>
>> Yes - you are right to the extent that MOST "warped rotors" are not.
>> But you are absolutely WRONG when you say they never warp in
>> street/highway use and anyone who says they have had a warped rotor is
>> lying and hasn't measured the rotor to prove it.
>
> I never once said "never" but "almost never" which is different, and we're
> only talking street, and I have references that back up everything I say
> whereas you provided zero references for what you said.
>
> I'm not here to argue opinions.
> I only argue using logic.
>
> Just read the references I provided and then provide some references that
> back up your point of view.
>
> The "Warped" Brake Disc and Other Myths of the Braking System
> <http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths>
>
> The 'Warped Rotor' Myth
> <http://www.10w40.com/features/maintenance/the-warped-rotor-myth>
>
> Warped Brake Rotors - Vibrating Reality or Internet Myth?
> <https://blog.fcpeuro.com/warped-brake-rotors-vibrating-reality-or-internet-myth>
>
> Stop the +IBg-Warped+IBk- Rotors Myth and Service Brakes the Right Way
> <http://www.brakeandfrontend.com/warped-rotors-myth/>
>
> Raybestos Brake Tech School, Part One: Rotors Don't Warp
> <http://www.hendonpub.com/resources/article_archive/results/details?id87>
>


--

Xeno

On 6/11/2017 3:48 PM, RS Wood wrote:
> Xeno wrote:
>
>>> Lot of us keep a car until repair cost exceeds book value.
>>
>> I trade my cars in when I'm sick of them.
>
> For me, I get a new car when the old car has a repair that isn't worth
> paying. That's less likely nowadays as I'm retired on a low budget.
>
I've been buying new cars since retirement - two last year.

--

Xeno

On 6/11/2017 3:48 PM, RS Wood wrote:
> wrote:
>
>> A cut-off wheel on a grinder or a "muffler chisel" - preterably on an
>> air hammer, also makes muffler repair a lot easier - but the "blue tip
>> wrench" is pretty universal
>
> This is a good point in that my angle grinder would make short work of a
> reticent pipe, but when I worked on mufflers, I didn't have such tools.
>
> Did any of us have angle grinders at home in those days?
> Certainly we didn't have decent battery operated tools like we do today.
>
> I love the term "blue-tip wrench".
> I have a saying that no bolt will ever win, since I have that thing!

Ah, you mean an *oxy-spanner* or a *gas axe*
>
>> My 16 year old taurus has stainless exhaust, as does my 22 year old
>> Ranger. So did my Mystique, originally - but when a flange broke for
>> the original owner some bandit sold him a complete walker mild steel
>> system. After I got it, I replaced it again with stainless. The last
>> car s I ownwd without factory stainless exhaust were th '90 aerostar
>> and the '88 New Yorker. My daughres' Honda Civic and Hyundai Elantra
>> both have stainless systems - the Honda's a 2008.
>
> I think the consensus is pretty much that most of us have had SS for quite
> a long time, which is why the exhaust system now lasts the life of the car
> or nearly so.
>
> I haven't bothered to search, but it's my understanding the car companies
> did not do that out of goodwill toward us - but out of gov requirements
> that they have to warrant the exhaust system for longer periods of time.
>
Emission requirements.

--

Xeno

On 6/11/2017 3:49 PM, RS Wood wrote:
> wrote:
>
>> Even wiping down with armor-all will extend the life significantly as
>> it contains U-V inhibitors and restores the plasticisers somewhat.
>
> I understand that pretty tires are pretty.
> But I don't understand UV protection for car tires.

They have UV protection built in at manufacture.
>
> I have nothing against adding UV protection for car tires.
> But I have never had a cracked-sidewall car tire in recent years.

If you don't keep them for longer than 10 years or, alternately, always
park in a garage, you won't.
>
> In days of yore, yes, I have (because I bought junkyard tires until I had a
> bad experience and then never bought used tires ever again).

Indeed. Just like the bad girl, you don't know where she's been! ;-)
>
> So in my today world, a tire lasts about 3 years or less. Never more.
> So at 3 years, do I really need to care about UV protection additions?

No, the inbuilt tyre UV protection is typically good for 5 to 7 years.
>
>> Bercause EVERONE needs UV protection - one reason people wear
>> sun-glasses. My Crizal lenses block almost 100% of UV - by the end of
>> the summer I look like a racoon when I take my glasses off - no tan
>> behind the glasses. The UV protection is for the eyes - not the
>> plastic (generally)
>
> I have never in my life worn sunglasses or sunscreen or even bring an
> umbrella with me anywhere so I may not be the normal person.

I'd have said that!

FWIW, a sign of UV damage to eyes is cataracts.
>
> I hike every single day outside off the trail (I get lost on the trails),
> and I wear Rachle hiking boots (heavy as bricks) for my feet, and
> TIG-welding gloves for my hands (lots and lots of poison oak) and I bring
> rapelling gear (figure 8 plus 100' of rope) because it's mountainous.
>
> I never understood sunglasses.
> They're for wussies.

And people who won't have cataracts when they are old.
>
> One problem with me understanding sunglasses though is that I wear glasses
> full time, so, I've *always* had glasses. Sure I've tried the idiotic
> prescription sunglasses but who wants to carry around two sets of glasses
> everywhere they go. Sure I've tried that idiotic color-changing coating,
> which is a POS and don't even get me started on it. Sure I've tried those
> flip on flip off magnetic overhangs which make me look like the dork I am.
>
> In the end, I gave up on all that crap.
> I don't understand sunglasses.
>
> I just don't.
>
>
Ordinary glass has a degree of UV protection anyway. Same as the
untinted windows on your car - up to 80% I believe.

--

Xeno

On 6/11/2017 3:49 PM, RS Wood wrote:
> Ed Pawlowski wrote:
>
>> Better material, better tolerances, possibly better design. When is the
>> last time you got a ring job on your car? It was common in the 1950s to
>> do rings and bearings at about 50,000 miles. Lubricants are a factor
>> too, but engines today can easily last 200,000 miles with the same
>> internal parts. Do you think those rings are the same?
>
> I'm not going to argue that anything *can* be designed better.
> But a ring is a pretty simple thing.
> It has a certain cross section. A certain material. And that's it.
>
> I certainly can believe that a quantum leap in either the cross section or
> the material happened, but all I'm asking for is proof.
>
> I think the argument that ring jobs were common isn't really gonna fly
> because we already learned that a huge problem is gasoline liquid in the
> cylinders upon startup - which itself was vastly reduced by EFI over carbs.
>
> So, rings being better ... might ... be true.
> But it's a hard one to swallow without something said about how rings are
> better today.
>
> Especially since there are really very few possible factors:
> 1. Material, size, and cross section of rings, then and now, or
> 2. Geometry inside the piston (e.g., number or spacing of rings)
>
> What could possibly be better about rings today?
>
What they are made of, any coatings, their shape. Plenty of research
data available on the internet.

Oil control rings have to be better than before since cars use far less
oil than before - unless it's a GM product where it will use more than
before.

Almost forgot to mention - shorter stroke engines.

--

Xeno

On 6/11/2017 3:49 PM, RS Wood wrote:
> Xeno wrote:
>
>> The carburetor sprays atomized fuel into the cylinders but when the
>> intake manifold, cylinder head, cylinders and pistons are cold, it's
>> very difficult for vapourisation to take place so liquid fuel enters the
>> cylinders.
>
> Yup. I know. Just one press on a gas pedal while looking into my sixties
> Chrysler New Yorker 4bbl Holley Carb would show a ****load of gasoline
> squirting into the intake manifold!
>
> So I now UNDERSTAND something I had never thought about until this thread,
> which is that the amount of GASOLINE getting into the OIL is far lower with
> EFI than with carburetors!
>
> Who knew?

I did, since probably 1969 when I was doing my apprenticeship and used
to see worn out GM engines at 70k miles with bores like buckets. At the
same time, the same engines in taxis could do 2-300k miles with little
measurable wear in the bore. That's because those taxis ran day and
night with never a cold start. At half a million miles those engines
were still running untouched but just about everything else around them
had been replaced.

FWIW, auto transmissions last longer when always kept at operating temps
and, most importantly, never overheated. They use ablative technologies
and friction modifiers are critical.

> Perhaps all of you.
> But not me.
> Until now.
> Thanks.
>
>> It is difficult to rebuild the oil film above the oil control ring. It
>> takes a little time. In that time the cylinder walls and rings don't
>> have the protection of the oil film and most wear will take place. That
>> is why cylinder bores will always wear tapered with most of the taper
>> occurring above the oil control ring. A vehicle in continuous use and
>> always warmed up, such as a taxi or a long haul truck, has much less
>> cylinder wear.
>
> I always knew cold starts wore out engines far more than highway miles.
> I never understood completely why.
>
> I think just this one item ... condensed gasoline liquid ... which is we
> presume far lower with EFI than with carburetors ... is a biggie.

It would be the biggest issue by far.
>
> So EFI increases engine life.
> Kewl!
>
> I love learning.
> Thanks.
>
It's always good!

--

Xeno

On 6/11/2017 3:49 PM, RS Wood wrote:
> wrote:
>
>>> What's the old voltage? Something like 10K to 15K volts, right?
>>> What is the new voltage zap?
>> 60K plus
>
> The whole reason that the voltage doesn't kill us when we get zapped is
> that the current is low.
>
> Someone said the *duration* is longer nowadays, but nobody mentioned
> current.
>
> Is the current about the same?
>
I alluded to that when I used the term *high energy*. By *energy* I
meant current, not voltage. The use of coil packs these days in
multi-cylinder cars means that coil current is shared by, at most, 2
cylinders. In the good old days of V8s, that coil current was shared by
8 cylinders. That's why dwell time was such a critical thing - it was
the charging time for the coil. Insufficient dwell meant ignition
breakdown at high RPM since the coil had insufficient time to recharge
between plug firings. Nowadays a lot of car use an individual pencil
coil for each cylinder and each is electronically timed/triggered by the
ECU and each cylinder can vary in ignition timing from its adjacent
cylinders.

There have been huge developments in automotive technology in the past
couple of decades, most of it invisible to all but those of us who delve
deeper.

You want to see what developments have been made in engines, look no
further than the developments in HCCI engines.

--

Xeno

On 6/11/2017 3:49 PM, RS Wood wrote:
> Xeno wrote:
>
>> It's higher voltage to get a spark happening more easily in lean mixture
>> land but it's the *high energy* that allows the longer duration spark.
>
> You've said "energy" before, where I discount that word because it's not
> necessarily a physical entity (although I know what you mean).
>
> There is voltage and current.
> Together, that's wattage.
>
> There's also time, which gives us things like kilowatt hours, which, I
> guess is what you mean by "energy"?
>
>> It's one of the reasons manufacturers went to individual coils - only
>> need to supply spark to one cylinder so gets a very long dwell time with
>> plenty of coil saturation.
>
> This is interesting because what you're saying is that the single smaller
> coil delivers more of what you call "energy" to the spark plug.
>
> I think you mean watts though. Do you?
>
>>> What's the old voltage? Something like 10K to 15K volts, right?
>>
>> Up to 20k. All the old oscilloscopes had a range, from memory, up to 25-30k.
>>
>>> What is the new voltage zap?
>>>
>> 60k or better.
>
> Thanks. So the "potential energy" (aka volts) is two to three times higher.
> If the current is the same, then the wattage is two to three times higher.
> If they also increased the current, then the wattage is a *lot* higher.

The higher voltage pushes more current across the gap. But that only
occurs if the *energy* is stored in the coil in the form of a magnetic flux.
>
> I'm getting your point though, which is that the ignition systems of today
> are "stronger" and "longer" (probably far higher wattage and duration) than
> those of yesteryear, which allows for a more reliable combustion of a
> leaner mixture, which keeps gasoline out of the oil.
>
> Keeping gasoline out of the oil goes a *long* way to increasing engine
> life.
>
Especially if you have high sulphur content fuel, such as we have here,
which leads to the formation of *sulphuric acid* in the sump. Not nice!

--

Xeno