Hands-on experiments since the '70s in Performance (GPM) and/or Economy (MPG)

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Hipster

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What a video! I actually get goosebumps listening to him wind
out that 9000rpm SBC and speedshifting with authority. That's
gotta be the best 19 seconds in all of YouTube. :0)

One of the reasons I always had this guy on a motorhead pedestal is that
he went into every single nook & cranny looking for a performance advantage
over his competition. Check this out -- after watching him rowing through the
gears here's a short blurb (from a '68 Car Craft article) on how he modified
his transmission to give him the ability to reliably shift like that:

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How cool is that?

And right around the time I was in high school I discovered
his new book titled "The Chevrolet Racing Engine", and I read
that over and over. Some stuff (like cleanliness) I got on the first
pass, but there was a lot that I didn't fully comprehend for a long time.
(Longer than I care to admit in public. :0)

But man he made me think. Pretty much single-handedly turned
me into a lifelong student of internal combustion. What a gift
he gave to a perfect stranger he never met. (!)

How to make 2hp/ci using '75-era technology
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I recently reread my worn copy of this book, and I was
impressed by how much information he was able to convey
using clear & concise problem descriptions, setting up the
solutions he had devised. When he talked about how
he was combating several degrees worth of spark scatter
issues because the camshaft was winding up and releasing
(front to back torsional twist) because of the super stiff
valve springs they were running? My mind was blown.

****

Anyway, thanks for sharing that video, which triggered
this particular trip down memory lane. And I'm glad
you enjoyed some of the tall tales of my misspent youth.

Fun stuff!

Cheers --
Got into something similar with Harley transmissions, deburring gears and light polishing makes them silky smooth in normal operation and they drop in gear under load better, an company named Andrews makes back cut gear sets etc. unrelated but seems to follow some of the same principles. Just making sure everything is proper.
 

Road Trip

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-- When the Squish/Quench Zone becomes the Crunch Zone --

Recently there have been a couple of posts elsewhere in this forum focused
on what happens if the engine accidentally ingests a foreign object? These
posts reminded me of an old project back in the mid-'90s where a buddy
bought a basket case with low mechanical expectations & I offered to help
out with the drivetrain.

The motor was obviously seized tight and couldn't be turned over with a
breaker bar. A price was agreed upon, and the basket case (in the form
of a '68 Corvette in need of a full restoration) with the factory 390hp 427/4-speed
subsequently became one of the more interesting yard art installations in the neighborhood.

Silent as the monolith in the movie 2001, my hope was to get the big block
to belt out it's 7-liter siren song once again.

****

Today I was able to unearth some old project pics, and here's one taken
of this 427 that will help to explain the title of this reply:

Witness marks left behind when a spark plug ground electrode is broken off at speed. (Gomer sez: 'Surprise Surprise Surprise' :0)
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6000 rpm = 100 revs/second. How long did this ground electrode bounce around, pin ball machine style, before
it was finally ejected out through the open exhaust valve and into the muffler?

What I find interesting about this picture is that it becomes obvious from the carbon
that the PO must have replaced the spark plug & continued to drive the vehicle. And
if you look at how close the piston top is to the block deck, the connecting rod is still
standing tall. Looks like the weakest link is confirmed to be the forged aluminum
factory pop-up pistons.

BBC engines are famous for being able to take a licking and keep on ticking.

But sharp-eyed readers will see an even worse problem in the lower lefthand
corner of the photo above.. You see, if the PO runs straight water in the cooling system
and the temps fall below freezing, Mother Nature's frozen water is even stronger
than the General's finest engine design.

The punch line? If the engine was just seized, we could have brought it back to life.

But this engine was truly frozen. Unless you need a really interesting base for a glass
coffee table, then at this point the only other duty that this block would be suitable for
is (with the help of a chain) to prevent a boat from floating away from your dock.

What can I say? You can bring most of them back...but not all. But taking the glass is
half full perspective, at least you can get some pretty cool pictures of the carnage.
The hard part? Finding others who also share my appreciation for this mechanical entropy.

The takeaway? Pay attention to the antifreeze level in your GMT400. A big block is a
terrible thing to waste. :)

As always, thanks for visiting my tiny performance art installation on the interwebs.

More to follow.

Cheers --
 

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Hipster

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The gearhead opera :). I never had an issue with the two sidedraft Webers in the 2002. Stayed in tune great once balanced. But boy they sang a wonderful duet. Was never lucky enough to hear them live on anything else. I was lucky enough however to have a short ride in a 427 sideoiler clone.... goodness me but that was something to remember. Da Grump. I could watch this short video over and over. Thanks for sharing such a great compilation.

xc_hide_links_from_guests_guests_error_hide_media
Lol, just a casual Sunday drive.
 

Road Trip

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Big Block Senseless Beauty Appreciation Society

During a recent discussion of the difference in the sounds of cast iron exhaust
manifolds vs OEM (or similar quality) headers, this somehow reminded me of
what I thought was one of the most beautiful cast iron exhaust manifolds ever
created. And thanks to the big block heritage, this has at least a familial tie
to the GMT400 engine bays.

Check out this portrait style photo of the Chevrolet 427ci Mark II "Mystery Motor":

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(credit: Mickey Thompson's Z06 Corvette Mystery Motor Stingray article)

This pretty much covers all the bases. And that cast iron exhaust manifold rises up to the Senseless Beauty threshold.

Much ink has already been spilled about the Mystery Motors in racing, so I won't go into detail here. But I recently happened
across the nicest photo I've ever seen of one, so I thought I'd share the wealth for all the other BBC enthusiasts in here.

Check out the attached photos for more goodness. There's a David Kimble cutaway plus a couple of photos from back
in the day.

Pretty amazing what we could accomplish when the talent was unleashed and allowed to swing for the fences.

And to think that you can buy an entire chore truck for $3K and have a decent-running descendent of the
above sitting in the engine bay. The GMT400 platform has some stout heritage in it's roots.

Enjoy --
 

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Road Trip

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Counterfeit plugs in paradise? - DD kept hinting that it needed attention sooner than expected...

Recently the driveability of my 22 year old DD started to draw attention to itself, and not in a good way?
Here's what I observed:

* Longer/harder starting. Sometimes would take 2 tries in order to light off?
* But ran well during during warm up? (Open Loop)
* Would begin hesitating once the O2 sensor warmed up and engine went Closed Loop?

My first thought was maybe the (unknown age) upstream O2 sensor was ready
for replacement? After all, there were 162K miles on the odometer, with the PO putting
on the first 120K? But then again, the O2 sensor wouldn't explain the hard starting symptom?

Hearing one of @Schurkey's standard queries in my mind ("Are all the tune-up items in good condition?")
I decided to verify the common sense stuff first. You know, build on a solid troubleshooting foundation.

Pulling the plugs, I was completely surprised by the XL size of the gaps. I've never seen gaps this big in one of my own cars?

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So I measured the gap, and it was an astounding .088"? What happened? I *know* I verified/installed these at the factory spec of .044"?
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According to my records, I had installed these ~40K miles ago. I dug through my old photos,
and came up with this photo (dated 14 May 2020) showing these same plugs going in:

Spring2020: Same Denso IK20TT above, when new, on left, replacing PO's worn NGKs {unknown age/mileage}
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So why did the plug on the left go bad in less than 4 years and 40K miles while being driven by a pretty chill old man in not that big of a hurry?

NOTE: Back when Iridium plugs first superceded Platinum plugs, articles were written touting a 100,000 mile service life.
Here's the opening of an article written in a service magazine back in 2014 talking about the new Denso Iridium plugs:

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(credit: Spark plug article)

****

So I was trying to remember where & why I originally decided to purchase these? Since I've
bought so much online, I first thought that maybe I ended up with some counterfeit plugs,
especially since I hadn't yet learned about how all the 'jewelry level' plugs are so prone to
being copied. But no, I bought these at a brick & mortar store. And then I remembered
that I was going to purchase my default NGK copper V-groove plugs, and these were
being offered on deep discount for almost the same money?

And then this evening while researching spark plug lifespan, I finally found the real answer right
from the horse's mouth on the DENSO global website:

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(credit: Current page from their website on this subject: Denso plug life)

Wait a minute -- as a 'Murican I gotta translate those kilometers into things I can wrap my
head around. So, to ensure I avoid being 'inexpedient economically', spark plugs beginning
in I = ~12,500 mile recommended lifespan. Long lifespan plugs = ~62,000 miles.

Well I'll be dipped. As mentioned previously, I had installed a set of IK20TT Iridium Twin Tip spark plugs.
And by doing so I had managed to purchase a set of 'regular mileage' Iridium spark plugs that Denso
conservatively recommends changing every 12,500 miles or so?

And that's how I learned that an K24a motor will become a bit fussy/balky when you put 40K miles on a
set of Iridium plugs that were specifically manufactured to a much lower price point? At the time I thought
I was getting Iridium for the price of Copper. But those old V-grooves will last a long time in an engine with
good piston rings & valve stem seals. Sure, they would wear with a lot of miles, but they never just disappeared
on me like that?

So the final answer is that I didn't get counterfeit plugs. But now I also know why these plugs were such a 'deal' at
the time of purchase.

****

Almost forgot. The fresh set of plugs cured ALL of the driveability issues I outlined at the beginning of this article.
With fresh plugs verified at a .044" gap, the K24a motor starts as new, and takes the clutch (5-spd) flawlessly, hot or cold,
Open or Closed loop.

As per usual, Schurkey was proven right to (virtually) ask what is the condition that the normal 'tune up' stuff is in?
Trust but Verify. And just because I *think* I know I've covered all the bases...well, sometimes I haven't read all the fine print.

The moral of the story? Even when you manage to avoid counterfeit parts, you still typically get what you pay for... ;-)
 
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Road Trip

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Here's how I used to cram a little fun into a tight DD budget

Lately I've been so busy learning via remote troubleshooting that I've neglected this thread.

Which is too bad, for in my opinion this thread better reflects my outlook on the
vehicular hobby. Essentially, I did my fair share of adulting over the years, and yet I always
used wheeled vehicles as a place to blow off a little steam/fit in a little fun where none was
scheduled. :0)

Without further explanation, I recently dug through a box of old photos and rediscovered
my personal state of the art, circa '98:

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* '80 Ford Fiesta. PO used it as dedicated Winnebago dinghy. Bought in spite of it's Signal Orange interior & exterior.
Eventually migrated a big valve head, 4-1 header, and rally suspension (from BAT) from the previous Fiesta to this one.

* Previously enjoyed Ducati Sport 750. PO kept it in nicer than brand new shape. Bike was more capable
than it's new owner. :0)

* Well-used Holsclaw trailer w/factory coil springs & shock absorber suspension. 4'x8' platform pivoted in
center, allowed back to drop down to the pavement. The smoothest, best-behaved utility trailer I've ever
had the pleasure to use.

****

This setup seemed to attract a lot of attention back in the day. Mostly befuddlement on the faces of
fellow travelers, but occasionally I'd get an enthusiastic thumbs-up from a fellow enthusiast who
understood that the need for speed can become the mother of invention.

As always, thanks for visiting my little sideshow here on the forum.

More to follow when time permits.

Cheers --
 

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Road Trip

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FTFY. The orange is glorious.

You know what? It was my 3rd Mk. 1 Fiesta in a row. The first and third ones had been given up
on, not running, "As Is, As Shown" on the bill of sale. (The 2nd car was a NH commercial pilot's
Logan Car - "Always started, never stolen.") No kidding, it was too homely to steal -- that car was
too many different yellows, and the only solution was to camo the thing in gray primer. (See attached.)

But I digress. By the late '90s the well-used buy it for a song '78-'80 Fiesta supply chain was drying up.
My 2nd Fiesta's powertrain & suspension was strong like bull, but bad structural rust was winning the race.
A buddy, sensing my impending separation anxiety, spied one hiding behind a semi-abandoned
Winnebago. More eyesore than yard art, both had seen better days.

At first the owner seemed incredulous that I wanted to buy the car instead of the 'bago, but they
had a clean title for it, and after a little back & forth the car was mine for $350. (They emphasized
that it hadn't run in years, so at first they didn't want to sell it, only to have it come back a few days
later with me demanding my money back. {More on this later.})

I had to actually promise them that I wouldn't come back with the car no matter what. To the casual
observer it must have looked like a computer geek begging to buy a craptastic ride. What can I say?
I had a rep for being deep into the cheap thrills groove back then, and I didn't want to disappoint
my friends, coworkers, & neighbors. :0)

****

Anyway, I managed to get it running, plated, inspected, and on the road again. And after driving
a white one and a primer one, I decided that the third time's the charm, and I was going to paint
this one a genuinely nice, non-preschool color. Maybe even have the new color clear-coated so that I
could wet-sand it to the next level.

At the time, I was seriously considering the Corvette Steel Cities Gray -- I had seen a couple of these
in person in that color, and I really liked the understated look. (See attached) Enough that I willing to
go through the extra aggravation to color change the car. I know, kinda Ridonkulus.

So, after a quick buff to remove all the heavily oxidized factory paint I drove it to work for the first day,
fully ready to excuse the look with my plans to paint the car a real color. Now this was at a computer
system manufacturing plant that had maybe 600+ employees at the time. When I went into the
cafeteria for my morning cuppa joe I remember looking out the windows and seeing the car
standing out as the only bright orange car in the entire parking lot, like a subcompact exclamation point.

Well, that entire day there was a steady stream of people who stopped by my cube and told me
that this was the ugliest car that they had ever seen in person. I spent that morning explaining
that it was slim pickings out there, I took what I could find, and that I planned on color changing it.

By the afternoon, I was telling people that "Not to worry, I'm repainting it." And given everyone's
reaction, the only thing I could do was to take it to the guy in VT who painted the FFR Cobra replica,
and asked him if he could paint this car the factory Signal Orange, with plenty of clearcoat so that I could
wet-sand it?

He replied, "Sure. But are YOU sure?"

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(For comparison purposes, go back to the Fiesta/Ducati shot, where the car was still sporting the PO's Yellow, Brown, & Maroon Winnebago stripes on top of the tired factory Signal Orange paint.)


The camera that took this photo couldn't do justice to the sheer orangeness of the repainted machine. Other people's
kids seemed to like it, even though my own daughters were at the age where both their dad and his Signal
Orange car were very embarrassing in public. (By the way, I had upgraded from the skinny stock 12" donuts to
sticky 185/60-R13 Yokohamas on the car. Went from 0 to 19mm euro rally rear sway bar, full suspension upgrade,
and had even lowered the engine with 1" thick spacers in order to flatten the halfshafts and further improve the CG.

Between all that and a Formula Ford-ish engine build, this thing would haul the mail. Way quicker than it looked. Like
a Rabbit GTI back in the day, but with the wheels neatly tucked in under the stock sheet metal.

Apologies for the length. I've owned everything from warmed-over EF Civic hatches to a Fiat Spider and
even a Peugeot 405 Mi16, but these welterweight Mk. 1 Fiestas with a hot crossflow 1600 Kent engine
was the closest I ever got to driving a gokart on the public road with a legal license plate.

Q: How much fun were these cars?
A: They are the only cars that I never installed a radio in them. My best buddy & fellow car enthusiast used
to refer to them as a "Tuna can on a skateboard." This pleased me no end, for this wasn't intended to be
a compliment. The doors had an extra-tinny 'whaaaang' sound when you closed them. But the harder you
drove them, the happier they seemed to be. A very poor man's Lotus. :0)

I really miss that tiny Signal Orange sleeper. But somehow 24+ years after the fact the big block chore truck
seems to be filling the same void, even though it's an 8-lugger on the other end of the vehicular continuum.
It's my fervent wish that I can someday make people laugh as hard at the chore truck as they used to laugh
at this thing. (!)

****

Erik, funny how great minds think alike. It just took a little negative peer pressure multiplied by a touch of
reverse snobbery (and the fact that I love a good sleeper) in order for me to wake up and See the Light.

That Signal Orange really was glorious. Super fun memories that have lasted 24+ years & are still as vivid
as the paint job ever was. :0)

As always, thanks for indulging in my trip down memory lane in the vicinity of my misspent youth.

The takeaway from all this? Be sure to enjoy those GMT400s for as long as possible. Don't let the good ones
get away, for all of a sudden all the For Sale ones will all quietly disappear, and you'll be stuck with what
you've already brought to the dance. (!)
 

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