perf-list-digest Thursday, September 3 1998 Volume 01 : Number 078



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Ford Truck Enthusiasts - Performance
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In this issue:

FTE Perf - A Little More on Springfield
FTE Perf - Quench Clearance
FTE Perf - FTE t-shirt

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Date: Wed, 02 Sep 1998 06:53:56 -0400
From: The Neighbors
Subject: FTE Perf - A Little More on Springfield

Hey all!
I let myself fall behind on checking my e-mail, so I didn't notice
until this morning (Wednesday) that a few of you need more info. Sorry
about that! "Springfield '98 - Fall" will be held at the Clark County
fairgrounds in Springfield, Ohio, near Dayton and Xenia, and within
sight of I-70. For those of you who like to camp out, there are
campgrounds at one end of the fairgrounds with hookups for those who
need them. Campsites with hookups cost $20 a night, general admission is
$5 a head.
For more info call (937)376-0111.

See you there!

- --
Don Neighbors
'54 F250 Named Grover

"Any dropped tool or part will automatically fall into the most
innaccesible part of the vehicle."

grover ford-trucks.com


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Date: Wed, 2 Sep 1998 16:48:02 -0700
From: "Chris Samuel"
Subject: FTE Perf - Quench Clearance

Date: Tue, 1 Sep 1998 11:11:55 -0400
From: Sleddog
Subject: RE: FTE Perf - compression ratio's

sorry, clarify this a little. that would be 0.000 running clearance. the
build clearance would be more. the guys that run this way sneak up on
0.000 clearance a little at a time on each new engine build till they find
the right build clearance. at teardown they look for signs of the piston
touching the head. this is of course harder on straight wedge heads like
the Windsor family IMHO. Then again, i may be wrong. i ain't ballsy
enough (rich enough?) to try zero clearance despite all of it's advantages.

aluminum rods complicate this more, with the increase expansion rate they
need more clearance. something like 3 times IIRC. Chris, are you there?
shed some light on this subject for us from your experience.

sleddog


The smaller the Quench Volume the better. As the quench volume is reduced
the efficiency increases. Theoretically power produced per pound of fuel
increases (BSFC, Break Specific Fuel Consumption), and emissions can be
reduced.
Again Theoretically you can use zero clearance, BUT (and that is a big but)
unless you are willing to spend the resources and the time on a well staffed
engine dyno facility and engine development program; Or have more $$$ then
you know what to do with (send some to me) you are asking for bad noises!!
and in reality outside of Pro Stock it is virtually not done.
On any non race engine the factory has given you the ball park that you
should play in. The original engine design had a Quench Volume/Distance that
was as small as it could be with a safety factor (Yes, production
tolerances. I know).
What safety factor?
The Clearance Volume/Distance safety factor accounts for all kind of things
like; Bearing clearance at low oil pressure and with bearings that have
acquired some wear, Wrist pin clearance again with low oil and wear, as
always rod stretch, piston flex, heat expansion, cold contraction,
Crankshaft flex, over revving the engine. The Safety factor includes
clearance for things like carbon build up on both the head and piston in
this area specifically, and for migrating carbon flakes that can and do move
around the chamber; or oil as it won't compress.
On a race engine you will be tearing down the engine regularly so you can
keep an eye on things and change parts as wear occurs. In this arena a
Clearance of about 0.015 - 0.020 would be the end of my comfort zone.
Generally (but not always) when you reach this point you are running
"Aftermarket Rods" and "High Quality Aftermarket Forged Pistons". But on a
street or high pro engine your going to simply run it, so not know when your
getting trouble... until... Whack/BANG!
So how much/little can you run?
The best answer is to ask your engine builder and then let them set it.
That way should you break it: they recommended it, they did it, and they
should fix it! But don't count on it as this would be a race type engine
and most race engines are not guaranteed.
If you are the engine builder you had better be asking the Rod and Piston
manufacturer before you order to make sure that you have enough deck height
to accommodate you intended combination. Then mock everything up with the
actual parts and record all of the measurements. These numbers then allow
you to have the machine shop move surfaces to fit your specific combination.

Opinion, Mine!)
Best way for me to answer is to say do not reduce it more then 1/3 of the
factory spec. when using "ANY" stock components. This will allow you to deck
the block and the heads a reasonable amount and run a stock type head gasket
while still making a reduction in the quench clearance and increasing the CR
to gain power.
As to the 0.000 clearance, Yes I have read and heard people say that they
are at zero.
Me? Not in your engine, my engine, not even in a chebbrolet!!! but then I
don't build short life engines as a rule.
If anything ever happens and that piston contacts the head at all, any, even
just kisses it by 0.0001 you are going to reduce component life by some (or
all) every time that it happens. Now figure that an engine set up this way
is generally a extreme performance engine and so is running at high RPM'z
and I'll let you do the math as to how many times impact would occur at say
7500 RPM in a 9 second truck! now figure it at 9000 RPM for 7 seconds. Or
10,000 for 6 seconds.
No... Zero clearance is not going to happen long... if it just reduces the
piston/rod/crank/head/block/bearing and/or pin & bore life by 0.0001% every
time there is an impact of 0.0001. Just estimating it at 7500 RPM and
figuring that there was a progressive loss of component life (not
Whack/BANG!) you would get say 13-14 minutes of run time. That is a bunch of
9 seconds passes but not long anywhere else!
Makes you wonder how a Pro Stock engine lasts a quarter mile. Then again
consider that the valves will open and close a cumulative distance that is
longer then the race; in the race! That they do these kind of things is a
testament to the component manufacturer and the engine builder!

All of the above is figuring ether aluminum or steel rods, could be
titanium or even state-of-the-art unobtanium. The material is not the issue;
as the material dynamics are one of the variables in designing any non stock
engine. The Zero Clearance issue is one of impact and hence Whack/BANG!
Running close to Zero or even at Zero can be done if you are willing to
accept the consequences.

CS

For the record:
Whack/BANG. SUCKS $$!


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Date: Wed, 02 Sep 1998 22:19:41 -0400
From: Ken Payne
Subject: FTE Perf - FTE t-shirt

This past Spring I mentioned putting together a Ford Truck Enthusiasts
t-shirt. Several list members sent in pictures for the design. Thanks
for the time you took to do this. Unfortunately, due to time constraints
and a lack of artistic ability, I haven't been able to come up with a
design.

I'd like to ask list members to come up with a design. It should show
the spirit of what FTE is all about and no focus on one specific type
of truck. Perhaps 2-3 trucks on the design from different eras. Peggy
and I are going to put together a prize pack (to be announced in the
next few days) and the winner will get the prize pack, along with their
signature in the design.

All designs will be posted to the web site, along with an anonymous
voting center so everyone can vote on it. We'll keep the final price
of the t-shirt reasonable.

Send the designs to kpayne ford-trucks.com. Note in the email that
its for the t-shirt contest. We prefer JPEG (JPG) formated files but
most anything else will work.

On another note, several people emailed me concerning the spammer. I'm
a little behind in my email and will reply to your comments/questions
tomorrow.

Regards,
Ken Payne
CoAdmin, Ford Truck Enthusiasts
http://www.ford-trucks.com

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End of perf-list-digest V1 #78
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