perf-list-digest Saturday, December 19 1998 Volume 01 : Number 176



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Ford Truck Enthusiasts - Performance
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In this issue:

FTE Perf - 40K
RE: FTE Perf - 410 build-up-The Start
FTE Perf - bigger valves 4v vs 2v, long was: 410 build-up-The Start
FTE Perf - Re: Suburban vs. Expedition
: RE: FTE Perf - 410 build-up-The Start
Re: FTE Perf - 410 build-up-The Start

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Date: Fri, 18 Dec 1998 08:21:40 -0500
From: am14 daimlerchrysler.com
Subject: FTE Perf - 40K

Darrell Dugan writes: >> Makes me wish I had another 40k lying
around so I could get one.


ANOTHER 40k lying around?????????????? I wish I had one 40k lying
around....

Azie
Ardmore, Al.


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Date: Fri, 18 Dec 1998 08:47:54 -0600
From: William S Hart
Subject: RE: FTE Perf - 410 build-up-The Start

>for what it's worth, i think that basically all engines benefit from bigger
>valves even as a "torque motor". torque means good low lift and low rpm
>flow and a bigger valve makes a bigger area for flow at ALL valve lifts,
>and that should mean better cylinder filling at all rpms, not just at 6000
>rpm. also, part throttle power should also improve IMHO with bigger
>valves. the only reason i would not choose bigger valves for any engine
>build would be because of cost. one possible drawback is the reduced
>turbulance of a bigger valve, but i think the flow offsets that enuff.

I dunno sleddog, this was my thought at first but EVERYTHING I've read
seems to say that if you open things up too much, you'll kill your low end.
The new Stangs have sort of proved this, the GT and Cobra both have 4.6L
engines, one has 32 valves, the other has 16 ... the 32 valve engine makes
LESS low end torque than the 16. Granted its still faster (hard to rev an
extra grand and be slower), but it doesn't have near the grunt. Ford
attempted to compensate by putting blocking plates on the intake side of
the 4v to make it run on just 2 until 3250 revs, and people have confirmed
that it indeed does lose some torque down low when they remove them (not to
mention making the Check Engine light come on if they don't put the kit in
to bypass this).

Maybe headers can compensate for the increased valve sizes ? Maybe they
hurt? Anyone know from experience, or for sure ? Do 360's and 390's have
the same valve sizes in them ? I never measured the 360's so I can't
compare them with the 390's I've gotten.


Just my 2cents

Bill

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Date: Fri, 18 Dec 1998 12:16:21 -0500
From: Sleddog
Subject: FTE Perf - bigger valves 4v vs 2v, long was: 410 build-up-The Start

you can't compare a 4 valve engine to a 2 valve engine. a 4 valve engine
has too much port volume/area and even more valve area than a 2 valve
engine. the plates that block off the one valve at lower rpms has been
done on many engines before the ford. it does help keep charge velocity up
and boost low end; as do other tricks like one large port and one small
port, or one long runner and one short runner.

also, the ford engine is still tuned for top end using the other parts such
as cam, and computer controls of timing/fuel curves. 4 valve engines are
notoriously sluggish in the bottom. that's the tradeoff for increased flow
at the midrange and top.

with a 2 valve engine, they are always "undervalved" for the displacement
of the engine (american v8's, not some small engines, they may be ok) the
ports are also generally small.

the stock head was designed to flow for the stock engine, and increasing
power at any rpm means getting more charge into the cylinder at that rpm.
(other methods do include reducing pumping losses or mechanical losses)
to increase charge at any specific rpm requires increased flow and a
change in cam timing for that rpm. the stock cam works well as a torque
cam. put more cubes under it and the usable rpm range will drop. increase
cam "size" to regain the normal rpm range while increasing power through
that range (an RV type cam works well here, but an RV cam for a 360 is way
to small for a 410!)

just on an aside here, many engines have been designed with 4 valve heads,
but to help bottom end had 2 different runner sizes, 2 different intake
valve sizes, 2 different cam lobe profiles for those valves, and sometimes
even adjustable intake plenum/runner volume by rpm.

now, say you keep the stock cam, or one very much the same size and
duration and overlap. the rpm range can be extended by imporving flow (may
also improve at all rpms) bigger valves do a few things in addition to
increased flow.

pumping loss reduction
stronger pressure pulse signal along intake tract to carb
simulates a bigger cam without changing the actual valve timing events like
overlap (very important, as valve timing events decide the rpm range, or
"powerband")
similiar to putting in a longer rocker for a better rocker ratio in that
more flow around the valve is achieved faster and total flow from valve
opeing to closing is increased. many stock engines have been shown to
benefit from a longer rocker ratio with no other changes. if the heads
can't flow enuff for maximum power to be increased, the increase may be
seen at the bottom and midrange where extra flow is possible still.
remember that even when peple port heads, they are looking at the flow
under the curve from bottom to the the max valve lift, not just improving
the max lift flow. the power gains from increasing low lift flow are
amazing from the information i have seen of actual dyno runs. even the 30
deg intake valve seat is aimed at getting increased low lift flow for
increased bottom end power.

the 30 deg valve seat is also something to consider. low lift flow is
better as the valve curtain reaches a flowable amount sooner to start the
actual charge moving. this may also give a stronger signal to the carb.
stronger carb signal increases the carbs ability to meter fuel properly
and creates better throttle response and drivability and *maybe* mileage.

cost is really the only issue i can see as a negative in bigger valves.
but than again, if it is too much a 30 deg seat on the intake can be done
for much less and it gives very good results in a low rpm engine. it
hinders flow at higher rpms, but as a torque engine who cares, and even
with the 30 deg seat it should "hang on" until the cam is the real
hinderance to more rpms for a 410 cube engine with a smaller cam.

BTW, what size cam are you looking at??? maybe what i think is a torque
engine and what you do are 2 different things? i consider a stock FE of
any size except the 427, or other exotica, to be a torque engine from the
start, and although it can be improved to make even more torque it fits the
definition to me. even the 427 as stock is a torque engine in some ways,
as it pulls from idle up. not many cars came from detroit without low end
power. the 351 C 4v being a possible exception. once you want to rev past
5500 (and make power) then i think you are moving away from a torque engine
IMHO.

as for the headers, every stock engine i ever seen improved with the
addition of headers, from the bottom to the top. they will always help in
my experience and others i know, and will only help more with the larger
valves, or other mods.

also, FWIW, my experience shows that with a 2valve engine most mods that
increase top end also help bottom end and midrange. The cam being the part
that really will decide if the bottom end is usable or not. engines with
weel chosen combination of parts will run good from the bottom up. for
example: my pull truck will turn more rpms than most big blocks, makes
over 700 hp, and actually draws enuff air that it sucked to airfilter down
so that it collapsed to half its height once. yet it still responds to
throttle like lightning at just off idle, and pulls from at least 2000 rpm
with more torque than most street performance engines. with a 4000 rpm
stall special pulling converter it pulls harder when hooked to the sled at
2500-3000 rpm than my other 460 truck does at the same rpm or higher, and
that one has a approximately 3000 rpm stall street/strip converter. that
engine is a midrange brute, but really at around 5000 rpm can't touch my
puller's power. yet the puller will run past 7000 rpm without breakin' a
sweat!

sleddog

- ----------
From: William S Hart[SMTP:wish iastate.edu]
Sent: Friday, December 18, 1998 9:47 AM
To: perf-list ford-trucks.com
Subject: RE: FTE Perf - 410 build-up-The Start

I dunno sleddog, this was my thought at first but EVERYTHING I've read
seems to say that if you open things up too much, you'll kill your low end.
The new Stangs have sort of proved this, the GT and Cobra both have 4.6L
engines, one has 32 valves, the other has 16 ... the 32 valve engine makes
LESS low end torque than the 16. Granted its still faster (hard to rev an
extra grand and be slower), but it doesn't have near the grunt. Ford
attempted to compensate by putting blocking plates on the intake side of
the 4v to make it run on just 2 until 3250 revs, and people have confirmed
that it indeed does lose some torque down low when they remove them (not to
mention making the Check Engine light come on if they don't put the kit in
to bypass this).

Maybe headers can compensate for the increased valve sizes ? Maybe they
hurt? Anyone know from experience, or for sure ? Do 360's and 390's have
the same valve sizes in them ? I never measured the 360's so I can't
compare them with the 390's I've gotten.


Just my 2cents

Bill

Auto Links http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/cars.html
'73 1/2 ton 4x4 Ford
http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/Trucks/truck.html
'96 Mustang GT
http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/Cars/mustang.html
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Date: Fri, 18 Dec 1998 14:37:43 -0800
From: Vogt Family
Subject: FTE Perf - Re: Suburban vs. Expedition

On Thu, 17 Dec 1998 10:00:01 -0600, William S Hart
wrote:
> >sophisticated vechicle! I think the expidition wins against the 350 but
> >I think the 454 is still available in the tank though, might be wrong!
>
> Dunno, they're both pretty powerful, but still wear the wrong emblems and
> have those goofy exhaust ports ...

The Ch#^y big-block has the exhaust ports in the right place. Actually
I think the small block went that way also in its last years of
production. The small block is now gone I believe. Not that this has
anything to do with Ford trucks.

What I really can't understand is why Ford doesn't still produce a big
cube gas motor. Perhaps CAFE won't allow it, because if they did
produce such a motor everyone would buy it thereby dropping the CAFE
rating dramatically
a la GM and the Sub? It seems that they are forcing the diesel down
many people's throats that would otherwise have preferred a 460.
Anyone?

Birken
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------------------------------

Date: Fri, 18 Dec 1998 18:57:29 -0500
From: "The Freeman Family"
Subject: : RE: FTE Perf - 410 build-up-The Start

I've heard a bunch of stories on how to build torque. Torque is basically a
function of the cam? I havn't even started down that road yet, but I'd be
intrested on the "tricks" I need to do to this motor as I build it. I
really respect everyones comments on this list and really appreciate the
help!

Right now I'm about ready to have the block tanked and fluxed to make sure
it's okay. I hope to take the crank, balancer and flexplate to the machine
shop after Christmas to have it checked and balanced. I guess so far so
good.

Thanks again,

- -Ted
__________________
for what it's worth, i think that basically all engines benefit from bigger
valves even as a "torque motor". torque means good low lift and low rpm
flow and a bigger valve makes a bigger area for flow at ALL valve lifts,
and that should mean better cylinder filling at all rpms, not just at 6000
rpm. also, part throttle power should also improve IMHO with bigger
valves. the only reason i would not choose bigger valves for any engine
build would be because of cost. one possible drawback is the reduced
turbulance of a bigger valve, but i think the flow offsets that enuff.

sleddog



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------------------------------

Date: Fri, 18 Dec 1998 18:59:28 -0500
From: "The Freeman Family"
Subject: Re: FTE Perf - 410 build-up-The Start

I'm really pumped about the project. Can't wait till she's done!
________________
When my dad did his 410, he used the 360 heads and left the valves at stock
size. I'm not sure as to what the specs are on the cam, but I do know it
was
degreed 4' (adv?) to improve the low end torque. And this baby has plenty.
You can really fea; it. As far as fuel delivery goes, he has a stock
Autolite
4v carb on an Edelbrock perfomer manifold. Good luck, I promise you will be
very pleased with that motor.

Darrell Duggan
74F-350 "Tweety"....

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