3r!c84 build

[3r!c84]

Originally Posted by nbpro

so your c-clips were fine? looks good man. now let's see some videos of that burnout you've promised.

yea i forgot the rod in the middle comes out. so it worked fine. and going to the track wednesday

[nbpro]

good

[oldblue1968chevy]

sweeet, anticipating pix

[nbpro]

Updates ?

[3r!c84]

nope nothing realy. just driving it. the tach is giving me problems. going to start on the carmero tach in about a week. going to the track tomorrow ill post pics and my times then

[oldblue1968chevy]

did you every change your springs/weights around (in the dizzy)

[nbpro]

To maximise power and economy potential from any engine, burning the compressed fuel/air mixture at precisely the right point throughout the engines entire rpm range is essential. This ‘point’ is generally somewhere before the piston reaches TDC on its power stroke described in degrees - i.e. 10 degrees BTDC. This point isn’t constant throughout the rpm range. Low rpm values are normally less than high ones.



Ultimately the dizzy provides this spark at exactly the right point to effect this burn. Engine size, cam type, head mods/efficiency, valve sizes, compression ratio, fuel used, inlet/exhaust manifolding and carburation all influence just when this should occur for optimum power. From this it can be seen that one dizzy from one performance type engine may not be suitable for another of similar output, and that a standard dizzy is unlikely to be right for a modified one.



All dizzies contain the same system for controlling when the spark occurs at different rpm - two weights and two springs. The weights are mounted on a plate fixed to the dizzy spindle. As the dizzy spindle spins faster with rising engine rpm, the weights slide outwards under centrifugal force. These then rotate the cam that operates the points - making the spark occur earlier (advancing the timing). The rate at which they are allowed to move is controlled by the springs that are connected to the points cam at one end and anchored to the fixed plate at the other. The springs are of different tensions, one controlling low rpm advance the other high rpm advance. Total advance is controlled by a stop on the points cam. These three things altogether influence what is commonly called the (centrifugal) advance curve. Altering the combinations and parameters tailors each dizzy to their respective engines.



The fourth parameter used to further control how the advance curve is applied is the vacuum advance unit. At part throttle openings, the engine isn't inhaling a full lungs-worth of fuel/air mixture, so is performing well below its dynamic compression ratio value. In other words, there's less in there to squeeze prior to ignition for the power stroke. To this end, higher ignition values can be used to produce better power and economy without detonation becoming a problem. As the dizzy is already tailored to supply the only set of values it can - being mechanical - the vacuum advance unit literally pulls the advance curve forward so it produces these required higher values. Once the throttle is opened to give more acceleration/power the vacuum is lost, and the dizzy returns to its original mechanical advance curve values.

copy and pasted from pdf file on advance curve values.

[3r!c84]

Nope didn't mess with that yet. I will in a few weeks.
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[3r!c84]

got a tag for the rear end

[3r!c84]

gotta say. the truck is faster then i thought at the track

[nbpro]

Originally Posted by 3r!c84

gotta say. the truck is faster then i thought at the track

how so ?

[3r!c84]

first run out..

r/t .129
60: 2.100
1/4 14.173
mph:94.84

[nbpro]

not bad at all

[3r!c84]

fasted run was a 14.01 they cut my off. i needed a helmet to run after then a 13.99

[nbpro]

Originally Posted by 3r!c84

they cut me off. i needed a helmet to run after then a 13.99

needed a helmet? even with a Hard Head like yours

[3r!c84]

haha i know right. forgot the timing light. or it woulda been into the high 13s

[3r!c84]

here are so crappy pics

[3r!c84]

my neighbors built pinto-wagon blew the motor up in it 10 years ago. just threw a 80s mustang 302 in it. besides that everything is race car. he left me at the light (trans brake) but i pulled him down at the big end

[3r!c84]

too high on the verttter and pushed up in deepstage. then red lit

thats all the pics i got. ran like 6 or 7 passes that night

[mwooten92]

hey man. just went through your whole build thread and uve got one bad ass motor haha. anyways ive got a question. im droping in a new motor for my truck soon and im in the process of putting all my old brackets onto the new motor and ac compressor bracket that bolts down around the header doesnt fit unless i do some modifications to it.. how did u get urs to work? cut the bracket?

-Michael

[nbpro]

Originally Posted by mwooten92

how did u get urs to work?

He didn't his dad did

[3r!c84]

Haha thanks! And yes we got a ear off to fit around the header. An made a bolt the pushes it out as if it was bolted to the manifold . I'll get a pic for you
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[mwooten92]

Originally Posted by 3r!c84

Haha thanks! And yes we got a ear off to fit around the header. An made a bolt the pushes it out as if it was bolted to the manifold . I'll get a pic for you
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alright cool

[nbpro]

Originally Posted by 3r!c84

Haha thanks! And yes we got a ear off to fit around the header. An made a bolt the pushes it out as if it was bolted to the manifold . I'll get a pic for you
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[3r!c84]

Originally Posted by nbpro

i used a manifold bolt and put a bolt on it. its in a tight spot to take a pic. sorry