Re: Just returned from the track....Something is wrong!
[Re: 64Post]
#254921
03/17/09 01:42 PM
03/17/09 01:42 PM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Well, I suggest you fix the obvious problems first. The 5/16" fuel line you are running is too small. That blue Holley pump you are using has a 3/8" NPT on the "in" and "out" for a reason. I'm not sure what a decent CR means, but with that cam ( it is an older grind ), you my very well not be able to run todays pump gas by the time you get the DCR where it should be to make power in the 3-4 grand area.
Fastest 300
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Re: Just returned from the track....Something is wrong!
[Re: Mr.Yuck]
#254923
03/17/09 01:57 PM
03/17/09 01:57 PM
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Joined: Jan 2003
Posts: 4,085 Indiana
W5Duster436
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master
Joined: Jan 2003
Posts: 4,085
Indiana
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Just curious, were the compression tests that yielded 140 done with the carb open or closed? I can see the 140 if the throttle was not strung open.
'70 Duster - SDSS 436 W5 4spd (Gone) '71 Dodge D100 '70 Dodge W100
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Re: Just returned from the track....Something is wrong!
[Re: Mr.Yuck]
#254924
03/17/09 02:00 PM
03/17/09 02:00 PM
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Joined: Aug 2003
Posts: 8,716 Baltimore/Denver
64Post
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
"The 5/16" fuel line you are running is too small" I'll say it again your fuel line is fine. You can run 11's w/ a 5/16 ine and mech pump...even w/ a 440-6 in a B-body. If it's fuel issue you either have a clogged filter or you car is lean. changing the line to 3/8 won't do squat.
I agree. I'm running a 450" B engine with CNC Eddys, a big solid cam a 950 HP with a 5/16 fuel line. Fuel delivery is not a problem.
Quote:
If you have 140 across the borad you have a compression problem...either your valves are a tad open or you don't have the 11:1 you thought you had.
Also agree.
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Re: Just returned from the track....Something is wrong!
[Re: 64Post]
#254926
03/17/09 04:14 PM
03/17/09 04:14 PM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
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Joined: Oct 2003
Posts: 7,506
Az
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Straight from a very well known carb MFG. " When your car isn't performing, alswys carry out the gas can test first - it's one of the least expensive diagnostic aids you will encuonter. Keep in mind that valve springs, ignition systems, torque convertors, even engines have been changed, when all the time the fuel system was at fault". I give on the line size ( but it's too small ) - if you wanna run in the 12's, your gonna have to fill a 1 gallon can in 35 seconds or less - from Barry Grant, Holley, and others. If you can do it with a 5/16" line, God bless you! Hope everyone remembers this thread when there motor goes lean through the second MPH lights and sections of the top ring lands on their hypereutectic pistons start exiting out their collectors! Been there - done that!!!!!! Here is a web sight with a ton of really good on line calculators: http://www.csgnetwork.com/compcalc.html
Fastest 300
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Re: Just returned from the track....Something is wrong!
[Re: Crizila]
#254927
03/17/09 04:32 PM
03/17/09 04:32 PM
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Joined: Feb 2003
Posts: 12,675 Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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I've also supported 550hp with a factory mechanical and 5/16 line. Many lines now have kinks and guy dont cut them properly so the flow is much lower than it should be. That fact is, overkill sells, and in many cases, meaning a car that runs in the 12s or high 11s, they simply dont need that much pump or line. In somecases, you add so much volume in the line the milder pumps have trouble pumping against the inertia of the fuel in the line in first gear.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Just returned from the track....Something is wrong!
[Re: moper]
#254928
03/17/09 05:51 PM
03/17/09 05:51 PM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
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master
Joined: Oct 2003
Posts: 7,506
Az
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overkill = cheap security. If you are pushing the edges of the envelope, you will only go lean once! Could I see a show of hands of those on this thread that even have a fuel pressure guage in their car?
Fastest 300
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Re: Just returned from the track....Something is wrong!
[Re: HealthServices]
#254932
03/17/09 10:11 PM
03/17/09 10:11 PM
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Joined: Aug 2003
Posts: 8,716 Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
Quote:
overkill = cheap security. If you are pushing the edges of the envelope, you will only go lean once! Could I see a show of hands of those on this thread that even have a fuel pressure guage in their car?
for two cars
Dude, is that Hitler, or what???
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Re: Just returned from the track....Something is wrong!
[Re: 69L78Nova]
#254934
03/17/09 10:27 PM
03/17/09 10:27 PM
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Joined: Aug 2003
Posts: 8,716 Baltimore/Denver
64Post
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
Theyre not flat tops. They have a .050" quench dome, and a .039" head gasket, sitting .009 in the hole...with a .050" recess machined in the chamber
So do you have all the piston numbers to run the calcs (dome volume, valve reliefs, chamber volume, etc.) starting with the static CR? Cam card?
You can also work backwards using your known cranking pressure of 140# to come up with a theoretical static CR.
I'm at a loss to explain how a small fuel line effects cranking compression readings. Unless of course the motor already went lean and pinged itself on to life support.
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Re: Just returned from the track....Something is wrong!
[Re: moper]
#254935
03/17/09 10:31 PM
03/17/09 10:31 PM
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Joined: Aug 2003
Posts: 8,716 Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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Quote:
I've also supported 550hp with a factory mechanical and 5/16 line. Many lines now have kinks and guy dont cut them properly so the flow is much lower than it should be. That fact is, overkill sells, and in many cases, meaning a car that runs in the 12s or high 11s, they simply dont need that much pump or line. In somecases, you add so much volume in the line the milder pumps have trouble pumping against the inertia of the fuel in the line in first gear.
There have been many threads on that subject. There is also the matter of friction loss in the lines. The more pressure you force through the line the higher the friction loss.
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Re: Just returned from the track....Something is wrong!
[Re: 69L78Nova]
#254939
03/17/09 11:26 PM
03/17/09 11:26 PM
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Joined: Dec 2007
Posts: 7,759 So Cal
HealthServices
Why would you even post that?
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Why would you even post that?
Joined: Dec 2007
Posts: 7,759
So Cal
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So you checked preload and adjusted it by using shims?
Allen
Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first.
Life was a little easier when I was just a wrench.
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Re: Just returned from the track....Something is wrong!
[Re: HealthServices]
#254940
03/17/09 11:28 PM
03/17/09 11:28 PM
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Joined: Jan 2003
Posts: 9,826 las vegas
70AARcuda
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Joined: Jan 2003
Posts: 9,826
las vegas
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you can run the stock non adjustable rockers with the eddy heads with a hydraulic cam...
been there...done that...
Tony
70 AARCuda Vitamin C 71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield) 71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas) 71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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