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Discussion Starter #1
Hello All. Here is the problem. My engine pasues or hesitates when I mash the gas to the floor. After the hesitation it then gets up and goes. I have checked and adjusted the timing to 6BTDC as specified in a Chiltons repair manual. The idle is set correctly and I have no issues when starting the car. Even after the car warms up the pause or hesitation continues. No smoke and no leaks. I recently put some Crane Posi Stop lock nuts on to keep the Rocker Arms nuts from backing off. This has been a reocurring problem having to readjust them when the rocer arms begin to tap or make noise. When readjusting the valves I adjusted them as Crane reccomends by turning the engine in the normal direction of rotation until the exhaust pushrod starts to move up, then adjust the intake valve to zero lash with no preload, then between 1/2 to 1 turn more. Then turn the engine over again until the intake opens completely and then is almost all the way back down then set the Exhaust to zero lash. The specs are as follows... 350 4 Bolt bored .030, Forged .030 over Speed Pro Pistons, Crane Hydraulic CAM and lifters Cam is 480 int 494 exh grind h-228/3200-2s-6 operation range is 2800 to 6500 RPM's part number is 110591, Edelbrock Tranchula Single Plane Intake, Holley 670 Street Avenger, Turbo 350 tranny with heavy sprags and clutches (mild kit) plus transmission cooler, 3500 TCI stall converter, 2 1/2" Exhaust with balance chamber and 40 Series Flowmasters, and 12 bolt limited slip rear with 410 gears. Any help with this problem will be greatly appreciated.
 

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Don't know if this would help, but with the engine off, I would open the throttle while looking down the carb bores. If there's no gas, could be a bad accelerator pump.Or could be jetted wrong. Does it have the stock vacuum advance? Are you setting the timing with the vacuum hooked up or unhooked? Try setting the timing a little more advance. You are setting the timing by Chiltons which is for a stock engine but you have an after-market cam. What does crane suggest for that cam?
 

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Discussion Starter #3
Gas is good. And the Distributor is a Mallory UNI-LIGHT Electric with no Vacuum advance. I will check Crane for the specs on the timing with this particular cam. When I do adjust the timing I have been leaving everything connected and just have been adjusting the position of the distributor. Thanks for the input. If you have any more suggestions please feel free to add. I wonder if I could just toy with the timing by adjusting and then opening up the carb to see if the engine pauses when initially opened up to full throttle. Then if it does make another adjustment and try again. Let me know what you think.
 

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lewisdanw said:
Gas is good. And the Distributor is a Mallory UNI-LIGHT Electric with no Vacuum advance. I will check Crane for the specs on the timing with this particular cam. When I do adjust the timing I have been leaving everything connected and just have been adjusting the position of the distributor. Thanks for the input. If you have any more suggestions please feel free to add. I wonder if I could just toy with the timing by adjusting and then opening up the carb to see if the engine pauses when initially opened up to full throttle. Then if it does make another adjustment and try again. Let me know what you think.
You could try adjusting the timing with a vacuum guge. Just turn the dist. back and forth until you find the maximum vacuum.
 

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Discussion Starter #5
I will take a look at that. Perhaps I could pick one up locally or from JEGS. Thanks for the advice. How would this hook up? Would it connect to the Carb? The distributor does not have a vacuum connection since the advance is electronic.
 

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lewisdanw said:
I will take a look at that. Perhaps I could pick one up locally or from JEGS. Thanks for the advice. How would this hook up? Would it connect to the Carb? The distributor does not have a vacuum connection since the advance is electronic.
Find vacuum below the carb.
 

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The Smell of Nitro in the morn
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Just use a intake vacuum port to the gauge, adjust in gear to highest vacuum on carbs idle screws.
A bog is to big of a squirt. This was just talked about last week on the same carb. I recommend on changing the squirters 3 #s under what they are now.
With that setup you wont really lite up until 3200 rpm at least.
I missed something on the use of this motor, 3500 stall plus the rest of the combination on the street with your setup I question.
On the valves, I would adjust them while running.
 

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Discussion Starter #8
Below is the information for the cam that I am running. I am trying to determine what the timing should be since there are some different pieces of information in this chart. I am thinking that it should be set to 12BTDC but I may be wrong and just wanted to get a second opinion. Let me know what you think. Thanks again for the help.

Part Number: 110591 Grind Number: H-228/3200-2S-6
Engine Identification:
Start Yr. End Yr. Make Cyl Description
1957 1987 CHEVROLET 8 PERFORMANCE USAGE, GOOD MID-RANGE TORQUE AND HP, BRACKET RACING; STREET, HEAVY, ETC., AUTO TRANS W/3000+ CONVERTER, 10.0 TO 11.5 COMPRESSION RATIO ADVISED. BASIC RPM 2800-6200
Engine Size Configuration
262-400 C.I. V

Valve Setting: Intake .000 Exhaust .000 HOT

Lift: Intake @Cam 3200 @Valve 480 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 3294 @Valve 494
Rocker Arm Ratio 1.50

Cam Timing: TAPPET @.0040
Lift: Opens Closes ADV Duration
Intake 36 BTDC 68 ABDC 284 °
Exhaust 71 BBDC 39 ATDC 290 °

Spring Requirements: Triple Dual Outer Inner
Part Number 99846
Loads Closed 115 LBS @ 1.750 or 1 3/4
Open 303 LBS @ 1.290
Recommended RPM range with matching components
Minimum RPM 2800
Maximum RPM 6200
Valve Float 6500

Cam Timing: TAPPET @.050
Lift: Opens Closes Max Lift Duration
Intake 12 BTDC 36 ABDC 102 228 °
Exhaust 47 BBDC 7 ATDC 110 234 °
 
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