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  #16 (permalink)  
Old 01-26-2008, 06:28 PM
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Quote:
Originally Posted by talleyho
i will check wires again 5 and 7.yes i used a new base gasket.you said shoul be 18on gaugh.at idle or in drive?i will check compression with cap off.the distributer advace hose is connected to BASE OF CARB PORT.20 deg of advance i HAVE HEARD on a web site with a guy with a 307.i will try.
thanks yall.oh one thing i did change before installing engine was HEADERS and the exhaust is DYNAMAX.
18 at idle in gear or not it really should not matter much. If you used a new gasket make sure it is the corrrect one.
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Old 01-26-2008, 07:38 PM
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backfire

First things first: Set your timing: for a base-line, plug your vacuum advance hose and set your timing at 6 degrees BTDC. With the timing set still connected, hook up your vacuum advance hose and see if your timing advances. If it doesn't, your vacuum advance is defective.
Now, with the timing light still connected, plug your vacuum advance hose again. Slowly open your throttle while watching your timing mark. Your timing should advance. If it doesn't, your centrifigual advance is stuck (typical with HEI distributors). Either one of these problems will cause hesitation and backfire. Fix your timing first, then you can concentrate on the rest of the tune-up. You may pm me if you want to know an easy way to set total timing for 36 degrees.
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Old 01-28-2008, 12:08 PM
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y112 i did what you said and yes it will advanced with both of your suggestion.i ALSO tried cliping something to the bottom of my vac sec rod to see if it would even open and in park revig up OR IN DRIVE whether i punched it or slowly built it up the cliped thing NEVER seemed to move so.i THINKthe secondarys arent even opening which would cause bogging like it is and a lean backfire.but why still would the plugs be sooty?maube to big a primary jets im going to order a 2 sizes down spring today.
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Old 01-29-2008, 09:03 PM
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actualy i ordered 6 sizes down to make sure.
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Old 01-29-2008, 09:29 PM
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Do you have a vacuum secondary diaphram carb.?
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Old 02-02-2008, 02:35 PM
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yes its vac secondary.today i put the 60 jets in over the stock 66 and sounds like its not getting enough gas .really slow excelerations and backfires with smoke and flame through carb alot mor than befor.sounds like really tryen.goin to check if its i tooth off but HOW oh HOW can it make ANYDIFFERNCE if you can just twist the distributor ro change spark advance or retardd???? should i try puttin 63s in???
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Old 02-02-2008, 03:26 PM
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back firing ?

I don't know the answer to that, but I'm sure someone will.
I used to set the timing mark on 38 deg. advanced. with rhe engine not running, but the switch on, Retard the dist. With and induction timing light on # 1, I'm slowly advance the dist. until the light flashed ( do't look at it, shine it at something) then lock it down. If you can't get it to flash, its probably off. dist. off a tooth.
Usually if you watch the timing, and varies the chain's worn, bad dist. gear, or worst case the cam.
I always found that if it backfires, the valves are not in time with the spark.
Make sure the inside of the cap is clean, (no carbon) and watch it at nite and make sure the wires aren't cross firing, it should show a spark jump from wire to wire.
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Old 02-02-2008, 05:18 PM
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Quote:
Originally Posted by talleyho
yes its vac secondary.today i put the 60 jets in over the stock 66 and sounds like its not getting enough gas .really slow excelerations and backfires with smoke and flame through carb alot mor than befor.sounds like really tryen.goin to check if its i tooth off but HOW oh HOW can it make ANYDIFFERNCE if you can just twist the distributor ro change spark advance or retardd???? should i try puttin 63s in???
It almost sounds like your distrubtor is 180 degrees out..
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Old 02-03-2008, 10:51 AM
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its sounds to me like you should put the 66s back in and take your dist cap off get the number one cylinder up on top dead center and look at your rotor button and see if its lined up with number one on the number one dist cap wire [the wire going to number one spark plug]if it is then you should be good to go the timing would have to be awful low to make it loose power and you would have a problem starting it ,but if the rotor button end that has metal on one end and not on the other the metal end has to be the end that is lined up with the dist.wire number one if its the other end its 180 out so take the dist straight up not all way out[just enough to be able to spin rotor button around freely] hold base firmly and turn top rotor clock wise around to point to number one cylinder,,then you will be good to go and make sure when turning you hold the bottom part of dist tight so the advance on the dist dont move out of its position a whole lot.hope this helps.
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Old 02-03-2008, 12:12 PM
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If the distributor was 180 out the car would not run. If the timing can be adjusted as recomended above to about to 6-10 BTDC then the distributor is ok, it may not be oriented correctly but that doesnt matter really except to help the next guy working on it.
Your vacuum secondaries will never open reving it up in park, they dont work that way, they requirre engine load to open. This has been covered in many threads if you care to look it up.

You need to find out why the vacuum is low, did you replace the timing chain by any chance.
Vacuum leaks are usually easy to locate with a can of carb cleaner or WD-40

You said you had the distributor and carb off, was anything else removed like the intake, timing chain, etc.

get back to us

Chet
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Old 02-03-2008, 12:18 PM
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I would not start changing jets or anything else about the carb until you find the vacuum issue. Changing jet sizes or squirter sizes is not going to help the idle vacuum. This is your best symptom right now, if you find the cause it will probably fix the other issues. If you start playing with to many things you are going to end up in deeper trouble than you are right now.
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Old 02-03-2008, 02:19 PM
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holley backfiring thro carb.

Everybody keeps talking about the dist. being 180 out. I have never had a chevy v8 to be 180 out start, more less run? Now how do you do it? He did say it cranked, but backfired through the carb.
Lets start over, Pull # 1 plug, disconnect the power to the dist. Now with help to spin over the engine, using the switch, put your finger in the plug hole if possible and have them slowly bump the engine over until it blows your finger out off the plug hole and stop. Now check where the rotor is pointing. If it at # 1 or close it in right. If not the dist. is in wrong. If you can turn the dist. to make it point to # 1 it alright, but if not, it out.
He didn't say this was the same carb. that came off the engine when it ran as I remember? Or the same dist. ?
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Old 02-03-2008, 02:27 PM
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I gotta agree w/ t-bucket on this one!! there are too many variables if you try to fix allot of problems all at once,jumping from one system to another! your problem started when the carb and distributor changed right?!! NEVER make a jet change more than 2 no.'s to change mixture. working with Holley carburetors for ever, most off-idle bogs are fixed by changing the squirter from a #28 to a #31. but just changing system after system to fix a problem, is sheer madness!! Make sure you don't have a vacuum problem,then check your distributor and it's settings, BEFORE changing any carb settings!
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Old 02-03-2008, 02:46 PM
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Quote:
Originally Posted by lanierledford
Everybody keeps talking about the dist. being 180 out. I have never had a chevy v8 to be 180 out start, more less run? Now how do you do it? He did say it cranked, but backfired through the carb.
Lets start over, Pull # 1 plug, disconnect the power to the dist. Now with help to spin over the engine, using the switch, put your finger in the plug hole if possible and have them slowly bump the engine over until it blows your finger out off the plug hole and stop. Now check where the rotor is pointing. If it at # 1 or close it in right. If not the dist. is in wrong. If you can turn the dist. to make it point to # 1 it alright, but if not, it out.
He didn't say this was the same carb. that came off the engine when it ran as I remember? Or the same dist. ?
Years ago when I was working for a engine builder we had 1 towed in from another shop doing the same thing. It did run if I kept my foot in it.
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Old 02-03-2008, 03:04 PM
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my vaccum at idle after warm up is about 20.i think thats a good number.plugs look better running the 60 jets.didnt run it long though gets hot fast cause no fan shroud.i didnt take it out.im gonna check the compretion in a minute.and see where the rotors pointen.
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