farting carb??

Uli · Posted: Thu Jun 12, 2008 12:26 pm Post subject: farting carb??

Hello,
I have a brand new holley 600 on my 305 '79 still i get some farts out of it (By farting i mean there are little explosions of air kind of).
I'm hoping it's not a broken valve. What could cause this problem? Bad wires? Bad spark plugs??

Thanks

CoyoteOn2 · Posted: Thu Jun 12, 2008 3:24 pm Post subject:

Crossed plug wire, timming, cracked Dist. cap, flat cam lobe, out of adjustment Carb., Valve, lifter, just to name a few. Even the Power valve in the Carb if it's an older carb. will blow if the car backfired at some point.
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awest · Posted: Thu Jun 12, 2008 5:08 pm Post subject:

I would suspect the power valve, too.
Main reason I have junked ALL my Holley carbs.
They very seldom seem to operate correctly.

Uli · Posted: Fri Jun 13, 2008 12:04 pm Post subject:

Thanks for the replies.
The carb is brand new and tuned up, spacer is new. I'm going to check the wires and i'm hoping it's not the valves...
If it's valve related, how can i check it out??

CoyoteOn2 · Posted: Fri Jun 13, 2008 12:29 pm Post subject:

First ~~~ Try a compression test.

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Keep the Shiney Side Up
The Rubber Side Down !!
aka Larry

awest · Posted: Fri Jun 13, 2008 1:31 pm Post subject:

Replace the Power Valve, IN the carb.
I saw no mention of intake or exhaust valves.
MAJOR difference between the two.

Uli · Posted: Wed Jun 18, 2008 4:54 pm Post subject:

alright so i'm trying to go in $$ order...
So i've just replaced the 8 spark plugs, they were old and dirty. All wires were unplugged one after another with only 1 wire unplugged so i don't mess up the wire order. I've charged my battery to 85% (was at 50%). Before that i could start it up but now with new spark plugs, it won't go anymore. The weird thing is, after a few tries, it was acting like the battery was down, so i plugged in my charger/checker unit and it reported 80%. So it's like no matter how strong my battery is, after a few tries, it dies, acting like the battery is down. The best chances i have are for it to start in the early seconds. It's like something gets hot and there's too much friction or something... then it won't turn no more...
Any idea??

CoyoteOn2 · Posted: Wed Jun 18, 2008 8:32 pm Post subject:

With what you have been discribing,"popping in carburator ~~~ now ~~ don't turn no more", it sounds like you have more than ONE PROBLEM.
A severley out of time motor, could give you similar results "Carb backfire and starter drag". Another thing, Starters will burn up in a heart beat if it is cranked for to long without having a chance to cool. Never crank a starter longer than 10 seconds without a cooling down period. Your last discription does sound like you have Starter Drag, and after it heats up, it binds so to speak == Bad / Weak and failing Starter.
NOW--- That could also be caused by a bad or faulty connection. Clean and tighten both battery cables at the Battery, check for a good clean tight connection at the starter + Battery cable, and a good clean / tight connection of the battery cable Engine ground. After that, if it still drags after a few short tries of starting, have the starter checked, it may need replacement. As far as your original issue goes, that can not be addresed
untill it is determined why it won't turn over enough to get it started.
_________________
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Keep the Shiney Side Up
The Rubber Side Down !!
aka Larry

CANTED · Posted: Wed Jun 18, 2008 8:46 pm Post subject: no start

I agree with Larry ^ on the starter/connections but never rule out the battery. Regardless of what a tester says, batterys don't play by any rules.
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CoyoteOn2 · Posted: Wed Jun 18, 2008 9:11 pm Post subject:

Boy are you SOOOOO Right on that Jim, all it takes is one bad or shorted cell to mess up ones WHOLE DAY.
_________________
http://elcaminocentral.com/gallery-album_CoyoteOn2s77Cage.html

Keep the Shiney Side Up
The Rubber Side Down !!
aka Larry

CoyoteOn2 · Posted: Thu Jun 19, 2008 6:21 am Post subject:

Uli READ THIS link http://www.aa1car.com/library/us1296.htm and this one http://aa1car.com/library/no_spark.htm
_________________
http://elcaminocentral.com/gallery-album_CoyoteOn2s77Cage.html

Keep the Shiney Side Up
The Rubber Side Down !!
aka Larry

Uli · Posted: Thu Jun 19, 2008 11:45 am Post subject:

Thanks for the tips fellas.
So i've changed progressively the distributor angle and it really seemed to help as this time it almost started (it had troubles getting a good combustion but was better than before). I can't do any more tests for now as my battery is down again from the morning tests. I've checked again my wires, installed a new battery to starter wire, even installed some spark plug wire plastic spacers. My battery is back on charge.

Uli · Posted: Thu Jun 19, 2008 12:34 pm Post subject:

Quick question : Do i need to hook on the valve covers a vacuum line and one breather cap or 2 caps is good enough?

dwagner1974 · Posted: Thu Jun 19, 2008 2:07 pm Post subject: Carb problems !!

I would recommend running a vacuum line with a PCV valve in one valve cover if you use it as a daily driver or drive it on the street alot . The PCV valve will help your vacuum advance on your distributor(which could be one of your problems ), power brakes and any other vacuum operated accessories operate properly . If you are using it as a race car the the two breather caps are just fine . I would have to agree with what the guys said earlier . I would check your timing first . If its totally out of time it will cause backfires thru the carb and cause it to drag when trying to start it . I would also replace the plugs,wires,distibutor cap and rotor button . These are very inexpensive . If you use an older Holley Carb when your engine backfires it usually blows the power valve . You might want to research that avenue also . If your carb is not new out of the box within the last couple years then it probably doesnt have power valve blowout protection . After you change all those things check to make sure you have your plug wires on in the correct order . 100% no doubt . Start by finding your #1 plug wire and go from there . The correct firing order is 1-8-4-3-6-5-7-2 in a clockwise pattern . I would also play with the timing a little . Loosen up the distibutor hold down just enough to be able to turn it with slight pressure .. not too loose .. Then start by turning all the way to the left counter clockwise to where the vacuum advance is against the right side valve cover try to start it . then move it just a tad each time and try to start it .. repeat this process and it will start .. if you smell a strong odor of gas let it sit a few minutes before trying to start it again to allow the starter to cool and the gas to mostly evaporate .. you will get it .. One quick question .. At anytime did you remove the distributor ?

Good luck !!

Dennis
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awest · Posted: Thu Jun 19, 2008 2:22 pm Post subject:

Would be wise to at least hook-up a line to the PCV.
Should help evacuate the internal crank-case pressure build-up.
If not, you will be blowing seals.