What effect will a blown power valve have on the operation of a Holley 4 barrel?? All of a sudden, 2 days ago, the car started running real rough and backfiring out the headers pretty bad. If it wasn't for a couple of rodder friends that just happened by, I never would have made it home. We never could get it running right even tho there was fuel getting to the carb. The primary bowl was pulled off and the float setting appeared to be normal when inverted. Couldn't tell about the jets. The squiters were also working normally. I might pull it off today but at the moment, I'm out of ideas. I've never had so much problems with a carb before and the thought has passed my mind to pull the Edelbrock off and reinstall the old cast iron manifold and go buy a new original 2 barrel for it. About as trick lookin as a red baloon that just burst!... The Holley is a 390 cfm 4 barrel. Anyone know where I might find a thermite grenade?? lol FredP
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Fred P.

Fred, Pull your plugs abd take a reading. Check to see if they are carbon fouled.
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The "New" and Unimproved edcroozer... Charter D.S.R.A. member

They are fouled Ed and there's a lot of carbon at the turn out tips. FredP
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Fred P.

Well Fred,,,Theres the popping, You may want to check your jetting, you may want to go down a few jet sizes. Too rich.
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The "New" and Unimproved edcroozer... Charter D.S.R.A. member

Ed, it's been fine for at least a couple of months then started the backfiring and then stopped running all together. It's kinda embarassing to have some friends bring ya home on a trailor. I'll probably look at it tomorrow but I'm not even sure where to start. That's why I asked if the power valve might be bad. I never had one go bad on me before and was wondering what the symptoms would be. I have a fuel regulator set on it to 2.5 lbs and that's been the "sweet" spot for a long time. I've always wondered why it wouldn't run directly from the mechanical (original) pump. I might be taking the chicken way out when I pulled out the original 2 barrel intake today and wondering about just getting an original carb and if it runs ok, just getting the intake manifold powder coated. FredP
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Fred P.

Fred, try this site to find out what's going on in your Holley. http://www.bob2000.com/carb.htm Best site I've found for diagnosing a Holley
Rochie

Thanks Rochie! Good site.. went out and tried it for grins and it cranked right up and ran fine...took it around the block and fine until I pulled into the drive, then it started backfiring again and quit. Somethine is heating up and it may not be the carb after all as I recently installed and MSD "Blaster" coil and something may be breaking down after heating. Think I'll go down to the local electronics emporium and pick up a can of circuit cooler. This stuff works better that freon!! LOL If it's not the Holley, I'll apoligize to the gods of carburators and throw myself on their collective mercys!! Thanks all!
Sure wish I had room for the original HEI and am looking at a "hole maker" (sawzall)! FredP
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Fred P.

Fred, probably not it, but just to be on the safe side I'd check the fuel filter while your diggin' around. Had one clog on me...one minute fine the next minute it sounded like Independence Day including fireworks out the pipes when it was blocked off.

All this thanks to the moron that built my first aluminum gas tank out of STREET SIGNS! I learned that gas + street sign paint dont mix. Talk about a gummed up mess!
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DSRA Earlybird Member / Co-Founder..
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If it dont fit, shoe-horn it!

How many thermite grenades do you need?(lol)
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Lynn Stallbaumer

Just one! It would set neatly into the middle of the Holley! Saw a demo in the Army of one going right thru a company safe and I WAS impressed! FredP
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Fred P.

Fred..Holleys are a bit tricky but it looks like you have the first clue with a regulator..they hate high fuel pressure. Secondly, the power valve can blow out if the engine back fires through the carby..result is a gut full of fuel at idle. Most Holley problems can be overcome with a a partial stip down and a blow out with compressed air. An inspection of the power valve will the metering plate is off is easy...I just suck on them and see if they pull in. The gaskets sometimes break up when you pull them down, so get a new fuel bowl, metering plate and power valve gasket before you start...One more suggestion, if you have a good inline filter, remove the holley gauze/stone filter from the inlet..they will you down and can break up with reactions to fuel in time .

see ya
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see ya
Pep

Thanks Pep! Sounds like you've been down the same road too. I still have a new power valve from the last kit I bought for the gaskets and needles.
Awhile back I found a problem or rather thought I found a problem of a bad coil and bought the MSD "Blaster" and when that didn't cure it, I went inside the Mallory dual point and found that one of the wires that plugged into one of the point sets was , as far as I could tell, was shorting due to the very restricted space. I found what caused that and it was the feedthru screw where the capactor connects on the outside. When installing the wire from the distributer, I tightened the nut down too hard and it turned the inner connection and pulled the one wire tight and against ground shorting the points. I eventually ended up grinding a 5/16 open end thin enough to fit over the outside nut so the wires could be tightened down without turning the thru screw and turning the inner wires. Another one of life's little lessons to not assume Murphy isn't looking over yur shoulder when doing small work!! The only reason for the Mallory in the first place was not enough firewall room. I may rectify that and cut out the necessary clearences and rebuild it with one of the pieces on the market. Thanks all
FredP
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Fred P.

Fred, before you start whacking a hole in your firewall, have you thought about an original Delco distributor with a Pertronix conversion in it??? I know there are a lot of differing opinions on Pertronix but all I can say is that I have had one in my 57 for 3 years and not a lick of trouble. I had to go to an original dist. to clear the Tri-power. Works great for me !!!
Rochie