Need help with my brain - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*zzChevy* · 02-24-2004, 08:52 PM

Hello everyone. Hope all is well.

Here is the situation, I am getting quite a bit of the eye burning
smoke. The floats are settup correctly (botton of sight hole) and I get 21 inches of vac at 1000 RPM, 17 with it in gear at 800. I've pulled the plugs once before, they were running rich.

ZZ4 350 Crate approx 90K miles

Holly 650 Double, MSD 6A, Hypertech Cap,Rotor,Coil at 53K volts. All has less than 2K miles

My next guess is going to be pulling the heads and having them run through.

Other than that, I'm all thunked out. Any other ideas?

Chris

*rage'nrat638* · 02-24-2004, 09:04 PM

lean out the air screws ....smaller jets......hotter plugs

walker · 02-24-2004, 09:08 PM

Don't know alot about holleys but "running rich" is usually a jetting issue. Could be a timing issue too, I suppose. I would not pull the heads for a rich carb. Look in the archives for Holley carb tuning tips, as that is most likely where your problem lies. The board seems to be pretty equally divided on the love/hate holley carb issue. There is a reason for that! You have to have some inate understanding those carbs, you have it or you don't. I don't, hence I like fuel injection, or carters(edelbrock).

**JDL** · 02-24-2004, 09:09 PM

don't forgit the bower valve

walker · 02-24-2004, 09:11 PM

Oh, and the Johnson rod, those are notorious. Also, might post this on the regular message board, not the parts board

*zzChevy* · 02-24-2004, 09:37 PM

This doesn't seem to be occuring off idle, only if I sit for a moment at a light or something or while I'm letting it warmup in the garage.

Would rejetting the carb have any affect at idle?

Going through the heads is almost a must, This engine has a bad rep for breaking springs. As this is not the case here, I am wanting to get them reconditioned anyways.

*rage'nrat638* · 02-24-2004, 09:45 PM

turn the air fuel mixture screws in

*rage'nrat638* · 02-24-2004, 09:57 PM

HERE'S MY 1250 DOMINATOR....
YOU THINK YOURS WILL BLACKEN A SET OF PLUGS ......
BOLT THIS ON IT

**JDL** · 02-24-2004, 10:19 PM

power valve is near the jets if is bad or the wrong one it will dump gas even at idle

MOTHERTRUCKERS · 02-25-2004, 08:35 AM

Replace the power valve and check the number on the jets, reset the float levels and mixture screws put autolite 25 plugs in it and try it, still rich drop 4 numbers on the jet size. If their 66 go to 62. You can also block off the power valve and run larger primary jets but thats a whole new ballgame.

eat · 02-26-2004, 02:55 AM

yes I would adjust the idle screws first
if the engine has backfired threw the carb
wile getting the timing set or some other reason
then it has most likley blew out the power valve if you take the carb off to replace
the power valve
they sell a kit with a little ballvalve and drill bit called a power valve saver that
is a good idea to install so you dont blow them out all the time
and it sounds like you may have
I have 2 of the power valve savers installed on my 850 double pumper
most speed shops carry them
if you have trouble finding them let me know I think i have a couple spare kits in the garage it most likley dosent need it but if you have to go to another size jets get a holley trick kit and it will come with asorted
jets gaskets pump cams and what not

if some junk got threw could be a sticky float

well thats all i got good luck

MAC67 · 02-26-2004, 03:10 AM

has anyone ever been into it ? sounds like someone has messed with the low idle cicrcuit in it , or at least that what i call it , mine does the same thing but it is set that way for a reason , no matter how cold it is outside or how long it has been running , when i stab it it goes to the moon with none of that afb st sts sttstttuddder

02-24-2004, 08:52 PM	#1
zzChevy BANNED Join Date: Dec 2003 Posts: 105	Need help with my brain Hello everyone. Hope all is well. Here is the situation, I am getting quite a bit of the eye burning smoke. The floats are settup correctly (botton of sight hole) and I get 21 inches of vac at 1000 RPM, 17 with it in gear at 800. I've pulled the plugs once before, they were running rich. ZZ4 350 Crate approx 90K miles Holly 650 Double, MSD 6A, Hypertech Cap,Rotor,Coil at 53K volts. All has less than 2K miles My next guess is going to be pulling the heads and having them run through. Other than that, I'm all thunked out. Any other ideas? Chris

02-24-2004, 09:08 PM	#3
walker Registered User Join Date: Jul 2003 Location: north of Phx AZ about 30 miles Posts: 698	Don't know alot about holleys but "running rich" is usually a jetting issue. Could be a timing issue too, I suppose. I would not pull the heads for a rich carb. Look in the archives for Holley carb tuning tips, as that is most likely where your problem lies. The board seems to be pretty equally divided on the love/hate holley carb issue. There is a reason for that! You have to have some inate understanding those carbs, you have it or you don't. I don't, hence I like fuel injection, or carters(edelbrock). __________________ Andy,Phx AZ '67 C-10 (Ahhh, done at last. Well there is that disk front end I want to put in and...) "23 C-Cab-sold '48 Ford 8N tractor(still working) '67 Scout(Now on the road) '70 MG B.-sold

02-24-2004, 09:09 PM	#4
JDL Senior Member Join Date: Sep 2000 Location: Agency IA. Posts: 1,838	don't forgit the bower valve __________________ 72 Chevy short step side with 454 air and tilt. 72 nova project car 63 chevy II drag car Agency Iowa

02-24-2004, 09:11 PM	#5
walker Registered User Join Date: Jul 2003 Location: north of Phx AZ about 30 miles Posts: 698	Oh, and the Johnson rod, those are notorious. Also, might post this on the regular message board, not the parts board __________________ Andy,Phx AZ '67 C-10 (Ahhh, done at last. Well there is that disk front end I want to put in and...) "23 C-Cab-sold '48 Ford 8N tractor(still working) '67 Scout(Now on the road) '70 MG B.-sold

02-24-2004, 09:57 PM	#8
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	HERE'S MY 1250 DOMINATOR.... YOU THINK YOURS WILL BLACKEN A SET OF PLUGS ...... BOLT THIS ON IT Last edited by rage'nrat638; 07-12-2007 at 07:07 AM.

02-24-2004, 09:04 PM	#2
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	lean out the air screws ....smaller jets......hotter plugs

02-24-2004, 09:37 PM	#6
zzChevy BANNED Join Date: Dec 2003 Posts: 105	This doesn't seem to be occuring off idle, only if I sit for a moment at a light or something or while I'm letting it warmup in the garage. Would rejetting the carb have any affect at idle? Going through the heads is almost a must, This engine has a bad rep for breaking springs. As this is not the case here, I am wanting to get them reconditioned anyways.

02-24-2004, 09:45 PM	#7
rage'nrat638 Account Suspended Join Date: Mar 2003 Location: THE FALL GUY CHICAGO IL Posts: 5,883	turn the air fuel mixture screws in

02-24-2004, 10:19 PM	#9
JDL Senior Member Join Date: Sep 2000 Location: Agency IA. Posts: 1,838	power valve is near the jets if is bad or the wrong one it will dump gas even at idle __________________ 72 Chevy short step side with 454 air and tilt. 72 nova project car 63 chevy II drag car Agency Iowa

02-25-2004, 08:35 AM	#10
MOTHERTRUCKERS Registered User Join Date: Dec 1999 Location: BRADENTON FLA Posts: 3,269	Replace the power valve and check the number on the jets, reset the float levels and mixture screws put autolite 25 plugs in it and try it, still rich drop 4 numbers on the jet size. If their 66 go to 62. You can also block off the power valve and run larger primary jets but thats a whole new ballgame. __________________ Rest in Peace Ed. Thanks for all the good times.

02-26-2004, 02:55 AM	#11
eat Registered User Join Date: Aug 2001 Location: WA Posts: 43	yes I would adjust the idle screws first if the engine has backfired threw the carb wile getting the timing set or some other reason then it has most likley blew out the power valve if you take the carb off to replace the power valve they sell a kit with a little ballvalve and drill bit called a power valve saver that is a good idea to install so you dont blow them out all the time and it sounds like you may have I have 2 of the power valve savers installed on my 850 double pumper most speed shops carry them if you have trouble finding them let me know I think i have a couple spare kits in the garage it most likley dosent need it but if you have to go to another size jets get a holley trick kit and it will come with asorted jets gaskets pump cams and what not if some junk got threw could be a sticky float well thats all i got good luck __________________ 1972 Cheyenne Longhorn C30 Big block Turbo 400 Eaton Corporate 410 rear with Detroit locker

02-26-2004, 03:10 AM	#12
MAC67 " SHOW ME" Join Date: Jan 2003 Location: shelbyville illinois Posts: 2,624	has anyone ever been into it ? sounds like someone has messed with the low idle cicrcuit in it , or at least that what i call it , mine does the same thing but it is set that way for a reason , no matter how cold it is outside or how long it has been running , when i stab it it goes to the moon with none of that afb st sts sttstttuddder



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