Team Camaro Tech banner
1 - 8 of 8 Posts

72'camaroguy

· Registered
Joined
·
18 Posts
Discussion starter · #1 ·
i have a 72' camaro with a newly rebuilt 350 engine ,it has a holley 750 carb with vacum secondary,comp cam magnum 270H series cam with a 224 dagree duration and a .470 lift,edelbroch rpm intake, and a newly rebuilt pair of G.M. hp heads with 2.20 intake and 1.60 exhaust, my compression is 9.73:1.

my problem is that i can get the engine to run right. my engine runs rough it sounds like it has a miss, so i checked the compression all cylinders read good at 180 psi and i also checked the valve train by pulling the valve covers off and seeing if all the rocker arms where moving about the same, and they seemed to look fine. i also changed the spark plugs and most of them where oily. i started the engine up and it ran some what better but the problem was still there, when i reved the engine quilky a big flam poped out of my holley carb, and also i have black rich exhaust out my exhaust pips, so then i thought that my jetting where the wrong size, they where #72 so i decided to drop 10 sizes down so now i have #62 jets and still it's running like it was with #72 jets.and also i put a power valve pluge in just to see if it had any differaince, by stil it runs rough.i checked my engine vacume it read 10hg but was vary bouncy, so i checked if i had any vacuum leaks by spraying carb cleaner on the carb gasket and by the intake gasket but still i could not find a vaccun leak,and also i checked the hoses they where fine. also i ajusted the igniton timing at 12 degrees.

now i don't know what to do now. got any suggestions?
 
Check the level in the fuel bowls. Check for crud on the needle and seat. I had a similar problem last week because I put a used fuel filter back on backwards. All that built up crud went right for the carb!!! Yuk! It caused the carb to flood and I had lots of dark rich smelly exhaust. Hope this helps.

-Mark.
 
Is the distributor stock? Or electronic? Sounds like you have checked most everything else…. How about the plug wires? With the flame and the pop out the carb, it sounds like something in the timing / distributor and the carb to me….
Mark (A.K.A. Z28 Mark)
 
I would replace the power valve if you drop the jets 10 sizes and it dont help that sounds like you could have blown the power valve with one of thoughs back fires you can also put your hand over the top of carb to see if it settles down this will show a vac. leak also cause if you have a leak when you put your habd over top of carb it removes some of the air which then makes the mixture
closer so it then gets a more realistic idle
if it dont your pretty sure of no big leak
 
Discussion starter · #6 ·
and about the power valve. i put a power valve plug in my carb just to see if it would make my richness broblem go away but still the same problem,but the power valve plug is just temporary untell i solve my problem and then i will put in the right power valve back in.
 
don't know about the oil on the plugs, but are all the wires on the right terminals on the cap? it is easy to get 5 and 7 mixed up, for example. what is the timing set at? are the valves properly adjusted?
set the timing at 10 or so advanced, trace every sparkplug wire and make sure it goes to the right place- the firing order is 18436572, with the rotor moving clockwise as you look at it from the top- in case you didn't know. idle mixture screws 1.5 turns out, everything tight, and all vacuum hoses hooked with extra ports plugged. fire it up, and see what happens. only change one thing at a time, until it is fixed, and let us know what the problem was.

------------------
1971 Nova(looks like 69 camaro from underneath!)
355sb, vortec heads, HOT cam,T-10 tranny, 3.70 gears 16X8" IROC wheels. 12" Corvette brakes on the way.
see pics here http://community.webshots.com/user/novaderrik
 
I take it your car is running bad at idle and at all other rpm's?? If it does it at all rpm's, you've probably got crud in the carb, as mentioned above. How does it idle? Does it load up there as well? Follow the advise above...check float levels, if that doesn't clear it up, i'd pull it apart and clean everything really well and go from there. Let us know your progress.

Bob
 
1 - 8 of 8 Posts