The carb is most effient at high rpms and crap at low...thats the draw back of carb over injection.

I figured it just need a new carb maybe a 600 holley cfm vacuum secondary and the timing figured out. what do you guys think?

Yep you are on to it

i took the car to a machanic to have timing set and he couldnt get it set.

Find a new mechanic m8...did he do basic compression test?
And timing, just find TDC #1 at at top of firing stroke...rotor pionting forward. and take from there...
Oh you may find that the secondary butter flys are set to far open to be able to get any adjustment out of the mixtures...close them down with adjusting scew to just off fully closed 1st.

 

If your mechanic cannot set the timing, you will need to find someone who can. I recommend learning how to do that yourself. Search the forums and read up. It is not hard, if you understand it.

You should also make sure the ignition system is working properly before messing with the carb.

The old design intake on vortec heads does not have the best port alignment. double check to make sure there is not a leak at the intake to head joint. you may be sucking some oil from under the manifold into the cylinders?

TTFN
Mat

 

Ii took the car to a mechanic to have timing set and he couldn't get it set. he also tried adjusting on the carb but said since he couldn't figure out the timing strip on balancer and the timing set up on timing cover there was no since in messing with carb.

He couldn't find top dead center? I don't recommend you ever go back to him. Like mentioned before, you should learn to do this yourself. Its VERY easy. To index top dead center you need to get a piston stop. you can pick them up for a few bucks anywhere. Screw it into the number one spark plug hole. Turn the crank by hand until it stops.... loosen the stop a quarter turn, SLOWLY trun the crank by hand till it hits. paying attention to the timing strip and the pointer.... keep repeating this until it clears. this is top dead center. I mark it with an awl, but you can use a sharpie marker.... then that is 0. then its simple math from there to set the timing.

 

He couldn't find top dead center? I don't recommend you ever go back to him. Like mentioned before, you should learn to do this yourself. Its VERY easy. To index top dead center you need to get a piston stop. you can pick them up for a few bucks anywhere. Screw it into the number one spark plug hole. Turn the crank by hand until it stops.... loosen the stop a quarter turn, SLOWLY trun the crank by hand till it hits. paying attention to the timing strip and the pointer.... keep repeating this until it clears. this is top dead center. I mark it with an awl, but you can use a sharpie marker.... then that is 0. then its simple math from there to set the timing.

ya the guy has like 30k in tools and his own shop. I think he was just tired and didnt feel like messing with it. he had worked on a dump truck all day and wife came down to shop and was wanting him home lol. think i just got blowed off. he has the tools best of the set of tools to have fixed it just think he was burned out. ill try and fix the timing myself. i also bought a 650 holley vacuum secondary carb today along with a fuel pressure guage. maybe i can figure something out. the intake on heads is a old style scorpion intake thats been modified to fit on the vortec heads. guy stuck somebolts in wholes that wouldnt be used and JB welded them up.

 

Robert..sqaure away your ignition timing first or you will be chasing carb issues forever.Timing first..carb second.Fine tune the spark curve and then finish up on the carb tweak.
Get this right on an engine with no blow by and watch your plugs clean right up.:yes:

 

You are going to need a good spark curve with that Scorpion intake. Most street cars like 16o to 18o initial, 36o total. Get that set first. Then onto the carb.

Get the carb back to its baseline. Find out what Holley you have. Put the original jets in. Set the transfer slots on the primary side to .020". The transition slots should look like squares when looking from the bottom of the carb. Set the primaries this way and leave them there. Then set you idle speed using the small secondary screw under the throttle plate. It is hard to get to so make sure it is loose and/or oiled slightly to allow it to move when the carb is bolted down. .020" t-slots on the primary side are critical to Holley metering.

From there, make sure your floats are set right. Dial in the carb using a vacuum gauge to set idle mixture. Make sure you have instant accelerator pump shot. Don't do the Holley feeler gauge method. You want to take all slack out of the accel. pump arm. By the way, only use the green or blue pump cams. NO pink cam. With how crappy gas is now, you need the cams with high initial lift.

Start with these things and then go from there.

The Scorpion intake is good but will make it harder to tune around. It can be done though. It will probably need more accel pump and timing mainly, as mentioned above.

 

I bought a new 650 vacuum secondary carb holley. and replced the 750 and o man does it seem to run alot better. im having problems getting it to idle right idles good when car is in park but when I put it in drive it goes dead. Id have to move the idle screw to where rpm's are at 2k to get it to hold an idle in drive. and when i hooked up the electric choke the starter seems to be binding and whinning alot. postive wire I hooked to the back of the alt.

 

ya the guy has like 30k in tools and his own shop. I think he was just tired and didnt feel like messing with it

An attitude like that is unprofessional, un professional attitudes create issues...
If he didnt fel like messing, with it, should have said so, or booked it in at some other time....but to come up with "cant figue out timing...needs an engine rebuild" diagonis is extreme BS.and incompetance

 

Set the idle screw to factory...(2 1/2 tuns down I think)
Get a rivet, flatten the end into a blde screw driver and put a 90 deg bend in it
on the otherside of the carb, under the edge is a stop screw for the seconaries...
Now using the rivet close the seconaries up (or open) till it idles at the speed you require, at the same time adjusting the mixture screws....same as u would if doing the idle screw.

 

The mechanic said he couldn't find the timing strip on the damper. The damper may not have etched marks on it and the timing cover may not have the pointer on it. It may not be the mechanic, it may be the timing cover and the damper, but I do agree that he needs to learn how to do this himself. If you are running an old style intake and newer style Vortec heads, the alignment of the ports between the 2 may be out of alignment just enough to allow oil to be sucked into the combustion chamber, but white smoke is coolant, not oil, but if the ports are misaligned, then you may be sucking in coolant as well. I suggest you get yourself an intake designed for Vortec heads. The ports will be a match and the newer intake technology will far outflow the old.

 

ya agreed, I ordered a RPM airgap from summit last night. had it shipped over night will be here tomorrow lol. man this car thing is really getting me down. Ive bought a new carb, wires,plugs,intake,rebuilt the front end. repaired tranny leaks. now I have a bad leak comin from back of intake. I wanted to download some pictures from my camaro on here to show you guys some pics of the leaks and plugs and such but says my pictures exceeds the storage space allowed for the site. dont understand that ive seen pictures on here alot bigger than what Ive taken. but o well. I feel like banging my head against the wall. there is a car show next week i wanted to take my 2 sons too so bad, but doesnt seem like ill make it. if any of you guys want me to send some of the pics to your email just private message me with email and ill send them to you. there of the plugs and back of intake.

 

I have to tell you my experience with the RPM Air Gap. They are great manifolds, but IMO, are made for racing, not street use. I ran one on my 350. Is your car ONLY driven in summer during HOT weather? I ask because I used to run one and found that the air gap feature actually hindered performance on cool days because it didn't allow proper atomization of the air fuel mixture. I switched to a standard RPM and picked up 10-15HP at the wheels. The reason is because the air gap doesn't allow enough heat to build up in the plenum area to allow for proper air fuel mixing and atomization. If this is a car that is driven ONLY in HOT weather, then you may be ok, but if the car is a multi weather vehicle, I suggest sending it back and going with the RPM ONLY!!!. Also, if you decide to keep it, did you make sure you ordered the RPM Air Gap Vortec(part #7516)? If not, then you will be in the same situation you are in now.

 

I would guess the reason it dies is from low vacuum from the cam/intake combo and the distributor starts pulling advance out and killing it.
A band aid fix would to be use a ported vacuum source and re time the engine, or run mechanical advance all together.
My car did the same after a head, cam, intake swap.
I still need to work on the ignition curve,and if your using a some what stock distributor with a performance cam, they will clash, there's almost no way is heck it will want to idle.