so this isnt a camaro.. its an 83 el camino but its still a SBC and i figure this is the place to ask the question.

before i get to the issues i figure i'll start with the mods. stock 305, we put a basic edlebrock performer manifold a holley carb and a full accel ignition system(distributor cap rotor coil and wires)

the car ran great for about a week. then it started acting like it jumped time.. so we put a new timing chain on it. gutless and wouldnt idle right.

now it will idle but if you try to rev it at about 1500 rpm it bogs like its choking and spits gas out of the carb its more of blows the gas out of the carb..

we though maybe it was the cam timing so we pulled it back apart and re did the timing. lined it up dot to dot. and its still doing the same thing.


I need some help here, its my dads dream car and he is really bummed about it.


also, we pulled the valve covers and all pushrods are turning and moving up and down.


I'm a good mechanic i just havent had much experience with SBC's. the problem is staring me right in the face but i just cant figure out what it is.



someone here has had to have dealt with this problem I could really use some help here.

 

Did you maybe have it 180 degrees out? It may have been on the exhaust stroke instead of compression, just a guess.

 

If the timing sprockets timing dots within the shafts' centerline, cam at 6 o:clock, crank at noon, #6 cyl is firing.
If both timing dots are at 12 noon, then #1 cyl is firing.

You might advance initial timing a little.
Hopefully , the spit of fuel through the carb will quit and not a sticking intake valve.

Also, with valve covers off, you might check intake bolt-to-pushrod clearance.
If one bolt is too long, as in a thinner aftermarket flange, the 1.25" long bolt may be binding against the pushrod, use a 1 inch long bolt.

 

The engine isn't going to run if timing is out 180 degrees. It sounds like timing may be off a bit, or it's a valve lash issue.
1) Where do you have your timing set at? Are you sure it's really there? You may be using the wrong timing tab, or a harmonic dampener with the notch in the wrong clocking position (yes, there are different ones).
2) What procedure did you follow when setting the valve lash? You may have some valves set too tight or too loose, especially if you followed the useless repair manual way of setting 8 valves at TDC #1, then the other 8 at TDC #6. Here's one way to set them: http://www.crankshaftcoalition.com/w...valves_SBC_BBC. Here's another way: Engine Valve Adjustment Procedure - The Right Way. Pick one you're more comfortable with. The second way is better, but takes longer.
3) What vacuum source do you have the advance hooked up to? Hopefully you do have vacuum hooked up. Did you check with a timing light to make sure the timing is advancing with engine rpm's? The distributor might be bad and not advancing, either by vacuum or mechanically.

 

I'm stumped. the valve lash is close enough i dont think it would cause a problem.

the disty timing has been moved around quite a bit but it still does the same stuff.. im thinking it might be a stuck valve


it still has the factory cat if it were clogged would it cause this?

 

I had a 1969 Pontiac lemans that was 180 out and would idle fine but would not rev and had no power but it ran. That was a Pontiac with a 350. Well, I think 180 out, it was timed on the exhaust instead of compression on the #1 cylinder.

 

if it helps at all the engine is not factory its actually out of an 82 c10. the engine code is UAT
atleast thats what my research has told me. im going to go out and keep messing with it till i get it working.

with the mark on the harmonic balancer on 0 the distributor rotor should be pointing at #1 correct?

 

Right, that's assuming your marks are correct. Do you have a custom timing chain cover, different timing tab, and/or a non-original harmonic dampener on the engine? The next thing you might want to do would be to get a piston stop and find your true TDC on #1, to make sure what you're seeing on the timing marks is what it actually is.

 

ok thats what i thought. tomorrow when its not 12 degrees outside i'll go back and keep messing with it. i also picked up a compression tester. to help rule out valve issues.

the timing tab and harmonic balancer appear to be original.

 

Might put a vacuum gauge on the manifold vacuum port and adjust the timing until you get maximum manifold vacuum. That will get you very close, without wondering if the timing marks are correct or not. Once you get max vacuum you can drive it and check to see if it starts OK when the engine gets totally warmed up. If it's a little hard starting after that you can back it off a few degrees.