cam sound one side of exhaust lopes one doesn't

I just freshend up my sbc 350 with rebuilt 419 heads, timing chain and sprockets, rebuilt carbs, installed a new cam, lifters and pushrods. I broke in the cam according to the directions and I believe all went well with no real problems. However, I'm now at the point where I'm setting the timing and adjusting the carbs. I got the car to idle good and when I step on the gas it accelerates fine without missing or misfiring seems to run pretty smooth, I haven't taken it out for a street test yet. My concern is that at idle only one side of the exhaust lopes (p***enger side) the driver's side is just a steady exhaust tone with no real loping. Is this normal or is there a chance the cam did not break in correctly or something else might be wrong? Thanks for any input.

 

That's wrong, if it seems to be dead steady on one bank, and REALLY loping on the other...but it could be a lot of things...and my coupe had a little Chevy in it, I should add, that had 3 Rochesters on it ( which it looks like you might have...) and it DID, depending on idle speed, have different qualities on both sides, however, they were random...I would have to say if it sounds like 2 completely different cams on each side, sumthin's funky!
Are you SURE its not missing?
How did you adjust the valvetrain?
What are the cam specs?
How is Oil pressure?
Has Oil pressure been slowly falling off?
Need some more info, definately...carbs, etc...
Is there any valvetrain noise? On one side?
Firing order correct?
Headers the same?


Watch your oil pressure, especially @ idle...check all your rockers, paying attention to the adjustment on the smooth-sounding side closely, check for metal in the oil...

 

All good thoughts...
My first thought was valve adjustment as well. I've seen goofy idle situations when they are too tight. After readjustment, the idle was as it was supposed to be. That guy was lucky that he didn't wipe the cam out..
Is it hydraulic or solid? Some more detailed info would help..

 

I forgot to mention, new oil pump steady at about 50 psi, I have three 2gc carbs (matching set with correct front and rear and center) but only running the center right now trying to get the car running first and then adjust the outer two. No distinct valvetrain noise that I can hear. I adjusted the pushrods to zero lash plus a 1/4 turn (starting with the first one at tdc and working all the way through the others). As far as I can tell it doesn't seem to be missing? Thanks again for any help

 

It's hydraulic with flat tappet lifters, I pulled the valve covers and they didn't seem too tight. I guess I can try to adjust them while running now that it will idle.

 

Should have bought the full race cam !! That would make it idle lopey on both sides !!! LOL >>>>.

 

I would without a doubt go back through and readjust them with it running.
It's very possible, and pretty easy to over adjust when on the first time around..

 

firing order is correct and both headers are same (I now have lake pipes)
cam specs:
intake duration 227
exhaust duration 241
0.479 intake lift
0.65 exhaust lift
107 lobe separation

 

Thanks for the input, I will go back an readjust while running. Does anyone have a particular way they prefer to adjust them?

 

This is how I do 'em on a hydraulic...
I wouldn't try to do it while running!



B. You will need a breaker bar or a large 1/2 drive ratchet and socket to rotate your engine by hand via the bolt on the front of the crankshaft. This is much easier if the spark plugs are removed. Rotate the engine clockwise and watch the exhaust valve on the particular cylinder you want to adjust. If you’re unsure of which valve is the exhaust valve, look at your exhaust manifold or header, and the exhaust valve will line up with it. When the exhaust valve begins to open, stop and adjust that cylinder’s intake rocker arm. This is the point in the rotation of the camshaft where the intake valve is closed and the lifter is directly opposite of the cam lobe.

C. Loosen the retaining nut on the rocker arm to remove any tension from the pushrod. If the lifter is filled with oil, wait a minute or two for it to return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so. If you are installing new lifters, which are not oil filled, you don’t need to wait. You can start adjusting right away.

D. Gently rotate the intake pushrod with your fingers while tightening down the rocker arm retaining nut. When you first feel a slight resistance at the pushrod, you are just starting to compress the spring inside the lifter. Turn the retaining nut down one half to one full turn from this point. Lock the nut into position. The intake is now adjusted properly.

E. Hand turn the engine again, watching the intake valve that you just adjusted. It will open fully and then begin to close. When the intake valve is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. This is the spot where the exhaust valve is on the base circle of the cam. Adjust the exhaust rocker just like you did the intake.

F. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again. In summary, adjust the exhaust valve just as the intake is closes, and adjust the intake just as the exhaust valve is beginning to open.

 

"When the exhaust valve begins to open, stop and adjust that cylinder’s intake rocker arm."
"When the intake valve is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder."

Easier for commiting to memory.

 

Well, i never give them the extra 1/4 or half turn they say to. I've always adjusted them until they are quiet and stop there.
Been doing it that way for 20 years and never had one issue. I just don't like the load the extra adjustment puts on the motor..
That's just me, and i'm sure everyone has thier own opinion on it...

If it's not running, i do exactly what Dirty Thirty just said......

 

Thanks, that is the process I used the first time around. I guess I will go back through them again to double check. I appreciate your time and help. David

 

Listen to them! I fought with a weird "one side only" problem with my1966 Plymouth 318... fought it for a while and finally decided to just loosen the affected sides exhaust valves 1/2 a turn- No more problem.

 

I went back in and readjusted all valves/rockers and adjusted the idle screws on the carb and that seemed to work. Thanks to all for the input and suggestions. DK

 

You must have bought a stereo cam, only the mono ones sound the same on both sides