Hot Rods Valve problem

Have 350 Chevy engine. It was backfiring through the carburater. I thought it was water , tried to correct that.
The studs pulled out of the rocker arm on one cylinder. I put screwed in rocker arm studs and set the valves on what I thought. It won't crank.
Any suggestions??

jaggordon

 

Back them all off 1/2 turn, see if it will start then

 

Do you mean it won't turn over or won't start?

 

It won't start.

 

It won't start. I can loosen the valves real loose, and then it acts like it will crank, but it won't.

 

How long a time has it been since you started the repair work? Battery maybe? Try turning engine over by hand to see if there is any interferance issues. If it turns fine, it's not the valve or valves.

 

Let's ask the question again then... does it crank over?

 

It will turn over, but it won't start.
I have looked at it some more and think maybe it's the camshaft that is worn.
I appreciate all the helpful suggestions.

 

If it was running when you did the pulled stud repair, it should run again. Did you just do this repair on the one cylinder and then try it, or did you put in all studs and reset the lash on all cylinders?

 

Check for bent pushrods.

 

A lot of missing info here. Did it run when you pulled it apart to do the studs ? How did you install the screw in studs........remove the heads ? What all came off of the motor between the tear down and when you tried to start it.

Don

 

plug wire/firing order... after repair

 

From the way you are describing the problem, I gather you don't have much mechanical background.
Aside from learning basic diagnostics, which you should certainly do!, to get some specific help here, we need to really know what is happening.
From what I assume, you had trouble with backfiring. You also had some studs pull out of the head. Might be 2 separate problems. Backfiring, first you need to see if all plugs are firing when it is running. Checking the temps of each exhaust port is a beginning, but a scope is a better idea, especially for intermittent non-firing. If you establish a dead cyl. then find out why is it not firing. Check ignition, check compression, then check valve action. By now you should see something.
As for studs pulling, it could be someone tightened up the rockers WAY too much, or they are just shot, or you have a mechanical interference problem.
Oh...and IIRC, if you change out the pressed in studs, to FACTORY screw in ones, your valves are probably too loose. I think you have to face off the top of the stud boss if you do that. If not, the stud is too high, and you might not get your valves adjusted tight enough.
Proper valve adjustment is an issue too, if you follow shop manual recommendations, they are usually too tight. I only go 1/2 turn past zero lash on hyd. flat tappets. Whether doing it static, or running.