I've just installed a new cam and when I finally got the timing right to make the car start, the valves are ticking like crazy. What do I do to adjust them?
How do I adjust my valves?
- Thread starter streetstang67
- Start date
I have factory heads and rockers. I thought I had adjusted them correctly, because I followed the directions out of Hayne's Repair Manual, but something isn't right. Not only do I need to adjust my valves, but now I need to adjust my timing as well; or at least I assume I do, becuase I think I'll need to advance it to certain specs (which I don't know what they are).
I went through the heads, before I read your reply, and tightend each stud down when the valve was closed, until the rocker would no longer have any play in it, then 1/2 turn more. As I understand, that's what the directions said. But now, the car won't start. I'm so confused...I set the timing around 5* and yesterday it would run, but only if I held it around 2000rpms; and at least a couple of valves were ticking. After adjusting the valves as I described, I can't get the car to start.
5 degrees BTDC is retarded too much, if you set it at 5 degrees ATDC, thats WAY to retarded and would be almost impossible to start. I set most of mine to 12 degrees BTDC. As for your adjustment, that sounds too tight as well, try tightening the rocker till the pushrod just starts to get hard to spin between your fingers, then 1/4 to 1/2 turn more.
What is the difference between BTDC and ATDC? I just used the TDC mark on the harmonic balancer as reference.
BTDC-- Before Top Dead Center ATDC-- After Top Dead Center The fire needs to be lit before the piston reaches TDC, to get the maximum push on the piston. The explosion doesn't happen instantly, relatively speaking, so it needs to be set off before the piston gets to TDC to where the explosion pushes at the right time. All this happens in the blink of an eye, remember, electricity travels at the speed of light, but the explosion in the chamber doesn't.
Great, Thanks! I got the car running, but it will barely idle. I haven't adjusted the valves to be perfect yet, because I want to set the timing. I set mine at 12 TDC as you suggested, but as I said, it will barely idle. The factory specs for my engine call for 6, and comp says they machine their cams 4 degrees advanced. So, what should I set mine at?
The cam timing's really got nothing to do with the ignition timing, they're two separate issues. Cam timing controls the events of the intake and exhuast flow, not the ignition of the charge. If it will barely idle warm with 12 degrees, try adjusting the carb's idle speed screw. Every engine I've set at 12 degrees BTDC idles fine at that, but it takes a mix of adjustments to the carbs idle speed and mixture screws to make it happen as well.
alright, I think I have the valves and timing set prettty good. the problem now, is that as I drive it, it will randomly skip or miss about every 10 seconds +/-5. I'm not sure if this it the valves, timing, or carb??
EDIT: mabye its the valves, b/c you said tighten them until it starts to 'miss' then loosen. I adjusted a different way, becuase I don't see how its possible to adjust them with the engine running spitting hot oil and throwing the rockers around soooo fast.
EDIT: mabye its the valves, b/c you said tighten them until it starts to 'miss' then loosen. I adjusted a different way, becuase I don't see how its possible to adjust them with the engine running spitting hot oil and throwing the rockers around soooo fast.
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