I had a concern that I may have wiped a cam lobe. I couldn't tell from watching the movement of the rockers, which I guess was a good sign, but I took the intake manifold off anyway. I removed each hydraulic lifter and looked at its contact point with the cam. There is absolutely no wear, marks, scratches,,,nothing on any of them. I assume you can't have a wiped lobe without the hydraulic lifter showing some kind of clue.
Correct?

 

correct.......

 

Whats wrong,why are you looking ?

 

Well, I am trying to eliminate things in general. My 383 complete re-build was broke in about 2 weeks ago. I followed the timing sticky exactly and everything was fine on the recommended numbers as far as I can tell. Great throttle response!
I could never get a good idle. It runs rough.
Timing scatters back and forth
dwell on the points goes from 30 to 36 during acceleration.
Then I went to adjust the carb. It had no response on either screw.
Vacuum OFF THE MANIFOLD is abnormally low, 11 inches at about 750rpm and also jittery. I don't think it can run the B26 vacuum can on the distributor as it is clattering at idle. Just off idle it stops.

I figured I may have 2 problems, carb. and distributor. Both rebuilt by LARS. So I sent them to him to check out.
Yesterday LARS said he tested extensively on the test stand and in his car and it is all correct.

he suggested the possibility that my timing light is defective due to the fact that it is physically impossible for the dwell to go up with RPM and because the timing is scattered. In addition that maybe there is a wiped lobe(s).

So with what I did today I now know that I do not have a cam problem. I do think that my rockers needed adjustment though as they were not, well, all the same when I wiggle them.
I guess the carb doesn't respond on my car because something else is so out of whack.
So I am hoping that the timing and dwell are related to a bad light. To test I have an old fashioned timing light (no advance) and another dwell meter. I will compare data from both.
The vacuum may be due to the incorrect pre-load on the hydraulic lifters, I guess, as I do not believe I have any leaks or open ports. Even if I did that would not explain the jittery vacuum, only low vacuum. Maybe it is also the bad timing gun. The timing may be off too much and the valves are not open enough on the down stroke?

Unfortunately by the time I get the carb and Dist. back next week I have to go out of town. It won't be till October 10th that I can get back to it.
Any ideas would help. I think I will copy the above into a new thread. So if you ugys want to respond, go there. It is titled Still trouble with the new 383.

 

have you verified TDC with a piston stop and then looked at your harmonic balancer?

 

Actually you answered another thread I started on this. Once I have the stop I will do this. The short block was built professionally by a really good shop. But I want to use the stop to prove it. I want to make sure I rule things out 100% as I go along so I am not running in circles.

 

I know when I wiped the lobe on mine, it was very visible on valve action with the valve cover off. I also had a pop thru the carb whenever i went above idle...