Knocked a lobe off of a cam? In here!

[33 IMP]

Haven't had that problem lately, but I sure knocked a bunch of lobes off the direct connection mushroom cam I had. I don't remember if it was too much, or too little, spring. Probably was just poor amateur break-in.
I've got a solid roller out of a friend's rat motor that had too little spring, and too much rpm. Several serious divits in the lobes. I keep it as a lesson in what NOT to do.

 

[fratzog lover]

Sometimes membership is not voluntary.......

How very true.

 

[Nxcoupe]

Sometimes membership is not voluntary.......

Lol.

 

[Nxcoupe]

Don't trust a visual confirmation of valve movement, use a dial indicator to measure travel..

Found my dial indicator that I use to check backlash on my rear end cart. I set it up and had to use a mirror to see the dial but got it all set up and then cranked the engine over and watched its furthest downward movement. Then I moved the gauge setup to the #5 exhaust valve and repeated the procedure. They are exactly the same. Looked to be in the .420 to .450" range. So the lobe is not worn. Intake is the same. So now what? I inspected exhaust and intake springs and found no issues. So nothing there.

 

[Nxcoupe]

Don't trust a visual confirmation of valve movement, use a dial indicator to measure travel..

Checked the intake valves on a few others as well as the one on 7. All the same amount of lift. I just found out today my pico scope has an adapter to go over a plug wire and give spark patterns. I'm going to look at that and then go from there. Carb is leaking for sure.

 

[Don Frelier]

1. I'd take the plug out and ground it with a jumper cable, crank it and check the spark.
If it's an Autolite plug then it may not fire.

2. If the spark is good then compression test.

 

[AR67GTX]

I’m not real clear what the symptoms were but have you idled the car in the dark to look for voltage leaks and maybe a bad plug wire or broken terminal connection.

 

[Nxcoupe]

1. I'd take the plug out and ground it with a jumper cable, crank it and check the spark.
If it's an Autolite plug then it may not fire.

2. If the spark is good then compression test.

It is a Champion plug. I will use the scope, it's easier and basically tells me the same thing as well as my spark tester which I forgot about till you brought this up. Compression is 130, I believe that is in the first post.
It has boiled down to either an issue with the petronix distributor or it is getting fuel dumped in it by a leaking carb and can never clean itself up.

 

[Nxcoupe]

I’m not real clear what the symptoms were but have you idled the car in the dark to look for voltage leaks and maybe a bad plug wire or broken terminal connection.

Had same problem before and after new plugs and repro wire set. Wondering if it is a petronix dist issue. I will do as Don suggested and test my spark.
Original issue is a misfire at idle and part throttle. Can hear it in the exhaust. AFB has never been rebuilt or serviced. Compression is good. Changing wires and plugs did nothing. I can't recall if it was there before the petronix dist install? I'll check spark after I put it back together.

 

[Don Frelier]

Compression is 130, I believe that is in the first post.

Not that I saw...

I recommended the jumper cable because then you know what that particular plug is doing. You can see it.
I've never had/used a spark tester someone would have to explain to me the advantage.
Seems improbable that one cylinder gets enough fuel to foul badly and the others can clear out the excess fuel?

 

[Nxcoupe]

Not that I saw...

I know I put it somewhere, I say way too often. Lol.