caddyman

I had the brakes on my 71 mustang w/351C worked on the other day and to improve the vacuum at idle they adjusted the dist until there was approx 15lbs of vacuum. Now when I accelerate or there is a moderate load on the motor I hear what sounds like slight lifter/rocker noise.

Any thoughts?
Do I have them set it back to stock?

67t5ponycoupe

What you may be hearing is ping. It sounds a bit like gravel in the engine. Almost like a diesel. I would retard the timing slightly and see if that helps.

caddyman

too bad I'm 1800 miles from my timing light.

Clockwise twist or counter clockwise of the dist?

67t5ponycoupe

I'm 90% sure it is CCW to retard, someone sanity check that for me please. If you go slightly CCW and it gets worse then that is the wrong way.

KMatch

First, kick your "mechanic" REALLY hard for attempting to set it by ear without test driving it. Nothing was accomplished here unless he is looking for return work when you burn holes in your pistons. DO NOT DRIVE IT WHEN IT'S DETONATING.

For all distributors with a vac advance, moving the distributor in the direction the vac unit "points" will advance the timing. You could probably move yours back (ccw) 1/2 to 1 inch measured where the vac hose connects and be close enough until a light is available. Too much and it will overheat.

JMD

I would turn that distributor a little bit counterclockwise, timing light or no timing light....

Ping that is THAT noticeable can hurt a engine..

FoMoJoe

I ws experiencing the same thing yesterday while going out for a cruise, glad I ran into this thread. I plan on bringing mine to the mechanic tomorrow. I am good at most things, but timing and electrical is not my forte'. Today I opened up the valve cover and expected things, everything is tight and looks good. Not only do I hear a knocking from my driver's side, but I also hear a pinging noise once I am pushing in the clutch at a higher rpm, but the pinging sounds more as if it comes out of the exhaust vs. under the hood at that point. Any ideas out there?

I have a newer 347 w/ hydraulic roller lifter and comp crane roller rockers. I've put maybe 750 miles on it over the last year, my distributor is locked in place. Dunno how or why my timing could be off if the distributor is locked in there good, but I still feel it's the timing. Can timing be thrown off even when the distributor is locked in?

Maybe a new set of plug wires in case one or a couple are not getting spark??

JMD

Another thing to consider is that more often than not, a roller cam is going to make more noise than it's flat tappet counterpart.... especially with a more aggressive cam profile....

Some OEM's switched to plastic valve covers, in part, due to this issue.

FoMoJoe

Come to find out, I had an exhaust leak on the passenger side. I replaced the gasket (3 hours, which I am sure could be done faster but I was working quickly) and everything sounds a hell of a lot better. Knocking gone, pinging when engaging the clutch is gone, everything is better. Might be the same thing you have??