What’s an acceptable level of ping

[larrylarry]

I know I have pinging but it’s hard to hear because of my exhaust being loud. Sounds like a rocker arm that’s loose. If it was a loose rocker it would happen no matter what rpm the engine was at, right? It only happens when I get on the gas going up hill or when I romp on it hard. Doesn’t last long, only a second or two. If I drive like a normal person it doesn’t happen at all. Just wondering if everyone deals with pinging.
I wrote this post yesterday an stopped because I remembered I have a tank full of regular gas, 89 octane. Last time I checked the compression I had 185 psi + or - per cyl. I figured using regular gas wouldn’t hurt. My initial is 18*, Mach is 12* = 30* Seem kind of low to me but I’m using Vortec heads. Engine runs fine, plenty of power, good torque. So is there an acceptable amount of ping in a performance built engine?

 

[COPO]

You should be using at least 91 octane premium fuel with 0% ethanol.
When you have a pinging problem, it does NOT go away after you hammer it. It should ping until you let off the gas. Sounds like you have a different problem.

 

[larrylarry]

It’s hard to hear with my almost straight through exhaust. I did have a problem with a couple of rocker arm nuts that wouldn’t stay tight, replaced them with new nuts & that cured that problem. Do you think rockers could clatter when under load an not clatter when there not. Any thing is possible I guess.

 

[mallard]

My ‘74 with LT1 heads pings a bit with premium unleaded so I use a small amount of octane booster in the tank, problem solved. Don’t want to risk a piston with a hole in it.

 

[Twisted_Metal]

Take a degree or two out of the initial timing.

 

[larrylarry]

Take a degree or two out of the initial timing.

Yea, I‘ll do that but first I’ll go get a half tank of premium and see what happens.

 

[COPO]

My compression is 10.2:1 and with Shell 91 Premium fuel with 0% ethanol, I can hammer it all day long with no ping at 36* total advance.

 

[larrylarry]

My compression is 10.2:1 and with Shell 91 Premium fuel with 0% ethanol, I can hammer it all day long with no ping at 36* total advance.

I don’t know where I could buy non ethanol gas at around here. Why no ethanol? I’m not going to worry about ethanol,I know it’s not good for carburetorts, my chainsaw doesn’t like it.

 

[John Wright]

ping = broken parts, be careful

 

[sandlapper]

Larry
In spite of distinct certainty of raising compression --- running a thinner gasket and thereby attaining an Effective quench distance/height may very well solve pinging. If you have a configuration which permits a thinner gasket, it may be worth a try. Sometimes that which may seem counterintuitive is the way.

Also, Gently ease any sharp edges / burrs within chamber-piston crown.