Engine Ping 1981
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Intermediate
Joined: Aug 2001
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From: DURYEA pa
Engine Ping 1981
Had been using 89 octane, was hearing a ping in the engine, just put in 92 octane and it didn't go away. If at all, how long do you think it might take for the ping to go away. If it doesn't, I will try 94
:(
:(
Melting Slicks
Joined: Jan 2000
Posts: 2,386
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From: far, far away
Re: Engine Ping 1981 (ALIEN)
A stock L81 shouldn't ping even on regular unleaded gas. It's compression ratio is too low to cause those problems. I suppose that it's possible that you've got enough carbon built up in the combustion chamber that your compression ratio in one or two cylinders has increased to a point where it could cause pinging, but I kinda doubt that.
I would check your timing and the various emission control systems, especially the EGR. Be aware that your timing mark is scribed on your harmonic damper, and that a 20-year-old damper's elastomeric ring isn't so elastic anymore. If that rubber ring in the middle of the damper un-bonds from either the outer ring or the inner hub, then your timing mark will begin to wander around. You can have the timing way, way too far advanced even tho the mark looks spot on. That happened to mine, with only about 70k miles on the engine. It's an age thing, more than a mileage thing.
Good luck!
-=Gator81
I would check your timing and the various emission control systems, especially the EGR. Be aware that your timing mark is scribed on your harmonic damper, and that a 20-year-old damper's elastomeric ring isn't so elastic anymore. If that rubber ring in the middle of the damper un-bonds from either the outer ring or the inner hub, then your timing mark will begin to wander around. You can have the timing way, way too far advanced even tho the mark looks spot on. That happened to mine, with only about 70k miles on the engine. It's an age thing, more than a mileage thing.
Good luck!
-=Gator81
Thread Starter
Intermediate
Joined: Aug 2001
Posts: 40
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From: DURYEA pa
Re: Engine Ping 1981 (Gator81)
Hi thank you for responding, one other note, would the temperature of the engine have anything to do with the ping. I seem to hear it more so when the engine is hot. It ins't so bad when the engine is cold. What would cause it to do that? :confused:
Melting Slicks
Joined: Jan 2000
Posts: 2,386
Likes: 3
From: far, far away
Re: Engine Ping 1981 (ALIEN)
Yeah, I would expect the pinging to get worse with more heat. Basically you've got the fuel/fair charge going off before it's supposed to, due to its exceeding some threshhold value for the combination of heat and pressure. In the confined space of the combustion chamber, heat and pressure are more or less interchangable.
How does it run? Is the power and performance generally good, other than the ping? That would rule out the bad damper theory...
I hope some of the other guys will pick up this thread. I know just enough about the subject to get it completely confused... :rolleyes:
Gator81
How does it run? Is the power and performance generally good, other than the ping? That would rule out the bad damper theory...
I hope some of the other guys will pick up this thread. I know just enough about the subject to get it completely confused... :rolleyes:
Gator81
Thread Starter
Intermediate
Joined: Aug 2001
Posts: 40
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From: DURYEA pa
Re: Engine Ping 1981 (ALIEN)
Basically it run good, but since this is my first, I have nothing to compare it to.
I did post before that when I kick it down, it cuts out and I was told on this forum it was the carb.
thanks again for all your help. :chevy
I did post before that when I kick it down, it cuts out and I was told on this forum it was the carb.
thanks again for all your help. :chevy
