HOW Much Ping Is TOO Much?
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Melting Slicks
Joined: Jul 2010
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
HOW Much Ping Is TOO Much?
I recently finished installing my newly rebuilt distributor back into my '77. When I tried to time it I discovered my damper had moved and was rubbing against the timing cover. After installing the new damper I wanted to time my newly recurved distributor for all in 36 degrees advanced before 3000 RPM. The initial timing ended up at 12*BTDC and the car runs, and starts great,the throttle response is better then ever! IF I lug it down to 1500-1800rpm in 4th gear and floor it on a slight hill I can "induce" just the slightest bit of detonation. Of course you would never do this in normal driving! and the car had left over 87 octane in it! I have been told by some very sharp old time hot-rodders that if I have to work that hard to make it ping that it's probably setup perfect. I want to try the same test w/ some 93 octane or 89 but the winter weather is not cooperating. What do you think??
Last edited by BPHORSEGUY; Dec 22, 2012 at 08:16 PM.
Team Owner
Joined: Jan 2006
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From: Crossville TN
Early detonation can be very damaging to the engine; so you don't want it to ever happen. I would recommend that you back the distributor down a degree or two to eliminate it altogether.
Thread Starter
Melting Slicks
Joined: Jul 2010
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Tech Contributor
Joined: Jun 2004
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I recently finished installing my newly rebuilt distributor back into my '77. When I tried to time it I discovered my damper had moved and was rubbing against the timing cover. After installing the new damper I wanted to time my newly recurved distributor for all in 36 degrees advanced before 3000 RPM. The initial timing ended up at 12*BTDC and the car runs, and starts great,the throttle response is better then ever! IF I lug it down to 1500-1800rpm in 4th gear and floor it on a slight hill I can "induce" just the slightest bit of detonation. Of course you would never do this in normal driving! and the car had left over 87 octane in it! I have been told by some very sharp old time hot-rodders that if I have to work that hard to make it ping that it's probably setup perfect. I want to try the same test w/ some 93 octane or 89 but the winter weather is not cooperating. What do you think??
Knock isn't an indication of a correct or incorrect timing curve (only a dyno or cylinder pressure sensor can tell you), but from your comments on how well the car is running, it sounds like you're pretty close to what the engine wants.
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Burning Brakes
Joined: Oct 2001
Posts: 1,241
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From: Okinawa Okinawa
I would set it one or two degrees less, run the old gas out and retime it when you are running better gas. If it still pings at 12, go down 1 or 2. Why pay the money of a rebuilt motor just to set the timing too high and have detonation damage? JMO.
Safety Car
Joined: Mar 2007
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From: Bridgewater nj
if you have to work that hard to get a rattle its not that big of a deal.
Thread Starter
Melting Slicks
Joined: Jul 2010
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Thread Starter
Melting Slicks
Joined: Jul 2010
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
I think 95% of drivers would say the car does not Ping. I had to be very **** and do things most of us would not do, to get it to ping !
Melting Slicks
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2024 C3 of the Year Finalist - Unmodified
Dump a few gallons of VP's C12 race fuel (108 octane, leaded) in there. Smells great when you run the car in the garage...with the door open, of course. 
If I were you, I would not have any ethanol fuel in my tank for winter storage, regardless of what Mike Ward thinks. He doesn't have a single penny invested in my car. Can't you run it near empty, then go find some non-ethanol "Recreation 90" fuel somehwere...like where boaters go?
Advancing the distributor until the engine pings under heavy load is probably the best way to maximize performance. A number is just a number and is only used for a point of reference. Conditions change and so does that number. Unfortunately I can't hear the death rattle in my car because the pipes are way too loud and my hearing ain't what it used to be. I really don't lug the engine, nor do I wind the **** out of it until the valves float..
BTW, how old does one have to be to be called an old timer anyway?
If I were you, I would not have any ethanol fuel in my tank for winter storage, regardless of what Mike Ward thinks. He doesn't have a single penny invested in my car. Can't you run it near empty, then go find some non-ethanol "Recreation 90" fuel somehwere...like where boaters go?Advancing the distributor until the engine pings under heavy load is probably the best way to maximize performance. A number is just a number and is only used for a point of reference. Conditions change and so does that number. Unfortunately I can't hear the death rattle in my car because the pipes are way too loud and my hearing ain't what it used to be. I really don't lug the engine, nor do I wind the **** out of it until the valves float..
BTW, how old does one have to be to be called an old timer anyway?
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Melting Slicks
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
The term "old timer" is relative but I think he only needs to be at least 10 years older then the listener! I am a Commercial Pilot and my cars and bike are stored in hangers for the winter where 100 octane low lead avgas is available and they will all get some before January !
Burning Brakes
Joined: Mar 2005
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From: Ontario
Being an "Old Timer" I will tell you what we would do to set the timing if the mark on the pully was off or there was no light available .
Bump the timing ahead untill we could make it ping and back it off untill the ping was gone . Lots of times back in the late 60s - early 70s when we did a tune up and set the timing to spec the engine would ping . We would back it off untill the ping was gone and hope it didn't hesitate after .
Regards Bill
Bump the timing ahead untill we could make it ping and back it off untill the ping was gone . Lots of times back in the late 60s - early 70s when we did a tune up and set the timing to spec the engine would ping . We would back it off untill the ping was gone and hope it didn't hesitate after .
Regards Bill
Tech Contributor
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
The OP said it rarely knocks, and only when put in purposely unusual conditions. Higher octane fuel would be a waste of money at every fillup, and backing off the timing would be a waste of fuel and performance every time the car was driven.
Thread Starter
Melting Slicks
Joined: Jul 2010
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Last edited by BPHORSEGUY; Dec 23, 2012 at 07:26 PM.
Safety Car
Joined: Mar 2007
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From: Bridgewater nj
My car is set up like yours and I use it to find out who's selling crap gas 
. If I fill up and I get pinging then I know not to go back to that station. One time it was so bad I called weights and measures from the state to go down and check the guys pumps because my car rattled so bad I had to buy a bottle of octane boost!
. If I fill up and I get pinging then I know not to go back to that station. One time it was so bad I called weights and measures from the state to go down and check the guys pumps because my car rattled so bad I had to buy a bottle of octane boost!
