Had one instance of pinging today...why?
Thread Starter
Team Owner
Joined: Aug 1999
Posts: 28,616
Likes: 4
From: Fort Mill, SC via NJ
Had one instance of pinging today...why?
Very hot and humid day today.Was doing about 65-70 on the highway for about 30 miles with a/c on.
Engine temp stayed at about 210.
Got off on another highway for a few miles at about 55 MPH.
Hit a hill and punched it a little bit and had some pinging.One hill,one round of pinging.
Without the a/c on she runs at 180-190 without any ping in the same type situation or at least I never heard any.
Timing is at 10.
Any ideas?
:mad
[Modified by 69er, 6:52 PM 8/5/2001]
Engine temp stayed at about 210.
Got off on another highway for a few miles at about 55 MPH.
Hit a hill and punched it a little bit and had some pinging.One hill,one round of pinging.
Without the a/c on she runs at 180-190 without any ping in the same type situation or at least I never heard any.
Timing is at 10.
Any ideas?
:mad
[Modified by 69er, 6:52 PM 8/5/2001]
Safety Car
Joined: Aug 2000
Posts: 3,734
Likes: 2
From: Southeastern PA
Re: Had one instance of pinging today...why? (69er)
I've been having the same problem lately. I added a bottle of octane boost to a 1/4 tank and ran her hard. Car ran better. I added 93 octane gas later and pinging returned. My next step is to check timing. Pinging only occurs when I punch it hard or at very high RPM's.
Le Mans Master
Joined: Aug 2000
Posts: 9,662
Likes: 7
From: Semper ubi, sub ubi
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: Had one instance of pinging today...why? (69er)
Your temperature has a bunch to do with it. I did exactly the same thing yesterday. Temperature was close to 100, humidity high, and 30 miles at 70-80 miles an hour with A/C on. Temperature nailed at 210 for the whole time. I too had some pinging while accelerating in high gear. I was sort of loafing at 45 mph and gave it about half throttle to move around another car. I noticed some pinging, after a couple of minutes the engine temp had dropped below 200 and I couldn't get it to repeat.
Our 69's have iron heads and pretty high compression (10.25-1) for iron heads and the junk they call premium gas. That kind of compression with a more or less stock cam and timing curve is really pushing the envelope.
Our 69's have iron heads and pretty high compression (10.25-1) for iron heads and the junk they call premium gas. That kind of compression with a more or less stock cam and timing curve is really pushing the envelope.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Had one instance of pinging today...why? (69er)
One thing for sure, if you hear your engine pinging, Make it stop!!! Very bad for the engine. This pinging is created by downforce from the explosion while the piston is still moving upward. Think of it like pushing a kid on a swing. If you jump in too early to give the next push, collision, and the kids body jolts as thier momentum is suddenly halted. If you still get pinging on high octane gas, you could try retarding the timing a degree or two. Turn it back just enough to cease the pinging. If you loose to much performance by retarding timing to remidy pinging, then a dist advance recurve is probably whats needed. Some engines with poor compression/cam matchs are prone to pinging from too high of compression. This is how some guys get away with 11 to 1 on pump gas. They run high duration cams that bring the compression down some.
Melting Slicks
Joined: Jun 2001
Posts: 2,429
Likes: 14
From: CA
Re: Had one instance of pinging today...why? (Jvette73)
There are a couple of things you should know about detonation:
Part-throttle ping &
full -throttle ping.
The main difference between the two is the amount of vaccum during the ping.
Part-throttle is the most common ping if you have a vaccum advance. You can determine
between the two if the pinging starts at part-throttle, but goes away at full throttle.
If it's a part-throttle ping, you can get an adjustable vaccum advance kit to bring down the amount of advance.
If it pings at full / max throttle, you can adjust your timing down a bit, or get a retard
computer from MSD. It has a micro switch that hooks to the carb, and it signals to a computer to retard under full throttle. I have one and it works great.
:cheers:
Part-throttle ping &
full -throttle ping.
The main difference between the two is the amount of vaccum during the ping.
Part-throttle is the most common ping if you have a vaccum advance. You can determine
between the two if the pinging starts at part-throttle, but goes away at full throttle.
If it's a part-throttle ping, you can get an adjustable vaccum advance kit to bring down the amount of advance.
If it pings at full / max throttle, you can adjust your timing down a bit, or get a retard
computer from MSD. It has a micro switch that hooks to the carb, and it signals to a computer to retard under full throttle. I have one and it works great.
:cheers:
Thread Starter
Team Owner
Joined: Aug 1999
Posts: 28,616
Likes: 4
From: Fort Mill, SC via NJ
Re: Had one instance of pinging today...why? (71coupe)
Very interesting 71 coupe.
I wasn't going to do anything about it due to the fact I rarely use the a/c but this MSD part sounds good.
Which one is it from MSD?
There are a few models.
Thanks guys for your imput.
As always this forum is a great help for a non motorhead like myself.
[Modified by 69er, 4:40 AM 8/7/2001]
[Modified by 69er, 2:38 PM 8/7/2001]
I wasn't going to do anything about it due to the fact I rarely use the a/c but this MSD part sounds good.
Which one is it from MSD?
There are a few models.
Thanks guys for your imput.
As always this forum is a great help for a non motorhead like myself.
[Modified by 69er, 4:40 AM 8/7/2001]
[Modified by 69er, 2:38 PM 8/7/2001]
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Thread Starter
Team Owner
Joined: Aug 1999
Posts: 28,616
Likes: 4
From: Fort Mill, SC via NJ
Re: Had one instance of pinging today...why? (71coupe)
Which one is it from MSD?
There are a few models.
A MSD Digital Multi-Retard
A Vari-Curve Controller
Adjustable Timing Control unit
With this box I assume the timing could be brought back to 12-14 degrees which would get top performance back compared to timing set at 10.
How much is it?
How hard is it to install?
[Modified by 69er, 2:39 PM 8/7/2001]
There are a few models.
A MSD Digital Multi-Retard
A Vari-Curve Controller
Adjustable Timing Control unit
With this box I assume the timing could be brought back to 12-14 degrees which would get top performance back compared to timing set at 10.
How much is it?
How hard is it to install?
[Modified by 69er, 2:39 PM 8/7/2001]