How can I stop the pinging?
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
How can I stop the pinging?
I have an 85 that has been slightly modified and pings more than I want to hear. The block is bored .060 over with Keith Black domed pistons. So, I'm running approx 10.5:1 compression. Have a mild Competition cam, roller rockers and cat-back exhaust. I recently installed new injectors from FIC. I have tried retarding the timing and adding octane booster with little effect. I'm wondering if the cam has lowered vacuum a little resulting in a lower fuel pressure. Would an adjustable fuel pressure regulator help?
Thoughts?
Thoughts?
Melting Slicks
Joined: Aug 2007
Posts: 2,619
Likes: 1
From: Salem Oregon
St. Jude Donor '09-'10-'11
I have an 85 that has been slightly modified and pings more than I want to hear. The block is bored .060 over with Keith Black domed pistons. So, I'm running approx 10.5:1 compression. Have a mild Competition cam, roller rockers and cat-back exhaust. I recently installed new injectors from FIC. I have tried retarding the timing and adding octane booster with little effect. I'm wondering if the cam has lowered vacuum a little resulting in a lower fuel pressure. Would an adjustable fuel pressure regulator help?
Thoughts?
Thoughts?
Laura
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
I have an 85 that has been slightly modified and pings more than I want to hear. The block is bored .060 over with Keith Black domed pistons. So, I'm running approx 10.5:1 compression. Have a mild Competition cam, roller rockers and cat-back exhaust. I recently installed new injectors from FIC. I have tried retarding the timing and adding octane booster with little effect. I'm wondering if the cam has lowered vacuum a little resulting in a lower fuel pressure. Would an adjustable fuel pressure regulator help?
Thoughts?
Thoughts?
What heads are you running? At 10.5 CR I hope they are alum. You can also lower your operating temperature to 160 degrees with a t-stat and reprogrammed chip. The lower operating temperature will reduce the tendancy to ping.
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
I'm running premium gas with an octane booster. The heads are cast iron. Have not made the move to aluminum yet. AFRs are coming when the money tree blooms. I've already installed a 180 thermostat and wired both fans to come on at 195 deg. Pinging was happening as low as 200 deg. I also ran several tank fulls of injector cleaner to get rid of any carbon in the chambers. I'm stumped.
Instructor
Joined: Aug 2006
Posts: 247
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I'm running premium gas with an octane booster. The heads are cast iron. Have not made the move to aluminum yet. AFRs are coming when the money tree blooms. I've already installed a 180 thermostat and wired both fans to come on at 195 deg. Pinging was happening as low as 200 deg. I also ran several tank fulls of injector cleaner to get rid of any carbon in the chambers. I'm stumped.
/s/ Chris Kennedy
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Joined: Apr 2005
Posts: 3,624
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From: Dale City VA
10.5 SCR + Mild Comp Cam, likely = DCR TOO HIGH.
Cast Iron heads = TOO MUCH HEAT RETENTION IN THE COMBUSTION PROCESS.
Dome Pistons = POOR FLAME FRONT PROPOGATION AND EVEN WORSE FUEL BURN.
It SHOULD ping its *** off.
What's to be stumped about?
Will
Cast Iron heads = TOO MUCH HEAT RETENTION IN THE COMBUSTION PROCESS.
Dome Pistons = POOR FLAME FRONT PROPOGATION AND EVEN WORSE FUEL BURN.
It SHOULD ping its *** off.
What's to be stumped about?
Will
Thread Starter
Melting Slicks
Joined: Mar 2008
Posts: 2,141
Likes: 76
From: Santa Maria, CA
Thanks Chris.
I retarded the initial timing from the factory 6 to 4. Still knocking. Think I'll back off a couple more degrees. I agree that a little loss of performance is better than the potential damage. I understand this is not a great engine setup, but its what I got when I bought the car. I'm just trying to tune it as best I can until I have the funds to rebuild it right.
I really don't know if the knock sensor is working. I would expect it to sense the ping and retard the timing.
I retarded the initial timing from the factory 6 to 4. Still knocking. Think I'll back off a couple more degrees. I agree that a little loss of performance is better than the potential damage. I understand this is not a great engine setup, but its what I got when I bought the car. I'm just trying to tune it as best I can until I have the funds to rebuild it right.
I really don't know if the knock sensor is working. I would expect it to sense the ping and retard the timing.
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Joined: Sep 2001
Posts: 4,157
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From: Glenbeulah Wi
Thanks Chris.
I retarded the initial timing from the factory 6 to 4. Still knocking. Think I'll back off a couple more degrees. I agree that a little loss of performance is better than the potential damage. I understand this is not a great engine setup, but its what I got when I bought the car. I'm just trying to tune it as best I can until I have the funds to rebuild it right.
I really don't know if the knock sensor is working. I would expect it to sense the ping and retard the timing.
I retarded the initial timing from the factory 6 to 4. Still knocking. Think I'll back off a couple more degrees. I agree that a little loss of performance is better than the potential damage. I understand this is not a great engine setup, but its what I got when I bought the car. I'm just trying to tune it as best I can until I have the funds to rebuild it right.
I really don't know if the knock sensor is working. I would expect it to sense the ping and retard the timing.