detonation question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

76bonanza · 12-28-2004, 11:33 PM

I think I might be getting a slight detonation or pinging at about 4300 rpm in second gear untill about 4500 when it shifts and only at WOT. It is a daily driver and almost never sees those rpm. I tried lowering timing and such but can not shake it will it hurt it much?

I also have a slight collector leak think it could just be the collector leak getting loud?

Thanks for your help.

magnethead · 12-28-2004, 11:59 PM

What frequency level is the pinging sound at, high frequency or low? also try running different octane fuel.

76bonanza · 12-29-2004, 12:04 AM

I would say more high but in the middle sounds almost like crackling or spark like? Hard to explain can only hear if I listen hard with out radeo and really concentrating.

magnethead · 12-29-2004, 12:09 AM

I know on my mom's camaro, when the manifold leaked, it emitted a "ticking" sound from off-idle to about 1000 RPM short of red line. So it could be a loose header/manifold gasket, maybe that collector leak, or something in the engine.

What compression and octane rating do you use?

784X4GUY · 12-29-2004, 12:12 AM

If you have to really concentrate then it is probably a collector gasket in the beginning stages. It will only get worse as time goes by. If it is spark knock it will sound like a bunch of marbles in a coffee can. And yes if you persists with spark knock it will do harm before it helps out any lol. And if you put higher octane fuel in it and it goes away. It is diffently spark knock and you should fix it immediatly...Later Mike

76bonanza · 12-29-2004, 12:17 AM

So spark knock will be louder and more prononced?

784X4GUY · 12-29-2004, 12:35 AM

No No not exactly its hard to tell, I would check all my header and collector area and gaskets for leaks. Id even have someone rev it a little just to put that extra bit of pressure on the exhaust pipes to see if you got a little leak. If so replace gasket and see if that fixes it. It will not be louder if you have a really leaky exhaust gasket. I had one blow on me and made my truck sound like a tractor. Im not kidding. If you are pulling timing out and its still there it just doesnt sound like spark knock to me. Because it should go away if you pull timing out. Im sorry for not answering your question straight up. Its just that im not there and I can't make a positive statement without hearing it...Later Mike

12-28-2004, 11:33 PM	#1
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	detonation question I think I might be getting a slight detonation or pinging at about 4300 rpm in second gear untill about 4500 when it shifts and only at WOT. It is a daily driver and almost never sees those rpm. I tried lowering timing and such but can not shake it will it hurt it much? I also have a slight collector leak think it could just be the collector leak getting loud? Thanks for your help. __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

12-29-2004, 12:04 AM	#3
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	I would say more high but in the middle sounds almost like crackling or spark like? Hard to explain can only hear if I listen hard with out radeo and really concentrating. __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

12-29-2004, 12:12 AM	#5
784X4GUY Did someone say MUD? Join Date: Aug 2003 Location: Pullman,WA Posts: 1,089	If you have to really concentrate then it is probably a collector gasket in the beginning stages. It will only get worse as time goes by. If it is spark knock it will sound like a bunch of marbles in a coffee can. And yes if you persists with spark knock it will do harm before it helps out any lol. And if you put higher octane fuel in it and it goes away. It is diffently spark knock and you should fix it immediatly...Later Mike __________________ Im in the market guys...so keep ya eyes peeled -------------------- Mini trucks are for guys who cant get it up!

12-29-2004, 12:17 AM	#6
76bonanza Senior Member Join Date: Mar 2003 Location: St robert Mo Posts: 2,001	So spark knock will be louder and more prononced? __________________ 1968 c10 lowered 3" 4" 355/Th400 built by Hatfield racing in joplin MO

12-29-2004, 12:35 AM	#7
784X4GUY Did someone say MUD? Join Date: Aug 2003 Location: Pullman,WA Posts: 1,089	No No not exactly its hard to tell, I would check all my header and collector area and gaskets for leaks. Id even have someone rev it a little just to put that extra bit of pressure on the exhaust pipes to see if you got a little leak. If so replace gasket and see if that fixes it. It will not be louder if you have a really leaky exhaust gasket. I had one blow on me and made my truck sound like a tractor. Im not kidding. If you are pulling timing out and its still there it just doesnt sound like spark knock to me. Because it should go away if you pull timing out. Im sorry for not answering your question straight up. Its just that im not there and I can't make a positive statement without hearing it...Later Mike __________________ Im in the market guys...so keep ya eyes peeled -------------------- Mini trucks are for guys who cant get it up!

12-28-2004, 11:59 PM	#2
magnethead 7000 #'s of american IRON Join Date: Dec 2004 Location: north tx Posts: 883	What frequency level is the pinging sound at, high frequency or low? also try running different octane fuel.

12-29-2004, 12:09 AM	#4
magnethead 7000 #'s of american IRON Join Date: Dec 2004 Location: north tx Posts: 883	I know on my mom's camaro, when the manifold leaked, it emitted a "ticking" sound from off-idle to about 1000 RPM short of red line. So it could be a loose header/manifold gasket, maybe that collector leak, or something in the engine. What compression and octane rating do you use?



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.