Over the last several months I have noticed a slight detonation under hard acceleration. While cruising and normal acceleration everything is fine but if I floor it, it pulls hard and runs fine but I can hear a little pinging.
This is a 427 small block I had built about 4 years ago. It was set up with 18 degrees initial timing with 38 degrees at around 3000 rpms. It ran great with no issues. I got a rear main seal leak last year and this issue may have started after I pulled the engine to change the seal.
As I said, unless I floor it everything is fine. The first thing I checked was the rotor and springs and was surprised that the rotor screws were very loose and thought that was the issue. After tightening them it was a little better I think but still heard some pinging under hard acceleration.
I have checked the timing a few times. I had initial set at 18 degrees and full advance around 38 degrees. I backed off my initial to 14 degrees and I think the hard acceleration detonation was a little better but still there.
The MSD and MSD distributor are about 18 years old. Everything looks fine but does it make sense to try changing the rotor, springs and distributor cap? I am hoping it is not the distributor gear. I had it out when the motor was out and everything looked fine. It has an Erson cam and when they ground the cam they sent the builder a distributor gear to use and the builder put it on my distributor.
Today after a cruise I checked the timing again and it is 14 at idle (no vacuum) and increased with higher RPM but today I lost the timing mark at high RPM's. I am guessing at around 3000 RPM's it was flashing with no marks on the balancer and when I lowered the RPMS it would fall back into the marks. I will try another timing light but that seemed weird.
Any suggestions? I am still fine cruising but would like to be able to floor it without hearing any detonation.
This is a 427 small block I had built about 4 years ago. It was set up with 18 degrees initial timing with 38 degrees at around 3000 rpms. It ran great with no issues. I got a rear main seal leak last year and this issue may have started after I pulled the engine to change the seal.
As I said, unless I floor it everything is fine. The first thing I checked was the rotor and springs and was surprised that the rotor screws were very loose and thought that was the issue. After tightening them it was a little better I think but still heard some pinging under hard acceleration.
I have checked the timing a few times. I had initial set at 18 degrees and full advance around 38 degrees. I backed off my initial to 14 degrees and I think the hard acceleration detonation was a little better but still there.
The MSD and MSD distributor are about 18 years old. Everything looks fine but does it make sense to try changing the rotor, springs and distributor cap? I am hoping it is not the distributor gear. I had it out when the motor was out and everything looked fine. It has an Erson cam and when they ground the cam they sent the builder a distributor gear to use and the builder put it on my distributor.
Today after a cruise I checked the timing again and it is 14 at idle (no vacuum) and increased with higher RPM but today I lost the timing mark at high RPM's. I am guessing at around 3000 RPM's it was flashing with no marks on the balancer and when I lowered the RPMS it would fall back into the marks. I will try another timing light but that seemed weird.
Any suggestions? I am still fine cruising but would like to be able to floor it without hearing any detonation.
