steve r

wouldnt setting the timing back fix it?

67mustang302

Pre-ignition and detonation are not the same thing, but pre-ignition almost always leads to detonation, and is worse. And yeah, if you had detonation at start up it would only get worse when you drove it.

steve r

If its not detonation im not sure if its lifters making noise becuase when you go on the ground under the engine it gets louder

HACKGT350

hmm might be time for a rebuild your bearings might be making some noise. how many miles are on your car and how well do you keep up with your oil changes and what not?

steve r

I bought the car about 8 months ago so im not sure..the car was a 4 cylinder now an 8 and the engine looks very clean compared to my friends mustangs but im not sure the mileage. You couldnt here the noise until when I did an oil change and i used royal purple 10w 30.

HACKGT350

i know the difference between the two. what i mentioned about the two flame fronts because you have something else igniting the mixture at the same time as the spark plugis detonation, its only a few things that will cause that. something extra in the combustion chamber or excessive amounts of carbon on the piston tops

94StinkinLincoln

sounds like bearing failure if it only does it at start up

steve r

Its hard to explain it..it comes back here and there...when I hear it and give gas it disapears then come backs when idle again..it started to happen the first start after i used royal purple...if it were a bearing wouldnt it get louder when i give gas? Is it possible that royal purple loosened something up?

HACKGT350

do you think you could get a video or sound clip of this?

steve r

I tried before and it doenst come out right