- Joined
- May 7, 2012
- Messages
- 250
- Reaction score
- 3
- Location
- Near Houston, TX
- My Car
- 1971 Coupe. 302 2V - C4 trans
So last week my boy is driving the car and hears a small "pop" while driving. Not to major, but definitely a "hearable" event. He wondered what the noise was, but attributed it to something he had done inside the car at the same time he heard the noise.
Next day I am in the car with him, and I am hearing a sound that is engine-speed dependent. hard to describe. something between a "tap" or a "rattle" that has a frequency of about one cylinder per engine revolution. One might describe it as similar to a "ping" heard in a pinging engine due to low octane or non-optimal tuning. Hard to hear at idle speeds, more noticeable when the engine is under load and/or accelerating.
So i need some ideas about what I might check for. It seems that something is a-mis, but nothing too major because the engine still idles really well when it is warm. It may be missing on a cylinder, I am not sure my ear is sharp enough to tell for sure via sound if a cylinder is missing or not at idle on this V8.
I haven't checked anything yet, not much time to work on it yet, but here are some things I am thinking, I am looking for more ideas:
- check engine vacuum (have gauge and know how to read it, interpreting what it means can be tougher)
- check individual cylinder compression (have a gauge and know how to use it)
- check spark to cylinders
Another clue: the sounds seems to definitely be coming from the drivers-side bank of cylinders. The engine is a 302 V8. Engine running at idle seems ok, no noticeable sounds (other than a subtle "clatter" that could be attributed to power steering, AC compressor or other). Engine revved and in park doesn't exhibit any significant noises wither.
Other than that, I am struggling for what I can check. I am wondering if perhaps we have had a valve go bad, or some other valve issue. Burned, sticking, cracked etc.
My questions are:
- what else can I check
- what precautions should I take (if any) to protect the engine
- how can I rule out valve issues
- etc.
Sorry for the vagueness. I know to listen to these engines, and I've been hearing…. something. Question is what does it mean?
Thanks for any help or suggestions.
Jay Estes
Next day I am in the car with him, and I am hearing a sound that is engine-speed dependent. hard to describe. something between a "tap" or a "rattle" that has a frequency of about one cylinder per engine revolution. One might describe it as similar to a "ping" heard in a pinging engine due to low octane or non-optimal tuning. Hard to hear at idle speeds, more noticeable when the engine is under load and/or accelerating.
So i need some ideas about what I might check for. It seems that something is a-mis, but nothing too major because the engine still idles really well when it is warm. It may be missing on a cylinder, I am not sure my ear is sharp enough to tell for sure via sound if a cylinder is missing or not at idle on this V8.
I haven't checked anything yet, not much time to work on it yet, but here are some things I am thinking, I am looking for more ideas:
- check engine vacuum (have gauge and know how to read it, interpreting what it means can be tougher)
- check individual cylinder compression (have a gauge and know how to use it)
- check spark to cylinders
Another clue: the sounds seems to definitely be coming from the drivers-side bank of cylinders. The engine is a 302 V8. Engine running at idle seems ok, no noticeable sounds (other than a subtle "clatter" that could be attributed to power steering, AC compressor or other). Engine revved and in park doesn't exhibit any significant noises wither.
Other than that, I am struggling for what I can check. I am wondering if perhaps we have had a valve go bad, or some other valve issue. Burned, sticking, cracked etc.
My questions are:
- what else can I check
- what precautions should I take (if any) to protect the engine
- how can I rule out valve issues
- etc.
Sorry for the vagueness. I know to listen to these engines, and I've been hearing…. something. Question is what does it mean?
Thanks for any help or suggestions.
Jay Estes