360 noise

[ta2drhino]

I have an ongoing problem with my 360. When I drive it on the interstate from where I live to OKC (about 25 miles), it will run smooth as silk up to 80-90 mph. When I head back home, though, it will run the same way until I am about 2 miles from town and...pop! I feels like an engine brake goes on and I have to back off the accelerator. It will slowly begin to pop with greater frequency until I get off the interstate at my exit. By this time I am running about 50-55 tops. When I get into town, it runs and idles great. I have already bent one pushrod and replaced due to this.

Second problem...this one has started since the first problem and is not in conjunction with the first problem. When I am driving (at any speed), it sounds like I have a pushrod knocking, but it only does it when I am idling in park, coasting (no accelerator) or driving at a constant speed. If I am accelerating or sitting at a light with the brake on, it sounds great (and idles perfect).

I am kinda struggling with this one.

Anyone with ideas or similar problems in the past?

[mljjones67]

Sounds like detonation or pinging.

[papabug71]

Both problems sound like a timing issue to me. Some of the other guys with better mechanical help will chime in.

The first problem kinda sounds like its trying to jump time. Is the timing chain original or older? Could be slack in the chain thats allowing the timing to bump off just a little. A little is all it takes sometimes.

The second problem, I dont know... Maybe a lifter going bad??

Some of the FE guys will chime in. Im not blessed enough to have a FE bump, justa lowly 302.

[willowbilly3]

My experience with jumping time is that an engine will barely run if it is a notch off, probably not at all.
The popping could be a valve issue or a weak spark, like a coil that breaks sown or more likely a fuel starvation problem. Have you tried loosening the gas cap? If you have an older version, I think 69 and earlier, you need a cap that is vented both ways and they don't make new ones afaik.
The bent pushrod is most likely from over revving and any knock that comes and goes like you describe sure sounds like bottom end, wrist pin, piston slap or a loose flywheel/flexplate. I have had fuel pump pushrods fool me though and sound an awful lot like a wrist pin.

[DuckRyder]

I think JB may be on the right track with this one...

A wrist pin usually sounds a lot like a lifter or exhaust leak, bottom end is deeper.

Does it matter how long it sits in OKC?

Any chance of a recording?

[My427stang]

Is the motor stock? Cam change? Anything done recently?

If its bending pushrods somethings certainly wrong. Get us more data

You could have a stuck valve, a burned valve coming on, vales hitting pistons if it has any cam in it, etc. However, I will say this, slow down until you figure it out, if you pop the head of a valve off the motor will be junk.