more problems with '88

[Bob Ash]

I don't want to make a mess in original thread, so I put this in new one.

1) My engine (305) makes a knocking noise. We thought it is a lifter, but that should stop knocking when the engine is warm. This sound doesn't. A friend of mine suggested a piston bearing. Do you think it's really that bad?

2) How to set an ignition advance?

3) It's got time, but I'll need a new exhaust and want to get duals with more aggresive sound, but don't want to get it too much noisy. I was thinking about flowtech headers, 2 1/4" tubes, dynomax mufflers and H-pipe. How you think it will sound?

[silicon212]

#1, where is the knocking coming from? Top, middle or bottom of engine, front middle or back? Many things can cause a knock and emulate a connecting rod bearing failure ... broken smog pumps and broken harmonic balancers are two biggies ... A connecting rod bearing failure (spun bearing) has a knock that might sound tame at idle, goes away during cruising, and makes a hell of a racket during acceleration or torque need. It is a sharp sound that resembles a baseball bat hitting a baseball. Generally this comes from the bottom of the engine, but can come from the cylinder head area if there is piston to cylinder head interference. A ticking, tapping or hammering sound from the top of the engine signifies valve train trouble - lifter, broken valvespring, pulled rocker stud, loose rocker etc.

#2, With engine running you pull the 4-wire plug from the distributor (the computer wire, SES light on dash will come on, ignore), attach a magnetic inductance pickup timing light (has a clamp that loosely fits over the spark plug wire) to cylinder 1 (front driver's side) spark plug wire ... loosen distributor clamp bolt, aim light at timing mark on timing cover - press trigger on light so you see the mark on the harmonic balancer in relation to the timing "fork" - turn distributor counterclockwise to advance or clockwise to retard as necessary.

#3, if you keep tailpipes on it, it will sound deep without being loud.

[Bob Ash]

Thanks for advices ...
ad 1 - it's ticking sound, which is best heard on idle, and goes away (or rather it's not hearable because of the engine noise) on the move.

[TommySS]

Ticking like that could be an exhaust leak at the manifold

[Bob Ash]

TommySS: really? I seems like metal to metal ticking ...

[silicon212]

Originally Posted by Bob Ash

TommySS: really? I seems like metal to metal ticking ...

Exhaust leaks can kinda mimic a ticking sound, but it's more of a soft ticking with a hissing with it ... hard to explain but you would know it if you heard it.

What you're describing sounds much more like a valvetrain issue.

[bobss396]

If you want to zero in on a specific noise, try this trick. Take an old section of wooden broom handle about 2 feet long. Anything like a wood dowel will also work. Hold one end to your ear, place the other end on where you think the noise is. You will be able to narrow it down quickly. I've used it to find bearing noises, water pump growling, etc. Just keep the stick out of the fan and belts.

Bob