[baw]

Question for the engine experts of 'NN.

Are pushroad engines prone to a slight ticking noise during fast acceleration or load? I've never driven a vehicle with a pushrod engine before until the other day. When accelerating there is a ticking sound but that disappears when I was just cruising or let off the gas.

I've read on the internet that say a slight ticking during fast acceleration or load is common in pushrod engines and others say any ticking is not normal.

[Spliffdaddy]

An audible clicking sound really isn't normal. The only time it would be acceptable is during the first few seconds after the engine is started - and only then if the engine has hydraulic lifters. This is related to the fact that the lifters depend on pressurized oil in order to expand and eliminate the gap between the cam lobe and face of the lifter.

A slight ticking noise during heavy acceleration is probably only a leaking exhaust system gasket. If it's more of a dull knock, then I'd suspect a crankshaft bearing. Knocking or ticking during *deceleration* is almost always a connecting rod bearing.

"Ticks" aren't usually a bad thing. "Knocks" are.

That being said, it is certainly possible that the engine has either worn/misadjusted 'solid' lifters - or perhaps a 'stuck' hydraulic lifter. But the 'tick' sound wouldn't disappear at idle, as you've described.

[ghporter]

What do you mean by "pushrod" engines? As opposed to what else?

Many engines will "knock" a bit when you accelerate hard-it's due to the valves tapping on their actuators (rocker arms, lifters, etc.), and this can be reduced or eliminated by using a higher octane fuel. It's often more obvious when you accelerate hard while various accessories are also loading the engine-the A/C for example can load the engine enough to make it knock even when normally it doesn't.

[sknapp351]

Pushrod as opposed to overhead camshaft. OHC engines often have the camshaft pushing directly on the rocker arm or the tappet directly. Pushrod engines ( such as typical older American V8s ) will have the cam centered in the engine with push rods that transfer the motion to the rocker arms that puch the valves.
SAm

[The Godfather]

<heresy>Just replace the ICE with a nice 20HP electric motor and slap a battery bank on the back seat.</heresy>

[ghporter]

Originally Posted by sknapp351

Pushrod as opposed to overhead camshaft. OHC engines often have the camshaft pushing directly on the rocker arm or the tappet directly. Pushrod engines ( such as typical older American V8s ) will have the cam centered in the engine with push rods that transfer the motion to the rocker arms that puch the valves.
SAm

I thought that's what you meant, but I don't keep up with engine terms lately. OHC engines knock too, by the way... If my A/C is on and I gun my Honda it'll knock for a bit until everything comes up to speed. Of course with a smaller engine it's more of a "rattle" sound than an knock.

[vmarks]

can also be ignition timing.

Or carburetor settings or fuel injection idle if it isn't computer controlled.

[greenamp]

Originally Posted by baw

Question for the engine experts of 'NN.

Are pushroad engines prone to a slight ticking noise during fast acceleration or load? I've never driven a vehicle with a pushrod engine before until the other day. When accelerating there is a ticking sound but that disappears when I was just cruising or let off the gas.

I've read on the internet that say a slight ticking during fast acceleration or load is common in pushrod engines and others say any ticking is not normal.

Sometimes it's just a matter of using a higher octane gasoline. Pushrod engines are more susceptible to precognition knock, since a lot of them were designed in a time when all gas was like 105 octane.

[baw]

Reason I'm asking this and the bed liner question thread is that I've acquired a 2003 Ford F150 4.2L V6.

While under the hood the left side of the engine ticking sound reminds me of a sewing machine. This sound does increase when I open the throttle. Some people say it could be injectors, manifold, or lifters.

I'll take it to a mechanic and see what he says.

[SVass]

In the "old" days, hydraulic lifters would click until the oil warmed up. Ping during hard acceleration is different. sam

[IceEnclosure]

Originally Posted by baw

Reason I'm asking this and the bed liner question thread is that I've acquired a 2003 Ford F150 4.2L V6.

While under the hood the left side of the engine ticking sound reminds me of a sewing machine. This sound does increase when I open the throttle. Some people say it could be injectors, manifold, or lifters.

I'll take it to a mechanic and see what he says.

I say fuel injector. (without seeing the thing, who knows really)

[Spliffdaddy]

From what I've been reading, the 4.2 V6 is prone to "spark knock" due to the advanced ignition timing. It is noticeable under load and even in neutral if the accelerator is blipped suddenly. The engine is equipped with knock detectors that are supposed to limit the amount of spark knock by allowing the engine computer to retard the ignition timing. The engine runs most efficiently with the ignition timing *right at* the edge of 'spark knock - so the "ping" or "rattle" is probably considered normal operation. You can try running a higher octane fuel - but from what others are saying, the computer will simply advance the timing up to the point of spark knock - again.

Supposedly, it's a very reliable engine - since yours is new enough not to be affected by the premature "lower intake manifold gasket failure" that plagued earlier models. While it sounds like a simple problem, it resulted in major engine damage because the engine coolant found its way into the intake manifold and into the cylinders...and since liquid can't be compressed, the connecting rods would bend or break.