eliminating piston slap entirely?

[3100]

Would a new set of pistons (and whatever cylinder bore work needs doing) eliminate piston slap entirely on one of these motors?

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[TGP37]

Would a new set of pistons (and whatever cylinder bore work needs doing) eliminate piston slap entirely on one of these motors?

Possibly, depends how you size them up. Piston slap is the piston not fitting properly when cold. If you let the engine warm up before putting load on it, the lifespan can almost double. I've heard of these blocks going 500k if allowed to warm up before hammering it.

If it's only piston slap when cold, I wouldn't bother it.

[3400-95-Modified]

I did new 30 over pistons in my old 3400 and it still had noise... those were the sealed power ones with teflon side coating.

[3100]

Interesting. It's more pronounced when it's cold (as in, it's loud enough for me to question how it still runs) but it still knocks a bit when it's warm, though it's as a manageable level then.


It's the worst piston slap I've ever heard, but it runs just fine, doesn't burn any oil either. Oil psi is good. Even the OEM (afaik they're original anyway) intake gaskets are intact

[TGP37]

If the car was driven hard while cold often...i.e. rush to work situation 3-4 times a week..... the combustion chamber can get ovaled from wear over time.

But, it might not be piston slap. Try pulling the spark plug while idling one at a time to see if the noise stops. It could be a bad connection rod cap bolt or bad rod itself, etc. Removing the load on the suspected chamber will stop the noise. I heard piston 6 slaps the most but I am not 100% sure about that.

Anyways, mild piston slap is healthy. And if the engine is allowed to warm up before any load is applied, it will last up to 500k miles. Considering the other fluids and maintainence items are cared for.

[3100]

If the car was driven hard while cold often...i.e. rush to work situation 3-4 times a week..... the combustion chamber can get ovaled from wear over time.

But, it might not be piston slap. Sometimes the pushrods and/or the lifters get clogged up and the rockers start to dry up. Making a tapping sound.

Anyways, mild piston slap is healthy. And if the engine is allowed to warm up before any load is applied, it will last up to 500k miles. Considering the other fluids and maintainence items are cared for.

Yeah, I take pretty great care of it. ~3000 mile oil change (5000 kilometers) and I don't lay into it until it's warmed up.

I know it was well maintained its entire life but knowing the previous owners, I think it was probably driven hard while cold often. The noise definitely isn't mild, though.

[TGP37]

Are you sure it is piston slap? A short video could really help if your trying to diagnos this. If the noise is more noticeable then normal it may not be piston slap.

Don't forget the 100k mile maintainence. Oxygen sensor get old and they create a richer condition, fuel filters are often neglected until they clog up. By then the pump is ready to die (if filter is neglected). And keep an eye out for the dreaded LIM leak.

[3100]

Fairly certain. It doesn't sound like it's coming from the valvetrain but I honestly have not gotten out the stethoscope to pinpoint the noise.

[3100]

I'd much rather it be lifter noise. Popping in a new set of lifters and maybe pushrods when it's apart for LIM gaskets is a damn sight easier than putting new pistons in.

[3100]

Are you sure it is piston slap? A short video could really help if your trying to diagnos this. If the noise is more noticeable then normal it may not be piston slap.

I'm trying to upload a video but it doesn't seem to want to work. Likely a PEBKAC error.