I've been searching for some good threads that cover any tuning that may help reduce some piston slap noise.
I have a 6.2 in a denali and they seem to be the worst of all the GM vehicles for piston slap when cold...especially when they get some miles on them
Noise goes away when warm, no debris in oil, but the noise is irritating (and my wife hates it) so if there is some tuning that can be done to help reduce the noise, I'd love to know what people have tried and what works well.
Thanks!
GM has no fix other than tell people it is "normal".
You could try a block heater.
Yea it seems to be quite common.
Short skirt, large bore, aluminum block, high mileage, minimal pin offset...it's a recipe for piston slap
I just was curious if anyone used the piston slap spark table to see any benefit or if it's a waste of time to mess with
Sounds like you have some creative selling to do on a forged piston set and a S/C or turbo "to get rid of that annoying noise".
Worked for a buddy of mine.
Not me. Hope your wife isn't from family of mechanics/gearheads like mine.
Hawk
I've tried almost everything that can be calibrated - nothing.Originally Posted by MaroonMonsterLS1
I've replaced pistons and got silence for 700 kmthen slapping came back.
Now I using "[ECM] 12630 - Idle Spark Adder vs. ECT (P/N)" with -20* retard up to 70*C to warm faster and remote start not to hear slapping
2011 Cadillac Escalade L94 w/LS3 valves and valve springs
You guys should try on-center wrist pins...the diamond pistons in my 427 chatter like a diesel lol. Once that skirt coating wears in, there isn't much you can do to fix it. Piston slap spark can help. A thicker oil can make a little more pressure/friction with the rod bearings to stabilize the rods on the crank journal. Beyond that...probably out of luck.
Outside of cutting some start up timing out, there's nothing you can really do in the tune that's truly going to quiet down piston slap. You could do what a buddy of mine did a long time ago and flex seal the whole block (outside of course), oil pan, valve covers and other various items. I don't think it worked but it was hilarious none the less.
On my rebuild a few months ago I used DSS FX 4032 alloy forged pistons on my l99 6.2 and have no piston slap at all. So far their great pistons
15w-50 oil helps a bit…
Not sure how the smaller motors can slap so bad, my 429 doesn't slap at all, Piston is 4.13" and is only 2.2" tall, and it doesn't slap at all. I did cut the piston slap table down to 7 deg from 16, cause an extra 16 seemed excessive. Thats with 2618 non centered pistons too, which should really slap till their warm.
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