slap noise.......

**SSMuscle** · 11-05-2009, 07:33 PM

My maro has about 80k miles, and after a full street tune from a guy i know (Dirty 30 on tech), I got this strange clanking/slapping noise from under the hood. I asked him about it and he stated that it's not because of his tune, that it is a mechanical issue on my car. I told him it didn't do it before the tune, and he continued to blame my ride. I get it all the time, it does not get louder with revs or wot, i only notice it when it's idling, and when first turned on. My car is too loud to notice it when driving it around. Any ideas?? I've heard a pushrod swap will prob fix it. thanks...............

**0rion** · 11-05-2009, 07:56 PM

does it do it on cold starts and then go away? If so that sounds like piston slap to me which is normal. I seriously doubt it's tune related from your description. The other thing it could be is lifter noise or a bent pushrod. It's hard to diagnose a noise on these boards but piston slap is extremely common on the LSx motors. Maybe you just didn't notice it before the tune? Like I say, piston slap will go away fairly quickly.....1-2 minutes or so. A lifter or pushrod issue would be there 24/7 most likely. You can almost completely rule out the tune. What mods do you have?

**SSMuscle** · 11-05-2009, 08:43 PM

Originally Posted by 0rion

does it do it on cold starts and then go away? If so that sounds like piston slap to me which is normal. I seriously doubt it's tune related from your description. The other thing it could be is lifter noise or a bent pushrod. It's hard to diagnose a noise on these boards but piston slap is extremely common on the LSx motors. Maybe you just didn't notice it before the tune? Like I say, piston slap will go away fairly quickly.....1-2 minutes or so. A lifter or pushrod issue would be there 24/7 most likely. You can almost completely rule out the tune. What mods do you have?

mods: slp lid, smooth bellows, ported t/b, msd wires, ngk sparks, slp cai setup, slp fan switch, no cats, slp loud mouth system, subframe connectors...........that's it.

as far as the slap, i notice it as soon as i turn it on, and let it warm up, i drive off and it's too loud to listen, but when i hit a stop sign/light...i can hear it again. it ain't real loud, but noticeable. And NO, i definitely know it was not there before the tune. the slapping noise will stay on the whole time i am driving it, does not go away after a few mins of driving.

**0rion** · 11-05-2009, 09:19 PM

have you went over the car to narrow down where the noise is coming from? If it never goes away then it's not piston slap. I would be pretty confident that it's not tune related but I'd have to see it in person and hear it to know for sure what's going on there. Car run and idle ok? Maybe pull those pushrods and see if any are bent.

**SSMuscle** · 11-06-2009, 02:00 PM

Originally Posted by 0rion

have you went over the car to narrow down where the noise is coming from? If it never goes away then it's not piston slap. I would be pretty confident that it's not tune related but I'd have to see it in person and hear it to know for sure what's going on there. Car run and idle ok? Maybe pull those pushrods and see if any are bent.

Yea, runs great, idles great, wot is fine too......... It's just that tapping that i don't like. It ain't a loud noise, but if you pay attention it's there. No, I haven't really taken a look at her to try and pinpoint where it's at. I was thinking the same thing tho, swapping the pushrods and springs and what not, hoping it might go away.

**redbird555** · 11-07-2009, 08:28 AM

you might wanna check out pistonslap.com they have clips of piston slapping vehicles a pushrod is usually a tap that will fluctuate with rpms and never goes away even when revving it also can be heard much louder on the top of the engine. Piston slap is a dull knocking usually.

**SSMuscle** · 11-08-2009, 02:38 PM

Originally Posted by redbird555

you might wanna check out pistonslap.com they have clips of piston slapping vehicles a pushrod is usually a tap that will fluctuate with rpms and never goes away even when revving it also can be heard much louder on the top of the engine. Piston slap is a dull knocking usually.

thanks.........

**SSMuscle** · 11-08-2009, 03:50 PM

I'm gonna go ahead and swap pushrods and springs, and see if slap goes away. Should I go with the 7.4 (which I'm guessing is stock replacement), or is there a performance swap i can do..........