[majj35]

Just sharing the sounds of my Piston Slaps from my rebuild. I went with the AMS Race 3.8 Short Block which has the Alpha Spec Extreme-duty Manley Pistons.

Noticeable sounds:
-Loud crank sounds on cold-start
-Loud slaps on idle (hood open - like the video below)
-Minor "Chittering" sounds while driving (faster chitters , as I increase speed and vice versa).

I know forged pistons are louder due to more clearance… I've never heard one in-person so I'm not sure if it's supposed to be THAT loud or not. Is it?

 

[240Z TwinTurbo]

In my experience on other platforms with forged "street" motors, having audible piston slap isn't normal. My current 2.15L EVO forged motor (3rd forged motor I've had) is very quiet even on cold start and dynoed [email protected] on Shell 93 pump. However, you purchased a "Race" short block so likely the clearance are much looser to account for piston CTE at the projected power level the engine was designed to handle. If the noise is indeed "piston slap" then either the piston-bore clearances are too loose or you aren't getting the pistons up to temp. Does it make that noise after you've been banging on it at high HP?

 

[Automotive.Cocaine]

Bruh you got conned
Rip to that engine

 

[colo_evo]

Whats going on with all the mismatched silicone hoses and couplers? Looks like a hot mess under that hood.

 

[majj35]

Whats going on with all the mismatched silicone hoses and couplers? Looks like a hot mess under that hood.

Temporary until I replace the upper ic pipes. These hoses are a little thicker than OEM


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[majj35]

Bruh you got conned
Rip to that engine

?? Why lol…


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[majj35]

In my experience on other platforms with forged "street" motors, having audible piston slap isn't normal. My current 2.15L EVO forged motor (3rd forged motor I've had) is very quiet even on cold start and dynoed [email protected] on Shell 93 pump. However, you purchased a "Race" short block so likely the clearance are much looser to account for piston CTE at the projected power level the engine was designed to handle. If the noise is indeed "piston slap" then either the piston-bore clearances are too loose or you aren't getting the pistons up to temp. Does it make that noise after you've been banging on it at high HP?

Same noise with the hood popped? I’ll check and see.. but yes while driving i do hear them.


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[240Z TwinTurbo]

Same noise with the hood popped? I’ll check and see.. but yes while driving i do hear them.
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Assuming the noise is audible when driving, does the noise go away after you have been jamming on the motor at full hp? Also, are you certain the noise is "piston slap" and not simply valvetrain noise?

 

[joshuaho96]

The answer is that it depends. A forged engine with high P2W clearance and heavy duty 2618 pistons for a big power build will slap like crazy in street use. Otherwise when operating at max power the pistons will lose all clearance and cause a lot of damage. If your engine was built for light power, not much more than stock bottom-end with tight rings and low clearance for relatively brittle forged pistons then the sounds you're hearing should go away within a minute of driving tops.

 

[L.L.]

I had a built motor on a different platform in the past with CP pistons and a sleeved block. They slapped when cold but went away after a few minutes of warmup. Nothing crazy sounding just a different tone of noise when cold. It wasn't as loud as what I hear in the video but you could tell it was not stock.

 

[majj35]

The answer is that it depends. A forged engine with high P2W clearance and heavy duty 2618 pistons for a big power build will slap like crazy in street use. Otherwise when operating at max power the pistons will lose all clearance and cause a lot of damage. If your engine was built for light power, not much more than stock bottom-end with tight rings and low clearance for relatively brittle forged pistons then the sounds you're hearing should go away within a minute of driving tops.

so mine is built to handle 860-900whp , and for the motor as mentioned the Alpha race, with the Alpha/manley pistons (which i hear that Manleys sound loud)

 

[majj35]

here's a video i just took in the morning.. you need to listen closely headphone or ear on phone lol.. you can hear the light "chitters" (slow and higher on higher speed).

 

[joshuaho96]

so mine is built to handle 860-900whp , and for the motor as mentioned the Alpha race, with the Alpha/manley pistons (which i hear that Manleys sound loud)

I would ask AMS if those noises are normal. It's possible that your engine has normal but high P2W clearance due to the intended use case, it's possible that your engine has excessive P2W clearance, it's possible that your engine has something else going on. I really couldn't tell you what's going on there.

 

[majj35]

I might do that yeah.

Any of you got idle videos with the hood open (built short block)


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[Wicked]

Do you have built heads?

 

[majj35]

Do you have built heads?

Short block only


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[Jd223]

Did you follow AMS's break in procedure?

 

[majj35]

Did you follow AMS's break in procedure?

What’s their break in procedure? I did my own 1,000 km low boost, keeping it under 3,500-4,000rpms


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[240Z TwinTurbo]

What’s their break in procedure? I did my own 1,000 km low boost, keeping it under 3,500-4,000rpms


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Not the best post you could make...

https://www.amsperformance.com/wp-c...Engine-Break-In-and-Warranty-Info-2-06-19.pdf

 

[majj35]

Not the best post you could make...

https://www.amsperformance.com/wp-c...Engine-Break-In-and-Warranty-Info-2-06-19.pdf

So steps 1-8 positive it was done before handing me the car. Shop Owner did drive the car to check everything before delivering it himself to me.

As for 10-12 , it was done too when i took back the car to the shop to replace the gearlock clip that snapped out


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