2G PTW Clearance Problem (piston slap) - 2.3 Build

[GofaST4life]

Hello everyone. I need some help, guidance, etc.

I recently assembled my 2.3 short block, and while everything went great, I realized I have a serious piston slap issue. So I started searching and doing what I could to see how I could remedy this as I cannot take the pistons back to Extreme PSI and obviously can’t make my block more narrow.

The “slap”. You should know that the pistons, yes all 4, have around the same amount of movement throughout the entire cylinder.

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Let me say, I know this isn’t the correct way to measure PTW clearance, but I wanted to do what I could with my limited tools to see if an obvious issue was apparent. If I need to go buy a bore gauge I will. But let’s look at the cheap and easy numbers first.

First, the notes from my machine shop. I trust these guys and have spoken to them a few times about the measurements. According to my phone call with Weisco, the .002 at the top is okay, and they would expect a small amount of movement at the top of the cylinder, but not throughout the entire cylinder.

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Now onto the measurements. I understand I’m not getting another decimal point, but at least this is in line with what the machine shop measured.

Cylinder #4

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Cylinder #3

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Cylinder #2

[URL=http://s285.photobucket.com/user/awolo/media/Mobile%20Uploads/IMG_20160512_175642593_zpsqhtimg1w.jpg.html]

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Cylinder #1

[URL=http://s285.photobucket.com/user/awolo/media/Mobile%20Uploads/IMG_20160512_175616787_zpsllkx1aij.jpg.html]

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Now I started measuring a piston i pulled out. Per the instructions below from Weisco.

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Measure at 1.300 inches from the bottom oil ring. Clearly, without the extra decimal point, the PTW clearance will be way over the spec of .0025 according to the Weisco sheet.

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And for gits and shiggles I measured the top of the piston….

[URL=http://s285.photobucket.com/user/awolo/media/Mobile%20Uploads/IMG_20160512_180026761_zpsfjrl7lls.jpg.html]

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Can anyone help me make sense of this? Clearly, it looks like my pistons are too small for my bore, but would/could Weisco/Extreme PSI have made/sent me the wrong sized pistons?[/URL][/URL][/URL][/URL][/URL][/URL]

 

[biglady112]

We have run as high as .007" clearance total. .0025" and your pistons will likely seize in the hole. Your micrometer needs to read down to the .001". That will help you make better sense of what is going on

 

[jery1234]

^ + 1 A minimum.005 is required for most of pistons unless you use Mahle pistons (I do) (.002 - .003) those pistons are low expansion pistons. 45+ psi no problem with .003 PTW .

 

[Kapok6]

Wiseco hd are like .002" I believe; my Ross were like .006".

 

[bastarddsm]

Put them in upside down and use a thin feeler gauge to check clearance

 

[GofaST4life]

Im going to work on getting some better measurements.

My second thought was to just drop the block and pistons off at a machine shop and ask them to tell me whats going on. Somthing I probably should have done in the first place, but I did buy everything based on their measurments.

 

[miliman13]

Your piston slap?? Did you run the motor and hear it? Or did you just wiggle the piston in the bore?

But to do this right, at minimum you need horse shoe micrometers and telescopic snap gauges.
Assuming those numbers are correct. Your actually on the tighter side of clearance.
Also measure at the widest point in the piston. Usually center portion of skirts.

 

[miliman13]

I'm currently building to..
I have .003 ptw clearance on average on all 4.
And I'm no were near the movement you have based on that awful photo-bucket clip.


Hate to be that guy. But never trust anyone, check the work yourself, I do. That's how I know my shops are staying honest.

And if it's only shaking at the top!! That makes believe it's tapered... Meaning... You'll need a new block, or new pistons or steel sleeves to resolve this...


Blast from the past.. I had a used motor that did that..... Didn't last.

 

[GofaST4life]

I'm currently building to..
I have .003 ptw clearance on average on all 4.
And I'm no were near the movement you have based on that awful photo-bucket clip. Video looks WAY beter on my phone, thanks Phtotbucket.

Hate to be that guy. But never trust anyone, check the work yourself, I do. That's how I know my shops are staying honest.

And if it's only shaking at the top!! That makes believe it's tapered... Meaning... You'll need a new block, or new pistons or steel sleeves to resolve this... They moved like that throughout the entire bore, on each cylinder.

Blast from the past.. I had a used motor that did that..... Didn't last. I wont be running it like this.

I never ran it, just assembled, heard the noise and started investigating.

 

[90laserRSfwd]

Fist thing you need to do is buy or borrow an actual bore mic setup (either T gauges and an actual micrometer, 3-4", or a dial / digital bore gauge, and get an exact measurement. Your caliper doesn't do any good in this case as it doesn't read to the thousandths decimal place. Also, verify you have the correct Pistons in their correct bored (there usually are a thousandths or 2 difference from piston to piston. Hope you get it sorted out!

 

[90laserRSfwd]

Pistons in their correct bores*

 

[miliman13]

Pistons in their correct bores*

Even then you still would not be able to rock all four like that.