BBC 2618 Icon Piston .008 piston to wall

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Bishop540
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BBC 2618 Icon Piston .008 piston to wall

Postby Bishop540 » Fri Aug 11, 2017 6:55 pm

Has anyone ever run an Icon 2618 BBC piston in a street engine with .007 to .008 piston to wall clearance? I believe the pistons rock in the bore about .025 too. Top ring gap is about .021.

Icon recommends PtW .0045-.0055 for street NA.

Will the engine beat itself up or just be a little noisy until it warms up?

492 BBC with 10:1 compression

Thanks

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Re: BBC 2618 Icon Piston .008 piston to wall

Postby Geoff2 » Sat Aug 12, 2017 5:36 am

The shorter the piston, the bigger the problem will be with excessive bore clearance...

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Re: BBC 2618 Icon Piston .008 piston to wall

Postby PackardV8 » Sat Aug 12, 2017 10:47 am

Been several discussions here recently about using custom coatings to take up the slop.
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Re: BBC 2618 Icon Piston .008 piston to wall

Postby Bishop540 » Wed Aug 16, 2017 9:02 am

Thank you for your replies. I will check into coatings.

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Re: BBC 2618 Icon Piston .008 piston to wall

Postby mag2555 » Wed Aug 16, 2017 9:52 am

You had better run a Barrel face second ring if your having less then pefect PTB issues , as all the coatings in the world will not help the rings seal better!

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Re: BBC 2618 Icon Piston .008 piston to wall

Postby Bishop540 » Wed Aug 16, 2017 8:58 pm

Line2Line claims their coating will fill up the sloppy clearance between the piston and bore. Sounds like magic to me. I wonder if anyone has successfully done this on Speedtalk. From Line2Line's website:

ADVANTAGES:
Restores and Holds Clearances
Highly Wear Resistant
NHRA Pro-Mod Tested

AND
Piston Skirt Coating reduces operational clearances, protects piston skirts from scuffing, retains oil, and reduces friction. Recommended when piston and bore dimensions are providing stock clearances. Reduces slap and ring flutter compared to uncoated pistons, effectively improving ring seal and reducing wear on the pistons and rings. Also protects the interface from foreign particle wear. During a short break-in cycle (5-15 min), excess coating thickness will wear away where contact stresses are highest. Where there is room, lower contact stresses allow the thickness to remain and reduce operating clearances.

ADVANTAGES:
Reduces Stock Clearance for Best Fit
Reduces Slap for Better Ring Seal
Protects Against Scuffing
Retains Oil Film
Promotes Hydrodynamic Sliding
Reduces Friction
2 Strokes Run Quieter Crisper

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Re: BBC 2618 Icon Piston .008 piston to wall

Postby tenxal » Wed Aug 16, 2017 9:21 pm

Bishop540 wrote:I wonder if anyone has successfully done this on Speedtalk.


Yes.

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Re: BBC 2618 Icon Piston .008 piston to wall

Postby PackardV8 » Thu Aug 17, 2017 8:45 am

Recommended when piston and bore dimensions are providing stock clearances.
Reduces Stock Clearance for Best Fit


Anyone else having difficulty translating this?
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Bishop540
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Re: BBC 2618 Icon Piston .008 piston to wall

Postby Bishop540 » Thu Aug 17, 2017 9:24 am

PackardV8 wrote:
Recommended when piston and bore dimensions are providing stock clearances.
Reduces Stock Clearance for Best Fit


Anyone else having difficulty translating this?


I guess stock clearances are too loose for them and need to be tightened up..... :D

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Re: BBC 2618 Icon Piston .008 piston to wall

Postby MadBill » Thu Aug 17, 2017 3:03 pm

Yes, I think they are saying that stock clearances are designed to live long and prosper under worst case conditions, so coating them up to/near zero allows it to open up only where and how much required for your app. Under this scenario, the worst that could happen if a rare extreme arose would be self-clearance a tad more.
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Re: BBC 2618 Icon Piston .008 piston to wall

Postby Bishop540 » Thu Aug 17, 2017 10:49 pm

MadBill wrote:Yes, I think they are saying that stock clearances are designed to live long and prosper under worst case conditions, so coating them up to/near zero allows it to open up only where and how much required for your app. Under this scenario, the worst that could happen if a rare extreme arose would be self-clearance a tad more.


Yes Sir, I think it is my best option at this point.


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