BBC 2618 Icon Piston .008 piston to wall

[MadBill]

That would be the equivalent of the Sun rising in the West!

[ProPower engines]

That would be the equivalent of the Sun rising in the West!

[Bishop540]

Just started the build again. And I ended up using Line2Line.

[ProPower engines]

Just curious what the cost was to do all 8 pistons and what the turn around time was

[Bishop540]

Receipt shows $294.32, plus i had to initially ship it to them for $34.04. I wanna say it was less than 2 weeks to get them back. That was around the time of Hurricane Harvey here, so everything was kind of a mess.

[engineguyBill]

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!

Piston coatings will work very well in reducing piston skirt to cylinder wall clearance, as .008" is way too much. BUT barrel face rings should never be installed in the second groove!! The second ring is designed with a tapered face, in order to control oil and keep it out of the combustion chamber. The oil ring assembly meters the correct amount of oil up to the cylinder walls and combustion rings and the second ring scrapes excess oil off of the cylinder wall and insures that there is oil within the crosshatch pattern of the cylinder walls. Most ring manufacturers describe second ring as 20% combustion control and 80% oil control, although some people dispute this.

The only exception to this is the fact that some Top Fuel teams have installed Dykes type rings in both the top and second grooves. This is workable due to the fact that so much combustion pressure gets past the top ring and will actually help seal combustion pressures at the second ring. Oil control is a secondary issue in these Nitromethane-fueled engines.

BTW, Line2Line coatings is an excellent choice for piston coatings in my opinion and the company is used extensively by Icon's patent company.

[pdq67]

I think that Dave Vizard talked about using a contoured nut and bolt as a home made press and closing up the skirt clearance.

Not the best, BUT my old junk301 had like .0075" clearance in it and the oil burning, knocking SOB ran like a, "scalded dog", so go from there.

I'm talking 7,500 rpm here..

Being unbalanced it would kick a damper off before it rattled the rods!

pdq67

[Bishop540]

I think that Dave Vizard talked about using a contoured nut and bolt as a home made press and closing up the skirt clearance.

That would be interesting.....but my skirts would be jacked if i tried that.

[Paul Kane]

Has anyone ever run an Icon 2618 BBC piston in a street engine with .007 to .008 piston to wall clearance?

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

I’ve known race engines that ran other brand pistons with 0.008”. Hell I’ve known race engines that run more than 0.010” and ran very well.

That being said, the Icon at 0.008” piston-to-wall was a complete and instant disaster in a race application because the crown/ring land area of their design does not have the adequate diameter reduction nor the necessary taper to run it that loose, and so when the piston rocks over the ring land area scrapes the bore hard and embeds it with aluminum. You might be okay in a street application with that particular design, but let them warm up completely and don’t flog the engine too hard.

Or perhaps you can get the correct piston for your bore size, such as a custom at 0.004” over with file fit rings. That would be my first choice; the thick skirt coating deal would be the Plan B.