Blueprint 107 - piston-to-cylinder wall clearance

This video covers how easy it is to calculate piston-to-cylinder wall clearance. It's too easy. This is important because too loose of a gap and the rings won't seal properly. Too tight and the pistons will scuff the cylinder walls, ruining the bores.

We've touched on thermal expansion several times now, and the reason it keeps coming up is because turbo engines achieve much higher cylinder pressures, and therefore generate more heat than a normally aspirated combustion chamber experiences. This affects the growth of the metal parts when they're at operating temperatures, so turbo pistons need more cylinder wall clearance to account for this.

I will cover the ring grooves, compression and oil rings in a 200-series video while assembling this engine with new pistons. For now, these will just be saved for a rainy day. After all, I have a stock bore stock 4g63 engine in the Colt.

Happy Thanksgiving!

Category:

Autos & Vehicles

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• Jafromobile
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• 4g64
• turbo
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• 7bolt
• 6-bolt
• 7-bolt
• assemble
• disassemble
• cylinder
• wall
• clearance
• piston
• skirt
• gap
• inspect
• blueprint
• short
• block
• shortblock
• measure
• caliper
• bore
• test
• do
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• yourself
• diy
• VFAQ
• calculate
• stand
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• high-mileage
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[MrRandomkillz]

i need to get better at this engine rebuild stuff, im trying to rebuild my 420a for my 97 eclipse. what do u recommend as in parts?, i am trying to go for a turbo build

[Jafromobile]

@MrRandomkillz This might be the wrong place to answer this... but buy the turbo car instead. As a former GS owner, don't read anything into that.

You can get a whole 1g or 2g car for less than the cost of building a solid 420A rotating assembly + all the supporting mods. You'll never have any regrets with a GSX. When it comes to tuner cars, it doesn't matter what it is... it won't be reliable. You'll always need something that you can count on to get you to work. A GS does that very well!

[watchforfinger]

what are you going to do with this engine and how soon

[Jafromobile]

@watchforfinger I'm going to make another video with it, and if I'm lucky, maybe upload it later tonight. xD

[DJDevon3]

You make it look so easy that I want to tear apart my engine. I kind of have to do that anyway at least head removal. Would you recommend measuring specs before, after, or both if I'm getting a valve job? All I can afford is to have 1 burnt valve replaced. :(

[jeepcherokee40]

you make some of the best vids keep up the great work

[djdarkmunk]

@Jafromobile yea man prob is i make about 10k a year so my budget is super tight

[robertbaxley]

I really can not think of a more comprehensive set of Free videos. Thank you for all of your time and effort as it is all appreciated. Great video once again, I look forward to seeing this thing in Richmond upon completion.

Robert

[suprast91]

I NEED MORE videos!!!!!!!!!!!!

[Jafromobile]

@djdarkmunk If everyone has insurance, it will most likely work for the best. It's tough in the short term, but give it time and see how it plays out... in the meantime, there's DSMtrader... Maybe something AWD would be a better winter car? Just sayin'... :)