Cylinder sizes are all different....
Thread Starter
Drifting
Joined: Jan 2002
Posts: 1,498
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From: Sacramento CA
Cylinder sizes are all different....
Has anyone heard of this? I have my engine at a VERY reputalbe machine shop and they told me that these LS1 blocks sometimes have different bore sizes in the same engine. There are three different piston sizes to go with that also. NE ways they are going to make my bores all the same and it will basically be blueprinted...I cant wait!!
Burning Brakes
Joined: Feb 2002
Posts: 1,154
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From: Jasper GA
Re: Cylinder sizes are all different.... (Jackal)
Normal manufacturing tolerances may result in bores that differ slightly from cylinder to cylinder, but I doubt that the differences will exceed a thousandth of an inch (.001"). Blueprinting eliminates these relatively loose tolerances, which also apply to virtually every other dimension in the engine.
Le Mans Master
Joined: Mar 1999
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From: delmont pa
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Re: Cylinder sizes are all different.... (Jackal)
i have been to the corvette engine factory and the bores are "air gauged "for diameter and the cylinder are marked and the correct diameter piston is installed in the cylinder.
:chevy
Has anyone heard of this? I have my engine at a VERY reputalbe machine shop and they told me that these LS1 blocks sometimes have different bore sizes in the same engine. There are three different piston sizes to go with that also. NE ways they are going to make my bores all the same and it will basically be blueprinted...I cant wait!!
Drifting
Joined: Oct 2000
Posts: 1,957
Likes: 1
From: Albuquerque NM
Re: Cylinder sizes are all different.... (SpinMonster)
:skep:
Racer
Joined: Sep 2002
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From: Austin Tx
Re: Cylinder sizes are all different.... (Jackal)
The factory can afford machining that does all 4 bores on one side at once (or all 8 at once if they so choose). Using 4(8) boring tools simultaneously can lead to different boore sizes. Even if the use a guage and rest the tools to identical specs each hour (day) by the end of the hour (day) the tooling will be 'differnet' than at the start. Since the factory make so many engines , it is easy for them to simply mix and match parts to the correct tollerance. This is also why blueprinting shops redo every critical piece of machining in the block!
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Instructor
Joined: Sep 2003
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Re: Cylinder sizes are all different.... (Mitch Alsup)
The factory can afford machining that does all 4 bores on one side at once (or all 8 at once if they so choose). Using 4(8) boring tools simultaneously can lead to different boore sizes. Even if the use a guage and rest the tools to identical specs each hour (day) by the end of the hour (day) the tooling will be 'differnet' than at the start. Since the factory make so many engines , it is easy for them to simply mix and match parts to the correct tollerance. This is also why blueprinting shops redo every critical piece of machining in the block!
My question for the "blueprint" shop is are they changing pistons, or just increasing the piston-bore clearance on the stock pistons? Why?
As to gaining 2 cubes: It would take about .011 overbore on all cylinders to get that much. You'd definitely need new pistons. Isn't the first oversize LS1 piston about 0.2 mm or about .008 in. ? That's close to 2 cubes.
My $.02.
Thread Starter
Drifting
Joined: Jan 2002
Posts: 1,498
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From: Sacramento CA
Re: Cylinder sizes are all different.... (OldSStroker)
Yes they are oversize pistions, and they know what they are doing. he has built engines for Nascar, indy, and all kinds of drag cars.
Instructor
Joined: Sep 2003
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Re: Cylinder sizes are all different.... (Jackal)
Yes they are oversize pistions, and they know what they are doing. he has built engines for Nascar, indy, and all kinds of drag cars.
So did you go .010 over?
[Modified by OldSStroker, 1:27 AM 12/13/2003]