Opinions on sleeving for a 470

[Gunner1]

.004 is way to big a spread for cylinder to cylinder variation. That’s just substandard level work. 4.375 is minimum diameter for those pistons. even the production shop I worked in they bored to within .001 of piston spec size then hone to spec. 4.375 is suppose to be the recommended bore. Then the piston skirt has the clearance built in. Say 4.372 if it’s a tight skirt forged. Lots of new spec pistons have different skirt shapes that expand less than the old speed pros like my engine has.

 

[7t500]

.004 is way to big a spread for cylinder to cylinder variation. That’s just substandard level work. 4.375 is minimum diameter for those pistons. even the production shop I worked in they bored to within .001 of piston spec size then hone to spec. 4.375 is suppose to be the recommended bore. Then the piston skirt has the clearance built in. Say 4.372 if it’s a tight skirt forged. Lots of new spec pistons have different skirt shapes that expand less than the old speed pros like my engine has.

I agree. However, I was measuring the diameter of cylinders that were already damaged. Once we got the shortblock to.his shop and started taking pistons out of holes, everything was checking out at spec, with the exception of the cracked cylinders. The cracked cylinders were within spec at the very bottom of the holes but got worse and worse as you moved up the hole. Plus, I was using a bore gauge and standard mic. Once we used the machinists ID mic, the spread dropped to within .001.

 

[66Satellite47]

Sometimes the block has either been overstressed before the build or is just a weak block. My 1st 400/452 block cracked after three seasons of racing at 7000, 7200, 7400 RPM. Took it apart at the end of the season, #4 main in two pieces, and the 440 steel crank had no ring, a really small crack in the #1 cylinder. My high RPM was not good for the motor, but it made power. The BB Mopars were designed for about 5500 RPM at most. When we exceed the OEM design limits, eventually stuff breaks.

 

[Gunner1]

As long as there is enough meat to leave a small step at the bottom for the new sleeve to bottom out on it should be ok. We always did the step setup. That way the head clamped the sleeve in place and it couldn’t move up or down under load.