Machining cost to address PTW clearance?

[MVM]

Anyone have a ballpark cost on machining the cylinders to loosen up the piston to wall clearance?

I'm thinking about buying and engine and, since it would already be out of the car, it would be a good time to do this as a preventative measure.

Thanks,

Mike

 

[blackvenom77]

$300

 

[broke7]

You could have a motor that is fine, who knows....... I think you would be wasting your time honestly.

 

[SlowSVT]

If the block doesn't have a lot of miles and the bores are straight you may get away with running a couple of passes with a flexi hone. You just need to be careful to making one pass at a time to each cylinder and carefully measure the bore taking reading each step of the way at various points in the cylinder. Some people may scoff at this but keep in mind you are only removing .001 to .0015". The machinist will basically be doing the same thing with a boring bar and a honing stone but with so little material he would be removing he probably won't be much more accurate then you when you consider set-up and machining tolerance. Get a steel pipe with a 3 1/2 ID and get a feel for the hone and practice maintaining a 45 degree cross hatch before honing the block.

Something to consider

 

[Modular Racing]

Before doing anything it is best to measure first. If you want the job done properly it is also best to torque plate the motor when honing and boring, this insures a perfectly round bore when preloaded by the cylinder heads. Depending on the piston we like to see .003 to .0035 PTW. Good luck with your new build!

 

[black 10th vert]

Before doing anything it is best to measure first. If you want the job done properly it is also best to torque plate the motor when honing and boring, this insures a perfectly round bore when preloaded by the cylinder heads. Depending on the piston we like to see .003 to .0035 PTW. Good luck with your new build!

Is this .003-.0035 total diameter over the piston diameter, or are you saying .003 on each side (meaning the bore would be actually be .006 -.007 larger)?

 

[MVM]

Thanks for the info.

Mike

 

[oldmodman]

Is this .003-.0035 total diameter over the piston diameter, or are you saying .003 on each side (meaning the bore would be actually be .006 -.007 larger)?

Total clearance 3 to 3.5 thou. Don't make the mistake of going 3+3=6

But since you are going to have to go to the trouble of pulling and dissasembling the engine to hone it you might want to consider just going 20 over and replacing the pistons and rings with good forged pistons like Mahle or CP. Yes it will cost you some money but it's something that i would only want to do once.