Thread: EEK Motor Back From Machine Shop To Find This!!

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Sounds like a costly error for you. (you already know how I feel about it)

i went .040 all 8 cyl's

You may luck out but you have made the same mistake again-------when you have a bad gouge in a cylinder wall you need to have a shop with a Sunnen CK10 type hone -hone it out until the gouge disappears and then measure to see what oversize you need-order the parts and then finish hone to size-----

In the shop your of that shop you listed, I didn't see any bore/hone machines and your pattern looked like it was done with a hand drill----

And don't let them mount your new pistons until the bore/hone is complete on all cylindersm( that way you can return them) and get new nuts for the rod bolts.

Originally Posted by jerry clayton

when you have a bad gouge in a cylinder wall you need to have a shop with a Sunnen CK10 type hone -hone it out until the gouge disappears and then measure to see what oversize you need-order the parts and then finish hone to size-----.

And that's the point I was trying to make all along. All the measuring needs to happen before any part is purchased. If someone in the future reads this, I hope they can understand that wear and damage can change many dimensions and these need to be verified before parts selection should happen. This is the time to be involved with the machinist / shop. I'm not throwing stones (or anything) at the Original Poster! I just want some new or first time "builder" to consider the steps taken and why there is (or needs to be) this structure. The old addage measure twice / cut once applies well here I think.


Backyardbuilder,
I wish you all the luck with the completion of your project and thanks for sharing the experience with us. Maybe your build will help someone else. Now of course we want to see pics of it installed and running! LOL..

He said it cleaned up after .004 it's now back home and awaiting back ordered parts :| (thanks summit)

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You seem to be using .004 and 0.040 interchangeably. Which is it?

had to go larger then the po .030 so he went .040 but while honing he said he checked it at .004 the mark was out

Glad you got it resolved to your satisfaction, and hoping that you have many, many trouble free miles from the new engine.

The machinist probably meant that when the scratch disappeared, he checked the size and he had went .004 of the .010 he had to go to get from .030 to .040-common talk among chip makers and honers

What is the tolerance for a bore?
If he honed out .004 then the bore was effectively .034, so must have been out of tolerance to have required an .040 bore.

The guy had already bought .040 over pistons a few posts ago---------