Mode A Piston expander/ knurling tool to Buy

[mike657894]

I had some serious egging in the bores but it was all in the center in the bores and tapered out to less at the top and none at the bottom. my thought being if you knurl you may need to bore to your knurl size. check your bore size at multiple locations in the bore.

[Synchro909]

Originally Posted by mike657894

I had some serious egging in the bores but it was all in the center in the bores and tapered out to less at the top and none at the bottom. my thought being if you knurl you may need to bore to your knurl size. check your bore size at multiple locations in the bore.

Bores always wear barrel shaped. A decent rigid bladed hone can get you back to a (near enough) parallel bore. Do you take the bore out to suit the expanded pistons or expand them to suit the bore after cleaning it up?

[Terry Burtz, Calif]

Curious. To those that did not like the idea of knurling to expand a piston, could share your reasons please??. While my current opinion is that it's a good thing (in the right circumstances) that opinion is subject to change pending compelling arguments to the contrary.


In San Jose, CA, in the 1960's, there was a commercial engine rebuilder that would rebuild a V-8 engine for less than $100.
The name of the shop was Automotive Engineering.
Their rebuilds included knurled pistons, knurled valve guides, and knurling on most anything else that was worn.
Their engines sounded good after the rebuild but had a very short life when the knurls wore off.

[KR500]

Just a note that nurlizing is recommended to be done on the thrust sides of the piston only. I have also taken worn Model A valve guides and used the Knurling pilots for Knurlizing while holding the guides in a 19/32 5C collet and then reaming them. Takes them back to size and leaves a spiral surface to the guide to hold lubrication.

[Bob Bidonde]

Here's a photo of piston skirt expanders. I common see these in vintage Model "A", "B" & V8 engines.

[ursus]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by KR500

Just a note that nurlizing is recommended to be done on the thrust sides of the piston only. I have also taken worn Model A valve guides and used the Knurling pilots for Knurlizing while holding the guides in a 19/32 5C collet and then reaming them. Takes them back to size and leaves a spiral surface to the guide to hold lubrication.

Which side of the piston is considered the thrust side?

[Afordman31]

This is from my post on 10-14-2013 about piston expanders!