Print Page - Modified flywheel and piston??

General Category => Engine & Transmission => Topic started by: CharlieT on September 19, 2013, 05:35:59 PM

Title: Modified flywheel and piston??
Post by: CharlieT on September 19, 2013, 05:35:59 PM: Ok, just started to tear down a 1947 H model engine and have come across a couple of interesting things.

One is the flywheel attachment to the crank.

(http://i3.photobucket.com/albums/y73/PenontISDT/simplex006_zpsf9eac2bd.jpg) (http://s3.photobucket.com/user/PenontISDT/media/simplex006_zpsf9eac2bd.jpg.html)

(http://i3.photobucket.com/albums/y73/PenontISDT/simplex007_zps4047ba13.jpg) (http://s3.photobucket.com/user/PenontISDT/media/simplex007_zps4047ba13.jpg.html)

All the pics of cranks I've sen have a threaded end. I'm guessing that at sometime in the past, someone buggered up the threads and resorted to welding the thing on. ???

Item #2....the piston.

(http://i3.photobucket.com/albums/y73/PenontISDT/simplex009_zpsab1300c3.jpg) (http://s3.photobucket.com/user/PenontISDT/media/simplex009_zpsab1300c3.jpg.html)

(http://i3.photobucket.com/albums/y73/PenontISDT/simplex010_zps8c04020c.jpg) (http://s3.photobucket.com/user/PenontISDT/media/simplex010_zps8c04020c.jpg.html)

Ok, I've slotted or drilled holes in 2-stroke pistons on the exhaust side when there was a bridged exhaust port. I've also have had pistons with a window cut into the intake side. However I've never come across a piston with slots cut thru the intake side. And yes, I mean cut thru...all the way thru the skirt.

Are my assumptions correct that these are non-standard?
Title: Re: Modified flywheel and piston??
Post by: kartjockey on September 19, 2013, 05:45:33 PM: That is a factory piston. It is the thrust side of the piston and when the engine fires it offers some flex as the combustion takes place.
Title: Re: Modified flywheel and piston??
Post by: Mike Sal on September 19, 2013, 06:10:10 PM: Well, one thing about it, who ever welded that crank was a talented welder......your going to have to go in with a mill cutter to cut it off in order to save the flywheel I think.

Lots of old cars & motors used slotted pistons in the old days. Offered some flex during the power stroke as well as a chance for oil to get to the cylinder wall.
Mike Sal
Title: Re: Modified flywheel and piston??
Post by: pd on September 19, 2013, 07:34:02 PM: Welcome CharlieT . :)
Title: Re: Modified flywheel and piston??
Post by: CharlieT on September 20, 2013, 01:28:31 PM: Well, I'll be. Had never come across a piston cut like that before. Vertical shallow grooves cut in the skirt to aid in oil retention, but never cut clean thru the skirt. I suppose with the piston thickness and the low compression, wasn't too much danger of shattering the skirt.

Thaks for the info.