Vintage Karting Forum

Luckily i can hack about a tiny bit. it's added to original post now or will be in a few minutes!!

You da man David

Thanks Steve

Question , Is it .020 clearance on both sides of the rod , or total clearance ? .010 on both sides?

Thanks Steve and Dave.  Most helpful.

.020 total is sufficient, even for gasoline. The rod will center itself, so there will be ABOUT half the clearance per side once the rod's in the engine. Tolerance stackup and dynamic loads mean that the rod finds its own position when running. The spacers and hardened washers keep the big end of the rod much nearer to the center of the crank journal. Steve and Bonbright have saved a lot of Benders and increased their performance by this method. Ted

ok went in and added text to video post so you'll know what you'll be watching.sadly i noticed i added the videos out of order on steves first post. at some point i'll redo the order so it makes more sense but outta time right now.
one request for steve.
   PLEASE make an additional "video how to" on making the thrust washers. unless i missed it somehow there seems to be a section of advise missing. the construction of the spacer washer or how to order them ie : miking the pin diameter , measuring the extra end gap from the removed shoulder and why you're doing all of these mods. the older guys know why as we've done engine mods but assuming little or no knowledge when you make a video will be better for the newbes we're trying to get into the U.S. 820 class.
if you're super inspired a video on adding the boost ports and why would be awesome too!!
   me i figured it out but in all your videos you're assuming a certain level of basic high school shop skills which our generation consider normal. Sadly the kids following us have almost none of these skills from shop classes in high school as these classes were eliminated as being obsolete. don't get me going how insane that idea was to implement.
yer bud

The second video down shows you how to make the aluminum spacers, and the hardened thrust washers that go between the aluminum spacers and the rod are a standard hardened thrust washer such as that used with radial needle thrust bearings. McMaster Carr sells the hard washers separate. The part No. for the 1/2" size for West Bends is: 5909K44, and they sell for a bit over a dollar each. They are .032 thick, and are .938 in O.D.. Ted

thank you Ted. However the last time I tried to get them for McMaster they weren't selling them anymore so I had to source them from a bearing supplier.

McMaster-Carr seems to have them now......