Guidance for Scraping Bearings

[Dan Burkart]

We have a 25 HP South Penn Engine that has been sitting idle for the past few years because the bearings that connects the connecting rod to the cross-slide and the connecting rod to the crankshaft both need to be scraped, and none of us really wants to do it. I have decided it is time to just take a few days and get the job done (once the summer semster is over) so...I was hoping someone who has done this before can point me in the right direction. The way I understand it is I should shim the bearings a little then "blue" up both ends of the bearing and assemble, and torque the nuts to a given amount and stay consistent with this torque value. Roll the engine over by hand a few times. Disasemble scrape the high spot. Reassemble and start over. Also I am thinking it is necessary to scrape both of these bearings at the same time, is this true? Any guess as to what I should use as a torque value? Any advice would be great. Thanks
DanB

[Andrew Mackey]

You basicly have it right. bleu nthe bearings, assemble and roll over the engine. You want at least 80% contact. The rest will hold the grease needed for lubrication. Set up the bearing so that when you tighten ite cap, it is just snug to the shaft. If you take out too many shims, the bearing will bind, and you wont be able to turn shaft. Make sure the wrist pin bearing is OK, otherwise you will get a false reading on your bluing.
Andrew

[Bob Johnson]

Hi Dan,

You mostly got it right but you must remove shims to tighten up the shaft on the bearings before you blue it. If you do not have a bearing scraper you can easily make one buy taking a large 3 corrnered file and grinding the file smooth as a triamgle. this will make a nice sharp edge that will cut the babbit nicely using slight pressure per cut.
Lots of luck
Bob Out west on the high desert