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Cal-look/High Performance => Pure racing => Topic started by: jay c on February 21, 2016, 15:12:17 pm



Title: Con rod resistance
Post by: jay c on February 21, 2016, 15:12:17 pm
Can anyone help??
Just fitted new bearings to my rods and I'm not sure if they are too tight. They have a bit if resistance. You can move them reasonably easy with a push but they definitely don't fall under their own weight. Also noticed the bearings going shiny in the corner nearest the tang . They seem to fit in the rod and cap ok.[attachment=1]


Title: Re: Con rod resistance
Post by: j-f on February 21, 2016, 16:22:37 pm
Looks like the coating is already peeling. Did you check if the bearing was flush with both rod and rod cap end? If the bearing protrude it will be crush and fail.


Title: Re: Con rod resistance
Post by: jay c on February 21, 2016, 17:19:28 pm
It looks like when the bearings were stamped a small amount of metal was left proud at the tang. It try filing that to see if it makes a difference [attachment=1]


Title: Re: Con rod resistance
Post by: DWL_Puavo on February 22, 2016, 08:54:38 am
I've seen this problem also - in my case, when the "clip" has been stamped, there has been a bit of residual material between the "clip" and the rest of the bearing, "in the cut" and the tang has been pressed a bit too deep. Then when bearing is installed and torqued, the clip presses the corner of the bearing a bit. (...how this can be so hard to describe in english now :-\ ) So check out the back side of the bearing and the tang, and if necessary, clean it out before installing.

Even if filing of the bearing sounds something you shouldn't usually do, it sometimes is necessary: for example if you're installing stroker crank with stock con rods, you usually have to file out one of the camshaft bearing's corner quite a bit, at least if you're using "HD-cam bearings" with two flanged bearing halves. The area of the filed part is very tiny compared to the rest of the bearing area so it shouldn't make any difference.


Title: Re: Con rod resistance
Post by: dragvw2180 on February 22, 2016, 13:02:14 pm
If it is convenient I would return it to the shop who sold it to you and exchange it for another one. It seems like everything I purchase I have to modify in one way or another. Mike MCcarthy


Title: Re: Con rod resistance
Post by: jay c on February 25, 2016, 00:30:57 am
Swapped them for a set of kolbenschmidt. Perfect now


Title: Re: Con rod resistance
Post by: WPS on March 26, 2016, 15:10:37 pm

Never had this problem until today when I tried installing a set of 'Yellow box' big end shells (this is what was supplied as no KS or Mahle in stock apparently ::)) I've used the 'Yellow box' mains before without issues as they're steel backed and it seemed all KS were not (although this might have changed now).....never had a problem with those. Anyway....they looked wrong...felt wrong when installing in the rod, so I bolted one to the crank just to see....and sure enough...Wrong!!!! :( Tight spot/resistance when rotated.....took it off and there's that shiny bit by the tang....these are no good for me.....went to my NOS bearing dungeon and found a genuine KS set which I was obviously saving for such an occasion :)  Chalk and Cheese!! Lovely fit and feel!! :)
I shall not be using those 'Yellow box' shells again unless they fix the problem....looks like the tang has been made by a blind man with the wrong size hammer so it distorts the shell when torqued up.....
Wouldn't it be nice if the quality of the things we bought got better rather than worse!!!....there are of course exceptions but generally quality drops as buyers go for better margins and cheaper components force the good guys out etc etc....
Rant over but thought I'd share.... Happy Bloody Easter!!  :-*


Title: Re: Con rod resistance
Post by: baz on March 26, 2016, 18:50:57 pm
I'd be interested in finding out the part numbers from these yellow box bearings


Title: Re: Con rod resistance
Post by: jay c on March 27, 2016, 02:17:23 am
The yellow box mains were fine. Just the rod bearings that were no good


Title: Re: Con rod resistance
Post by: baz on March 27, 2016, 14:03:26 pm
It's the rod bearings I'm interested in.