Damaged connecting rod

[Macsteve829]

I recently spun bearing 6 and the connecting rod bore is enlarged .0009 The crank is also ground down about. 0009 on the number 6 journal. All the other rods and mains are stock tolerance. Can I throw a used rod in the mix successfully, or should I go with new forged? On another note, are there any reputable machinists near Flint/Detroit Michigan area?

 

[87GNSteve]

If you are running a balanced assembly then the replacement rod should match the others, if they are all stock then a used factory replacement can be used. But since it all has to come apart you could upgrade to the forged units as they are reasonable priced, but I always advocate a balancing of the rotating assembly be done anyway.

 

[Macsteve829]

Its still stock right now, I'm scared about the local machinists, the first 2 calls I made, I asked about experience with these motors, and they both said "they're all the same to me". So I'd rather find a stock rod and do the work myself. But, if I could find a reputable guy in southeast Michigan, I would like to have the crank cleaned up to match some new forged rods (K1?) and punch out the bores a little for some new pistons and have everything properly balanced and measured for clearance. When I toasted this motor, I got a couple degrees retard at the top of second, then let off (was around 12.0 a/f). I saw that the knock was still there after the pull at low rpm, and pulled over immediately and flat-bedded it back home. I have a brand new CPT-60 bb turbo from cotton's and it has somewhat of an inlet filter/restrictor (small metal screen). I have about 2 hours on the new turbo. The turbo shaft has no play and is very smooth, doesn't sound scratchy when I spin it but the oil in my motor had that metal sheen... should I send out the turbo for inspection or are bb turbo cartridges pretty durable?

 

[bison]

The crank is .0009" under? Sounds like it needs to go to the crank grinder


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[Macsteve829]

The crank is .0009" under? Sounds like it needs to go to the crank grinder


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Yes hopefully I can go 10/10 on the crank so I have room to blow it up again

 

[87GNSteve]

Maybe you can contact Mike at Full Throttle he is a vendor here He sells the K1 rods too. He is not a machinist but since he is in MI I am sure he could direct you to one. Mike has been in the GN world since the beginning.