I can find out from my local machine shop guy in the AM, but I'm curious if anyone here my have the answer????

I spun a rod bearing in my #7 cylinder which lead to a "slight" rod knock. I caught it pretty quick so the damage was minimal and weirdly enough, I had the #7 cylinder pegged as the problem cylinder from the drivers seat. Dumb luck I guess.

The stroker crank will definitely need to be turned, but is the rod okay?

I don't mind replacing the rod if I have to, but if I do, the rotating assembly should be re-balanced.... no?

TIA,
Dave

 

you shouldn't need to rebalance. if you know the weight of both ends of your old rod. the machine shop can remove weight off the new rod if its heavier. I don't know if the machine shop can add weight to a rod if it is lighter than the old rod.

 

I am NO expert Dave, but in my experience I have spun rod bearings.

The deal is, the bearing is softer than the rod. If the big end shows no signs of wear, I would not change it. Its a judgement call.

Like 70stang said, they can try to match the weight, usually, but youll have to provide a good rod to match.

Edit: Actually I take that back. I was 'assuming' a steel rod. The machinest can tell you whether it is round and in spec. You may get lucky!

 

The rod can be fixed if its not to out of round or excessive clearance. You may only need to have the crank polished depending on how bad everything is damaged. Let me guess you had clevite bearings in the motor.

 

^ what he said

 

Ok Michael,,,,

Up until now I had thought Clevite bearings were good,,,, some publications and peoplehave said that they are"the best".

For one reason or another I used Federal Mog. bearings in the 408, but I can see that I could have used, or possibly even requested Clevite based on their (perceived?) reputation.

I am inclined to take what ever you say on this matter at face value..... so give me the low down and teach me brother!

 

As far as the rod goes, if it has no visible signs of damage, I would put the cap on and torque the rod nuts to spec. Then measure the bearing bore in several directions. If it measures to specs, throw it back in.

 

I have to wonder if that bearing spun becausethe engine overspeed may have temporarily deformed the bigend of the rod or streached the bolts....

 

We had a few engines that had spon bearings in every case they were clevite bearings. But have had no problem at all out of King bearings. I had the job of tearing one 347 down with 2 spon rod bearing for some resson I don't know the engine had both King and clevite bearings. The clevites were all torn up and the kings looked new.

 

That very well may have happened thats why the rod should be checked. They usally only have a tolarence of .5 thosand of out of round. which you need a very acurate gage to measure.