Friend Jerry and I have been speculating on possible causes for the failure of the con rod babbitt on the #4 rod a couple days ago: (http://www.mtfca.com/discus/messages/506218/567999.html?1441856384)
Here's one idea. We have had an occasional, random misfire for the past week… occasionally as often as a few times in several seconds, usually not for many miles on end. There didn't seem to be any pattern, i.e. uphill, downhill, humidity, etc.
When it does misfire, one can feel it as a perceptible jerk in the motion of the car. Jerry, as the usual passenger, notices this more than me.
Might this misfire, if at cylinder #4, be enough to stress the rod bearing and perhaps lead to its failure?
And if so, how might we isolate which cylinder is misfiring, particularly here on the road as we are still 300+ miles from home.
Fiber timing gear?
John -- bronze or aluminum, can't remember for sure. Probably bronze.
If misfires ruined babbitt, there would hardly be any T's running. No, I don't believe misfires caused that.
Looks like the babbit was not stuck well to the rod when tinned. I have one explode a couple of years ago into nothing but tiny specs from the rod and cap. It had to be faulty babbit. There were no pieces larger than the end of a ball pint pen left.
Agree with Jim, the babbit should never come loose like that.
Might check the other rods too. Could be that the spark timing is wrong for the load and speed and is knocking from that.
I had a rod that was Xed spit one quarter of the babbitt. I thought it was the fact that it was x grooved. I was told that it was because it wasn't tinned properly.
A circle groove should never used in a bearing, unless it is pressure fed.
Thanks to all for your comments. That makes sense to me.
Jim, there were also many many 1/16" and smaller babbitt bits in the sump when I changed the oil.
Is there a way to check for proper tinning/bonding when I check clearance and inspect the other three rods?
You would be wise to change out the rods, if you have any doubts about their condition. Good chance you could ruin the cranks if one goes bad.