An expensive lesson learned

[Mike Bradbury]

As many of you know this all started with a bent push rod in my SBC on the way to the Brothers truck show in July. My work schedule is pretty tight so I have not been able to dedicate a lot of time to fixing the problem.

I did not know why the rod failed because there was no piston to valve contact and there was no damaged component other than the push rod. I ended up upgrading the valve springs and push rods, converted to threaded rocker studs and guide plates. I then wanted to inspect the timing chain to make sure it did not slip a tooth, the timing chain has about 1/2 inch slop in it, but has not slipped. The one thing that made my heart sink was when I pulled the pan on my 14,000 mi crate motor there was all kinds of microscopic shavings in the bottom. Almost looked like graphite, until you get a magnet next to it and the slivers stand on end. Now I am looking at a complete rebuild. The main bearings are shot and I am now tearing it all down to a bare block.

The reason I am posting this in the general discussion and not the engine forum is because I was not planing on touching the engine during my build, it was the newest part on the truck when I started. But when it failed I when into investigation mode to figure out why it died after only 14,000 miles.

As a warning for all you guys out there who think motor oil is motor oil, take it from me and my expensive lesson, that they are not. I have run most of my vehicles on Mobil One so that is what I put in the C10. After about 6 months I started hearing stories about the zinc content in the modern oils, and I thought that well I will just finish this round with the synthetic and then change to something else. Well it did not make it that far and I am paying heavily for it.

The modern engines of today come standard with roller rockers and lifters, therefore the motor oil companies have reduced the zinc in the oil which helps lubricate the cam and lifters. Check the zinc in your oil. I am fortunate to live right down the road from Crower racing products and they do a lot of testing on motor oil. Just talked to them today and they said that they do not recommend any synthetic oils on flat tappet engines because they cannot guarantee damage will not occur.