Center main boo boo

[George D]

Dismantled an engine puchased just for the block. When pulling the crank it was found that the center main was completely stripped of all Babbitt. The rods and other bearings looked like new. It appears that after the last rebuild the center main bearing oil hole was not drilled. Wonder how long it lasted?

[Kurt in NJ]

It could of had a hole and gotten filled by the failure

When my engine was first rebuilt I was done by a shop used by a local restoration shop that did teens cars specializing in Mercers ----after 3000 miles/7 years the rear main crumbled ---another local person had his A engine rebuilt by the same shop, it was still in short block stage so it was decided to take it apart for a look, the oil holes were there, but the pipes were still stuffed with wadding-----another person with a more recent rebuild from the same shop heard of this problem anf his engine was taken apart to find that not only were the pipes stuffed with wadding the holes hadn't been drilled, no oil grooves or wells ---this is when I decided to learn to babbitt myself

[Mark in MT]

I have found 2 different engines with the oil holes undrilled in #2 main, they were not plugged with a damming agent when pouring as the Babbitt plug in the pipe was 2" long when I drilled it out. The owners said that the engine only had 200 miles on it. They don't last long with out oil.

[Flathead]

Stories like this made me go to inserts.

[Bob Bidonde]

Sponsored Links (Register now to hide all advertisements)

One time I found the oil pump was tied up into the block with cotton clothes line. The clothes line disintegrated, clogged the oil pump and starved the main and camshaft bearings. Since the oil pump dilemma which was done by a well known engine builder at the time, I always dismantle and inspect a rebuilt engine before using it.

Typically I find something that needs attention. Things that I check for:
> Wadding left in oil capillaries;
> Rear main bearing oil drain pipe screwed in too far that impedes oil flow;
> Reuse of castle nuts and the use of cotter pins in the connecting rod caps in lieu of modern nuts;
> Valve seats not concentric with the valve guides;
> Valve seats lacking 3-angle grind;
> Run-out between the crankshaft flange and flywheel housing to clutch housing mounting surface;
> Improperly installed oil pan gasket at the rear main bearing;
> Oil breather baffles improperly aligned or missing;
> Metal fatigue and cracks in the oil troughs for the connecting rods;
> Oil drain boss not soldered / welded to prevent spinning.