Re: Webinar 181 on thrust bearings, perfect example of too much crankshaft damage

This is a 1987 Volkswagen PL 16v with the stock push clutch. My Machine shop guy told me the crankshaft was junk without flinching an eye, no surprise there. What surprised me is that said as quickly that the block was still ok.

It initially seemed clear to me that the crank and block were both damaged beyond reasonable repair because the thrust surface on the crankshaft had become significantly damaged. I thought the only way that surface could be galled/scored so substantially was if the Babbitt bearing had been worn through and there was hard part contact. What I seem to have learned is that bearings are only thinly coated with a Babbitt material and and a harder bearing shell underneath backs it up and is hard enough to damage the crankshaft (forged steel in the case of the following pictures).

Am I correct about this, that bearings have a core material that is strong enough to protect a forged steel crank from a cast iron block?

Before disassembly, I measured the endplay at 1.77mm with a magnetic base dial gauge.

It's not uncommon for the crank thrust surface to be damaged beyond repair but the block to still be serviceable. It all depends how long the engine has been run like this. I've had a few EVO 4 4G63 engines where both the block and crank were throwaways though so there isn't a clear rule.

I appreciate your input, and I'm sure that my situation falls on the ragged edge of being a re-usable block. I just found a great Wikipedia answer worth bringing up:

Question: "Am I correct about this, that bearings have a core material that is strong enough to protect a forged steel crank from a cast iron block?"

Wikipedia: "In more modern practice, the crankshaft and connecting rod big end bearings in a modern automobile engine are made of a replaceable steel shell, keyed to the bearing caps. The inner surface of the steel shell is plated with a coating of bronze which is in turn coated with a thin layer of Babbitt metal as the bearing surface.

The process of laying down this layer of white metal is known as Babbitting"