Why does building a Locost take so long? Well...

Yesterday brought some excitement in the form of a bench grinder I received from Northern Tool. Based on some orders before the holidays I received a $50 voucher for use online which I have since used to buy a bench grinder on sale for $49 with free shipping. My end cost was $1.45 for a 8" grinder that so far seems to be perfectly adequate for anything I will need :)

My other big realization is less happy. My Silverado was built with some flawed cylinder heads which allow micro-cracks to form over time. The result is coolant being pushed into the oil. The first time around I was unemployed when I made this less than happy discovery and had to do the repairs at the beginning of February in an unheated WI garage. That was three or four years ago and was the most intensive thing I had ever done as far as repairs. Here's what I found when I opened up the valve covers:

Coolant + oil = sludge and sludge is abrasive. It also plugs up oil passageways, so I was pretty terrified to see a vehicle I maintained to the Nth degree have these issues. GM recognized the problem in a Technical Service Bulletin and claims their supplier used a defective alloy. Despite the "defect" they refuse to stand behind their product which leaves guys like me on our own to replace the heads with known good casting numbers. Avoid any 4.8 or 5.3L GM motor with casting number 706 on the heads to be safe.

At least this time around I caught the problem very early on, have all the tools and experience to fix it, and have a heated garage. The cost to replace a bad head yourself is about $400 in materials and a weekend of time. Having a garage do the work would typically come in around $1500.

On a closing note: this is what the valve train is supposed to look like in a healthy engine. This is the Miata head with 187,000 miles on it (over double the truck's mileage):