Check the head and block for warping...

Hi,
How do I check the head and block for warping when replacing a head gasket? There are lots of good cars for sale on craigslist that just need head gaskets, and I figure if I can check for flatness right there, then I could snag a serious deal on a car.

Cheers

Each engine has specs for warpage. It requires removal of the heads. You simply lay a straightedge (a good one, not an old yard stick :)) from corner to corner and then use a feeler gauge under the straight edge at certain points and measure the warpage. Each engine is listed as being OK up to .00X" of warpage. Same goes for the block.

When buying a car like that, assume the worst, so research a rebuilt engine. If you tear into and find out that the previous owner drove it for a while with a bad head gasket it might have spun bearings, heavily scored cylinder walls, or other damage. Plan on the worst case scenario so you don't lose money or end up investing more than just buying a car with a good engine.