Assembly, part 1

We planned on using this engine to test some of the aftermarket parts available for LT1's, so the intention is to so a stock rebuild to get accurate baseline dyno numbers.  That's why, even though we needed a new crankshaft, we got a stock replacement rather than build a 383 using a stroker crank.  

Reassembling the engine is also very much like any other small-block Chevy that you've seen a million times before in print.  There are a few exceptions however...

Like most stock Chevy's the wrist pins are a press-fit design, ie. they are retained by tension in either the piston's pin boss, or in the LT1's case, the small end of the connecting rod. Some people say you shouldn't heat the stock powdered metal rods to install the wrist pins- it can potentially weakens the metal.  JMS's Mike Johnson says it's the rods can handle it in most cases, though, and we're shooting for just north of 400 hp.  Any more than that, and we'd be better off investing in forged rods anyway.  So he heated the small end of the rod to a dull red glow, and the pins slid right in.  Without heat, he said there's a really good chance of galling the pins and/or pin bosses by using a hydraulic press.  

Here's where things begin to fall apart and why the article never made it into August's issue:

The first snafu we encountered involved the piston rings.  We were sent a set of 0.030-over rings for a standard small block.  LT1's use low tension rings with faces (and ring lands) that are much narrower.  Note the comparison of the top rings in the photo.  The correct set was on back order, so that set us back a few days.


While we were waiting for the correct rings, we were able to install the cam, crank, and timing gear.  At over 250,000 miles, the stock timing chain was pretty sloppy, so we opted for the GM Performance Parts LT4 Extreme Timing Set (P/N 12370835--$249.95 from Summit Racing) which includes both sprockets, the chain, and a new water pump gear.  Remember, LT1's have a gear-driven water pump. The timing gear employs a toothed wheel cans behind the cam sprocket to turn the water pump driveshaft.

We slid the stock Caprice roller cam back in. The specs are: 191/196 degrees duration @0.050" tappet lift, 0.418/0.430" lift on a 111 degree lobe separation angle.  If that sounds small, it is, even for an LT1. Remember, this was a cop car, and the fuzz need torque and longevity more than they need peaky horsepower.  The cam specs in Camaros and Corvettes were a little more respectable.

We'll pick up more of the build up next week...