Ferrari 250GT engine running on test stand

Before we install any engine into a chassis we test run it on the stand for a few hours. The engines are just run relaxed for the first few minutes to get some heat in them and check for leaks or problems. It often takes 5 minutes of running just to get the assembly lubrication burned off the piston tops so the engine runs evenly and smoothly.

This gives us a chance to check for oil or water leaks and make sure that after it has run for an hour or so, the compression and leak down is good. On one 275GTB/4 engine that I overhauled, the number one cylinder was smoking any engine speed even when decelerating so I hoped that the exhaust valve had a bad valve stem seal. I replaced this easiest-to-remedy seals, put it back together and it still smoked! Next I decided that it must be the intake stem seal but this is harder to replace because you have to remove all of the carburetors. I replaced that seal and----- STILL smoking! Turns out that in the matched piston and ring set that I bought for the engine had one bad oil control ring so I had to disassemble the entire engine to replace this part. I ended up replacing the rings on all of the pistons because I just did not want any more surprises.

Needless to say all of this was much easier to remedy at waist level than braking your back over a beautiful paint job and delicate fender. Set up on the bench top also allows for easy carburetor and distributor tuning and most importantly checking the water pump seals. We cannot seem to put a Ferrari V-12 water pump together lately without having a leaking seal. Every pump needs to be "massaged" to make sure all of the tolerances are good with the questionable quality of the springs, we replace them with a "magic" spring to add slightly more pressure to the impeller.

Here is a youtube clip of the Ferrari 250 engine running.
http://www.youtube.com/watch?v=cUHjZja3NEU