GB400R Engine Rebuilding

Dissecting the blown gb400R engine

After the spectacular ending of our engine at the HSR West race in Las Vegas, we couldn't wait to find out what happened to the engine.

The disassemble process is just as important as building it. This is how we find out what parts work based on their wear and tear.

Considering that this engine was originally designed only for street use, it has proven to be a powerful and reliable combination.

	The first thing we observed was that only one cylinder had damage. We were not able to remove the spark plug which was a sign of total melt down!
We drained the oil pan and observed that prior to any oil , water was pouring out. Not a chocolate mixture meaning that a water jacket had been affected. Also would explain the amount of steam from the exhaust pipe on the race track.

Based on the amount of smoke or steam that came off the car during the race, we predicted that we would have a very expensive paperweight for our desks.

After draining the pan, Nick noticed that a minimum amount of metal shavings came out of the oil pan. We should have seen much more than that.

	Once the oil pan had been removed a large tin ball was found in it. A quarter of the windage tray broke and was crushed by the front rods.
After a visual inspection of all the bottom end Nick found little damage to any of the rods. The only harmed rods were the ones in the front from the windage tray piece that came off.

The major problem occurred in the back of the motor. A valve seemed to have gotten stuck open and hit the piston. This made it a little confusing to see the front of the windage tray broken causing the front rods to get slightly damaged but breaking the piston skirts.

	The damage was contained to only one cylinder in the block. However the particles managed to crack the cylinder wall. We need a new block!
The rust spots are actually deeper than they seem and if you look closer there are cracked spots.
	There is no trace of the valve seat here.
This is what the chamber should look like. Instead it looks like one of Bin Laden's bombed caves!

We have concluded that the damage was caused by the exhaust valve seat getting loose. It then caused the valve to stay open hitting the piston.

The day of the race we had to run unleaded fuel which runs hotter than leaded. Whether it was a factor in the looseness of the seat we don't know but its our major suspect so far.

We'll keep you posted for the actual building process of our next race engine. For more racing stories visit the "Show & Tell" page.