Lil Red - Duramax 6600/Allison 1000 Conversion & OBS/NBS Dash Conversion

[More Power]

This video short was of Lil Red at the Salt Lake City 1/4-mile track in September of 2005. Too much nitrous oxide too soon put the fire out during launch - nitrous is really-really cold. The nitrous was switched off just as the engine began losing rpm, which was followed by a backfire. You can see the white smoke (fuel vapor) stream out the exhaust during launch as the engine spooled down, followed by a "pop" sound in the video (the fire relit on its own before the engine rpms dropped to zero). You may need to replay it a couple of times to identify the pop.

Does it appear to you that after the bad start, Lil Red was gaining on the other truck about 2/3 of the way down the track?

I don't know why the track announcer sounds like he's related to Charlie Brown's parents. The trucks sound more or less normal. This was at a time when cell phone cameras were not as good at taking videos as they are now. Still, I'm glad I have this video. It was taken by a fellow TDP member that evening...

The backfire caused 2 head bolts near cylinder 8 to loosen ever so slightly, and combustion pressure began finding its way past cylinder 8's LB7 injector cup seal, as evidenced by a carbon track appearing at the juncture where the small end of the injector cup passed through the cylinder head deck. This resulted in pressure ever so gradually building in the cooling system over time as the engine ran, to a point of cooling system leaks and cooling system overflow. The truck was still drive-able, though the excess pressure became a nuisance.

Not long after this SLC event, Lil Red posted its highest HP/Tq at a Montana diesel dyno event, even with the "problem" (there's a video of that dyno pull earlier in this forum topic thread). The various engine parts were carefully inspected at tear-down during the head gasket replacement process in 2021. I couldn't see that any additional damage had occurred as a result of not fixing the problem soon after it happened. This excess cooling system pressure could have caused the water pump seal to wear and begin leaking, but the truck simply wasn't driven enough to get to that point. So, the engine is still running with the engine's original factory-installed water pump.

As of the time this post was made, it had been more than 2 years since installing new head gaskets and resealing the injector cups (in late summer of 2021), and by November 2023 the truck has accumulated an additional ~5000 miles without generating any excess pressure in the cooling system. Installing new head gaskets, installing new factory TTY head bolts and resealing all eight injector cups have definitely solved the problem. It's a good feeling to have that problem behind me. The truck is reliable enough now that I'm confident it could be driven from Montana to Miami and back without a problem.