Bikedad Go Boom!

[bikedad]

Went to Great Lakes Dragway for Street Tire Tuesday.
First run: 60ft= 2.177
               1/4mi = 13.20 @ 111.31mph

2nd run: 60ft= 2.124
              1/4mi= 13.07 @ 111.69mph

3rd run: 60ft= 2.068
              1/4mi= 13.06 @ 111.01mph

4th run: Motor go BOOM!

I had a fantastic launch and the car was pulling hard. Just before the traps I think I over revved the engine trying to break into the 12 second realm. I heard this sickening pop sound and then the car shuddered. I cruised into the shut down area and noticed the car had a miss and there was a bad tink- tink- tink sound.
I instantly pulled it over on the return road and shut it off.
I didn't vent the block but there was a loud enough clanking sound to know something definitely was broken.
I think I either dropped a valve or broke a connecting rod. I'll find out when I get the motor pulled apart.

Bummer! It's the beginning of summer and my toy is broken.

I was contemplating going stroker. I guess I might be doing that sooner than I thought.
               

[blacksi]

Could be something as simple as a rocker came loose.  On a positive vibe.

[bikedad]

Could be something as simple as a rocker came loose.  On a positive vibe.

I hope it's something simple but I'm not taking bets. I should be so lucky.

[Dr1ft1ng0wns]

That sucks. Sorry to hear that Don, hopefully it's something cheap.

[bikedad]

That sucks. Sorry to hear that Don, hopefully it's something cheap.

Me to.

[Jordan Innovations]

I remember Great Lakes Dragway!!  Great track.

Sucks, but as was mentioned, might just be a stripped rocker bolt or something up top.  Did you check oil pressure when you heard the pop?  That's always what I do.

[spacevomit]

Oh snap!

[Rayminator]

So close to a 12 sec. pass.

How did you get the car home? They do not let you leave them overnight at the track.

I will ask a friend what he has in his engine inventory, just in case it was a major event.

[BeatTheTunaUp]

Sucks, I know the feeling.   I left it in 4th too long and spun a rod bearing with 800 miles on the motor         Not bad times for those 60ft times.   Easy 12's with some drag tires.  Every tenth of a second in the 60ft equals 2 tenths in the quarter.  Looking at 12.50's with an easy 1.8 60ft.    Oh well, on the bright side, the new motor is faster 

[bikedad]

This is just wrong....   

http://milwaukee.craigslist.org/pts/2370585646.html

[zbrown]

Pics!  get that thing tore down!

[mattster03]

ouch! what rpm did the failure happen at?

[bikedad]

ouch! what rpm did the failure happen at?

I got a good launch on the last run my 60ft was down to 1.9
I was in my torque curve early in the run and was at 6500rpm before the trap. I should have shifted but thought I could push it a little more. I think it let go at 6700rpm.
I'm running solid lifters. The valves don't float. Something just gives.
When I heard the pop I slammed it into neutral and coasted to the return road.

[bikedad]

So, minor update.
Got home for lunch and had to pull the valve covers to start the investigation.

#6 exhaust valve adjuster was sitting in the bottom of the head. Looks like the stud snapped.
I haven't turned it over yet to determine if anything else is broken.

[theantirotor]

so the stud snapped, but all of the valves were still in position?  may be a good idea to do a leak down before tearing it apart.  who knows, everything else may be ok!