Take back the keys!

Seeing how the forums are slow... I figured I'd spice them up..

Long story short, last year around this time, the engine in my DSM blew.. I just got around to tearing it down tonight (lots of motivation, haha)..

Car made 720whp on 31psi on the dyno, and at the track it was holding 35-36psi, so I'd venture 750whp (35r I'm sure was out of steam).

I ran the car about 15 passes that day, the last 3-4 were being hot lapped and the car was being shifted at 9200-9500. Last 3-4 passes the car steadily lost mph, went from 141 to 133mph, I just figured it was lack of cool down. It popped while on the rev limiter in 2nd gear, at about 100mph.

I really wasn't too pissed, car reached the goals, and the engine was about 5 years old, shit happens.

I never checked anything in the bottom end after assembly, it had about 3k hard miles on it.

I'm pretty sure the rod bolts failed, and then everything else you see is the aftermath, that's at least what it looks like to me. Rod that failed was #3, but the bearings on #2 are pretty fucked up. I'm guessing this is what happens when the oil goes on the track and doesn't stay in the crankcase. Rods were Crower, rod bolts Crower. Seeing how it was FWD and spent alot of time on the limiter, maybe it weakened/loosened the bolts.

Can anyone explain what happened to the #3 piston? I'm guessing the rod chewed it up and spit it out..

Oil Pan:

http://doitbig.org/dsm/destruction2008/destruction.jpg
http://doitbig.org/dsm/destruction2008/oil_pan_junk.jpg
http://doitbig.org/dsm/destruction2008/oilpan.jpg

Rod bolts from #3:

http://doitbig.org/dsm/destruction2008/fuck_me.jpg

Main bearings:

http://doitbig.org/dsm/destruction2008/main_bearings1.jpg
http://doitbig.org/dsm/destruction2008/main_bearings2.jpg

Rod bearings:

http://doitbig.org/dsm/destruction2008/rodbearings.jpg

Pistons/misc:

http://doitbig.org/dsm/destruction2008/pistons1.jpg
http://doitbig.org/dsm/destruction2008/pistons2.jpg
http://doitbig.org/dsm/destruction2008/number3_piston.jpg
http://doitbig.org/dsm/destruction2008/windowed.jpg

damn.. well.. atleast you made it count! was that a 6bolt block or 7? just curious.


got any plans for future engines? looks like you got 3 good rods and pistons.
crowers the one that makes you send rods in so they can match them and everything right?

i like the glory hole

Looks like the piston just got chewed up on the cylinder wall once the rod gave. Slowing it down from a nice 9500 rev with lack of oil at a fucked up angle... wouldn't take long to eat it up lol

real similar thing happened to a friend of my dad, winging a smallblock to 10k.... mid track the rod bolt just let loose. Needless to say i'm surprised u were able to salvage as much as u were... he wasn't so lucky lol.

mains didnt look too bad.... crank probably got scarred up pretty good though id imagine

head ok?

man, looks like the shit i pulled out of my motor

cant view these pics at work, but loss of mph to me suggests a loss in compression. I never knew you cranked it up another 4-5lbs at the track. Were you monitoring knock? How were the a/f's? This was on C16 or Q16 right? I suppose your pistons would tell this story if I could see them...

lol @ parabolic rod #3.

Any videos of this beast when it ran?

Wow, carnage. Always sad to see another DSM down. Were you planning on rebuilding? I know you had a part out a while ago, I dunno how far you went with that though.

Rb25Cory wrote:cant view these pics at work, but loss of mph to me suggests a loss in compression. I never knew you cranked it up another 4-5lbs at the track. Were you monitoring knock? How were the a/f's? This was on C16 or Q16 right? I suppose your pistons would tell this story if I could see them...

From what I can gather, the car actually spun a bearing on #3 first... #2 was close behind..

#3 rod seized on the bearing/crank due to the spun bearing, and then finallly kicked the bolts out.

The loss of mph is usually what happens when a bearing is going south from what some heavy hitters in the DSM world think. I did have some bottom end knock, but it was light. Wasn't anything that sounded unusual...between the typical DSM noises you can't explain, a loud twin disc, open exhaust, lifter tick, who knows. I did hot lap the car the last few passes, so any noises the motor was making probably went unheard between having a helmet on, open exhaust, etc.

There was limited knock on the previous passes (basically none to be honest compared to what the motor had seen before on the old setups), AF never went leaner than 11.5 (which is nothing for Q16).

Pistons are fine, I forgot to take pics of the top of them. They had valve contact and it destroyed my $2k race head which can't be replaced.

Car was tuned to ~40psi or so, but it would only hold 33psi falling to 31psi on the dyno. On the track, with the larger DOT radials, it held a little more. Car could have been tuned much more aggressively.

Keep in mind the motor was built 5-6 years ago when DSM's were lucky to make 450whp. Clearances probably were a little tight and that was the ultimate demise.

Car is back together with a stock motor like previously stated. It doesn't run. I still don't have a job so no money to put it back together yet. I need another $2k to finish it up.

Interesting, well spining your engine to 9-9.5k. Did you modify your oil pick up at all? Increased sump capacity? Oversized volume oil pump? Head restrictions to keep the sump full? Could missing any of these issues cause this? Or slight knock over time you feel is to blame? Excuse my ignorance I'm not sure how the 4g63 is with oil control at high RPM.

Rb25Cory wrote:Interesting, well spining your engine to 9-9.5k. Did you modify your oil pick up at all? Increased sump capacity? Oversized volume oil pump? Head restrictions to keep the sump full? Could missing any of these issues cause this? Or slight knock over time you feel is to blame? Excuse my ignorance I'm not sure how the 4g63 is with oil control at high RPM.

I honestly just feel the clearances were a little too tight for the power I made. Keep in mind that when this motor was built 5-6 years ago, there were only a few people making 700whp, and their motors were built quite a bit differently than this one. Shepherd had built this one to handle 500whp.

Now a days, nearly everyone who builds a motor makes 500whp. Every shop has built a couple hundred engines by now, and they know what works and what doesn't.

This engine had been through hell even though it didn't have many miles on it. I had lost oil a few times, and lost coolant a few times, as well as went through a few headgaskets. Probably a thousand of the 3 thousand miles on it were cruising miles. The rest were driving hard, racing, etc. It had good compression at the start of last year, 175 in each slug.

Pick up is stock, you don't really run into problems with them until you're going 9's or so, and even though I had a 9-second trap speed, the car didn't pull the G's (such as an AWD car would have) to uncover the pickup. I always ran Valvoline Racing 20w50 in it, and always a half quart over filled for extra protection. Stock oil pumps are fine, they will eventually kill themselves at 900whp, but at that level, you are burning through quite a few other parts as well.

Nasty. Ever get that z06 then?