Casper's Autopsy Bonneville '09

[McRat]

No big surprise, I melted pistons. Again. I guess if 50 seconds at 750HP melts pistons, then 45 seconds at 900+ does it too.

No busted crank, no cracked pistons.

It still drove, and hopefully we will get time to rebuild it and get it back in the truck soon.

 

[Alligator]

Pat, what pistons were you running in Casper this time? And what were your EGT's during the the pass?

 

[JoshH]

So what now? Is there some kind of coating you can use that will reject the heat better?

 

[McRat]

EGT's peaked at ~1700 with twins. Thin air probably aggravated the situation. On the dyno, they were not nearly as high, about 1200 IIRC.

Pistons were SoCalDiesel forged .060" items. Last year we used stock pistons, and it yanked two of them apart at the wristpin and did tons of damage. This year, much less damage. We will slap new pistons in and run it. Heads were like new.

Since there are a couple of diesel shops who use my racing efforts for their negative advertising campaigns, I'm not going to go into a lot of detail other than listing parts that failed.

8 pistons, one set of rings. Everything else is AOK.

 

[mytmousemalibu]

Thermal barrier coating them this time? :hug:

 

[McRat]

Thermal barrier coating them this time? :hug:

Dunno, we are going to be making some changes though.

I think the engine would have perfect if it were 10 second drag passes, or 20 second sled pulls. We hit 200mph at about 40 seconds, which require 900hp on paper.

 

[SmokeShow]

Dang. Bum deal man. Any speculation on root cause or attempted remedies for the next go-round???

 

[McRat]

Dang. Bum deal man. Any speculation on root cause or attempted remedies for the next go-round???

We are working on it. I thought the additional oil and water cooling would fix it. I was wrong. But it did save the heads, which were destroyed last year at less power.

 

[SmokeShow]

How much boost?

 

[Alligator]

EGT's peaked at ~1700 with twins. Thin air probably aggravated the situation. On the dyno, they were not nearly as high, about 1200 IIRC.

Pistons were SoCalDiesel forged .060" items. Last year we used stock pistons, and it yanked two of them apart at the wristpin and did tons of damage. This year, much less damage. We will slap new pistons in and run it. Heads were like new.

Since there are a couple of diesel shops who use my racing efforts for their negative advertising campaigns, I'm not going to go into a lot of detail other than listing parts that failed.

8 pistons, one set of rings. Everything else is AOK.

Thank you for being honest Pat, and sorry about the carnage.

 

[mudygmc]

Is coating pistons that expensive? Wouldn't it be an added insurance measure? I am just thinking that a preventative like coating pistons could save alot of money. Is there any performance issues with coated parts? Just trying to learn.

 

[McRat]

Boost was kept to 60PSIG, but Bonneville was only about 11 psia, so that's about 75? ish worth of boost at sea level.

I have used piston coating before on the first built engine I ran. It ate through the coating, so if we explore coatings, it will have to be different coating.

 

[Dozerboy]

Thats to bad, but at least it was just the piston. Good luck

 

[dmaxvaz]

Dunno, we are going to be making some changes though.

I think the engine would have perfect if it were 10 second drag passes, or 20 second sled pulls. We hit 200mph at about 40 seconds, which require 900hp on paper.

what do you think about using steel monotherm pistons? i know they dont have them yet for the dmax (but they could), i saw them for the cummins though.

 

[McRat]

what do you think about using steel monotherm pistons? i know they dont have them yet for the dmax (but they could), i saw them for the cummins though.

I've been trying to get a non-aluminum piston every since we melted our first set, 3-4 years ago on Casper's stock engine.

Probably 100 hours worth of phone calls, and got me nowhere so far.

You're going to see that as the next big jump with the diesel racers. It will be necessary as the HP continues to climb. Even if you can get pistons to survive at 1200HP, at some point aluminum can't do the job on common rail injection.

 

[McRat]

Thank you for being honest Pat, and sorry about the carnage.

Thanks Chad,

It was a tough decision to make. At first I told all my friends "No WAY am I going to continue to post about my engine experiments and failures." I do get a lot of insults about it, and what kind of diesel tuner wants people to know he has failures?

Then I thought about it more. A big reason Casper is even racing is to learn about diesel technology, try new things, and share that with other racers. Secret Squirrel trucks are a dime a dozen, and probably don't capture the audience that Casper does. It's a "community project" of the Duramax racing crowd as much as it is my personal truck.

So to cave into criticism would be the easy path, sometimes the hard road is the better one.

 

[dmaxfireman]

sorry about the carnage pat always sucks to see something you put your heart and soul into break.

was that the stroker motor that broke or the stock displacement one?

 

[Gasuout]

Thanks Chad,

It was a tough decision to make. At first I told all my friends "No WAY am I going to continue to post about my engine experiments and failures." I do get a lot of insults about it, and what kind of diesel tuner wants people to know he has failures?

Then I thought about it more. A big reason Casper is even racing is to learn about diesel technology, try new things, and share that with other racers. Secret Squirrel trucks are a dime a dozen, and probably don't capture the audience that Casper does. It's a "community project" of the Duramax racing crowd as much as it is my personal truck.

So to cave into criticism would be the easy path, sometimes the hard road is the better one.

Well said . Sorry to hear it was damged . Good to hear it wasnt completely destroyed .

Thanks for posting the results . Many follow your dmax racing and have been dieing to know what happend . We all learn from your devastations to motors .

Your a stand up guy and in this sport to help others and have fun .

We all learn from your posts and issues with motors .

Thanks :beer2:

Johnny

 

[paint94979]

Well said . Sorry to hear it was damged . Good to hear it wasnt completely destroyed .

Thanks for posting the results . Many follow your dmax racing and have been dieing to know what happend . We all learn from your devastations to motors .

Your a stand up guy and in this sport to help others and have fun .

We all learn from your posts and issues with motors .

Thanks :beer2:

Johnny

Come on Johnny stop praising Pat:hug: Just Kidding I couldn't agree more with you Johnny... Pat it really sucks I know how hard you guys work and frankly it is not fair.

 

[RPM Motorsports]

Pat do you have a picture of the pistons? Reason im asking is to see where the galling is located! If it's in the middle of the pistons it would need more piston/wall clearance. If it's around the pin area, the pins need more clearance. Top fuel piston/wall clearance is absoluty crazy due to thermals. Can you send a damaged piston back to the mfg. and have them do a hardness test on the crown. You might need a set made out of 4032, wich would have less heat transfer from the dome to the skirt, giving less thermal growth @ the skirts. If the material is 2618, the thermal transfer would be much faster to the skirts. What were you showing for coolant temps? It might be time to start cooling the block through all freeze plugs or other way's, and ditch the conventional pump as well. Just my thoughts, thinking from the Gas/Methanol world.