02 Viper blew up @ 105Mph

stretchSXV · Jan 28, 2009

I hate to hear I can't run my viper at 105mph. What's the point if you can't run WOT ;)!

Tg5593 · Jan 28, 2009

svo11 · Jan 28, 2009

I just had my viper melt the center piston this weekend also, weren't doing any racing just some normal riding no warning just lost comp. on the 2nd cylinder. Had just rebuilt the motor from last year when lack of maintance caused power valve to stick and melted the same piston.

Tg5593 · Jan 28, 2009

alswagg said:
I thought when ethonal was added to fuel it bumped the octane to 89. This of coarse is if you start with at least 87 octane. If the fuel in this instance is 87 octane with 10% ethonal the base fuel must have been 85 or lower. Am I thinking correctly on this? If too much injection oil is added to fuel, the fuel burn will be lean, but the overall burn will have a lower temperature due to not being able to addiquatly burn the extremly oil rich mixture. The big question is now, 2nd seizer on engine, I would bet both are related. Why did the first siezure take place? Cloged main jet?? Was the carb boot bad at that time also?

carb boot was missing the clamp screw on the clutch side and i don't know for sure if it was leaking, that is just a possability.

alswagg · Jan 28, 2009

To me this does not look like a lean siezure, but a cold sieze and predetonation, The crank looks like it was lean on oil, on the lower crank brg. The needles appear to be missing and have been beat up on the case and piston top. How is the head?

Tg5593 · Jan 28, 2009

the head looks good

mopar1rules · Jan 28, 2009

i believe all the piston damage is from the chunks of the rod bearing. my buddy has the same thing happen on his viper @ 5600 miles. jetting was fine too.....perfect plug color. i would still get a clamp on that intake boot. also, double check the carbs. run 93 octane where ever you can. if you have nothing but ethanol junk by you, bump your main jets up 1 size or so.

9801srx · Jan 28, 2009

mopar1rules said:
i believe all the piston damage is from the chunks of the rod bearing. my buddy has the same thing happen on his viper @ 5600 miles. jetting was fine too.....perfect plug color. i would still get a clamp on that intake boot. also, double check the carbs. run 93 octane where ever you can. if you have nothing but ethanol junk by you, bump your main jets up 1 size or so.

x2... how many miles this season?could have been poor summer storage took out the brg.

Tg5593 · Jan 28, 2009

9801srx said:
x2... how many miles this season?could have been poor summer storage took out the brg.

about 800 miles so far. I found a new motor so i may salvage the season yet.

Maim · Jan 28, 2009

hmm. kirkswim lost the crank bearing with 50:1 mix synthetic and he had 91 octane in the sled at the time at muni. all float bowls had oil in them and the plug read ritch through the debris. he usually runs 87 octane with seafoam in it and it showed no signs of detonation on any of the other cylinders or the one that lost the bearing. sled is stored by doasing with seafoam and run the motor untill the return cooler is warm to the touch every 2-3 weeks. we have stored them this way for years and still have 1978 sleds that are all origonal.

Ding · Jan 28, 2009

I've found stock Viper jetting to be about right at -30C (-22F). There is not much margin for error below this.

It sounds like you were in the midrange. It doesn't take much throttle to go 85mph on a Viper. Can you tell us if you were 1/2 throttle, 5/8 throttle, 3/4 throttle, etc.?

Where are your needles at?

I now suspect either an air leak on that carb / intake, or issues with the fuel pump for that carb. The pics show lack of fuel and oil to that cylinder.

Was the carb bowl full of fuel in the carb?

You may want to send an email with pics to Don Pizor, or someone like him for input. Someone who spends all their time working on these engines. I have only seen a handfull of Viper engines.

crewchief47 · Jan 28, 2009

Some shots of the tops of the other pistons may help as well.

mopar1rules · Jan 28, 2009

crewchief47 said:
Some shots of the tops of the other pistons may help as well.

yep, i would like to see the wash on the other pistons. can you try to turn the flash off, so the pics of the plugs and pistons don't have such a bright glare.

YAMMIEGOD3:16 · Jan 29, 2009

TRUTH BE KNOW, 87 OCTANE ? TRY AROUND 76 OCTANE. 3:16 (yammie tony)

Tg5593 · Jan 29, 2009

mopar1rules said:
yep, i would like to see the wash on the other pistons. can you try to turn the flash off, so the pics of the plugs and pistons don't have such a bright glare.

9801srx · Jan 29, 2009

Tg5593 said:
about 800 miles so far. I found a new motor so i may salvage the season yet.

at 800 miles it was probally not pore storage related then.they usually go on the first ride from bad storage. you said it had a top end rebuild about a month before you got it,do you know why it was rebuilt? piston failure or other reason? i think the brg failure is what did all the damage .looking at your pictures i think the wash is good considering the tempreture when it happened and the other two pistons show no sign of lack of oil or deto.

Ding · Jan 29, 2009

9801srx said:
at 800 miles it was probally not pore storage related then.they usually go on the first ride from bad storage. you said it had a top end rebuild about a month before you got it,do you know why it was rebuilt? piston failure or other reason? i think the brg failure is what did all the damage .looking at your pictures i think the wash is good considering the tempreture when it happened and the other two pistons show no sign of lack of oil or deto.

I also suspect the rebuild, or a problem that existed before the rebuild. Those pistons do not look like they were replaced as part of the rebuild. Too much blow by for even 800 miles.

Do you have any pics of the undersides of the pistons?

I also agree that the failed bearing may be the root cause. Or more accurately lack of oil to the failed bearing.

How are the oil feed lines that run along the underside of the engine? If you want to use that oil pump again, you may want to test it and the hoses and passages.

no1chevyboy · Jan 29, 2009

too me jetting looks good i agree with mopar bearing took out cylinder

kl-ze · Jan 30, 2009

how would he check the oil pump ?
whats the best method for doing this test ?

thanks...

Ding said:
I also suspect the rebuild, or a problem that existed before the rebuild. Those pistons do not look like they were replaced as part of the rebuild. Too much blow by for even 800 miles.

Do you have any pics of the undersides of the pistons?

I also agree that the failed bearing may be the root cause. Or more accurately lack of oil to the failed bearing.

How are the oil feed lines that run along the underside of the engine? If you want to use that oil pump again, you may want to test it and the hoses and passages.

sideshowBob · Jan 30, 2009

I agree with the opinion that the Main Rod Bearing failure caused the "current" damage ...the question is what caused the damage to the Rod Bearing? My 1985 Vmax 540 went down like this once after it had the piston replaced because of damage from too lean jetting. I would suggest that this bearing has been previously overheated either from beeing too lean and or lack of sufficient oil. It probably had a lean burn down on that cylinder sometime in the past.

02 Viper blew up @ 105Mph

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