ROD Failure

[happyhour]

well I found the limit of boost on my stock motor this winter 20 lbs with out a head shim . I am finally getting all the new parts so hoping to get it back together before all the snows is gone figured I'd post some pics of the carnage and of the new rods vs the old ones

 

[up-high]

Now what do you think of running 20# without rods?

 

[rooster700]

What were you running for fuel?

 

[happyhour]

What were you running for fuel?

110 octane

 

[geno]

what elevation? who's control box? inquiring minds, want to know


are you fixing the crankcase? can't tell how bad it is, from the pics

 

[happyhour]

what elevation? who's control box? inquiring minds, want to know


are you fixing the crankcase? can't tell how bad it is, from the pics

elevation was 600 ft fuel delivery was done by tune with attitude crankcase was welded up just waiting to get it back from US crome bored it out to 1025
the center section of the rod in the top pic made the hole in the case found it up in the nose of the sled luckly it happened next to the shop just bent the 5 valves on that cylinder piston rod crancase and lower case were hurt welded up both cases as far as head work I am just going to have to wait till this summer, put stock valves in it for now

 

[Blue Jay]

How many miles did you get out of it before she blu?

 

[BigFish BC]

so what did the top of the piston look like was there any deto.

 

[Linc]

That engine was making noise before it let go,,,too bad you didn't hear it in time,woulda saved a ton of money,,,,oh well next time you'll know what that sound is though.

 

[geno]

Linc, why do you say that. I was thinking it happened, all in about 2 seconds. Or, are you referring to hearing, the deto, pinging?

 

[Linc]

You can see the rod bolts are broken,,that means that it was slapping for a bit ( not very long )before they broke,once the rod cap falls off then the rod gets jammed between the crank and the case and gets stuffed out( ported cases ) when the rod goes like that,it always makes a noise first,it doesn't make it for very long,but it does make noise.However when the valve shim is cocked it doesn't make any noise,it just blows without warning.

 

[geno]

third pic, shows the cap still on the rod. I see what you're talking about, just not convinced, you'd hear any knocking, before it let loose.

 

[Linc]

I saw that ,but I think it's just sitting there to show what happened.You can't see the cap.

 

[BigFish BC]

i think linc is talking from experiance

 

[ryan7]

How many miles on the engine?

 

[spring snow hero]

at 10k rpm he is turining over 150 revs per second.....reaction time would need to be pretty impressive to stop the carnage........but good eye.

 

[happyhour]

I believe there is 1500 miles on the sled there was no detonation involved on this believe it or not that was my first thought but it was the rod that let go the rod bolts in the picture had been cut off the, bolts where just to pounded to getting it off the crank journal

 

[Linc]

Oh,,,that changes things,the only other time I've seen that carnage is when a valve drops.Do you think you dropped a valve?

 

[happyhour]

Oh,,,that changes things,the only other time I've seen that carnage is when a valve drops.Do you think you dropped a valve?

Didn't drop a valve, they where just bent from the piston getting wedged in the block was that ever fun getting that out.

 

[Linc]

Well,,,I apologize,,,that's a stumper,normally overboosting will slice holes in the pistons and cylinders on an Apex and grease the rods on a Vector,,,but snapping the rod,,,that's odd.