any ideas....

[howmaann]

was in third stepped in, down to second just started to to break the tires loose and broke something else.. and boom , alky kit, 50lbs inj ...roller cam , forged pistons ,iron heads port polish , O ringed , all bearing look good, bult this 9 years ago,

 

[howmaann]

oh yeah bent a valve number 6

 

[Squid4life]

Crank or hub, one of them gave up. Hard to know which quit first...

 

[Squid4life]

Seems to be going around lately.

 

[howmaann]

crank was mag from engine bldr, however this was a stock crank . thoughts on block, mag it and line hone?

 

[fastblackracing]

wow this is like the flu going around, If no big chunks came from the block check the caps and the block webbing and main bolt holes up to the cam bearing area REAL good before proceeding. How many miles were on the crank and had It ever been detonated on hard before you did this build?

 

[howmaann]

80 k or so on crank and now that i remember i did have a detonation on it in the beginning,after engine was assembled , had arounfd 1 k on build and thats when positive cable was up not down grounded out at 21 lbs and collapsed a skirt 40 thousand , makes total sense now , you guys are good !

 

[Nick Micale]

Crank or hub, one of them gave up. Hard to know which quit first...

Unlikely the balancer or hub broke first? I have seen many hubs crack and run for many miles and just ruin the crank snout, but it will not apply any force or enough un-balance to snap a crank.

There are a few things going on here and one major cause is metal fatigue. A 20 year old cast crank beat-on for 9 hard years with hard pounding and what appears to be detonation and pre-ignition from the piston will most certainly take out a crank.

This is typical engine damage that we see often from alky powered cars that are beyond the boost limit for the build and supporting parts and then either leans out or runs out of octane, and sometimes both. Also using a cast crank at over double the design HP level and elevated RPM is asking a lot from it, and yes you will be seeing more damage like this as the cars age, and the owners get younger!

 

[Mr.Spool]

where did the rpm go to on the downshift?did the car go lean?i prefer to look at fp on both alky and fuel system right in front of me.you can log theses things also so you know where to look when things go wrong as guessing can be costly.

 

[howmaann]

Was relatively a low speed, slowed to @ 45 mph was coming off
Interstate to side route starting going uphill
And stood in it , started to pull big POP !! A couple
Yellow lights on knock that's when it let loose
ALWAYS run good fuel and maintain Alky , ill
Have to look may have had. My 107 chip in it, but time for
Steel crank , what manufacturer would you by
A crank from .. Thanks guys !!!