Broke my 440

[440mag]

Drove my car 300 mile to a car show and had to tow it home.  To make a long story short the car ran great all the way there until I was going to go for a cruise and it startind popping under load, found a bad vacuum leak on the intake. Replaced the valley pan and still would not run smooth, cleaned the Nettle and seats, checked the float levels and all was good but still would not run smooth.  Started changing spark plugs and the looks good until I got to #5.  All the porcelain was gone from the inside and the electrode was bent against the side.  The electrode drug on the threads all the way out.  I bore scoped the cylinder and the top of the piston and the pottom of the head got hammered.  Can't tell yet but the piston looks like it is cracked and part of the ring land is gone.  It has zero compression on #5.  Came lobes, lifts, pushrods and rockers look good.

I never heard this thing come apart.  I wounder what failed first the spark plug or the piston.  Time to build a new engine.

[RD]

that sux!  sorry to hear that.  cant wait to see what you plan on for the next build

[terrible one]

Man that's a bummer. Did you drop a valve?

[Chryco Psycho]

running lean is the fastest way to kill an engine you can melt a piston down in seconds running lean on nitrous
Sorry about the bad luck

[firefighter3931]

I wounder what failed first the spark plug or the piston.  Time to build a new engine.

As Chryco mentioned going lean (vacuum leak) can cause all kinds of problems. The spark plug will fail first followed by the piston carnage. 

Sleeve the cylinder and get a new piston and you'll be back in business   




Ron

[CB]

running lean is the fastest way to kill an engine you can melt a piston down in seconds running lean on nitrous
Sorry about the bad luck

does this also count for unleaded gas?
Sorry to hear about your bad luck!

[440mag]

I'm not sure the order things happened end but I believe the vacuum leak was caused by loosing the cylinder and was a result of the popping.

The engine was dyno tuned and had a good air to fuel ratio. (12.75 - 13.00 from 4500 RPM  - 6200 RMP)

I run 92 octane gas through Edelbrock Performer RPM 84cc heads, 10.5:1 CR, Keith Black Silvo-O-Lite flat top pistons.

The valves and valve train look good.  Still need to pull it all apart, took the pictures with a bore scope.

I plan to build a stroker engine.  Going to talk to 440 source and start planing the build.  Not sure hoe big I will go yet.

[Runner]

oh no,  let the kb piston bashing begin.     my sister in law bought a javlin with a 360 that always made a odd ticking sound. it turned out to be a bent piston skirt from something going through the motor. i had the head fixed, replaced the one piston, and its still running fine to this day.    man id love to hav e a bore scope!!

[440mag]

It would be premature to do any KB blasting with the engine not tore down yet.  This set up had about 10,000 miles on it.  I got a good deal on the un-run assembled short block.  Before finishing assembly we pulled the pistons a found the top rings too tight.  Filed the top rings and it had run good with no problems.

[Runner]

i wasnt bashing kbs, i run them in my 452.   it has been my observation that most people on this sight bash them thats all.

[Chryco Psycho]

I won`t bash KBs this time , the piston could have totally failed & taken the block with it , it didn`t happen ....good news