I hate to think that someone else works on my car....but sometimes i have to admit that I haven't the space and the tools to perform all the required works. Results? I have tons of parts to install and I never install parts due to lack of time.
So, monday I delvered a Canton pan, a Melling pump with the right pickup , a Powermaster starter, a VBP rear spring and a heated O2 sensor to the local mechanic.
I have about 3000 miles on this engine.
Yesterday I received a call...
mech: "Beppe, have you performed a rebuild lately??..."
me: "yes I raised the displacement to 383 c.i...... what's happen?? ..."
mech: "I found pieces of a piston on the oil pump pickup..."
me: "....................................... .......
........................................ . "
mech: "Beppe...Beppe... Beppe... I lost the line ..."
me: "No, I'm here........I'm coming.."
2 hours later i was at the garage.
He said that has dropped the old pan, changed the old oil pump, installed the new pump/pickup and installed the new pan.
When he was taking apart the old stuff he heard a strange noise from the old pickup/oil pump assembly.
He found pieces of a piston in the stock pickup, trapped between the net and the half moon screen.
These are skirt pieces.
here a some pics:
I have all 8 piston from the old engine and all are good.
So these pieces are for sure of the 383 KB pistons.
What cause a skirt break?? I found NO little parts of aluminium in the old pan ... and this make me think that the failure happened at the beginnig of the life of this 383. I never found the oil with aluminum pieces.
I made at least 3 or 4 oil changes and I never found alum trace...
The only one time I have not searched for traces of metal in the oil was at the first cahnge of oil that has been 300 miles after the first start up.
I check the oil level all the time and I never seen traces of metal ...

Now I asked to the mechanic to drop the new pan again and check wich piston is witout a part of skirt.. and if there is some scuff on the clinder wall.
What I have to do now??
I really don't want to drop again the engine....
Help me .... I'm simply frustrated...
-Beppe-

 

here the pics:

 

that sucks. but maybe not as bad as you think. seems to me that if the pieces didnt damage or scar any other part crank, cyc walls bearings ect... could be a simple as just replacing that piston? although there would be that thought of how and why did this happen. lucky the parts were big enuf to just drop to the bottom of the pan instead of floating around harming other parts.

 

Yes. BUT the part I found are trapped on the sreen pickup...and the others more litte???

 

I made at least 3 or 4 oil changes and I never found alum trace...
looks like you dodged a big one.

 

When I change the oil I don't remove the pan....
...I only drain the oil. There was no way to detect these BIG parts. These big parts were in the screen pickup!
the arrow shows where I fond the pieces:

 

Beppe, do I understand correctly that you have Keith Black pistons currently in there? Were the specs correctly followed in terms of the ring end gaps?

My heart goes out to you that this failure occurred I do know just how you feel.

 

Thanks, All specs on the ring end gap are good.
An incorrect ring end gap follow a top land failure....
I'm speaking of Skirt failure...so if you are speaking of "Piston To Wall Clearance"
I have .0020" as suggested.
-Beppe-

 

t the phone with the machanic...
the piston is the piston #8.
He bet the next is the #7
I don't know how he can say this...
3 or 4 hours and I will see the car.






-edit-
just to add some additinal

 

Oh man, that is terrible news. I have no suggestions, just empathy with you on your situation. Any possibility it was a defective (or 2) piston itself? Crankshaft looks ok, or not?

 

Beppe, that piston to wall clearance appears to be in spec, for your bore size (.030 over, right?). I dunno, either the machine shop blew it or the pistons are defective. A determination has to be made.

Get your mechanic to provide a written analysis/testimony as to his opinion is regarding the cause of the failure. This will be a starting point. Measure the bores, the pistons. Whatever you do, don't lay down and allow finger pointing from those directly involved on the process to end up pointing at you. This happens too often, the customer is left holding the bag. Many in the performance business do not like rework, or paying for their mistakes. All is well and good when the $$ is flying in, but when things turn sour, it can get ugly. This is fact, not fiction. Good business owners don't subscribe to this of course, but there are ALOT of actors out there who hide in the shadows and avoid taking responsibility. They will tell you, oh its performance work, all bets are off. THATS BS, ITS A LIE. Do not let this go until you're satisfied that responsibility by whomever is acknowledged and a remedy is in order. Somebody blew it here, and hopefully they won't let you pay for it all over again.

 

Was the block honed with torque plates?
Sometimes a skirt will break when you "stick" a piston.
This happens when a piston momentarily binds in the bore. Anothe possibility is the crank hit the skirt. Last stroker I built needed minor clearancing at the skirt. It just nicked the edge of 2 pistons. I made an equal notch to maintain the balance of all 8.

 

Pete has great points, and he has alot of intimate knowledge. The machine shop has questions to answer.
Lets hope they're truthful, for example they actually did use torque plates and not just say they did. These things can be hard to prove, and they know it. Don't quit until you've got direct answers to direct questions.

 

I only mentioned torque plate because I am curious. Not using one causes the top inch or so of the bore to pull in and tighten the hole up. It likely could not affect the skirt much, if at all. However, if the skirt clearance was set at, or very near minimum, the piston could have "stuck".
Based on the photo's, I am betting a shiny quarter on counterweight hitting the skirt. Disassembly will tell the tale.

 

Sorry to hear and see this Beppe
Crank vs skirt does look like a posssible cause

 

Thanks to all...
Is there a"minimum clearance " for counterwheight/skirt ?
I can't say for sure if a torque plate was used....
Hotrod90... there is no way to start a battle with the builder of the engine...he's a friend that made the engine for free ..." I made it as if this engine was mine... maybe better" He said...
I bought parts and he made the works. Then someone else (that I paid) installed back the motor on the car.
He is maybe the only one in Italy with many many many 383 and 427 SB built.
I think we will find an half way to solve the problem.
I'm very interested in techinacal aspect of the failure...
I can't say for sure if a torque plate was used....
Is there a "minimum clearance " for counterwheight/skirt ?
I cant believe that my friend has not turned the crank even one full turn to see if a possible contact between the counterwheight and the piston skirt was possible...
I don't know if I understand:
I have to check if there is a shiny mark o the very end of the conterwheight, locating, in this way, the point of contact??
Thanks
-Beppe-

 

What led you to bring it in the shop? DId you have engine noise, excessive smoking? I would think you would hear somethings seriously wrong if a piston let loose while you were driving it.

 

My vote favours contact with the rotating assembly as the cause rather
than whether or not a torque plate was used.

There may have been enough clearance to rotate the engine by hand
but not enough clearance to run the engine. While I'm not sure that
you will find a mark on the crank - the bottom of a KB Hypereutectic
piston skirt would probably break without much of a fight, the pieces
are large enough that I bet you could put them back into place on
the piston and get a good idea of what kind of clearance there was
before there was contact.

As for your concern about small pieces, again, you can reassemble the
piston skirt bits to see how much is missing. I think you will find that
most of the broken parts are there in the pan and I would guess that
anything missing MIGHT have come out in an oil change. A look at
the bearings will tell the story but I don't feel the skirt would break
into tiny fragments that could make their way into the pump and galleys.

The concern I have is whether the wall(s) were scored. Depending
on which side of the skirt broke, there is a greater or lesser chance
of this.

.

 

good question.
I have the car in this new garage (the local mechanic ..not my friend the buider of the engine...) ONLY to install a new pan, the rear spring, the starter and other little things... this is the ONLY motif.
I NEVER suspected to discover a failure like this!
Probably the failure of the piston skirt occurred in the first 10 mins after the first startup and I NEVER heard some "BANG" or some hitting sound.
Yes from the day one the car uses a little of oil...but I was sure to have cured it a month ago sealing the rocker studs on the heads and sealing better the Superram I have.
until the last sunday the car runs good without ANY strange loud noise.
As I said probably I had this failure the day ONE just when I was performing some trip to try this new beast....and i was too excited to see or hear a strage noise .
Who know?? probably the new mechanic left a wrench in the pan and when he started the car to see if the new starter was correcly starting the car, he broke the skirt... then opened again the pan just to see the damage and then he said that the damage was an old damage....Who know for sure??
For sure I HAVE to listen at the sound of my car NOW just to hear if there is a strange sound that was NOT present BEFORE the new mechanic..
I'm in a bad trouble..
-Beppe-

 

Just wanted to say that I do not disagree with Pete K that cylinder
distortion could lead to a momentarily stuck piston and a resulting skirt
problem.

But Beppe mentioned that the pistons were fit to 0.002 clearance
and this seems enough for Hyper cast pistons to be able to tolerate
a bit of distortion in case the plate was left off. Pistons were fit to
tolerances like these without issue before torque plates came to be
commonly used.

.