I started a post to ask about something like this but it was whether
the Canton needs special attention on a 383 - I was thinking along the same
lines that this new mechanic might have caused the problem and
then tried to cover his tracks. But I concluded that the skirt couldn't
hit the pan or the windage tray, just the rods or counter-weights
would, I believe.

Yes, it's possible a tool or something got left in the pan - but I think
you'd have a good chance of seeing damage in the new pan if a wrench
or screwdriver had been in there. Won't hurt to take a look when
you visit but I'd wait to be sure before suggesting that THIS guy
might have caused the problem.

.

 

i have 2 questions:

around when did common use of tq plates come into being?
was this after the mid-70's when engine blocks have since been less sturdy?

 

I'd bet on the counterweight/skirt, while it's up I'd slowly rotate the engine and watch closely.

 

you say: "I can look up my piston's skirts pretty clearly with the pan off and the oil pump removed. Try that."
This is my concern ...
How the mechanic CAN'T see a kind of big damage, replacing the oil pump, replacing the pickup and bolting up the new pan ??
In addition the damaged piston is the #8 ! JUST NEAR the oil pump!
Obiouvsly as Slalom4me said I can't say that the mechanic is the culprit...but it's a thing that i have to consider and i have to investigate..

 

This is an Eagle rotating assy. It's a proven combo fully tested. And all cast kit like this are sold for the 90% with KB piston.
I know...I'm using the short 5.7" rods (and this can play a role in the crearance with the counterweight)....but how many pipole have used a popular kit like this grinding the skirts to gain room??
-Beppe-

 

At this point I'd sure as hell not worry about what the mechanic can or can't see, I'd want to have a peak and see for my piece of mind, see if I could see any way that skirt or anyother could come in contact..listen, I feel for you and your situation....but who do you trust more? him or yourself. I may be wrong on this, and I hope so, but it seems like I've heard about having to check for clearance problems like this before....hope I'm wrong guy. Good luck.

 

I think that enthusiasts like me began to become aware of torque
plates in the e-70's, thanks to performance magazines and engine
books. Back-dating from here, I would guess that a very few smart
people were using them in the later 60's. Can-Am, Formula 5000
and Trans-Am racing back then led to a lot of money being thrown
at optimizing SBC & BBC performance and durability.

I know from trying to have blocks done with a plate in the e/m-70's
that very capable shops didn't have them. The few that did had
theirs custom-made and they started off being much thinner than
is the norm today - 1", IIRC. Nowadays, you and I can get online
and order up a thick plate easily and relatively inexpensively.

As for the rise in use being in answer to a change in block construction,
I would say no. Plates helped improve power by loading the cylinders
into a shape during machining that was similar to the one they'd have
during operation. As demand for this rose, price of the plates fell and
that, along with growing experience and time-saving steps for using
them led to the cost of machining with them going down is what led
to their use being common place for performance work today in my
opinion.

.

 

Torque plates became popular and necessary when rings more exotic that cast iron hit the market. Cast iron will tolerate some cylinder distortion, plasma/moly will not.

 

wow Beppe, I am sad to see your engine with problems.

Probably alot of particles in the oil filter(the first one).
Not enough guys cut them open anymore to see what is floating around in the oil.

I would rather clearance the crankshaft counterweight than clearance a piston.

 

Please be aware that I asked the torque plate question just because of curiosity. Last time I mentioned it in a reply, I got my head ripped off for suggesting it. I think it is highly unlikely a lack of torque plate caused this problem. As I said, mostly curious.
When the geometry of a motor(more stroke) is changed many things can go wrong. Aftermarket parts often do not fit like oem and require triple checking. My last 383 "should" not have had crank to skirt problems. But it did. I caught it and corrected it during mock up. Builders, regardless of reputation, need to finish every motor so they can begin the next one. One whoops is all it takes for something like this to happen. Does not make the engine builder bad, things get by sometimes. I agree that the problem should become quite easy to find while the motor is being disassembled on the stand. Hopefully, it can be repaired.

 

So this is the torque plate you guys are talking about?

(sorry for the rice motor pic)

It bolts in place of the head and is only used for boring/honing?

So the block can actually twist, or deform from heat during machining, leaving out of round or tapered bores?

 

 

And while we're on the subject, just so folks will know, main caps should also be torqued in place during these operations. I'm very distressed to hear about this problem, Beppe.
Have you ever heard from Dana? I sent him your email address and explained your situation. I haven't heard back from him either by phone or email in over a week now. It makes me wonder if this is who you really want for that project.

 

Was this 'KIT' complete, or did you buy the pistons separately (or crank separately)? Possibly could have been sold a crank designed for 6.00" rods or longer, but NOT shorter. Possibly could have been sold a piston not designed for a stroker crank, with or without the correct compression height. Oil pump interference is possible.
Also, I have heard from one or two reputable sources that do not recommend KB Pistons because of observed piston distortion, assumably from thermal expansion uncharacteristic for a quality piston/alloy.
If you think this is all the damage that has been, or will be done, I would consider driving it until you hear it knocking (when cold). If you are afraid that subsequent damage may occur, or think you have mismatched parts or improper clearances/assembly procedures, then you might as well take it apart and go back through it and address these particular issues before reassembly.

 

The kit was purchase as a kit. But even if it was purchased separtely, I really dont know how a 5.7" rod designed piston (the difference in the compression height is too big...) can be put on a rotating assy with a 6" rod..
For what I know ... the 3.75 crank designed for 350 engines (not the 3.75 for 400) is the same for application with 5.7" and 6" rods. Only the compression height of the piston is different. (obiouvsly the compression height on a piston on a 6" rod application is much moooore less). So no errors about crank/rods/piston was made-for sure-)
About the thermal expansion of a KB piston I disagree.
Someone is free to prefere others piston... but it's sure that the thermal expansion in an Hypereutectic KB piston is very very low allowing tighter fit application.
The only difference that this kit has compared to other Eagle cast kits is that my kit is with an internally balanced crank....not the usual kit with the 400 external 8" balancer with imbalance. I'm continuing using my stock(neutral) 6-3/4" harminic balancer.
-Beppe-

 

Chris, I asked you to call to Dana. Why? because the email way does not work with him...
I was thinking you called with the phone # I gave you 10 days ago....
I think he's a busy man and he can reply only if contacted by phone ...speaking with him directly.
I will try to contact him directly even if I know that with my poor english it will be very difficult...
Thanks
-Beppe-

 

OK, I seen the engine and the broke piston.
I can say that it's really IMPOSSIBLE to say if the counterwheight had a contact with the skirt... Even trying to put the piece that I have on my hands near where the skirt broke, I can ONLY EXTIMATE the original room that the counterwheiht had before the crack....Yes, I can say that the edge of the counterwheigt was real close.
There is NO problem on the others counterwheigts (the central ones are thin compared to the one at the end of the crank)
The problem of clearance IS NOT about how tall il the counterwheigt, but on HOW LARGE is the counterwheigt.
On the suspected counterwheight (real large), I tried to see the clearance on the opposite skirt of the same piston.
Yes, we are very close. we are very close laterally speaking.
The skirt is not so large to contact the counterweight, but ...if it was more large (the skirt) the contact would be for sure...
There is clearance only because the counterweight has a diagonal notch.. a stock deburring work on all the perimeter.
It's best to do a drawning ...
I can only imagine that the cracked skirt was in the same situation as the one in the design.
So, only a lateral change of the position of the piston during a normal or sustained speed of the engine can lead to a contact.
Can a piston laterally change the position for over 0.040" -0.060" ?

 

Everything in an engine grows as a result of heat. Rule of thumb is minimum .050 between anything that moves inside the motor. I always aim for .050-.070. I will not allow anything tighter than .040.
The fact that everything was sold as a kit guarantees nothing regarding proper fitment. As I mentioned earlier, when you change geometry inside, all the rules change. Every single piece must be tripple checked. I have never seen 1 stroker motor, Ford or Gm, that went together without some silly issueinvoling additional notching or grinding

 

I have called him and can only leave a message. He never returns the call. Same with the email.

 

What to do now?
I have sufficient ways to think that the failure occurred in the very first part of the life of this engine.
So I used this engine always with the skirt craked.
This is not the best way to use an engine...but I utilized the engine in these condition .
I observed the surface of the bore of the cylinder #8 and there is no sign of scratches...
I really don't want to drop the engine (too much time involved).
I'm planning to use the car as normal, and then, at september or october ...thinking at a new rebuild.. maybe with forged parts.
BUT,
Is it possible to change ONLY the offended piston from under the car?
(Just thinking to remove and reinstall the SUPErRAM make me fell mad.. ).
Thanks to all