Wonder if the piston seized in the bore? That would explain the rod being pulled apart.

I love a good mystery.

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Official Cookie and Mater Tormentor.

I've seen more block failures and valve failures in the speed game.

did you pull the valve cover yet ?

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slant six's RULE!
http://www.usajon.com

I looked back at my build and found my clearances on the rods were at .0025, which seems a little loose for a brand new build. Now that things have gone south, it makes sense that perhaps the rods bolts oblonged the rods causing my reading to be high at the middle of the cap and probably tight on the sides.

I have not touched the car other than to drop a magnet into the hole, but I will pull the valve cover in the morning and just take a quick look and make sure that all the valves are still in the head.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

In thinking about it I think it is most likely that a valve or something kept the piston from going all the way to the top and thus the elongated small end and eventual break. I think Jon is on the right track.

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If you didn't drive it there, it's not a street car.

Not likely that your bearing clearance was too much Rick. I know a lot of guys also look at their Mopar service manual as the holy grail of engine specs, but it is really meaningless when it comes to prepping an engine for any kind of performance usage. It was written specifically as a stock engine guide, and shouldn't even be considered as a tool for prepping any sort of performance apps. Building and prepping an engine for performance is in a completely different league and has its own set of rules and specs that are rarely the same for a stock engine rebuild. Your rod bearing clearance is really right on the money. What was your rods side clearance also? I also have found in my years in the machine shop that the worst rods were the so called ones that were already "reconditioned" ones you buy at the parts store, the same goes for crank kits and rebuilt heads. So if you hadn't changed the rod bolts in these rods, chances are you wouldn't have had them checked to confirm they were dead on on their housing bores either, and could likely be facing the same problem.
Your rod failure problem was more than likely caused by the rods being out of round and caused this. Just look at the bearings in your surviving rods and you'll probably see a recurring pattern of telltale signs showing it. This was just an oversight and shouldn't make you steer clear of attempting to use their products. To answer your question in the other post, you should always consider upgrading to better engine fasteners, especially rod bolts, because you never know the history of the rods or blocks you buy from junkyards or swap meets, its just good cheap insurance. And people are going to always tell you the engine came out of their grandpa's truck our their 90 year old aunts car when they are trying to sell something.

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There's no such thing as too much cam....only not enough engine!

I rode this Harley chopper 3 years straight as I it was my only transpo. I retarted the timing so it would start in the winter.(kick start only) Being retarded it heated the exhast valve so much it shattered, bounced around the head /and went out the exhaust at 85 mph on route 40 headed to my bros house in Monrovia( 4wheel Harry) , Maryland.piston had dents, spark plug was shot, but sanded down the combustion chamber/piston and new valve and ran OK...
http://www.youtube.com/watch?v=-vTe0yrLEoU

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slant six's RULE!
http://www.usajon.com

Your lucky, it usually at the least bends or twists the rod by some amount and/or closes up the top ring land on the piston.

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There's no such thing as too much cam....only not enough engine!

One more piece of the puzzle.

Pulled the valve cover and it did not drop a valve. Everything is in tack up top. However when I got a small flashlight out and began to look a little closer behind the headers you can see in through the front frost plug hole. There is a large hole through the cylinder wall.
Perhaps the cylinder wall gave way and started all of this. Or perhaps the rod just poked a hole through it. Time will tell. It is .100 oversize. Time will tell

Rick

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

the valve never dropped. just the face part in photo shattered/rattled around did some minor damage then flew out the open drag pipes..

_________________

slant six's RULE!
http://www.usajon.com

rick I did not read your build, but those chevy 2.2 pistons look short/stubby compared to the regular slant six coke can pistons..
correct me if wrong on the pistons..
has anyone else had an issue with stubby pistons in a slant ?
they would seem to rock more in cylinder then a stock length piston 2me.

_________________

slant six's RULE!
http://www.usajon.com

Nope, not that I know of. Lou is running the same exact piston/rod combo in project V.

Rick

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I was able to get the intake and headers out of the way on my engine and get a better look at things. The crank did not spin a rod bearing. If you look at the pictures the journal is perfectly smooth on the one side and beat up from the pieces letting go on the other. But it did not spin. I also fished out a ARP bolt that was snapped in the middle and it still has the nut on the stud.


Nice smooth journal


Other side of the same journal

I also fished out some other pieces of the cylinder wall and the thinnest piece I have found measured over .177 thick.

Pulled # 2 spark plug and it looks perfectly fine.

More to follow.

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Rick, does it look like the bolt broke underneath the head where you had to grind it to fit the rods?

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There's no such thing as too much cam....only not enough engine!

No it broke in the middle, about where the rod would part. I'll get a picture.

Rick

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

No, the piston pushed down easily through the spark plug hole. So it is not seized.


Here is the picture of the rod bolt. It looks like a smoother break on both sides and jagged it the middle. Does that mean somthing? I don't know. I may get the head lifted off tomorrow, and then I can see the bore and piston (whats left of it)

Rick

_________________
2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6