Well, I now know why the number 8 rod went though the oil pan.
From what I saw and what the 'new' engine builder said it appears that one of the rod nuts or both were not torqued down because it was backed off about 3/8" of an inch when we did the inspection. This destroyed the rod (Eagle H beam) two pistons, busted the cylinder skirts (destroyed block). I cannot get intouch with the original builder as he is hunting for two weeks. I originally did ask about the warranty on the new motor and he stated that "if it cranks and runs it is yours". Well I got about 15 dyno runs and six total passes at the track and only one fair pass at 11.5 and a 1.63 sixty foot and let off the gas 1/2 down the track as it was going towards the guard rail. The car put out 401 HP through a Turbo 400 and it was awsome!

Here is the QUESTION: Has anyone ever heard of and ARP Connecting rod NUT "Backing off" the bolt/stud on the main cap side? The 3/8" was the amount the NUT was off the seat and the bolts are inserted from the piston end of the journal with a flat end. The other Connecting Rod Nuts on the rods were very tight where they "Pinged" when removed.

Damaged parts: Block $$$$, crank $$$, 2 rods $$, two probe forged 12-1 pistons $$$, HV oil pump $$$, Milidon oil pan $$$, milidon oil pickup $$, heads have a ding in the aluminum (can be repaired), valves where piston hit need to be checked (Manley SS Severe Duty 2.055" and 1.6").

I have the stock block in the back yard, thank God for that.

Serious opinions are appreciated.

Jim in Orlando

 

If they were not torqued with a rod stretch guage,or not retorqued 3 times they WILL come loose.
Refer to ARP's torque procedures.
Or maybe that one was missed?????

 

Torque procedures can cause this. Also the mating surface of the nut/bolt to the actual rod cap can cause this if things are not parallel.

Search a little further before blaming a broken or loose rod bolt. Many times there are other things that cause this to happen first, then things go to hell

-Shannon

 

I have Eagle 4340 H beam rods, and they use bolts, not studs/nuts. Do you have any pics of the carnage?

 

Yes, I have pictures, I have a good one of the Eagle I beam rod twisted in half and most of it missing (little pcs throughout the engine) really pretty cool. The pic of the nut backed off the bolt did not come out, I was not happy about that pic not being clear. Another pic is the bottom of the cylinder skirst with big chunks torn out (block is now a boat anchor).

I took some of the PM's and post on this tread to my NEW engine builder and he said "JIM, he forgot to tighten the NUT, end of story". He knows his stuff and has seen this before.

Now my delema is either tear down the stock block in my backyard and go through the One month or more machining / balancing process or purchase a short block , 383 or greater. Either way it is going to be expensive but a short block is quick, ready to go. Then again it is a drag car and season does not start until April.

 

Find out where "he" is hunting. I understand that it is open season all year round on bad engine builders.