Loose Rod Bolts

[440sixpack]

I'm doing a light rebuild on a low mile 428 mainly to stop oil leaks.  since it's out I'm putting in now rings and bearings .

My question is all of my rod bolts are loose, they'll fall out.  other than being a pain when I go  to put the pistons back in I don't suppose it matters but is this normal ?   should I be doing something about it ?

[cjshaker]

No it's not normal, and I would definitely look into what the issue is. Just a guess, but I wonder if they used the smaller 3/8 bolts typically used on standard 390/428 rods, instead of the 13/32 that was used on CJ/Low Riser rods? Is it a CJ engine, or are they CJ/Low Riser rods? Either way, I wouldn't feel comfortable at all unless the bolts were properly sized, installed (they should be press fit), and then the big ends resized.

[e philpott]

Getting the cap alignment correct would be a crap shoot with loose bolts , you need new bolts and Rods reconditioned

[gt350hr]

No it's not normal, and I would definitely look into what the issue is. Just a guess, but I wonder if they used the smaller 3/8 bolts typically used on standard 390/428 rods, instead of the 13/32 that was used on CJ/Low Riser rods? Is it a CJ engine, or are they CJ/Low Riser rods? Either way, I wouldn't feel comfortable at all unless the bolts were properly sized, installed (they should be press fit), and then the big ends resized.

   +1 I've seen this happen!

[Falcon67]

Some of the above or possible bolt stretch.  Either way, replace.  Rod bolts have the hardest job in the motor, last place to skimp.  Also buy a rod bolt stretch gauge to ensure proper bolt torque on re-assembly.  Worth the $ to add to your toolbox.

[440sixpack]

By loose I mean they push out easy.  if I implied they're sloppy I didn't mean to.

Sounds like whatever I do I need new bolts so I'll get a set and see if they're loose as well then go from there.

[440sixpack]

ARP lists 2 sets.   a 155-60001  for the cobra jet and a 155-6002 for a 352-428  .    I don't have CJ heads but I don't know if I have CJ rods or not.  how can I tell ?

[RJP]

The quick & dirty way to tell is a 9/16" socket will not fit the 13/32" rod nut. The CJ nut takes a 19/32" socket. Bolt shank is .406" and std 390/428 bolts are .375"

[440sixpack]

My rod bolts and the holes in the rod both measure .373.  so they're standard bolts.  I'll order some.

[rcodecj]

My bet is you are going to have to recondition the rods.
I would measure for diameter and roundness for sure.

[440sixpack]

Very possible.   though all the bearings looked normal after 66,000 miles. 

I notice the ARP bolts are serrated while mine are smooth.  this might tighten things up.  though other problems could still exist.

[gt350hr]

  Yes and they will distort the rods a bit too. At the least have them checked for roundness.
      Randy

[440sixpack]

Well the ARP's fit plenty tight.   

So is it best to carefully  pound  them in or pull them in with the nuts ?

[cjshaker]

Neither. Nothing should be pounded on or in, and using the nuts will damage the threads. They need to be pressed in. If a proper supporting piece or jig is used, a regular press, or even a vise will work. Still, they should be checked for roundness afterwards.

[440sixpack]

I put a few in and it took 40 lbs of torque to seat them. ARP says to torque them to 50 for the stretch set.  but I can press them in if it's better.


I'll probably get them checked but I really think it's a waste.   I measured each of them before and after on the thin side and I had 1 that distorted .001 the rest were zero.   that's with a professional quality mic so I'm confident it can't bee too bad. my crank has a little wear too.


I suppose the caps could be a little misaligned though with new bolts.