I had my new Ohio Crankshaft connecting rods installed on my new pistons and 2 of the rods were installed 180 out. I had this done at a local small shop with older equipt. I took the two rods to the machinist who bored my block to have them turned around, This is another machine shop. He pressed the pins out and just checked the upper end the holes were out of round and he thinks because of excessive heat applied when installed the pistons. Now I have to buy two more rods. The question is: Should I have all of the pistons pressed back off and checked for out of round condtion? or do I leave it. I have not had the crank balanced yet (1st mistake having pistons installed before balancing). This is on a mild Big Block 402 2 bolt. It won't see more than 5500 rpm. Please all help is welcomed.

John,

Did the rods have any visual indication of being overheated ? They usually just barely start to discolor a bit when properly heated. If they are real "blue" then they might have been overheated. I don't know how out of round they were, but very rarely are they perfectly round once they have been installed and removed one time. I would be more concerned about how much interference fit there is to hold the pins in. I have seen a lot of rods lately that do not have enough interference. I started checking them religiously about 10 years ago when an 454 engine I built had one pin come out and scarred up a cylinder wall pretty bad. A lot of the rebuilders hone the small end of the rod, I try to avoid it if at all possible because of this issue. I have also found a fairly large difference in wrist pin diameters from different manufacturers. If you get a pin that is on the small end of the specs and a rod at the big end, there will not be enough press fit.
Bottom line is it might not be a bad idea to have them checked if the ones he removed were "big"

Why run "pressed-pins" at all, almost all pistons now come with provisions for lock rings. Also, you may want check the pistons that were pressed off, it usually doesn't do them any good being placed under a pin press. We've seen many a "distorted" piston done in less than adequate shops. For the price of rods(250.00/300.00) it doesn't pay to run an antiquated press pin. H-beams run a bit more, but it's nice to be able to assemble/dissassemble the pistons on your own, if you had to for any reason. Thanks, Gary in N.Y.

Bill is right and so is Gary.

Next rebuild, I'm going to floating pins.


BTW, I did an engine rebuild for my Father-in-law once upon a time.
I inadvertantly overheated a rod end getting ready to drop in the pin.
Turned Nice and blue. We threw it together anyway and it went nearly
200K miles before the body fell apart. so, I don't think the heating was
a "problem".

Dave

Thanks for the advice! Yes they do have "blueing" half way up the neck of the Rod. Out of round was what they showed me at the machine shop, strait up and down the rod was good interference fit but the 90 degrees to one side and the would not have the interference fit. I am afraid that the pins would work it self out to one side and score cylinder walls. The pistons are new Speed Pro 2240 and so are the rods I6135P from Ohio Crankshaft. I don't think they come with provisions to install floating pins. I would have to have they machined for ring clips. I think I'm going to buy new rods. 2 rods are $60 and for another $120 I could have a piece of mind that there good. Thanks