Might have Over-torqued Rod Bolts 250 I6

[jjester6000]

So I'm doing main and rod bearings in this 250 I6 and I seem to have gotten the torque spec wrong on the rod caps. I thought it was 45 FTLB's when the Chilton's book says 35-40.

I also broke one of the bolts accidentally, so I scavenged one from one of my old engines.

Do you think I may have any issues in the future? Should I loosen and re-torque them?

 

[Ricko1966]

So I'm doing main and rod bearings in this 250 I6 and I seem to have gotten the torque spec wrong on the rod caps. I thought it was 45 FTLB's when the Chilton's book says 35-40.

I also broke one of the bolts accidentally, so I scavenged one from one of my old engines.

Do you think I may have any issues in the future? Should I loosen and re-torque them?

Sorry you're not going to like this advise, take all six rods to the machine shop and have the rod bolts replaced and the big ends resized.

 

[MarineOne]

If it broke going 5 ftlbs over those bolts (used?) Are smoked. I wouldn't trust those in my engine

 

[pduffyd]

Look at it this way.
Do you want to pull the engine again and redo the bottom end if your lucky, if the rod bolts let go it could be rods through the block. Then you need a whole new L6.
For the cost of a set of bearing shells and bolts. Replace them now, and know its good.

 

[jjester6000]

Here's the thing, this is an old worn out engine that I was just throwing bearings into just for due diligence. I wasn't planning on taking it fully apart. I was wanting to throw this one in there while I sent the other one off to be rebuilt (by a professional).

Do you think I could do the rod bolts with them still in the engine? Also, it seems that the only set 11/32 rod bolts I can find on short notice are a set for a small block chevy, are they the same? I know the bearings are the same.

 

[MarineOne]

ARP-132-6001

Best 70ish dollars you'll ever spend and yes they can be done in block just Jam rags around the rod your working on

 

[pduffyd]

As marineone said.
Remember to get a couple pieces of small hose to fit over the rod bolt threads so you are sure not to nick the crank journal as you replace the bolts out and in.
Simple trick to stop some (more) cussing!
You arent the first to have over torqued a bolt.
Thinking about the shells, you should be ok as the end caps can only go as far as the rods. Its just the damage to the bolts by over torque is the real issue here. Its not like you over torqued the bolt by double the amount or more.

 

[jjester6000]

Just picked these up today, the guy at the speed shop told me he had made the same mistake I had before, and that replacing them while in the engine is totally doable.

 

[Ricko1966]

Okay the shop I worked at from Feb of 85 until May of 01 we had our own machine shop, we did our own machine work. I did as I was taught, I was taught if you changed rod bolts you needed to resize the rod big ends, so that's how they always got done. IDK why, maybe just paranoia.

 

[jjester6000]

Okay the shop I worked at from Feb of 85 until May of 01 we had our own machine shop, we did our own machine work. I did as I was taught, I was taught if you changed rod bolts you needed to resize the rod big ends, so that's how they always got done. IDK why, maybe just paranoia.

I won't lie, I was getting a bit paranoid myself, but no problem.

Imagine what would've happended if I hadn't broken off that bolt. I would've put it back together, and it would've probably thrown a rod.

As soon as I replace the bolts and torque them to 35ft/lbs the engine will be ready to go back together. I could have the truck running by the weekend.

 

[Bennyt]

Hmmm, my opinion/concern is that you upgraded to an ARP bolt(200k psi?) which is going to stretch different than a stock bolt(140-160k psi). In my opinion, if you aren't going to resize, I'd look for a stock, used bolt.

When I worked at PAW, we resized probably a 1000 rods a day and on 99% of those stock bolts were reused after verifying they fit in a go/ no go for stretch. New nuts were always used. There was no way to tell other than that gauge if a bolt was abused, under/ over tightened in the past and probably a few million were done that way with a handful of engine failures attributable to a true failure of the bolt. Most of the failures were believed to be from undertorqing a bolt evidenced by the wear marks and no stretch.

You must be registered for see images attach

 

[Bennyt]

Just picked these up today, the guy at the speed shop told me he had made the same mistake I had before, and that replacing them while in the engine is totally doable.

Please don't take this the wrong way but not all counter salespeople are equal, but...a guy that is probably on commission and sells parts for a living told you it would be ok, because he did it once but isn't doing the work and won't help you when it breaks by either holding the flashlight or with some $$$, isn't who'd I believe.

 

[Ricko1966]

When I'm doing questionable things in a bottom end with the crank installed, I wrap my crank journals in cardboard followed by a couple of wraps of masking tape,easy to remove,no residue on the journals and reasonable protection. But seriously, why not pull the head have it valve jobbed,ball hone the cylinders,rings, and rod bearings . You'll have an engine with decent compression,shouldn't have oil control problems,and will be a dependable work horse for years. I can't count how many ring rod bearing,valve job budget builds I've done to get people by.

 

[pduffyd]

If you wanted to be sure you could plasti gauge the rods ends bearings to make sure the clearance is ok. Its your engine after all.

 

[Rusty Nail]