Warning against using ARP L19 rod bolts...

[blykins]

Guys,

A few years ago, I had a rod bolt break on a very high end race engine.  Luckily, it was idling on the dyno so it didn't hurt much, but it was still a punch in the gut.  The rods were Oliver and the bolts were ARP L19 bolts.  All of the rod bolts were torqued by the stretch method and recorded.  Before the oil pan went on, they were checked again, and I put my paint dabs on the bolt heads to indicate that they had been checked.  After the failure, we located both bolt heads, with my paint dabs still on them, with the bolt shanks still in the rod. 

I contacted Oliver about it, but of course they had never heard of such thing, so I wrote it off, repaired, and went on. 

Fast forward to yesterday, I went to dyno, and was discussing engine stuff with the guys there who build some pretty high end race stuff.   One of the guys told me that their shop rule was that whoever bolted the oil pan on also had to go through and check the rod bolts before the pan went on.  He was doing that very thing, cycling through and checking torque, when he rotated the engine over and found a rod cap missing a bolt.  On further inspection, the shank of the bolt was still in the rod, so he started looking around and found the rod bolt head laying on the floor 5-6' away from the engine.  It had broken under load, just sitting on the engine stand, after they had torqued the rod bolts upon assembly a day or two before. 

It was an ARP L19 bolt. 

After they remembered my own incident, they removed all the L19 bolts, threw them away, and installed ARP 2000 bolts. 

I'm telling you this to be cautious...most here won't have rods with those bolts in them, but if you do, please consider changing the bolts out to ARP 2000 or Custom Age 625 bolts if possible.  Obviously, these are isolated incidents, and obviously all L19 bolts won't fail, but you have to realize that these two incidents are not coincidental.   Please be careful.... 

[427LX]

So just sitting there under the stress of being tight they just break?  That's a first for me!  My Scat H rods use 7/16 cap screws and well after 11 years of running I hope those are okay.

[blykins]

So just sitting there under the stress of being tight they just break?  That's a first for me!  My Scat H rods use 7/16 cap screws and well after 11 years of running I hope those are okay.

Yes.  After my failure, I did a lot of internet research and found several sources that stated even your finger oils could affect them.  Not sure if that’s 100% true but I don’t have a good feeling about them.

[67xr7cat]

The ARP L19 rod bolts are susceptible to stress corrosion from hydrogen embrittlement.  You never handle them without wearing gloves and should keep them covered in fresh oil.

[e philpott]

This is similar to Jay’s SOHC snapping off adjusters just sitting on the stand

[67xr7cat]

The ARP L19 rod bolts are susceptible to stress corrosion from hydrogen embrittlement.  You never handle them without wearing gloves and should keep them covered in fresh oil.

Yes it is true. Years ago when I worked for a shop that build race engines we used them many times. Used proper handling and never had a failure.

[MeanGene]

I remember an article many years ago with David Reher where he spoke of bolts, and about an L88 rod with the "boron bolts", and said the head popped off one while sitting on the bench, as he watched. The gist was that the bolts were so hard that they couldn't deflect, and could not conform to a very slight out of square condition of the machined spot that supports the bolt head, and broke from the stress. Old-timers may remember the problem with the "white" NASCAR rod bolts for the LeMans rods- before we had the good aftermarket bolts. I learned about them in an article with Robert Yates, telling about them from his NASCAR engine building days, the white bolts went boom, black bolts were the replacement. Cantrell had given me a set of NASCAR bolts from their large Holman & Moody sale purchase in the late 70's, when I bought one of the NOS sets of C9 SCJ rods. Went and looked, and sure enough they were white- pulled them out and bought a new set of SPS bolts- which are still in the rods, in my Galaxie

[philminotti]

Hmm...I have a set of Oliver rods with L-19 bolts for my new build.  Food for thought.

[blykins]

Hmm...I have a set of Oliver rods with L-19 bolts for my new build.  Food for thought.

I'd consider swapping the bolts out. 

I've used many sets of Oliver rods with L19 bolts over the years, but before a couple of years ago, I had never seen any warnings about how you should handle them.  It wasn't on the spec sheet, but if you do some research, you're supposed to wear gloves, not use certain solvents on them, keep them in oil, etc.  For most scenarios, the ARP 2000 bolt will be just as strong, without all the finicky-ness, or you can switch to the ARP Custom Age bolts. 

[galaxiex]

From the ARP website....

"L19: This is a premium steel that is processed to deliver superior strength and fatigue properties. L19 is a very high strength material compared to 8740 and ARP2000 and is capable of delivering a clamp load at 260,000 psi. It is primarily used in short track and drag racing applications where inertia loads exceed the clamping capability of ARP2000. Like most high strength, quench and temper steels – L19 requires special care during manufacturing to avoid hydrogen embrittlement. This material is easily contaminated and subject to stress corrosion. It must be kept well-oiled and not exposed to moisture."

[jayb]

This is similar to Jay’s SOHC snapping off adjusters just sitting on the stand

I had exactly the same thought.  It's hard to believe that can happen until you see it first hand.  And those SOHC adjusters were certainly not L-19 material; suspicion at the time was a bad heat treat.

[Rory428]

Not sure if it was the same model of bolts, but several years ago, a local racer I knew had just finished assembling a new SB Chevy for his Nova drag car, and he was just about ready to turn off the lights and call it a night, when he heard a strange "ping" sound, followed by a clink. He looked around the shop didn`t find anything. The next morning when he rotated the engine on the engine stand, to install the motor mounts and oil filter adapter, he heard an odd rattle noise. He removed the oil pan, and found the heads of 2 of his rod capscrews had popped off. If he had put oil in the pan, or left a few minutes earlier, he would not have heard anything, and had no idea there was a problem until the engine blew up on the track. It makes you wonder if a rod bolt is so delicate in handling, if inside a race engine, with oil flying around was a good place for such hardware.

[67xr7cat]

Hmm...I have a set of Oliver rods with L-19 bolts for my new build.  Food for thought.

I'd consider swapping the bolts out. 

I've used many sets of Oliver rods with L19 bolts over the years, but before a couple of years ago, I had never seen any warnings about how you should handle them.  It wasn't on the spec sheet, but if you do some research, you're supposed to wear gloves, not use certain solvents on them, keep them in oil, etc.  For most scenarios, the ARP 2000 bolt will be just as strong, without all the finicky-ness, or you can switch to the ARP Custom Age bolts.

An ARP 2000 bolt is not as strong as a L19.  The Custom age 625+ is stronger than an L-19. Are so many applications that even an ARP 8740 bolt is fine that we forget to consider what is needed for a given application. Without knowing the weight of the rod/piston, stroke, and RPM and calculating the load the bolts will see nobody can say a lesser bolt will be ok.  If the rods are new and have been stored/handled properly I see no reason not to use them.  If you want to go with a different bolt I'd suggest call Oliver and let them recommend what bolt will work for your application.  Whenever possible before changing anything with rod bolts always best to speak to the rod manufacture as the design and material of the rod go hand in hand with the rod bolt.  Most connecting rod manufactures custom spec their rod bolts.

Just remember changing to a different bolt may require resizing the rod big end.  Really should check the big end with the bolts properly stretched regardless.

[FERoadster]

I've got 2 packages of ARE FE rod bolts, both packages are 155-6001 are these the L19's to be wary of?
What info would be on the package?
Richard >>> FERoadster

[galaxiex]

I've got 2 packages of ARE FE rod bolts, both packages are 155-6001 are these the L19's to be wary of?
What info would be on the package?
Richard >>> FERoadster

Those are 8740 Chromoly. not L19.