Interesting youtube video's...

[Wade]

Yeah I can’t find the video powerhouse posted up not long ago, talking about arp. Pretty much backs up what you’re saying. He’s got a ton of really good info on his channel as well.

[Wade]

https://youtube.com/shorts/f7I2kqD5vDg? ... y7cufGda9L

[immortality]

https://youtube.com/shorts/pf5Lz4gd8Fg? ... 4h1y1pAQmH

That's interesting and answers a question that has been in the back of my mind for a long time.

https://youtube.com/shorts/f7I2kqD5vDg? ... y7cufGda9L

That's very poor design but probably not ARP's fault but rather whom ever sent the specs to ARP for manufacture. With stuff like aftermarket bolts/studs I'd expect more thread engagement, not less.

Something I saw online, Steve Morris Engines, he makes his own custom engines/blocks and he puts his threads for the head bolts much further down into the block, it makes the whole thing stronger and takes the clamp load away from the deck surface which is something I've seen mentioned by another engine builder, if the threads in the block come right up to the deck surface, when you torque up (your preferred) fastener it will actually lift the deck surface ever so slightly and you should undercut the threads into the block to prevent this. Obviously you need longer fasteners to ensure proper thread engagement.

Another question, who here torque cycles their fasteners as I believe is recommended by the likes of ARP?

[vlad01]

I was referring more to the metallurgical issues that have cropped up a few times over the last decade or so. These are failures of the ARP 2000 rob bolts that showed clear defect such as fractures in the radius of the head to shank, looking like internal corrosion fractures, perhaps inclusions or hydrogen attack or preexisting stress cracks. Install errors lack the evidence of such in these cases.

Seen also issues with the head studs, where entire kits had majority of the studs shatter/splinter like glass well before torque was ever reached, then seemingly resolve with a new kit. Hard to prove with 100% certainty, but they have been widespread enough with what seems like a pretty clear spike in issues every so many years, just like the bad batch idea people refer to. ARP are good when they are good, then occasionally they are bad and all hell can break loose.

I saw an instance of this even bite the Holden formula guys the other year, rod bolts failed with no obvious cause. Bearings and journals were like new other than being mangled from the cap suddenly coming off. The heads of the bolt just popped off like nothing. The shank and thread were still in, nothing had come loose, just the heads abruptly came off during a race. iirc, the bolts were all in spec and records of their stretch were all good. Other owners of the FH group chimed in and a few said it was a known issue with the ARP 2000 bolts, those that had the same thing happen all recommend switching to Carr bolts. Reading all that from guys that are in the historic class that are well versed in having engines refreshed to exact specs regularly was good enough for me to know the issue was very likely real.

[immortality]

I've not seen what you are referring to so can't comment on that specifically however there is a issue with broken rod bolts that I've seen that is not brand specific. Top fuel teams never leave bolts/studs torqued up and manufacturers recommend not leaving bolts torqued up for extended periods if the rods aren't used.

It's been covered by the likes of Steve Morris and Clay Millican on Youtube.

Sadly, the bigger a company becomes the greater the chances of failures occur, people aren't infallible and the more people you employ the greater the probability. It's a reality of mass production and no one is immune unfortunately. Another big issue is quality control with imported steel from China, stuff comes in all the time that isn't to spec, various companies my missus works for get their own testing done regardless of the paper work that comes with the product and I don't think US manufacturing is immune from these problem either. The US is not what it used to be.

The joys of global economics where for most companies the price point is the main driving factor and the bean counters at the top of the food chain get the last say.

[vlad01]

I have read something like that on Carrilo's site regarding specific bolt series they make, where they are only good for a certain amount of cycles (use or install, I was not sure, but I assume they meant install cycles) , most of the common range has indefinite use and install cycles based on those alloys. I did not read anything like that on ARPs page from what I recall, some mention of certain alloys have hydrogen embrittlement sensitivity and must not be handled by bare hands iirc from years ago when I looked into their range. I can't imagine those doing well long term in an engine as there are always some acids and moisture present in the oil after even a single run, normal combustion products after all that lead to small traces of hydrogen being generated.


You are 100% right, bigger companies have more chance for stuff to slip through QC, and these alleged bad batches reported amongst communities are probably just that.

[brindo]

I’ll stick my hand up and say next to no automotive experience here.
But larger industrial stuff in some instances is reused 5 times. One engine in particular had multiple rod bolt failures and consequently multiple revisions of rod bolts. It was never reuse.
As for distortion, one of the larger connecting rods if measured just rattled up was 0.005” out of round. Torque it up – 180 ft/lb and 90 degrees - and it was true.

[Wade]

https://youtu.be/tMZhhLWuP84?si=eLA-2nGxsRcYkpSo

[Wade]

https://youtube.com/shorts/jC7FPcsd5M0? ... bq0yBIgnO2