A Better Look At The Most Critical Fasteners In An Engine

In this episode of PowerNation Extra, Engine Power hosts Mike and Pat talk in depth about the most critical fasteners in an engine, the rod bolt. The rod bolts see the most stress during engine operation, which makes them critical to know about.
The rod bolts act like a spring. In high performance builds, usually aftermarket parts are used because they are made with superior materials. The torque value and stretch both depend on the material it's made of. When it comes to measuring torque, don't rely solely on a torque wrench as they can vary. The best way to get an accurate reading is with a rod bolt stretch gauge.
Pat and Mike go over why it's important to have, and know how to properly use, a rod bolt stretch gauge. Also, what happens if your measurements aren't reading right, and how to fix it.
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[@ryancork5281]

Very descent video. With respect you should have talked about bolt lube and its effect on torque/stretch values.

[@blackericdenice]

Bolt lubing? People are always creating new problems that didn't exist before.

[@jsquared1013]

@@blackericdenice using lube on the bolts to get the correct torque value is part of the manufacturer's spec.

[@blackericdenice]

@@jsquared1013 No it's not. This problem was created by Companies trying to sell lube. I've never seen a shop manual say to lube bolts before torque.

[@blackericdenice]

@@jsquared1013 Funny how people with no videos are always trying to school someone. Upload a video showing people how to torque bolts.

[@xy-yt3xp]

@@blackericdenice Dude are you serious? Lubing the bolt makes a huge difference. The friction value change and there fore the stretch of the bolt relative to the torqe. Also you get more torsion forces in to the bolt. That said I think torque specs should be held very loosely and using a torque wrench is usually counterproductive to just torquing them by hand.

[@DiegoAlvarez-lf8us]

That last bit about manufacturers keeping torque specs low to keep them and us out of trouble makes so much sense

[@davidgruen7423]

Why do you have to loose the bolt when doing increments? I mean if it didn’t turn after the first increment, the second or third increment will eventually turn the bolt, so that step is completely useless.

[@jsquared1013]

You're looking at it wrong. It isn't about "whether it turns". Loosening it and tightening again with a new setting is more accurate/precise then trying to add torque to an already-tight bolt. The lube used and, especially, the difference between static and dynamic coefficients of friction play a part but I'm not sure I'll explain it correctly 😂. But basically it takes more torque to "unstick" the bolt (static coefficient of friction) and start it turning than it does to gradually increase the load on an already-turning bolt (dynamic coefficient). If you're only trying to increase the fastened torque spec by 5 ft-lbs, it might take more than that to "unseat" the bolt and get it to turn initially, at which point you've already overtorqued it. By loosening it, you're "unseating" the bolt at a much lower torque to get it to spin, and approaching the stretch/clamp needed at a more gradual rate.

[@peanutbutterisfu]

Loosening bolts is for accuracy and sometimes to make sure the part is centered

[@curlracing276]

I would bet money that big end of the rod is now out of round.

[@stock.cars.2ned]

Also why i requested my ARP studs on fa24 vb be torqued to 115ft lbs instead of 90 as recommended in instructions, per tuner recommendations. Got declined by many local shops, except one.

[@bluegizmo1983]

I would've thought head bolts/studs are under far more stress during running than rod bolts!

[@ViewThis.]

The most critical fastener on an engine is the Nut behind the Wheel

[@westhouse4641]

How do we do that measurement on the crank. You dont need to torque those bolts without it

[@Limeayy]

great info

[@pantherplatform]

Are those Ford 300 con rod bolts torque to yield?

[@killawattgarage]

Interesting

[@owaismehmood1871]

so cool man ot good🙂🙂🙂☺☺😉😉😉😀😀😀

[@hectorheath9742]

Very interesting.

[@markdstump]

OMG I'm just happy to finally hear someone say Pound*Feet for Torque, instead of the lazy but ubiquitous habit of using the unit of Energy (ft*lbs), which is so different that--I admit--there is little chance of confusing one for the other.

[@Mastermindyoung14]

ft*lbs is not a unit of energy.

[@markdstump]

@@Mastermindyoung14 Why would you say this; you obviously don't know what you are talking about. Have you ever taken Physics? Look in any Physics book, look here: en.wikipedia.org/wiki/Foot-pound_(energy)

[@blackericdenice]

I was rebuilding my 96 Tahoe 5.7 engine. I tried to reuse the stock head bolts. Yes I knew they were torque to yield. I also know that people tell me I can't do a lot of things I can do. After installing 7 bolts, one broke. Yes I had to remove the head to get the bolt out. I was going to buy ARP head bolts until I found out they cost $100 for the set. I went to Autozone and bought a set of Felpro for $36. Before you guys call me names. Think about it this way. My engine went 305,000 miles with torque to yield bolts. Felpro are reusable and I'm sure are stronger than the stock bolts. I could feel the stretching in the stock bolts. The Felpro had no stretch.

[@edbo10]

"I also know that people tell me I can't do a lot of things I can do." "I was going to buy ARP head bolts until I found out they cost $100 for the set." hmm, having to take out the entire head because a hundred bucks was too much for me, or fork out a hundred bucks for new, _decent_ head bolts...

[@lionelswart2396]

@@edbo10 I suppose everyone has a reason as to why they do things. I enjoy checking out different schools of thought. Always learning

[@edbo10]

@@lionelswart2396 if you are happy to reap the rewards of your choices then go right ahead. Personally though I prefer to avoid having to tear down an engine for a top end rebuild because i just wanted to save 100 bucks for something that would likely last me 20 or more years.

[@lionelswart2396]

@@edbo10 you're right I would rather do it the right way and spend the extra for piece of mind. I bought TTY bolts for a Hyundai 1.3 GL SOHC . One of the camshaft pillar cap bolts of which there are ten has overstretched close to shearing. The Hyundai agents say these bolts are supposed to be TTY bolts. The bolts have to be ordered from Korea. I bought ten high tensile bolts but am hesitant to use them in place of TTY

[@blackericdenice]

The engine was still on the stand. Removing a few bolts were worth saving $64. I bet you don't have a video of you checking the oil in your mother car.@@edbo10

[@JoshMustillo]

Hey guys is it safe to just remove factory conrod bolts, install and torque ARP bolts?

[@kevinshawntrolitzsch2100]

Nice advertisement, but so less information. Truth ist the manufacturer knows is shit. You, you're just here to get your product sold. Race engines are not build with the most expensive parts. Sometimes the middle is much much more recommended than the most cheapest or most expensive products. Budget builds show us the truth.

[@brent3569]

This is f ing rediculous. The correct way to torque bolts its the way specified by the manufacturers engineers in the spec. Unless you are racing Nascar or top fuel or something no one has that damn tool. Your overly technical mumbo jumbo is bs. You don't need maximum tension you need the tension the engineers designed the component for a holes

[@filibertobarrera3839]

It's kind of silly,so the torque is 90 and not 75.why bother with degrees.Its like head bolts,tighten to 65 then 90 degrees.Which on the torque wrench ends up being 80 pds.So why not just say torque heads to 65 then reset your torque to 80pds.

[@jsquared1013]

Because that's not how it works. The torque-then-degree procedure is for *torque-to-yield* bolts, the ARP bolts are NOT torque-to-yield. What they did here was measure the actual stretch for *that* particular rod/bolt combo.