Interesting but Conrods are designed for strength in compression and not in tension. Unfortunately whilst interesting, all a bit pointless.

Connecting rods are not optimized for tensile load. That is why the screws mostly break in this test. In the engine, they are mainly compressed.

As a mechanical engineer I can say that this test shows only the tensile strength of the bolts not the connecting rods. Also compression strength is more important than tensile strength in the case of connecting rods because they are mostly exposed to compresion forces.

You tested the screws, not the rods. The rods are made to be compresed😂

I thought you would compress it, not stretch it. So, it’s mostly about the bolts then - isn’t it?

For engineering purpose, technically you should have changed the M5 connecting rod at 5:03, cause results aren't accurate when a tensil trial fails. You can't do a second trail on an object that is already plastically deformed, because it will be falsing results.

but you're just testing bolts xD

I am sorry but this does not test the strength of a Piston rod. All you test is the strength of a bolt material. You should try to compress them rather than stretch. The force from the engine act compressing the rod rather than stretching.

I'm 42 and to this day I still dream that one day I'll have an 850. This was oddly satisfying to watch :)

Слава советскому автопрому!

Those old soviet cars were built to last and also in some of the toughest conditions. Not built for speed or high performance just a workhorse to get from A to B. Amazing to see. Thank you for the video.

I’m really impressed by the strength of the small shackle 👍🏻🇬🇧

"do not try this at home" we all happened to have a hydraulic press lying around at home

The failure isn't the rods mostly themselves its the bolts

The amount of effort that this video takes 😮 This deserves a million likes

Car 1968 is named Moskvici. My grandpa’s first car 👍🏼

Yes! A very interesting video! Congratulations and keep them coming!

I could see the rods stretching before the breakage,impressive!

Props to you always finding interesting objects to test for us to see. Thank you my friend. Love it how you collect different rods from different cars from different era. Cheers

Interesting test , i saw conrods as young bloke in a workshop come out of a ford v8 that had been hydro locked on a few cylinders , the owner thought it would be a good idea to drill some holes in the top of his air cleaner lid below the shaker in his bonnet , it rained over night and filled some cylinders with water , and the next day he fired it up and made some of his con rods come out in an S shape , truly incredible to see .

Exactly what happens in an engine at high revs during valve overlap. On active compression the forces are smaller, unless there's non compressable fluid in the combustion chamber. During the combustion , the rod gets loaded up, like a coil spring, and that energy will also be released during valve overlap, contributing to the mechanical forces, already at play.

Interesting that it was the bolts that broke and the old one was strongest, Would be interesting to see some high performance ones like what they use for top fuel drag racing or something. 1968 must have been a good year :).

Love it when a classic car shows better engineering than modern design. Just think if combined what you would get for results. Great job again as always.

The crankshaft completes a revolution, removing the compression stress. As others stated, fun test for the strength of steel bolts.

Basically you're testing the tensile strength of the big end bolts.

I agree with comments about compression. Something else I'd like to mention is the weight. You could make a steel connecting rod with a huge cross-section that would win this (and a compression) test. But how does it affect the engine performance?

Thanks mate. Enjoyed every test. My uncle had an estate Moscvitch back in 1977... Couldn't beat our Alfa Romeo but it was reliable!!!

Great video! Old and gold! MEGA LIKE 🚗🚗⚙⚙👍👍😉😉

this is one of the most interesting videos youve posted. Congrats on 1 M subs!

This test is good. Because now you know if you find a broken conrod in your oil sump that it withstood a pressure of 5 000 KG to 15 000 KG, and the dent in the head must be equal to the opposite reaction.

I just knew the 1968 would be the strongest by looking at how thick it is and the rust

This has nothing to do with connecting rods strenght test

Test an old Volvo B20 rod. That would be fun to watch.

In Holland we have a saying. Alles was vroeger beter meaning everything was better in the old times 👍

My knees are sore from watching this good video 😊

Гордость берёт за качество совка.лайк!

This is a little like testing a helmet for resistance to bursting when the head inside of it expands. Still fun to watch though.

Nobody is going to talk about how a Soviet-made Moskvitch conrod from the 60's outperformed BMW's conrods strength during test.

The Moskwich was built according to the motto: "when we have lack of tanks, then we will take this car"

I love your videos, I was kinda lost with this one though. Still cool either way.

love how bombproof the ole '68 proved to be!!

Now that you got the press warmed up lets go to the test that matters! Compression. Mr. Craig Waddell described it perfect. Love presses.

Good test for the bolts and the threads.

You should do this test with a set of Maxspeedingrods H beam conrods against their stock counterparts. It would be really interesting to see if they are any good. Maybe you can also devise a compression strength test.

So the old saying.."They don't make them like they used to" still applies

After market rod bolts would make a big difference

This suspens sound track is over the top.

I was waiting for the suparu test, these are wild

Cool topic! Would be great to see a conrod from the Volvo B18/B20/B30 tested to learn if it really is so over-engineered as their rumor.

Haha never underestimate Russian engineering

Only 2 broke at the wrist pin end, this might have a variable on floating vs. pressed pin applications, where the rod end is heated the wrist pin is placed in liquid nitrogen or in a cooler with dry ice, and pushed through the piston and rod with an arbor press until it contacts the retaining ring, this spreads the contact surface further. Floating pins require lube to achieve this effect. I also noticed the big end fasteners gave up on the rods who’s small ends held fast. Were the torque specs and bolt stretch percentages within limits? I know that it’s very critical when building extreme condition high rpm high output rotating assemblies.

This proof old is gold❤❤❤.

That 1968 rod probably weighted twice as much too affecting the limited RPM's it could produce

This is not a test of connecting rods but connecting rod bolts. It remains only to hope that the author used new screws and tightened them properly - according to the documentation, otherwise this test does not make sense.

Also remember the M5 V10 has 10 cylinders and is tuned sometimes to super high horsepower, it was essentially roughly based off a detuned BMW V10 F1 engine of the era, also the M3 engines are tuned too, although this was more of a bolt strength test lol 😂

My 1968 car rods are still just fine. I also liked how the drum roll got faster and faster right before the rod broke.

Interesting tensile strength test/comparison. Compression strength of the rods is just as or more important, because of the power and compression strokes putting more downward, compression, stress on the connecting rods, and wrist and crank pins.

Jako dobrý, až na to, že ta ojnice je namáhaná přesně obráceně

that's why arp rod bolts are a great upgrade if you are doing a basic rebuild, for those that failed at the rod bolts.

wow this is great never thought of bolt failure, will study that more

Did you torque the bolts with a torque wrench? If not, the results could be different.

I found this interesting, but just saw this as a strength test for the bolts, not the actual conrods themselves. Hopefully youll be doing a crush test on them 👍

To add my bit to the mix. In the 70's I owned a Ford transit and fitted a worked over 250 2V Ford I6. With exhaust opened it would rev to 7600 before valve float. Now onto the guts of my outline. We had a very severe rain storm. Unknowlingly, rain water ingressed into the intake ( 650 Holley double pumper. ) Car wouldn't start on SM. I decided to let it roll down the hill and kick start it. Fine in theory BUT dropping the clutch in 2nd gear in a 3660 lb tranny van. An almighty bang and the engine kicked over and started on 5 -1/2 cylinders. Pulled it down and found the bore had split from the hydraulic malady. Both the Ford factory piston and rod were still intact. Rod was checked and straight. Same with the factory piston. A testimony to the strength of the early Falcon I6s. Sleeved the broken bore refitted the recip assy and ran it for a another couple of years giving the 200HP hitrous kit a constant workout. LOVE DEM FORD I6s and now the Barras.

The highest loads on connecting rods are in compression rather than in tension as it's the expanding, hot gasses pressing down which provide the greatest forces. There are, of course, significant tensile forces too, as on the induction stroke, the piston has to be accelerated downwards quickly (on the firing stroke the hot gasses push the piston down). Not to say that tensile strength isn't important, but they are optimised for the compressive forces and will be stronger in that direction. You can often see the difference on an older, stripped down engine with different wear patterns on the big end bearings.

Awesome. You put together a great test proving failure points. Can you comment on what engine the M5’s had, V10? If it was the V10 S85 engine I’m surprized that the powdered rod held together. I expected them to fail at the small end. Maybe the OEM’s figured out how to make great powdered metal rods. It would be awesome to test the rods with new ARP and competitor bolts. Thanks

Can you do a compression test of these con rods next.

After doing some math, it became obvious that the forces on a connecting rod are greatest in tension despite the logical notion than the compression forces are the higher forces. The rapid change in direction during the overlap stroke is where the greatest forces exist. In fact, compression and power actually reduce tension stress on the connecting rod. I replicated this test many years ago with the same results- the bolt is the weak point! However, as the tension increases the shape of the circle distorts and the bearing shell clearance is reduced to zero at the cap seam. Without lubrication, the bearing slips, covers the oil passage and instantly fails. Sometimes the near instant increase in friction at high RPM results in the next weak point, the small end to break the rod at the point just below the small end bearing. Key thing here is use high quality rod bolts, torqued precisely, quality oil, and know the RPM limit because that is the failure point, not the combustion forces. Rev your engine till it spins a bearing, rebuild it and lower the red line by 500? Rev limiter?

Hi, amazing test, any compression forces test ? Thank you.

💪🔩💥 Interesting clash of forces! Connecting rods and tensile load don't seem to be the best companions. 🤔 It's intriguing how they hold up under compression in engines, yet fail under different conditions. I wonder if there's a way to enhance their tensile strength for better performance. 🏎 Let's dive deeper into the world of connecting rods and their design limitations. 💡

High RPM requires stronger rods, too. Usually, a bearing will go long before a rod. Turning a normally aspirated car by turbo conversion will have parts fail in the bottom end. Use forged pistons and rods and uprated bearings. Bit off topic there but im a petrol hesd.

Pas besoin d’être Ingénieur pour comprendre que se test ne démontre pas la fiabilité des moteurs. Mais j’avoue l’avoir regardé avec plaisir alors je met un like 😊

Don’t care what all the engineers have to say, this only reminds me of my Lada Niva’s toughness ! Too many salty winter Canadian roads (1982-97) but even after rust took the plates it did a few more years hauling at the cottage. Dirt cheap bare bones tanks, from Russia with love.

Stal w naprężeniu jest ponad 2x mocniejsza niż w kompresji. Czego ten test miał dowodzić?

Interesting concept of how to try to demonstrate the effects of tension stress in action! Would be awesome if someone could somehow demonstrate the strength of the rods themselves rather than the bolts. Perhaps by welding the bottom end to a extra strong steel bar? Either way, thanks for your efforts to demonstrate a theoretical problem in a practical way regardless of the practical value of the demonstration as such.

Would liked to have seen the comparison between stock rods & forged rods.

In automotive racing engines, the metallurgy with the connecting rods have improved immensely from the 1950s to the present; especially so in the US NASCAR race series; where the engines used, as its base, were the high performance engines from the US automotive manufacturers [General Motors, Ford, & Chrysler]. The term "blown engine" was used to describe engine failures among the participants in the NASCAR races in the 1950s through the '70s; and was especially common in the 1950s and '60s. Many times those "blown engines" were due to connecting rod failures. But in the 21st century, the rate of blown engines, in NASCAR races, are seldom, and I can't recall the last time there was an engine failure due to a broken connecting rod in the past 20+ years of NASCAR races.

Next you to push on them,

Would have been interesting to also note the weight of each rod

There are other actions going on inside the engine. My father owned a garage for over 60 years and I've seen a lot of broken connecting rods, although I've never seen the rod bolts break and I don't recall ever seeing one break at the wrist pin end. They usually break in the beam, sometimes in the middle, sometimes near the big end. I've also seen some that were just bent and not broken.

Seen quite a number of conrod failures. All have been due to tension, not compression. Applies to both plain bearing conrods with bolts and roller bearing boltless ones. So I think this tests are valid. Last one I've seen this winter had big end and small end intact and conrod in three pieces. Fractures was definitely due to tension. I thought this is common knowledge as it was known in the 1940ies possibly earlier.

All this really shows is whether the bolts holding them together are stronger or not

Sorry, but you not testing strenght of conrods, but strenght of screws. Conrods in engine must withstand the pressure, not tension. In the correct direction of stress, the screws are not stressed and the part can withstand much more force. Great video, out of reality.

Nice! Please, try a compression test also.

LOL for that old russian moskvich just destroying them all🤣🤣 also would be fun to test rods from lada niva, many times i have seen one suck in water when offroading, and that usually bends or breaks a rod, but those just don´t tend to break that easily...

Silly test, your testing the strength of the bolts.

That 530 stocker looked friggin tuff but, piss weak :o

I also believe a tensile test is secondary to compression test. And also I believe this test is stressing the bolts first.

Pero de ésa manera estás estresando a los tornillos, no a las bielas . . .

Comments regarding compressive strength being what matters- do you guys work on things? Do you find connecting rods crushed from compressive forces? I think maybe "no" on both counts. I have seen bolts break in tension, and rods snapped due to cantilevered forces, after oil starvation and seizing to a still a spinning crankshaft. I have seen rods bent due to compressive forces from hydraulic locking...water ingestion. One of those ran tens of thousands of miles very bent, and was found when disassembled for unrelated reasons. Never saw a rod fail in compression. Maybe top fuel guys do? Even rods from engines I knew were suffering from preignition showed no distress, and this is pretty abusive. Probably more so to the bearings. I think you may be imagining some impossibly large explosion occurring...not so. While forceful, it should be a somewhat smooth event. BMEP, or average cylinder pressure during the power stroke, isn't that awful high. Over 200 PSI BMEP is pretty good. Also, the bolts are irrelevant when the rod is in compression, but certainly matter @ TDC. "You're just testing the bolts.." is a strange comment. They are part of the rod, and are a failure point. I read in these comments, and elsewhere, that the rod's toughest moment is the piston deceleration between the exhaust and intake stroke. Similar forces probably exist at BDC...but, again, I see rods/bolts fail in tension, not compression. A last observation- this guy is breaking stuff in his press for our amusement, it's not an engineering class. Just enjoy it. I Crush stuff in my 75 ton press for fun sometimes, my kid loves it. Me, too.

ما رأيت أجمل من هذا❤ ارجو لك الدوام والتوفيق🎉

Its worth mentioning that when rods fail it normally on the exhaust stroke, when its under tension, not compression stroke , this assuming the big end is not seizing and bending the rod axillary, so this test does have a bit of relevance.

ridiculous test, rods have greatest strength on compression. Your testing the tensile strength of the fasteners. But interesting video regardless.

Sorry, but the conrods are made to resist compression and not forces of pulling it long.... So the conclusion is: wrong solicitation!

When you have someone who has been trained in equipment but not in physics

Decent test. Most rods fail on the exhaust stroke as they try to stop the piston and make it change direction - in a sound motor. In a wore out engine, it may be for any reason like spun main locking up the bottom end, etc ...

Soviet engineering comrade ☭💪

The 1970s trabant broke when it saw that machine!

I'd like to see if the ARP rod bolts I bought really are good for 120k/lb tensile strength. Especially in a forged I or H beam rod.

Great video❤❤❤

Not a very valid test at all, but still very cool to see. Would also like to see them in compression test if there is a large enough press.