I'm not an engineer, but it seems that these connecting rods were designed to resist compression end to end, rather than being pulled apart. The failure points (top ring, cap bolts) would not be so stressed in a compression test. Still an interesting video. Love the channel!
Yeah i saw bend rods because of long term use and to much power. But not because of a pull =/ Its not existent in a Piston Engine. I hope he can redo this one.
@@Fincher123The piston stops and starts one hundred times per second at 6,000 rpm. In the third stroke, during the intake, a tensile force acts because the crankshaft pulls on it.
Depending on the revs the engine is doing the tensile stresses of a rod can be significantly higher than the compressive forces. On a Diesel the compressive forces are definitely stronger under compression than under tension due to the low revs, high compression ratios and high reciprocating mass, while it's usually the opposite for most petrol engines.
They absolutley ARE The rod is naturally MUCH stronger in compression - its the weakest in tension when its trying to throw the piston off the rod at the end of the exhaust / beginning intake stroke at maximum RPM. This is why the diesel rod is so badly - it never has to rev very high, yet it experiences a much higher compression ratio and combustion pressures than the petrol - this is why diesel engines are cast iron. Quote "The 5.2-liter V10 that debuted in the 2009 Audi R8 has the highest mean piston speed for any production car (26.9 m/s) " " high speed diesel ~14-17 m/s for automobile engines"
@@tomast9034 I am not sure what you mean, do you mind explaining? I don't see how there are any gasses helping to offset the inertial force when the piston goes past TDC during the exhaust / intake stroke transition?
*EVERYONE IN THE COMMENTS SAYING IT NEEDS TO BE IN COMPRESSION* here are the facts: The rod is naturally MUCH stronger in compression - its the weakest in tension when its trying to throw the piston off the rod at the end of the exhaust / beginning intake stroke at maximum RPM. This is why the diesel rod does so badly - it never has to rev very high, yet it experiences a much higher compression ratio and combustion pressures than the petrol - this is why diesel engines are cast iron. Quote "The 5.2-liter V10 that debuted in the 2009 Audi R8 has the highest mean piston speed for any production car (26.9 m/s) " " high speed diesel ~14-17 m/s for automobile engines" CON RODS main failure is in TENSION, a compression failure usually occurs when hydraulic-ed or when the timing is advanced too much .
The piston rods were all fine and survived fully intact: it was the big end clamp bolts that all broke so really this test is completely inconclusive in virtually every regard!
How so? There's one little end failure and rod bolts failing is a thing, especially on modified or higher rpm engines! Often a bearing failure is the cause or even a money shift! strong bolts save block's!
This shows exaclt why the main thing is piston rods is a bolt upgrade. Even when you upgrade to aftermarket rods, the bolts in the main caps are critical. The rod is made to be placed under tremendous load during the power stroke, the bolts hoding the cap on the rod are loaded when the piston/rod assy hits the top of the stroke and there is a near immediate change in direction. The forces are gigantic on the bolts because the piston/rods assy has kinetic energy in one direction then it pulled in the opposite direction.
I agree I've been an engine mechanic building hard Rock engines 6 cylinders and V8 for about 55 years and definitely those rods could take a lot more being pushed down and pulled apart
As expected that diesel rod didn't do too well for stretch but the x trail did surprisingly well! Compression test next? Id bet on the 1500 or tdi rod not bending 1st!
Genial test comparativo, si lo enviamos al departamento de ingeniería de producto y de calidad en BMW, seguro que habría cambios en el departamento.... Jejeje
That was pretty cool. Should try a lateral force next time. See how strong they are pressing the I beam. That’s where I’ve seen alot of them fail. Right above the big end. And bolts breaking are the two most common failures I’ve seen.
Plus za pracę w teście, ale sam test nic nie wnosi, jedynie jakie są mocne materiały wykorzystywane jako zawiesia. Ale duży plus bo przygotowanie takiego testu to dużo pracy czasu i pieniędzy 👍👍👍👍
I have never seen a connecting rod in an automobile subjected to excessive stress. It is always subjected to compression👍. Perhaps you should test the whole thing under pressure.
Of the connecting rods that came out of engines that sucked up too much water and high water rain storms and those rods got shortened by quite a bit I have a slight s curve right in the middle
Many screws broke. Furthermore, cars back then had more metal, still didn't last longer. Look at the perfance today, a VW TDI makes 600,000 km, back then a Golf Diesel was finished with 150,000 max.
Meaning less test. Conrods are built to stand downforce to crank the shaft and rotate. The test shold be performed in the exakt way it performs in the motor until the conrod colapses due to high compression. This is more a bolt test but Intresting anyway!
The connecting rods of an internal combustion engine mainly support a compressive force during explosion. They certainly undergo a traction force when they reach the high point of their travel in the cylinder, but it is mainly inertia which manifests itself at that moment. This tensile test of the connecting rods is certainly interesting but, in my opinion, is not representative of what is really happening in the engine. Google translate from french : Les bielles d'un moteur à explosion supportent surtout une force de compression lors de l'explosion. Elles subissent certes une force de traction quand elles atteignent le point haut de leur course dans le cylindre, mais c'est surtout l'inertie qui se manifeste à ce moment là. Ce test de rupture à la traction des bielles est certes intéressant mais, à mon avis, nest pas représentatif de ce qui se passe réellement dans le moteur.
В основном лопаются болты, то есть чем крепче болт тем крепче шатун что-ли, тест не октуален надо испытывать не на разрыв а на сжатие , будет правильне
This test has no assertion of its own. You have to see the results in combination with piston weight, reving ability and combustion forces. On tow load you have accelleration forces because of pistons mass inertia. But this is in push direction, too. Additional in push direction comes compression and combustion gas forces. So the forces in pushing are higher than in pull direction. Then, because of these mass inertia forces, the pistons, piston bolt and also the connection rod is made as light as possible. So the connection rod is constructed near the needed strength to reduce the oscillating masses and resulting forces. So you can rev higher and get more power. I think, the diesel rod can withstand the highest forces because diesel engines have much higher compression and combustion forces. You only tested the wrong direction. I've to add, the old rod is so strong, cause it has much more material as needed. The engine isn't constructed so tight at it's limits. The construction methodes hadn't been so optimized like nowadays with FEM and so on. So they took better a bit more material, payed with lower reving ability. Nowadays products are constructed at the edge, to reach their purpose.
@@wtfbenny I cannot remember where I read it, but something within the engine was titanium, I'm almost positive it was connecting rods, which was why it could rev so high. (That's what I remember reading) I did find a listing on eBay for a used Honda NSX piston and connecting rod (titanium connecting rod specifically).. so Honda does make them.
interesting test, but the question may be - does it matter that one crank can withstand 60 and the other 140? In my opinion, calculations are needed to tell what strength each crank should have. There is no need to oversize, but there is a need to produce a full-value product. Regards
M10 12.9 bolt test , not really connecting rod test . Probably the engine gets killed as soon as the plastic deformation starts , and as we have seen all bolts can take a little stretch . Cool video tho' , just not really useful
To calm down the discussion two simple values for Jag 4.2l 6zyl engine: tension stress is 19.83kN at 6.000rpm and stress from gas pressure is 40.75kN. Add more rpm the tension goes up - add a charger the gas pressure goes up. Test show gives quite a good picture of the failures, but information about the dimensions/weights would be interesting!
