@@ChiefCabioch Unless there's another tach that I'm missing, the one I see is labeled "camshaft RPM", not crankshaft RPM, which means it's reading accurately.
An engine has a lot of mechanical noise. There's quite a bit of instantaneous stress on the cams and it resonates into the block. The best analogy is to tap on the block with a screwdriver, but in 16 different places. Sure, it's not really a tapping effect, but the end result is still lots of noise.
Valve lift increases at 8500 you can see the valves lofting and also they start to have a controlled bounce off the seat. its steady state lift near 0.740 range. above 8500 crankshaft rpm the lifter loses contact with cam lobe as evidenced by the pointy shape of the lift trace its up around 0.770" lift. Anyone care to elaborate on what those bounces and lofts are doing?
The valves and valve springs are near resonance. The additional lift, and the bounce are the assembly trying to pull itself taught, but the combination of stored energy and timing won't let it do it. The system is more or less doing all it can. Sure, you can scrape a tiny bit more out of it, but it won't live that long.
Good reply, Guns Cars and Digits. The lofting/launching of the lifter off the cam lobe can be used to get around lobe lift regulations in some racing classes - but thats not happening here. The engineers want the whole thing to be in control, but the valvetrain is starting to lose control over 8500. The valve bouncing on its seat upon closure is problematic. That beats up the valve seats, increases valve lash (which causes extra impact to the valve event, further beating stuff up. It also hurts valve seat angles important to ideal flow characteristics. It also causes a loss of effective valve lift. All negatives. Those giant valves in the OHV 2 valve/cylinder arrangement are really heavy, and have a lot of inertia. That is the key advantage to an OHC setup (though OHC comes with it's own drawbacks, of course). Back when I did testing like this, we ran them up to 9500rpm. On running engines, we used in-cylinder pressure transducers to evaluate other characteristics. To create a statistically significant dataset, we needed to capture at least 250 cycles of data. At 9500rpm, it takes 1.6 seconds to for 250 cycles to occur. You wouldn't believe how tight the engineers would pucker up at the end of a power pull when the engine would hang at 9500rpm for 1.6 seconds. It felt like an eternity! And all the while you know your valvetrain is somewhat out of control!
No manifolds. No fuel. No pistons, no rods, no "suck squish bang blow". Only thing happening here is a big electric motor spinning a crankshaft that's driving a camshaft that's actuating lifters, pushrods, rockers and valves.
For a pushrod engine that revs beyond 5500-6k rpm, the valve train kinematics become extremely important. There are a lot of parts interacting with each other moving at different velocities and directions. This kind of testing is used to study and validate the cam profile, spring rates and pressures, rocker geometry, or pushrod length without risking a prototype or race engine during testing.
----Look up "Nascar engines 101" so you can free yourself from idiots like mighty car mods or engineering explained. 80 hp at 9000 rpm. Most of that is piston to bore friction. It's not that much in the grand scheme of things. 1000hp is going right out the exhaust. The actual mechanical parts are very efficient. 10hp for the lifters and rockers. 15hp for the water pump. Less than 2hp for blowby. 150hp going through the radiator. ---- An engine is 30% efficient, but just because of the compression ratio, (that means that pushrod, DOHC, 4-valve, 2-valve all have no effect whatsoever) the engine stands a best chance of 50%, thus 62% nominal efficiency, 92% mechanical efficiency.
@@ghostxop2101 that was 4500 camshaft rpm which is 9000 at the crank. Not that it matters because there are no pistons in that block. It's only the valvetrain being ran(at 9000 rpm) on a block modified specifically for Spintron testing. There's also a hole cut in the side of the block in order for the laser to do data acquisition. It's shown more in this video ua-cam.com/video/BbqomNdBGKs/v-deo.html
First, this isn't an "engine" but rather an engine "buck". There are no rods or pistons, thus far less friction than a real engine. However, if it were a real engine: Friction Power + Brake Power = Indicated Power
@101742202879277534713 Any pushrod engine has more moving parts. An overhead camshaft is in direct contact with the valves, not using rocker arms or pushrods, which is less efficient.
Rick Taylor just because an engine is dual overhead cam or single overhead cam doesn't necessarily mean it has less moving parts there's two cams depending on how many valves per cylinder there could be twice as many moving Parts just in the valves two timing chains overall it is more weight try telling GM that they can't make a pushrod engine anymore it's just as efficient as a dual overhead cam motor
Rick Taylor I see you’ve never worked on cars for a living, the lobes on a cam don’t directly contact the valves in a ohc engine, they have cam followers, and they have tappets as well, DOHC engines have more parts than a pushrod engine
@@lwoodt1 and it's not the entire engine. Just the valvetrain. All pistons have been removed and a big hole cut into the block for the laser to do data acquisition. You can see more about the actual Spintron machine here ua-cam.com/video/BbqomNdBGKs/v-deo.html
Since the camshaft turns at half the speed of the engine, When it shows 4500 on the rev counter for the engine, it is really turning 9000 rpm.
4500 Camshaft RPM is 9000 crank shaft speed, someone should take a closer look at the Tach
Uhhh, cam runs at half speed of the crank. You didn't know?
@@joeseda8102 He is correct, why the criticism
...are you talking about the tach that's labeled "Camshaft RPM"? What the problem is?
@@RyTrapp0 the problem is, you don't seem to know actual engine RPM is twice camshaft RPM.
@@ChiefCabioch Unless there's another tach that I'm missing, the one I see is labeled "camshaft RPM", not crankshaft RPM, which means it's reading accurately.
isnt it crazy how much that sounds like a running engine??!!
compression cycle is still there
+Jesse G. there is definitely a rotating assembly in this engine. look at the dampener, aint spinning by itself
No pistons or rods
Its a straight shaft
An engine has a lot of mechanical noise. There's quite a bit of instantaneous stress on the cams and it resonates into the block. The best analogy is to tap on the block with a screwdriver, but in 16 different places. Sure, it's not really a tapping effect, but the end result is still lots of noise.
Valve lift increases at 8500 you can see the valves lofting and also they start to have a controlled bounce off the seat. its steady state lift near 0.740 range. above 8500 crankshaft rpm the lifter loses contact with cam lobe as evidenced by the pointy shape of the lift trace its up around 0.770" lift. Anyone care to elaborate on what those bounces and lofts are doing?
Good eye...
The valves and valve springs are near resonance. The additional lift, and the bounce are the assembly trying to pull itself taught, but the combination of stored energy and timing won't let it do it. The system is more or less doing all it can. Sure, you can scrape a tiny bit more out of it, but it won't live that long.
Good reply, Guns Cars and Digits. The lofting/launching of the lifter off the cam lobe can be used to get around lobe lift regulations in some racing classes - but thats not happening here. The engineers want the whole thing to be in control, but the valvetrain is starting to lose control over 8500. The valve bouncing on its seat upon closure is problematic. That beats up the valve seats, increases valve lash (which causes extra impact to the valve event, further beating stuff up. It also hurts valve seat angles important to ideal flow characteristics. It also causes a loss of effective valve lift. All negatives. Those giant valves in the OHV 2 valve/cylinder arrangement are really heavy, and have a lot of inertia. That is the key advantage to an OHC setup (though OHC comes with it's own drawbacks, of course). Back when I did testing like this, we ran them up to 9500rpm. On running engines, we used in-cylinder pressure transducers to evaluate other characteristics. To create a statistically significant dataset, we needed to capture at least 250 cycles of data. At 9500rpm, it takes 1.6 seconds to for 250 cycles to occur. You wouldn't believe how tight the engineers would pucker up at the end of a power pull when the engine would hang at 9500rpm for 1.6 seconds. It felt like an eternity! And all the while you know your valvetrain is somewhat out of control!
Now i see why engines sound the way that they do lol
@Mason George yeah I understand that but thanks. Even though it's not firing, it still sounds like a running engine. That's The point I was making
Does it have the exhaust manifolds?
Edit: wow, that’s weird, I never heard of a test like this before
Oh hey
No manifolds. No fuel. No pistons, no rods, no "suck squish bang blow". Only thing happening here is a big electric motor spinning a crankshaft that's driving a camshaft that's actuating lifters, pushrods, rockers and valves.
Youre a moron.
1:02 valve bounce creeping up?
I was told all Nascar engine's are basically just a Chevy engine?
Who ever said that's clueless
@@Starky513 I think each company has to build there own engine but keep it within limit's they have
Youre a moron for repeating that.
IMHO not a perfect test, bc the valves are not working in the right flow and temperature enviroment.
None of which have much effect on valvetrain stabilty.
@@dancancade7101 but always some.
@@jareknowak8712 not when it comes to harmonics.
For a pushrod engine that revs beyond 5500-6k rpm, the valve train kinematics become extremely important. There are a lot of parts interacting with each other moving at different velocities and directions. This kind of testing is used to study and validate the cam profile, spring rates and pressures, rocker geometry, or pushrod length without risking a prototype or race engine during testing.
How much horsepower does it take to spin the engine? And to spin it to what appears to be 9000rpm?
From what i know, because of the engines power band being miles away in the 8 - 9k rpm, at such low rpm the engine can barely hold its own.
evenmadderdawg Depends on friction and oil pump resistance.
----Look up "Nascar engines 101" so you can free yourself from idiots like mighty car mods or engineering explained.
80 hp at 9000 rpm. Most of that is piston to bore friction. It's not that much in the grand scheme of things. 1000hp is going right out the exhaust. The actual mechanical parts are very efficient. 10hp for the lifters and rockers. 15hp for the water pump. Less than 2hp for blowby. 150hp going through the radiator.
---- An engine is 30% efficient, but just because of the compression ratio, (that means that pushrod, DOHC, 4-valve, 2-valve all have no effect whatsoever) the engine stands a best chance of 50%, thus 62% nominal efficiency, 92% mechanical efficiency.
@@ghostxop2101 that was 4500 camshaft rpm which is 9000 at the crank. Not that it matters because there are no pistons in that block. It's only the valvetrain being ran(at 9000 rpm) on a block modified specifically for Spintron testing. There's also a hole cut in the side of the block in order for the laser to do data acquisition.
It's shown more in this video ua-cam.com/video/BbqomNdBGKs/v-deo.html
First, this isn't an "engine" but rather an engine "buck". There are no rods or pistons, thus far less friction than a real engine. However, if it were a real engine: Friction Power + Brake Power = Indicated Power
toyota should run the push rod motor in the tundra get better gas mileage
Not really, it's a much less efficient way of opening valves. Overhead cams are the way to go.
for a truck pushrod makes the torque at lower rpm and more reliable with less moving parts
@101742202879277534713 Any pushrod engine has more moving parts. An overhead camshaft is in direct contact with the valves, not using rocker arms or pushrods, which is less efficient.
Rick Taylor just because an engine is dual overhead cam or single overhead cam doesn't necessarily mean it has less moving parts there's two cams depending on how many valves per cylinder there could be twice as many moving Parts just in the valves two timing chains overall it is more weight try telling GM that they can't make a pushrod engine anymore it's just as efficient as a dual overhead cam motor
Rick Taylor I see you’ve never worked on cars for a living, the lobes on a cam don’t directly contact the valves in a ohc engine, they have cam followers, and they have tappets as well, DOHC engines have more parts than a pushrod engine
Am I ok,,,?? I didn't see an exhaust header,,,,,,,please explain......
they are just spinning the valvetrain over to examine the harmonics etc
cool,,,,,my oversight,,,,,,,thanks for the reply..great engine R& D...
And no carb either.The engine is not running,its just rotating.
@@lwoodt1 and it's not the entire engine. Just the valvetrain. All pistons have been removed and a big hole cut into the block for the laser to do data acquisition. You can see more about the actual Spintron machine here ua-cam.com/video/BbqomNdBGKs/v-deo.html
Toyota don't make a pushrod V8 though
lol you are literally looking at it
@@teachyoselfclips I meant commercially
Awesomus Maximus no nascar engine from any team is based off of a production engine
@@teachyoselfclips It should be by saying that i mean configuration eg Toyota uses a DOHC V8 so they should use a DOHC nascar variant
@@awesomusmaximus3766 NASCAR has a decades old rule of no overhead cam engines. That's why Toyota had to build a pushrod engine from scratch.