427 SOHC Ford Head at 9500 RPM Ottodyn Testing 107 Gram Lightweight Valve Ottodyn Test

[Sigurd82]

This is a strobe. Look at the oil bubbles move down by the spring. Also, that's some awesome valve float.

[bassbone1785]

fretwizard420 is right, it is filmed real time but at very specific timing so each frame 'looks' slow motion. I forget what that technique is called. 

[schatzisgirl1]

what is this in slow motion

[fretwizard420]

@schatzisgirl1 No, this is not in slow motion. It is simply put under a strobe light matched to the engines RPM to make it "appear" as though it is in slow motion.

[testy462]

@fretwizard420 It is most defiantly in slow motion. Realise that this thing is moving up and down 9500 times each SECOND. If it was in full motion, you would see nothing but a blur, timing light or no.

[johnnydanger57]

@testy462

You are pretty far off in this one.

First it is 9500 RPM (as in revolutions per minute) not per second.

Second, the cams move at half speed of the crank.

So actually its 9500 divided by 60 for 158 cycles per second, then half that, and you get 79 cycles of the rocker arm per second.

[testy462]

@johnnydanger57 Yeah, I meant minute. Regardless, its not moving at one time a second or looking thru a timing light. What your seeing is a slow motion video. There are about 100 of them on youtube.

Its pretty easy to tell this is a slow motion video by the shake of the valvesprings as they compress and decompress.