"Camshaftless" Engines

[Flieger]

Originally Posted by kiwiokie

I think they use pneumatic opening for intake valves but regular camshaft for exhaust valves.

Nope. Cams to open, pneumatic springs to close.

Edit: I assumed that kiwiokie was replying to the comment about F1 engines.

[Flieger]

F1 Engines _ Valve technology

[legion]

Originally Posted by Laneco

Rotary?

angela

Yep.

[asphaltgambler]

Actually, this idea is not new. Smokey Yunick (I think) in the early 60's with a small block chevy tried electric solonoids with very mild springs on each valve actuated by a crude 'computer'. I believe they used a punch-card setup to control the 'on' time. The primary reason this was tested was the lack of good valve train hardware and materials so a really agressive cam lobe profile could be utilized. IE: Instant max lift / instant close.

Some of the more forward thinking people in racing engine development then started to hit a wall with cam lobe / lifter angles. There is a lag moment in time where the valve is not fully open or not fully closed resulting in loss of static compression, combustion pressure marginal airflow through the ports. With a solid base lifter there is only so much angle in relation to the lobe ramp that can be run W/O mechanical binding or very rapid wear.

Ideally you want to 'yank' the valve max opan at the last micro second then slam it closed. You can make a lot power all over the RPM range with little downside. But in reality you can only accelerate the valve train so much and then de-accelerate so much to achieve that before something breaks.

The 'camless' SBC idea was soon abandoned. They had a runing prototype on the dyno but technology, solonoids and controlers had not progressed far enough to be practical in a racing engine.

The next step was roller lifters. Some of you may be suprised that roller lifter technology had been developed by ........get this....................Harley-Davidson in the 1920's on their board track racing engines. Chet Herbert (of the cam company - Doug Herberts father) used to race Harley's at El Mirage and then Bonneville. He lost the use of his legs after a bad racing accident an turned to cars and engine building to continue his passion.

You can credit Harley-Davidson with the original design and use for the roller lifter in combustion engines but it was Chet Herbert who adapted them to automotive engines to achieve quicker valve openings and closings so much more lift and duration could be ground into the profile W/O sacrifcing so much low-end power. With a rollerized valvetrain you could now extract a lot more usable power per cubic inch.

Also there is huge parasitic HP loss in spinning all that ***** around. Next to piston rings and skirts draging up and down in the cylinder bore, a racing engine's valvetrain requires a lot of power to spin and actuate all that stuff @7500RPM.

It will very interesting to see where the technology goes concerning this

[5String43]

I think the deal with F1 engines is that they do indeed have cams to open the valves, but compressed air stored in an onboard tank is used to slam the valves closed.

[flipper35]

Originally Posted by Hugh R

The way I heard it no camshafts. Near the end of the video he talks about the left side of the head only having a cover area where the camshaft chains used to be.

Sorry, I meant on the F1 engine, not these.

My daughter has a camshaftless engine as well. Not a rotary either. Fouls plugs if she doesn't ride it hard though.

[kiwiokie]

I sit corrected

Originally Posted by Flieger

Nope. Cams to open, pneumatic springs to close.

Edit: I assumed that kiwiokie was replying to the comment about F1 engines.