Camless Modz - PeachParts Mercedes-Benz Forum

Rashakor · #1 05-02-2007, 11:39 AM

I was adjusting my valves yesterday on the 300SD while daydreaming of performance mods for our beloved OM616 and OM617's.

And remembered that Camless technolgies offer some interesting promises if manufacturers ever manage to pass the 5000-6000 rpm range...

Well Benz oel motors rarely if ever even come close to those rpm levels. What would you folks think of an aftermarket Camless modification for 616 and 617? Nothing electronic just a electromechanic timing wheel and the 8 or 10 solenoids under than valve cover.

Daydreaming

Jadavis · #2 05-02-2007, 12:01 PM

About 5 years ago I was talking to the head of the mechanical engineering department at the University of South Carolina. They were actively researching camless technology, expecially being able to vary the timing to match load conditions. They were concerned with gas engines. Maybe they need a nudge toward diesel engines.

Check out their website, maybe there is something there.

-Jim

slojoexxx · #3 05-02-2007, 12:17 PM

there was a truck that was camless that climbed Pike's Peak about 5 years ago... it was not fast, but it does run and made it all the way to the top.

bgkast · #4 05-02-2007, 04:00 PM

What's the advantage? Variable valve timing?

This would probably require a computer eh?

pawoSD · #5 05-02-2007, 04:04 PM

What happens if one of them fails? Valve hits piston?

Sounds like the risk of timing chain failure, except times 10!

Matt L · #6 05-02-2007, 04:19 PM

Quote:

Originally Posted by pawoSD

What happens if one of them fails? Valve hits piston?

Sounds like the risk of timing chain failure, except times 10!

Actually, it sounds like a whole lot less risk. It would be easy enough to design the valves to fail in the closed position only. As things are now, if you quit turning the timing chain, some valves are going to be open.

Jadavis · #7 05-02-2007, 04:21 PM

Yes, computer controlled timing.

As for the valves, depends on the engine design. I have a 1994 Mazda protege with the single overhead cam engine. If the belt brakes there is still enough clearance for the pistons to go to Top Dead Center without striking any of the valves. Very few engines are designed like this.

-Jim

Rashakor · #8 05-02-2007, 04:37 PM

All Camless systems are designed for closing the valves in case of failure so not a problem of valve failure.

Now, onto the question of what is the advantage. On countless tests with valves between 15-35% of the energy output of the engine is lost in trying to turn the cam against the valve springs. Camless systems allow therefore to get than energy where it belongs, in the crankshaft.
on a OM616 that would bring it to 90 hp and OM617.95X to 150hp.

Mileage is also improved. and that is without VVT hence no computer.

Hatterasguy · #9 05-02-2007, 10:12 PM

With a diesel you can only rev them so high, before the combustion explosion starts to chase the piston.

6k rpm when is that a lot? Most gas cars these days will go past that, some way past that. The Finn's run 603/6's up that high as well.

Heck the new batch of AMG V8's run to damn near 7k.

My understanding of the 617 is the way the head is designed they run out of meaningfull steam at 4k. I beleive the dyno charts start to show a sharp drop in torque at that point. So can this technoligy improve your power down low where it matters? Like 2k rpm?

Ara T. · #10 05-02-2007, 10:15 PM

New M3's 4.0 V8 revs up to 8200 RPM i think. So doesAudi's RS4. Of course they are high horsepower, relatively low displacement engines so they are built to be revved the hell up to get all that 400+ HP.

Hatterasguy · #11 05-02-2007, 10:18 PM

They also lighten the internals. Thats a lot of rotating mass, figure out what the pistons, crank, connecting rods, and all the bearings and bolts weigh. On high RPM engines they have exotic things like titanium connecting rods, light pistons, and usualy timing belts. I guess you can spin a belt faster then a chain.

deerefanatic · #12 05-02-2007, 10:28 PM

Quote:

Originally Posted by Hatterasguy

My understanding of the 617 is the way the head is designed they run out of meaningfull steam at 4k. I beleive the dyno charts start to show a sharp drop in torque at that point. So can this technoligy improve your power down low where it matters? Like 2k rpm?

yes & no......

Yes, due to being a crossflow head, the 617 has some problems breathing at high revs.....

No, the sharp drop in HP is not the motor... At 4600 - 4800 rpm's, the rev limiter begins to kick in.... It doesn't limit engine speed at these levels, but the effect really puts a dent in the torque/hp curve right there......

Brandon has been able to alleviate this on his car by circumventing the rev limiter.... but that has it's own risks!

#13 05-02-2007, 11:07 PM

Quote:

Originally Posted by Hatterasguy

My understanding of the 617 is the way the head is designed they run out of meaningfull steam at 4k. I beleive the dyno charts start to show a sharp drop in torque at that point. So can this technoligy improve your power down low where it matters? Like 2k rpm?

That's from the governor starting to reduce fuel to limit RPMs, not a limitation of the engine itself. Brandon has adjusted his injection pump's governor to let the engine revv 5700rpm without problems.

http://www.youtube.com/watch?v=jAC9htZfScQ

Rashakor · #14 05-03-2007, 10:20 AM

Well the big problem with camless since the 1930's was that there was not an hydraulic system fast enough to go beyond 6000rpm. But the 617 almost never go there so there are ideal candidate for camless.

I this would not have been an obstacle all IC cars nowadays would have been camless.

Hatties: the gain in hp and torque is immediate at all rpm levels because you remove the resistance to spin of the cam. Actually it is claimed that the major gain at at low rotational speed.

riethoven · #15 05-03-2007, 11:19 AM

Quote:

Originally Posted by Rashakor

I was adjusting my valves yesterday on the 300SD while daydreaming of performance mods for our beloved OM616 and OM617's.

And remembered that Camless technolgies offer some interesting promises if manufacturers ever manage to pass the 5000-6000 rpm range...

Well Benz oel motors rarely if ever even come close to those rpm levels. What would you folks think of an aftermarket Camless modification for 616 and 617? Nothing electronic just a electromechanic timing wheel and the 8 or 10 solenoids under than valve cover.

Daydreaming

The F1 engines that Honda was running years ago had servo actuated valves that were hooked to the computer that had a wireless interface to the pits. With the touch of a button the valve timing can be changed.

The precursor of camless used to extract high RPM out of a typical engine with a cam was the desmodromic system where the cam not only opens the valve, but also pulls it closed so there is never any chance of a floating valve contacting a piston crown. The first engines I know about that had this were the Mercedes Grand Prix cars from the 30's like the W125 and it was later carried over to postwar with the W196. Now Ducati uses it on their engines.