Viper's variable valve timing set up
 

I was reading an article about the new Viper in Hot Rod, and they described the engines VVT system. It uses what they are calling a Cam In Cam system, which allows the lobe separation angle to be altered, while lift and duration remain the same. I wonder if a system like this might make it to the aftermarket for other cam in block engines. If an OE manf. is using it, I would believe that it has a lot of testing behind it. It would def be cool to see a set up like this for traditional engines.8-)

I doubt it because gm / ford people are too cheap to spend $2000 or more for a cam timing system

vtec?

I read that article. The cam in cam looks to be a major innovation. I have a feeling it would not be feasible for any Gen1-Gen4 blocks due to the size or the gear and hydraulic motor on the front of it. I think the whole waterpump and the coolant passages would need to be changed. It looks cool though....not like a p.o.s. vtec Kasey. The exhaust lobes themselves move,not the cam position.

That's cool, but have they figured out a way to make the Viper's exhaust sound better than a pissed off cat in a coffee can yet?

the center line is fixed in all cams - its the distance between the lobes in degrees as checked from your over lap #s -- that concept of moving the exhaust cam around has another effect it actually changes the spot the exhaust valve timing starts and ends - and of coarse it cant increase it only change it - the location at the start or end sweet - change your oil often hahahahha does the viper have 2 cams per chance if so +++ now that could be interesting -- ???? --- jz

forgot to add changing lobe center directly influences the top or bottom of the power band - jz

Supposedly they worked on it a lot with the new car. I guess we'll just have to wait and see though....

- Justin

I read that little tidbit in Hot Rod. I guess they are monkeying with the intake lobes with some kind of hydraulic setup in order to impact LSA. Trying to get some top end out of those motors – I guess they don’t rev like an LSx.

Looks like something that will break easy & often. Color me skeptical.

Here's the daddy company that put it all together: http://www.mechadyne-int.com/

GM does have VVT system for its pushrod engines.
The 3.5 and 3.9 V6 OHV engines have VVT
The 6.2 V8 OHV engine also has VVT.
They use a cam phaser, a bit less complex then the Vipers, but gives the same effect. Its similar to what they use for OHC engines.

GM had a XV8 concept engine that used 2 cams in the block. GM also will bring out a 3 valve per cyl OHV engine, first for a cam in block or pushrod engine.