Adapting Variable Cam Timing to DOHC Engines - Brian

[guitarrc6]

hey i was wondering if anyone can adapt variable cam timing to any DOHC engine? I was thinking in regards to the early northstar v8s. I have seen v-tec on hondas, and how it gives them basically more horsepower at a certain rpm. I think the gains would be more if you have a bigger engine. does anyone know of a v-tec manfacturer that can adapt to a northstar, or does anyone know a simple (well relatively simple, v-tec in general is not simple) way of making a v-tec?? i have some mechanical ability and can get to any tool just short of a cnc machinene. I was thinking of a oblong cam bearing with some sort of servo that pushes the cam sideways to change where the cam follower hits the cam. what do you think? i also what it to self activate at a given rpm. any answers would be helpful.

thanks, brian

 

[Cliff_J]

Well the timing is only part of it, having a different lift and duration would be nice as well. For that, I thought the Porche system would be the easiest to mimic, you could get a regular 'hot' camshaft reground to have a conservative profile in the middle and then have grind the lifter to have a smaller contact patch and then a 'ring' around the lifter that followed the outside lobes that could be locked with a pin to force the lifter to follow the more aggresive lobe profile. They used to have a nice animated demo, but this is still a decent pic:
http://content3.us.porsche.com/prod/911/carrera_models.nsf/usaenglish/enginevariocam_plus

Cliff

 

[faust9]

Is it possible? Yes. If you really want, you could completely redesign the NS head so it uses some VVT configuration. Question is how much would the new head cost and would thos costs be worth the possible Hp gain?

Windosor blocks are 2V heads but there is a company (do a google search fro 4 valve 302 or the like) that does make 4V windsor heads. They are 2 to 3 times more expensive that a good set of 2v heads though. I bring this up because the Windsor block is a push rod engine so the design of a 4v head was more difficult yet it was still accomplished. A VVT NS engine would be easy to design in comparison IMO, but due to the VVT setup it would cost much, much more.