dohc idea

[njspder]

Originally posted by cero:
ahh thx
DO you think that it would be possible to have it run the way i was thinking?

it would be a difficult and time consuming process, but it could thearetically work out, but it would prolly require more welding and filling of the heads than you can imagine to get everything lined up right.
it woudl be easier to develop a single overhead cam conversion using teh stock valve locations.
this would save a ton of head aches since you do not have to reinvent all of teh water passages and intake and exhaust ports to get the results you want.
all that you would actually have to convert woudl be the top of the head to contain teh cam and bearings(along with seals obviously) and design a new valve cover.
then we get to the really hard part, converting the ret fo the crap in teh car to work with it.
you woudl have to move froma timing chain to a long belt with a tensioner and everything. the space this takes up will require you to relocate or redesign all of your accesary brackets, the accesaries themselves will likely remain unchanged.
also, since a belt is wider than a chain this will cause issue with teh crank snout and balancer assembly. one possible answert is to go mitsubishi style and actually use the bablancer itself as an accessary drive pulley. or early honda race engine style and use the balancer as the lower cam drive cog.
there are definately a bunch of possible answers to going ohc with the 3.8, all of them will require someone who is willing to commit a good deal of time if you expect it to work right and be a real "bolt on" possibilty.

later
tim

[strobhen]

There is some experimentation going on in car companies w/ valves that are opened magnetically.

That would work quite well as you could program them for any behavior you want at a certain rpm.

Only problem is they haven't worked out some glitches -- like the valves slam into the head when they close and are ridiculously noisy. (Probably not good on wear & tear either).

Now, what your suggesting has been done, but in a more crafty manner.

The cam in many ferraries act differently at low or high rpms.

What they do is have a slanted lobe on the cam.

normal cam lobes are like so:
...
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The cam I speak of is like so:
.:|
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Though not quite that steep.

The result is that at higher rpms, the cam shifts forward (or backward) and the higher lobe gives more lift at higher rpms.

Problem w/ your idea is that the car would have to be able to engage & disengage cams (couldn't have both running at the same time). Which would be quite a feat and very problematic when everything is going at 4000 rpm.