wikkaco0

So I was searching Google for anything interested about D series motors and this came up.

http://rides.webshots.com/album/1458...WGtO?start=108

http://rides.webshots.com/album/1458...WGtO?start=120

Looks to me like a Civic from south east Asia. The pictures show the process for replacing the D17A2 rocker assembly, camholder and cam with the ones from the D16Z6. This would permit the use of D16Z6 camshafts and the more traditional single cam VTEC system (rather than the 12 to 16 valve switch found in the D17A2). The convertion from what I can tell looks fairly straight forward and bolt on other than a cam pulley that needs to be notched.


Left: A2 cam. Middle: Z6 cam. Right: Modified A2 cam pulley with notch for Z6 cam.


A2 head with Z6 rockers, cam holder and cam. (Look closely at the exhaust manifold studs, black plastic intake manifold and cam position triggers on in the cam pulley. It is a D17A2 head.)


View of the Z6 rocker assembly. No roller rockers unfortunately.


Left: A2 roller rocker assembly. A familiar sight. Right: Modified A2 cam pulley with notch for Z6 cam.


Modified A2 cam pulley with notch for Z6 cam. Looks like this one done with a machined plate.

What do you guys think of this? Interesting eh.

skipbarber

iTrader: (34)

interesting. very crafty. Id be interested to see what types of gains this would produce with a performance Z6 cam over a standard A2 head with a crower cam. Considering the shortcomings of still being a SOHC, I can't imagine this would produce significantly better results. Still, this would be a pretty neat alternative.

bakertime

iTrader: (7)

Wow very cool...

Wouldn't you also have to do some pretty serious checking of clearances for the cam caps for them to just be installed? I know that with the B-series (and I would imagine this applies universally), you cannot even buy them separately from Honda because they are not matched to the head. I'm sure a good machine shop can do this work, but it's a pretty important thing to consider!

Either way though, that's pretty neat. Question for you guys...do the regular single cam VTEC motors use 8 valves normally, before switching to 16? If that's the case, wouldn't you lose a lot of low end power by closing an extra valve per cylinder before VTEC on the D17's since they use 12 normally? The engagement would be a lot more pronounced than it is now, but i don't know that' that's necessarily a good thing as far as a smooth power transition. I guess if you have a high hp engine, the bottom end loss wouldn't be as noticeable. I guess the major advantage is just the use of the Z6 cams though.

Boilermaker1

iTrader: (16)

In prinicple I dont see a major issue... but I'd definitely be making sure the oil galleys line up before trying it out.
Honestly, I'd say just buy a Z6 head, they couldnt possibly be more than a couple bucks and do the comparo yourself. Before you start the engine (if you go through with it), definitely take the cam caps and the D17 head to a machine shop and have the journals line honed so you dont have any steps from the caps to the head journals.

Honestly though.... The car runs on 16 valves almost all the time (from ~2400 on up), so I'm not sure I see this doing anything. Whats the lift and duration on the Z6 VTEC lobe compared to the A2?

wikkaco0

The rocker ratio on the Z6 is different than the A2. Comparing lift and duration directly doesn't really work out. For me at least.

The specs are availible on Crowers website. I was thinking of this as a way to install different aftermarket Z6 cams.

http://www.crower.com/cat/import/honda/cams/d16z.shtml

http://www.crower.com/cat/import/honda/cams/d17a2.shtml

bakertime

iTrader: (7)

Good to know about when the car runs with 16 valves Boiler...thanks for clarifying that. +1 for you...

Getting a donor head is definitely the way to go! A Z6 head isn't too expensive...If there's an oil galley issue, I wonder if the Y8 is any different. I'm really not too familiar with the D's, but was always intrigued by the D17's when I had my civic. It just seems like there are going to be things that people figure out that will make these engines more and more efficient at making power. Looking at the B-Series motors that have been around forever, there is plenty of time for these motors to come into their prime as the aftermarket support, and stuff like this come into play (assuming there is a worthwhile advantage to a retrofit like this)