These heads incorporate Nissans version of Honda's VTEC, it's call VVL (Variable Valve Lift). Now before I go to far bothing explaining how it all works, I'll throw some links below that have already covered it.
As always, be careful what you read on the internet, nothing is as good as personal experience.
http://en.wikipedia.org/wiki/Nissan_SR_engine#SR16VE
http://en.wikipedia.org/wiki/Nissan_VVL_engine
All the SR20VE & VET motors are FWD east west configuration, so therefore there are certain challengers when converting them for use as a RWD option.
First one is the dizzy (16ve motors) and CAS on later models is placed on the back of the head when the orientation is changed to north south.
Second one is that the solenoids that switch the VVL technology on and off are also located on the back of the head.
3rd one is that one of the oil galleries on a RWD block do not line up with the VVL heads.
There are some other small differences, they will be discussed later.
If you have an SR16ve motor with the distributor, all is not lost. With a bit of machining and playing around you can actually reduce the size of the distributor smaller than a CAS you would buy from Nissan.
Below are some of those steps above explained, I may separate these into different topics later.
Details below (taken from sr20forum.com, full credit to the author for providing the information), most text is quoted and that of the original author, take note of their model numbers they mention against what wikipedia provides;
1.Making the Dizzy into a CAS
QUOTE(LanceSR20;1903077)
o.k. here are some pics and specs on how to make the one that i did. i dont have the time to make them for others, hell almost not even for myself sometimes, so if you have access to a lathe and a mill, or a machinist, then here you go.. im not goin to go into too much detail, just the basics, and whats needed. this will work for b14 or ve dizzys only.
here you have the unsuspecting b14 dizzy.. this is the same procedure for ve dizzy also.
remove the the screw and retainer from the dizzy, remove the disc, and the cas. set aside because you will need these later. becareful no to damage them. they are held in place with screws and silicone.
now remove the coil. it too is held in with screws and silicone. you can toss this, you wont need it anymore.
remove the shaft, bearing and seal from the housing. you will have to remove the gear from the end of the shaft, to press out the shaft so it can pass out the seal that is in the inside. good luck with this..i had to drill off the ends of the pin to remove the gear. this also has to be done so it be placed in the lathe. i still have not found a way to attacch the gear back on... maybe a roll pin...? use you imagination.
here you can see the remachined shaft next to the original. see the lenght difference.
now after everything has been removed from the housing. it now has to get machined. i did this in my lathe.
here you can see it compare to its original size.
after machining.. this is the size it needs to be.
now back to the shaft.. there are three dimensions that have to be made. first is the lenght.
then is the o.d.
now the slot for the disk. it doest matter how far down the shft you go with this. just aslong as you dont go into the bearing race. this was done on a mill. the placement of the slot on the shaft has to be in the same place it was at originally.
now the retainer has to be cut down.
now reassemble the cas.
there are a few side notes i have about this.
you will notcie that the cas has two locating pins next to the attachment holes. these need to be made in to the housing in the same place it was originally before the housing was cut down. this can be done on a drill press.
after the shaft has been cut, you will have to drill and tap the end of the shaft to the original or other screw can thread back into it so the disc retainer can be reused.
well hope this all helped in making you cas.
here you have the unsuspecting b14 dizzy.. this is the same procedure for ve dizzy also.
remove the the screw and retainer from the dizzy, remove the disc, and the cas. set aside because you will need these later. becareful no to damage them. they are held in place with screws and silicone.
now remove the coil. it too is held in with screws and silicone. you can toss this, you wont need it anymore.
remove the shaft, bearing and seal from the housing. you will have to remove the gear from the end of the shaft, to press out the shaft so it can pass out the seal that is in the inside. good luck with this..i had to drill off the ends of the pin to remove the gear. this also has to be done so it be placed in the lathe. i still have not found a way to attacch the gear back on... maybe a roll pin...? use you imagination.
here you can see the remachined shaft next to the original. see the lenght difference.
now after everything has been removed from the housing. it now has to get machined. i did this in my lathe.
here you can see it compare to its original size.
after machining.. this is the size it needs to be.
now back to the shaft.. there are three dimensions that have to be made. first is the lenght.
then is the o.d.
now the slot for the disk. it doest matter how far down the shft you go with this. just aslong as you dont go into the bearing race. this was done on a mill. the placement of the slot on the shaft has to be in the same place it was at originally.
now the retainer has to be cut down.
now reassemble the cas.
there are a few side notes i have about this.
you will notcie that the cas has two locating pins next to the attachment holes. these need to be made in to the housing in the same place it was originally before the housing was cut down. this can be done on a drill press.
after the shaft has been cut, you will have to drill and tap the end of the shaft to the original or other screw can thread back into it so the disc retainer can be reused.
well hope this all helped in making you cas.
Completed product
2. Relocating the VVL Solenoids
The way to jump this hurdle is to either CAD and machine your own relocation blocks, or purchase a kit from either of the 2 suppliers I'm aware of that offer this service.
Below are some pictures taken from an impressive build thread over on nissansilvia.com by the name of Tarrick, he can also supply a bunch of other useful stuff for this conversion
I will add more pictures as we do our own build, for now here are some taken from Tarrick's thread showing the relocation blocks
You can also purchase these from a place in the USA called Mazworx, they also as well supply a bunch of other stuff that helps with this conversion.
Relocation blocks -> http://www.mazworx.com/index.php?l=product_detail&p=3076
3. Blocking up of the unused oil gallery in the block
You can either drill and tap, then install a bung into this gallery, or you can welded it up and machine it off. Below are the pics of drilling and tapping (again borrowed from TAARK's build up on ns.com)
More information to come.
