1994 Nissan Sentra SE-R going VEMS, then turbo.

[rob@vems.co.uk]

Well the trouble is getting the disk thin enough, the first disks I got done were laser cut in 0.4mm stainless.  The new ones are 0.2mm stainless that have been photo etched.

The ideal would be to use the S14 SR20DET CAS as I suspect it will be very similar to your existing distributor, I can measure up the CAS, but you'll need to either find a spare or extract your distributor to have a measure-up.

[BenFenner]

What exactly do you want me to measure? I'm not completely sure what you need.

Also, if I understand you correctly, the plan right now is to put the entire distributor assembly from a S14 SR20DET on my car, so I can use the disc we know will work? If I remember correctly, there is a difference between the FWD and RWD SR20s, and for some reason I remember their distributor locations being different. I will take a picture of the top of my engine an post it so we can make sure that will work. Maybe it's just in my head.

[rob@vems.co.uk]

The measurements will be of the CAS's outer dimensions.

Theres no plan ATM just option considerations...

[BenFenner]

So when I say the diameter of the disc is 54 mm, that is not enough? What specific measurements do you need?

[rob@vems.co.uk]

I guess that I am being too terse.

The disks I have wont work, you suggested going to coil on plug, so I am thinking about the possability of using an S14 CAS.
The key parts of the CAS are the drive gear, and the dimentions of the part where the CAS fits into the head.

Rob

[BenFenner]

I'm still working on figuring out that resistor.

I'm still open to exploring this S14 CAS, but while I'm milling that over, I'm curious about something else.

How much interest would make it worth it for you to develop a disc for my engine? What if I just paid for 10 discs? What would you need to make it worth your while? What if I could send you my disc, or one just like it?

Here's another thought. What if I just filled in 300+ holes with something like black nail polish, or covered them in some way that wouldn't put the wheel off-balance? Could this work? Have I gone off the deep end?

Just thinking.

[rob@vems.co.uk]

The minium order for these disks is 50, so if you think I can sell a few I'll invest...
It fits the Pulsar nicely so theres a potential out there

If we cant find a decent use for the resistor you could always use a different coil driven by one of VEMS's built-in igniters.

Rob

[BenFenner]

I guess this resistor problem could be solved by purchasing any normal (possibly MSD) ignition coil. I'll look into that, or forgo that entirely, and just do coil-on-plug.

About the CAS disc: I'm going to design my own disc using www.emachineshop.com so I can get a quote on it. I figure it it is less than $75, it would be worth it.

By the way, how much do you charge for one of your discs?

[rob@vems.co.uk]

I'd go for a cheap solution like the Bosch blue coil that all the VW boys seem to love, although MSD does look good under the hood

I charge 15GBP for a disk.

[BenFenner]

I designed my own disc this morning:



It is 0.2mm thick Stainless Steel Type 430C (Martensitic) using photochemical milling as the process. I was pretty foolish in thinking I could do it this way, as I'm sure Rob knows. The price per disc if I had one disc made would be $342 USD (171 GBP), yet the price per disc if I had 14 made would be $29.27 USD (14.60 GBP) which is about what Rob charges (minus shipping). If I had 50 made like Rob does, the price per disc goes down to $12.18 USD (6.10 GBP). I don't have that sort of money to spend on this sort of thing. =(
I wonder if there are 13 other people out there in a similar situation as me...
I could always try to start a group buy on the Sentra forums... But I doubt the interest would be high.

It looks like I'm back to square one.

I've given thoughts to purchasing a stock disc from Nissan and modifying it myself. I would join two or three holes together to make one larger hole, and I would blank out (somehow) a couple holes in between each enlarged hole. This could then be checked for balance on a high speed rotary tool (dremel). It might be worth it if I can get a disc cheaply. I'm going to call my parts guy and get a quote.

About the Bosch blue coil you mentioned. It seems like it would suit my needs just fine. I can purchase it for about $40 USD (20 GBP) shipped from www.jcwhitney.com and upon searching for an MSD ignition coil, I found they are only about $10 USD (5 GBP) more than the VW coil, so that is what I will buy, and we can consider this ignition resistor problem solved. I could also get the car running, and then use the stock coil pack with the resistor and see how that works, so we will know if it is even a real issue or not. You know, for future generations. =]

So, if the quote for the stock CAS disc comes back, and it isn't too expensive, you can assume I am ready to purchase VEMS and associated things.

[BenFenner]

Here's an update:

I got a quote of $361 USD (180 GBP) for a re-manufactured Nissan CAS disc, and I think to get that price I have to send in a core for exchange. I'm not sure if this is the price for the disc, or the entire distributor assembly, but either way this is not an option either. There is an auction on eBay for a used USDM SR20DE distributor (not sure what year, and I haven't gotten a response from the seller yet) that I might buy for cheap, giving me a disc to work with. If this doesn't work, I will just use my original disc, and modify it as I've described above. I am confident I'll find a decent method of filling in the unwanted holes, so I've decided this will be the method I take.

Also, I've decided to purchase a new coil (probably MSD) to avoid any problems with my current coil.

As far as I can tell, I've got a solution to the problems I was worried about. I'm ready to order my VEMS unit.

I will post again soon with the information on my specific VEMS order, and a list of the other things I got and why.

[BenFenner]

I bought the distributor that I hope has the correct CAS disc inside today from eBay.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=007&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=170142049892&rd=1

Hopefully it will be the correct part. We'll see.

[BenFenner]

Jon from the SE-R mailing list wrote this about the resistor; looking at pin-3 from inside the ECU:

---------

Ben,

I looked at the schematic of the ECU... pin 3 feeds through a resistor to a chip that appears to be a pulse detector, then through two flip-flops and into the uC. It looks like the pin on the uC changes state every time the ignition coil fires. I think you can safely ignore pin 3. It is probably used by the ECU for diagnostics.

Jon Davis

---------


So, I'm betting I won't need to worry about that at all. If I have to, I can always buy a different coil, but for now I'll assume the stock component will work just fine.

[BenFenner]

Rob mentioned AEM may make a disc for my distributor. I found a couple posts on their forum that confirm this. Here's one with pictures:

http://forum.aempower.com/forum/index.php/topic,20605.0.html

I've already ordered what I hope is another stock disc, but I will talk to AEM and see if I can get one of theirs, as it would be easier than modifying one. Here's hoping they can provide.

[rob@vems.co.uk]

Those disks are not any good for the front wheel drive (transverse engines) with the distributor cap - these are the RWD S-body and Skyline types which are exactly the same as the ones that I have.

I wonder if it would be better for you to send me a disk me to get them photo etched and take my chances with reselling them...

Rob