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Originally Posted by Joe Perez
(Post 244944)
My lathe has a 7" swing, but the chuck I have in it presently will only accommodate a maximum 3" stock, and that with the "outside" jaws installed and fully extended- from a practical standpoint it'll only hold about 2.5" with anything resembling decent clamping force and stability. A 5" chuck with plate is only $100, I should probably buy one...
I think a more practical approach however would be to have the pieces made by a small-run prototyping shop. I just did an ultra quick-n-dirty sample drawing with the emachineshop software, and it quoted me $39 ea in qty 10, $27 each in qty 25. So if a group buy came together, it would be pretty darn affordable. The trick would be to make sure we have a design that'll fit both the 1.6 (long & short) and the 1.8 pulleys. I'm thinking of a mushroom-shaped piece that replaces the flat washer-like thing that holds the pulley on, and is retained by the same four bolts. It would also probably be specific to a particular wheel, so we'd have to agree on that. If we could find something domestically like the one I linked to above (with the slots) that would be cool- or we could have those custom-made too... |
Originally Posted by patsmx5
(Post 244955)
Cough Cough.... I HAVE A LATHE.
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I also might have a cool job at a facility with an excellent machine shop so... there is that possibility as well.
Lets discuss hub design. Do we want to make a single piece hub or would it be ok to make standoffs out of like .75" round stock? The solid hub should have the center bored out of it for the sake of saving weight. It could have just about any pattern of holes drilled in it depending on what gear you wanted to use. The standoff design would utilize the stock 4 bolt pattern so the gears would have to work with that, i'm not sure how standoffs would like 7-8krpm though(for the high reving engines). 3" aluminum stock isn't too aweful expensive. Lets hear your design ideas. |
Assuming a wheel such as this:
http://trigger-wheels.com/store/cont...ightweight.jpg I was assuming a piece of 4" or so solid bar stock, lathed and drilled to make the following: http://img216.imageshack.us/img216/80/image1pv7.jpg It's not to scale, but the idea is that you remove the washer-thing with the four holes that holds the pulley on, and replace it with this using four longer bolts. On the wheel side, the bolt heads are recessed below the surface, and then the wheel bolts over top of them into the three threaded holes. In the center is a raised lip to center the wheel. Question- are the basic dimensions (diameter of center bolt, size and pattern of the four smaller bolts) the same on all Miatae? |
Hmm not sure where you want to put that now. Wish I had pictures now. Here is how my NB crank assembly is laid out from the rear of the engine forward.
Crank - Timing belt gear - Pully hub - Crank Bolt - Crank sensor wheel- Pully My pully hub is held onto the crank with the large 21mm crankbolt. My pully and crank sensor wheel are held on with four bolts that thread into the pully hub. Is the 1.6 laid out the same because it doesn't sound like it. |
1 Attachment(s)
Looks like several of us are having the same idea...
Jim |
I think the electromotive wheels aren't much different than $39 each anyway. if you can make both parts....
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Must MS have a 60-2 wheel? On a Link wire-in install I just used the OE 99 trigger wheel and sensor for spark trigger with the OE cam sensor for coil phase. The ecu just needs to "know" the location of spark triggers.
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no, the ms doesn't need it but there is accuracy to be had for the early cars without crank triggers. I'd venture a guess that a 4 tooth crank trigger is probably just as good as a 60-2 for most applications. does the later wheel/sensor bolt right up to the earlier cars?
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Originally Posted by m2cupcar
(Post 245011)
Must MS have a 60-2 wheel?
In theory, the more teeth you have, the better the resolution. Although I expect the difference between 36 and 60 is trivial compared to the difference between two and 36. Of course, as the number of teeth increases, the frequency of the sensor signal increases and becomes slightly more difficult to deal with from an electronic standpoint. |
IIRC the sensor bolts to a boss on the 99+ oil pumps- not the block. I think I have both the wheel and sensor - though I'd imagine been does too with his collection of engines.
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Yeah, the sensor bolts to the oil pump, and that's a good spot for it.
CJ, so far as I can recall, the 1.6 setup looks like this. I'm I bit hazy on the shield/spacer thing that guides the timing belt, but it's not important: http://img373.imageshack.us/img373/8...k16acadai5.gif The big bolt does not hold the main pulley on. It holds the timing belt gear on, then the main pulley goes over top of it and bolts to the timing belt gear. Four bolts and a big washer-like thing hold the pulley in place. My idea is to replace the washer with an aluminum hub, and use longer bolts in the same four positions to hold the hub and pulley to the timing belt gear. Then, the wheel bolts to the hub: http://img508.imageshack.us/img508/4...b16acadmb6.gif Here it is assembled. (There should be more space between the timing belt gear and the main pulley, just imagine a spacer in there. I can't remember exactly what it looks like) http://img371.imageshack.us/img371/8...sembledqx6.gif |
Btw, those of you with an MS1, a 60-2 or a 36-1 offers absolutely NOTHING compared to a stock CRANK-mounted 4-teeth wheel. Only the MS2 decodes every tooth. If you are using the stock CAS on the head, then there is some benefit in switching due belt stretch.
Jim |
Hmmmm......
(thinking hard) How thick is the '96+ crank plate? I'm wondering if it'll fit under the '90-'95 pulley without upsetting the alignment of the accessory belts? Or.... Getting a new plate of comparable thickness laser-cut would be relatively inexpensive- that would allow "normal" even tooth spacing and the elimination of the cam reference altogether. |
Originally Posted by Reverant
(Post 245029)
...there is some benefit in switching due belt stretch.
Seeing a tbelt on the dyno during a run makes you wonder how the CAS trigger works at all. I think most use the CAS because it's simple. I did. Just measured: .070" thick info I have/used on the NB crank wheel: http://i158.photobucket.com/albums/t.../NBtrigger.jpg |
the 96+ crank plate is just thin sheet metal.
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The "Big Boost Kit" for the Jackson Racing supercharger does a similar thing with the crank pulley, maybe you could get some ideas from it.
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With a 5 volt Hall effect crank sensor, using a crank trigger with an MSPNP is pretty much a matter of wiring up the sensor and changing the wheel decoder settings (one of the things the manual says not to touch on a typical install).
http://www.msextra.com/manuals/MS_Ex....htm#wheeldecr If you post how many teeth away the sensor is from the missing teeth, and if it's ahead of or behind them, I can post the settings that should get it working. |
There were many threads regarding the accuracy of the stock CAS vs the crank trigger wheel back in the old miatapower mailing list days. Not sure if there is an archive around. Shiv was an active participant back then. Jason Cuadra probably remembers them and could shed some light.
Frank |
I need a measurement
I think I've figured out how to do this on my lathe, but I need some data. Can somebody who has a spare 1.6 or early (pre-96) engine laying around take a few measurements for me?
First, with regard to the image below I need to know the outside diameter of the plate which I've highlighted in red. It's the one that goes on the "outside" (front) of the crank pulley, with the four bolts that basically hold the crank pulley on. I simply can't get close enough to mine with the calipers to get an accurate measurement. http://img29.picoodle.com/img/img29/...ym_3c819b0.gif Secondly, with just the bare pulley sitting face up on a table, I need to know the depth of the dish (with the washer thing removed) relative to the uppermost lip. In other words, if you lay a ruler across the front-most lip, how far is it to the flat surface where the washer-thing goes? http://img26.picoodle.com/img/img26/...hm_cd18485.gif For that matter, if anyone has a complete crank pulley assembly (ideally the whole enchilada including the timing belt gear) that they could loan me, I'd be hugely appreciative. |
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