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gtixpress
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 Posted: Mon Aug 15, 2011 8:20 pm Post subject: |
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If this mounts to the outside of the pulley, how is it for clearance at the bottom of the fan/belt shroud? I seem to remember that there was very little room for anything extra down there.
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Joe P.
1969 VW Type 3 Squareback
2002 VW GTI 337 (Limited Edition)
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supersuk
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Joined: December 20, 2010
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Location: Honolulu, Hawaii
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| Posted: Mon Aug 15, 2011 8:49 pm Post subject: |
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There is approximately 3/4" past the outer most edge of the pulley to play with down there. I'm hoping that this will work as it will only extend about 1/2" past the mounting point of the trigger wheel. That is why I'm having a prototype made. Everything will be tested on my car.
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Mick
Mick-n-chips
Joined: April 12, 2003
Posts: 415
Location: RADelaide
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| Posted: Mon Aug 15, 2011 8:57 pm Post subject: |
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| supersuk wrote: |
Mick, I have thought about installing the trigger wheel behind the pulley but there is no easy way to mount the trigger wheel without having a jig made. Most DIYers will prolly mount it crooked.
As for the slots, they are needed to mount the trigger wheel to the pulley. Bolts will screw into the existing holes on the pulley after they are drilled and tapped. Every pulley is different and have counter weights pressed into the holes on the face of the pulley. The counter weights will vary from pulley to pulley. The final revision will have 8 slots to account for this.
As for the balance, this has been taken care of. The dwg that I showed was an initial version I drew up to gain interest. |
Cool 
I dont think the relationship between the two it is too critical. As long as the sensor is square to the wheel and at a suitable distance, it should work. There is no need to make a jig, simply mount it where you like and then set the position in the software.
The main advantage of mounting it as I have suggested is that you do not need to remove the sensor to change your fan belt.
Imagine...
Cold dark wet night, fanbelt breaks, battery dies, you are stranded. You then have to remove the sensor to change the fan belt (good job you had a spare), flag a passer by to give you a jump start, only to find out it will not start as the sensor did not go back correctly, or it got inadvertently damaged when you took it off.
You will invariably be replacing the fan belt when you least want to have to do it, the last thing you need is to also have to reprogram the EFI to get car started.
I know that in all likelihood you can remove and replace the sensor and the engine will still run, by why take the risk when you can simply move the sensor location?
I can understand that you are suggesting an easy way to repeatably mount the sensor in the same relative position, but this is not necessary. (unless everyone is using the same map).
Additionally if a DIY'er is installing an EFI system, I would generally think that they would possess the skills to be able to mount the sensor in roughly the right spot.
A simply angle bracket should do the job.
(Not trying to rain on your parade, just suggesting what I would do from my own experience.)
Regards
Mick.
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Mick
Mick-n-chips
Joined: April 12, 2003
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Location: RADelaide
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| Posted: Mon Aug 15, 2011 9:09 pm Post subject: |
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Just noticed what you wrote RE mounting it behind the pulley.
Sorry, what I'm suggesting is still to mount it to the front as you have stated, but simply to move the sensor.
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supersuk
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| Posted: Mon Aug 15, 2011 11:57 pm Post subject: |
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The problem is getting the trigger wheel square with the pulley. There currently is no existing mounting point. It has to be made and this is where the jig comes in. You can take your chances and try to just drill it out and see if the trigger wheel mounts square on the pulley.
I could not over come the difficulty in changing the fan with this design without making installation of the trigger wheel difficult. I would like to design a new pulley, but that will require more time and the prototype will be fairly expensive to make a mold for casting.
I've selected the front of the pulley location for ease of installation, least amount of modifications and initial setup that can be repeated easily. The trigger wheel and the sensor must be visible to set the air gap properly, which can be done through the bellow opening. Once the air gap is set, you will never have to do it again with the way I have designed my bracket. If the sensor has to be removed, then it's just one bolt. However, it is up to the user to design their own bracket as I am only supplying the trigger wheel.
I may just make this for myself if installation becomes difficult. It's not as simple as you may think...
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Mick
Mick-n-chips
Joined: April 12, 2003
Posts: 415
Location: RADelaide
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| Posted: Tue Aug 16, 2011 12:21 am Post subject: |
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I agree, lots to consider when doing something like this.
I ran into the fan belt issue with the EFI setup on my Type 4, unfortunately at the time I made the trigger wheel I fixed it to the front of the pulley and not to the rear as is the norm now. The result was that there was limited space to mount the sensor.
[img]http://www.vdubber.com/m/photos/get_image/original/09b00e561c66661e5d9010601a786bd7[/img]
With the Type 3 I'd considered machining the flywheel, and also modifying the existing fan, but much prefer your solution. This mostly as the crank, fan, etc are already at the engine balancers and provided the trigger wheel is balanced it should hopefully not be an issue to add it afterwards.
Irrespective of sensor mounting locations I'm still interested in the wheel although would prefer one without slots. Would it be possible to get one with holes?
Cheers
Mick.
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supersuk
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| Posted: Tue Aug 16, 2011 1:45 am Post subject: |
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One with holes could be provided no problem. You just tell me where you want the holes since I don't know where your balancing weights are in your pulley. Just so you know, there will be a very long lead time. Oh and the price will be higher since it will be like a prototype.
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Mick
Mick-n-chips
Joined: April 12, 2003
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Location: RADelaide
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| Posted: Tue Aug 16, 2011 2:49 am Post subject: |
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| supersuk wrote: |
| One with holes could be provided no problem. You just tell me where you want the holes since I don't know where your balancing weights are in your pulley. Just so you know, there will be a very long lead time. Oh and the price will be higher since it will be like a prototype. |
Nice attitude. 
Could have sworn you were asking for expressions of interest to get the manufacture cost down???
| supersuk wrote: |
| I'm going to have a shop make some for me, but if I bought just one the price is crazy! However, if a lot of people jump in with me it'll be a lot more reasonable. |
I'm happy to help you out, but would prefer one without slots. 
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Mick
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| Posted: Tue Aug 16, 2011 5:35 am Post subject: |
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OK,
Here's how I would do it...
Drill out every hole, then it does not matter where your weights are fitted, simply make sure that your fittings are equidistant (you can use 3, 4 or 6 fixings) if you get a clash with a weight, simply choose a different set of holes.
Teeth are square to give better definition to the VR signal, and the material is thinned down opposite the missing tooth to balance the wheel.
I've drafted this in Autocad, so it can be sent direct to laser cutters. If I get a chance I will get some quotes tomorrow in 5mm steel.
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supaninja
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Mick
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| Posted: Tue Aug 16, 2011 7:44 am Post subject: |
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Not sure if signal degradation would be a consideration with the thinner and larger diameter wheel (linear speed at the circumference is much faster due to the increased diameter). Would be interesting to view the signal and check.
The wheel on my Type 4 is 5mm but if 3mm works then the lighter the better.
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supersuk
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| Posted: Tue Aug 16, 2011 8:54 am Post subject: |
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Mick, yours would he higher since it would be a one off piece. All other ones will be slotted to help reduce the chance of misalignment of the holes on the pulley that need to be drilled and tapped. Yours = prototype, mines = bulk. Therefore yours = higher price. Get it? You're more then welcome to create your own, I'm just doing it to help out me and the others thy don't have a solution.
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supersuk
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| Posted: Tue Aug 16, 2011 9:04 am Post subject: |
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Mick, you just gave me a great idea with your design...I'd produce precision alignment pins that would simply slide into two holes to keep the wheel in place while other ones would be drilled and tapped. I think this will have to be revision number two. I'll get one of each to see which one is better. Thanks for the idea.
Edit: Damn, I just looked at my pulleys and there are some weights that are not pressed all the way in. I guess this would be I would need a larger hole on the trigger wheel and a stepped pin... eh, I'll see which direction I go once I see how much I can get the pins made.
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KevinR
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| Posted: Tue Aug 16, 2011 10:28 am Post subject: |
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I have an idea, but not sure how it would work.
What if, instead of teeth, one were to make a trigger wheel to mount to the fan with 36-1 holes, kinda like that guy did on his flywheel, but smaller. Then the sensor could be mounted directly on the tin with its own hole, and not be in the way for the timing hole.
Like I said, not sure how this would work, but may be worth a shot. Seems like easier machining.
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supersuk
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| Posted: Tue Aug 16, 2011 10:56 am Post subject: |
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There is no location on the fan to machine the holes. The fan has 30 holes already machined into it, which are used for press in balance weights. We need a total of 36 minus 1.
With Micks and My design, you can mount the sensor anywhere you please. Just have to make sure that it reads 90 degrees ahead of TDC. I didn't want to make any more holes in the shroud. I saw the timing hole and thought that would be a good place since once you set the trigger wheel and sensor, you will never need to time again. Well unless you take off the trigger wheel and have to remount everything. Plus, the sensor will be easy to remove and replace since it will be right there in front of you.
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supaninja
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supersuk
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| Posted: Tue Aug 16, 2011 10:59 am Post subject: |
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Mick, I was looking at your drawing and noticed that the teeth are pretty fat. Is your sensor head that big? Which one are you using? I have one made by Neihoff for a Ford and the head is about 3/16" big...
Its a good thing that I use Autodesk products for work. We have Civil3D 2011 and I think Land desktop 2009. These come in so handy sometimes. hahaha
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KevinR
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| Posted: Tue Aug 16, 2011 11:22 am Post subject: |
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Super, I was actually thinking of a steel ring that would attach to the fan wheel just like what you are designing, not the wheel itself.
That does beg the question, with Megasquirt could you use the existing 30 things on the fan?
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supersuk
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| Posted: Tue Aug 16, 2011 11:50 am Post subject: |
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Ahh, I get what you mean. In the end, it'll be like teeth. The VR sensor needs something ferrous to create a change in voltage (its like a small magnet). The holes will act like the space between the teeth.
You could use the holes in the fan, but then you would have to press in steel pegs into all of them except for 1. The balance of the fan would be off. You could have it balanced though, but might not be enough material remove. I've thought of many ways to do this and the 36-1 trigger wheel is prolly the easiest option. Its been done a gagillion times before with other 4 cyl vehicles so if the need for help arises, then the vast community of MS users can chime in to help troubleshoot.
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supersuk
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| Posted: Tue Aug 16, 2011 11:59 am Post subject: |
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Hey Nick, I remember reading somewhere that you used a ford VR sensor and you bought a connector for it somewhere? Do you happen to have a link for that? I want to see if the connector is the same as my VR sensor.
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