Crank position sensor on an 8v mk2, options

Any of you got pictures of how you fitted a CPS to an 8v GTI, with Vee belts and PAS? I'd rather not chop the timing cover.

 

Going to do one very shortly, will post up pics...
Jon

 

I was thinking it'd be you, if anyone.
I decided, after changing a couple of internal wheel types, that one in a much easier accessed position is the way to go.

 

Yea I thought about that RJ, but I'm not going to drop the box and flywheel off, not this time anyway. My thinking is something I can change, on a hot engine, in 5 mins, if it failed at say a trackday or Ring trip.
Luckily a mate is a master machinist, like HotGolf, with his own workshop.
In my case I want it to fit without messing with my two v belt pulleys.

 

Last one I did I offset the crank pulley out by about 8mm and fitted the toothed wheel on the back side between the V belt pulley and the plastic cover.
Worked fine, thinking was I didn't want to disturb anything crank signal wise when replacing the fan belt.
Also kept the probe as tight as possible to the block (flying stones, rally car)
Downside was the other pulleys in the train needed the same offset
Jon

 

Mart can create something what you want.

 

The Irish Sea in the middle is a bit of a problem Ed! Lol.
I've a 165mm 36-1 wheel on order, going to use a Zetec VR sensor so wiring is idiot proof, the steel bracket for the PAS pump is perfectly placed to make a sensor mount.
And there's approx 7mm between the main- and pas- pulleys so the 5mm thick trigger wheel will fit easily.
And luckily my best friend has a cnc machine shop.

 

My setup is very similar to Tristan's description, 36-2 trigger wheel welded to PAS pulley and MK3 (ABF/ADY) hall sensor. I use the same setup in both my megasquirted cars - corro 9A and Mk1 golf 16v itb.

 

Nice, a picture is worth a thousand.
My setup avoided disturbing the probe to get the fanbelt off.
Rally car, so, probably more important
Looks good, sharing is good also, spread the info and joy
Jon

 

Excellent, looks exactly like what I've been planning in my head.
How did you secure the toothed wheel to the pulley?

 

it's welded, you can see the burn marks inside the pulley.

 

Oh I see now! I was fixated on attaching it to the inner pulley, I never thought of attaching it to the outer.... Hmm. Food for thought.

 

I got a generic 36-1 wheel from Triggerwheels.com. Nicely made in fairness.

Popped off the front crank pulley, cleaned up the front and skimmed it down a bit to leave a nice square shoulder.


Next the trigger wheel went into the lathe and had the same size diameter inner hole as the square shoulder on the front pulley.


Into the cnc mill then, and 6 holes at equal spacing drilled into the TW.



A nice snug fit, needs a gentle tap onto the front pulley, about 0.02 clearance.



And a bit of clearance still for the PAS pulley.



Once I've the sensor mounted, I'll clock the TW and drill and tap the front pulley.

 

nice job, bit of a monster wheel!
Jon

 

I know... Ideally I wanted a 150mm, as Omex said the 145mm could get have signal problems with being so close in diameter to the front pulley, but nobody seems to keep anything other than 145 or 165mm.
I'll drill a few more lightening holes, but it should be fine.

 

Lashed this up tonight. Originally it was turned on the ID to go on the back of a pulley, but this is a real quick and dirty method, if it works. There is only enough meat for M5 screws, so I'm going to double them up, so 6 bolts locktighted in. The pulley is cast, so the threads (5*0.8) are not going to be very strong. Drilled and tapped by eye, so real rough ready. May go countersunk, depending on what screwfix has in stock tomorrow. Spun it in the lathe and its within about 5 thou, will skim over when its all tightened and locked down. Doubt it matters if the gap varies a little.
Can back cut the pulley to provide a bit more clearance if signal is an issue, doubt it will be though.
Did this to open up the possibility of non engineering shop method(s), only using basic hand tools....
Jon
20 mins work

 

Lumenition recommend 1st tooth past gap trailing edge to be at 80 degrees BTDC. Used the bolts for nominal 12,3,6,9 o'clock. Divided the rest by eye. Its not critical as you verify the ECU timing with a strobe anyway and can tweek in the software tunables.
Jon

 

found this looking for something else. about 15 years ago I made two of these for the rally car. this is the spare I had forgotten about, may as well use it on the 8V...
Offsets the pulley out so toothed wheel goes inside, simple enough turning.

 

Do you run without a belt cover?