924Board.org

[markmazour]

Has anyone here replaced their Hall Effect sender assy? I have been chasing down a no spark issue and after replacing the coil I conducted the Clarks garage test and have spark at the coil but none at the plugs.

I pulled the dist cap off, removed the dust cover and found that the Hall Effect sensor that should be embedded in the plastic under the 4 window rotor is broken and lying loose in the bottom of the dist. I found a new one online http://www.autohausaz.com/pn/1237011050 but am just curious if this can be replaced with ease.
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Mark
1982 Porsche 924 Indiana Red Metallic SOLD
2001 BMW 325i Silver SOLD
2011 BMW335is Space Gray 6mt

[Ozzie]

not easy. Easier to get another dissy.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[markmazour]

May I enquirer as to where the difficulty lies? Does the distributor have to be removed from the car?

I realize the term easy is very relative...for example I've replaced the timing belt and water pump, while time consuming I felt it was straight forward, easy 1 - 10 I'd say 7. Control arm bushings I'd say 5. So based on that where does this lie?
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Mark
1982 Porsche 924 Indiana Red Metallic SOLD
2001 BMW 325i Silver SOLD
2011 BMW335is Space Gray 6mt

[Ozzie]

The rotor is pressed onto the shaft, and has a minute keyway which goes on at the same time.
Centrifugal weights and springs have to be disconnected and reconnected and overall is very fiddly.
I pulled mine apart as an attempt to replace bearings and springs.
Bought another dissy after many attempts to reassemble.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[pcelenta]

are you talking about the plastic pick up that is screwed to the hall effect plate? If so, this is pretty straight forward...I would definately pull the distributor....set the engine to TDC with the rotor pointed correctly and remove the dizzy. The plastic pick up is cheap and available aftermarket for like $30 bucks....provided that the hall effect tabs and reluctor tabs are not bent and distorted this is an easy remove and replace. there are two screws that hold the hall effect plate to the distributor body...these are on the outside of the body...you remove the hall effect plate and flip it over and there are three screws to remove to replace the plastic. I would not mess with the springs inside the distributor...or the weights...just clean with a q-tip and regrease with distributor grease.

[pcelenta]

that part you mention is a universal upgrade kit...it should work but is pricey and probably more work than you need to do.

[924RACR]

I've done it a bunch of times. Not really that complicated IMO... just as pcelenta said.

I'd maybe rate it as a 4 in terms of complexity. Plugs and wires might be a 2 or 3. I'd also rate a brake pad swap around a 4, let's say... not sure what a 1 might be, maybe airing up your tires?

Not sure if 10 would be building a motor, or rebuilding a trans, or maybe rebuilding a turbo...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[pcelenta]

standard motor products has the reluctor and pick up. shop around on the price...there is a little variation. go to their site for an online catalog as I don't recall the exact part numbers.

[Ozzie]

The US dissy may be different
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[musicalannette]

if you have removed the dizzy, just watch the gasket, you probably will get a small oil leak if its 30 odd years old.
so i would replace that or make a new one while your at it.

just remember it is a bosche unit(orange colour cap).
there may well be other bosche distributors in a scrapyard near you fitted to an audi or voktswagon (or maybee even ford if you in europe not sure about ford in the us? but the pinto one looks remarkably similar), that might have a hall effect sensor the same or similar, the metal rotor (i dont mean the rotor arm) will change and as the other guys mentoned the springs/weights wil definately be different, but the sensor might be the same in quite a few bosche products, it depends if you can find another dizzy easily.

im not even sure if the octane rating and timing curves and compression are the same us/australia/uk? be carefull if you just buy a replacement dizzy.

but the timing is all done with the distributor, the box at the front right of the car is an current amplifier to switch the primary of the coil.

i cant say there is no timing adjustment happening in there as all electronics have slight changes to their system function over a frequency range, but it certainly isnt going to be very large or is intended to be the case.

there is this kind of thing: aswell
http://www.123ignition.nl/brand/VW.html
i think if i remember rightly there were a few guys locking the distributor and creating the curve in another australian add on box.

but the reality is how much is a replacement? im not sure how much a "new" old one is going to be? probably less than half the price delivered?

do not get me wrong, best of luck rebuilding/modifying it? if its what you want to do? or changing it to a software curve if you go that route? or replacing it with another dizzy from a 924 scrapper? just when you put it back, make a new gasket!!

good luck.
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....

[musicalannette]

this should be adaptable with a bit of modification, mechanically fitting it will be the tricky part, quickly looking at it you dont need the ignition amplifier box if you fit it? its all in the red plastic (i would actually guess its ceramic) box.

http://www.hot-spark.com/1-Bosch-Distributors.htm

just another idea to add to the LIST!
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....

[pcelenta]

Ozzie wrote..."The US dissy may be different"

basically just the weights and springs are different....euro is curved different. all else is the same....well at least that is the case with the turbo's.

you could just gut the dizzy and run either a crane or pertronix pick-up assembly with your CD box.

[musicalannette]

if you use that hot spark system - just make sure you primary side of the coil has 3 ohms resistance total - which is tricky as:

a - your multimeter isn't very good at measuring small and large resistances - you need to make a whetstone bridge to stand half a chance.

b - the coil is made up of resistance and an inductance, take your measurements after 5 seconds of adjustments to allow for back emf or chokeing of any current to subside.

so if your coil was 1 ohm on the primary you would need to add a 2ohm resistor to make the 3 ohm minimum.

just remember if you were to fit any ballast resistor in line with your present coil it must be capable of handling the power it drops across it.

which will be roughly - (15v X 15v)/3 = 75 watts.

this is complete overkill, but in the very unlikely event there is a fault, the resistor will not burn out, even if your coil primary shorts.
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....

[musicalannette]

tbh - that hot spark looks perfect for the early points cars - its just a case of working out which car is similar as the 924 isnt listed. it might take a modification.
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....

[markmazour]

pcelenta (ref your post Thu Feb 05, 2015 8:53am),
I am talking about this entire assembly. In the photo items 4 & 5 have broken away from item 2 and were lying in the bottom of the distributor.

When you say