Delco Alternator Conversion
02-12-2006, 01:13 PM
#121
Originally Posted by SharkSkin
Houston, we have another problem... 
I guess that the regulator is a bit finicky about the lamp wire, and it seems I have no resistor at all in my exciter circuit. I had stated that I should have a 68Ω resitor in my system and they went on that assumption. I looked up inside the pod with a borescope and couldn't find a resistor. PET and 928 Specialists both mention a resistor that has to be added when replacing the alternator. I ran a parallel circuit, from the jump post through a 500Ω and a 68Ω resistor to the lamp wire, and it seemed to work fine. So, what I'm going to do is find out if I can get a regulator that will work without the extra resistor. Ideally, I hope they have one that can work with or without so it's easier for us, but I won't be able to check on that till Monday. If not, I'll go ahead and pull the pod and install the 68Ω resistor. BTW, I calculate that will pull about 3.3W so I picked up a 5W.
Bit by bit, I'm chiseling away at my ignorance on alternator theory and year-to-year shark variations...
I guess that the regulator is a bit finicky about the lamp wire, and it seems I have no resistor at all in my exciter circuit. I had stated that I should have a 68Ω resitor in my system and they went on that assumption. I looked up inside the pod with a borescope and couldn't find a resistor. PET and 928 Specialists both mention a resistor that has to be added when replacing the alternator. I ran a parallel circuit, from the jump post through a 500Ω and a 68Ω resistor to the lamp wire, and it seemed to work fine. So, what I'm going to do is find out if I can get a regulator that will work without the extra resistor. Ideally, I hope they have one that can work with or without so it's easier for us, but I won't be able to check on that till Monday. If not, I'll go ahead and pull the pod and install the 68Ω resistor. BTW, I calculate that will pull about 3.3W so I picked up a 5W.
Bit by bit, I'm chiseling away at my ignorance on alternator theory and year-to-year shark variations...
I'm still in full support here. 4lbs is a good weight savings, and the extra amperage is something I will not be able to do without.
02-12-2006, 02:24 PM
#124
Rennlist Member
Thanks for the support guys! Malibu, not sure what year your shark is, but AFAIK it's only the '81 and earlier cars that may or may not have an exciter resistor, depending on what's been done to the car in 24-28 years. If you had the resistor in place(for whatever reason) you were one step ahead of where I'm at.
If you had the resistor in place(for whatever reason) you were one step ahead of where I'm at.
02-12-2006, 09:12 PM
#126
Official Rennlist
Borat Impersonator
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Borat Impersonator
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Mine's an 80 and I have the resistor. I recently went through the pod and replaced the white backing plate and the circuit board.
02-13-2006, 01:37 AM
#127
Rennlist Member
Yeah Malibu, you had the most common setup anyway. From what I gather, with a resistor you'd be fine with almost any standard GM regulator.
Borys, sounds like yours has been retrofitted. Did it look like it had been added, or were you paying much attention?
Anyway, I'm kind of glad mine hasn't been updated, or I would have never run into this pitfall, I would have posted in my writeup "works great in a 78 shark" and someone else would have run into the situation. Fortunately PAECO has lots of different regulators available for different conversions. It sucks that this is taking so long though!
Borys, sounds like yours has been retrofitted. Did it look like it had been added, or were you paying much attention?
Anyway, I'm kind of glad mine hasn't been updated, or I would have never run into this pitfall, I would have posted in my writeup "works great in a 78 shark" and someone else would have run into the situation. Fortunately PAECO has lots of different regulators available for different conversions. It sucks that this is taking so long though!
02-13-2006, 09:27 AM
#130
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Borat Impersonator
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Borat Impersonator
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I do not know when it was federalized, but now that I think about it, the my oil pressure/voltage guage is a US guage because the warning lights are in english. The fuel and temp guage is in german. So upon federalization they could have used a guage from a newer model. So I dont need the resistor? Another thing is I thought that early models used a Paris-Rhone alternator. When I got my shark, it had a Bosch unit that looked original.
02-13-2006, 10:51 AM
#131
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Another thing is I thought that early models used a Paris-Rhone alternator.
Some people did convert to a Bosch but i got the impression this is not an easy route. Do you know which Bosch model you have?
Marton
02-13-2006, 11:44 AM
#132
Rennlist Member
Borys, I think life will be easier since you have the resistor. I was asking about the cluster because I was wondering how you ended up having the resistor on the early car. I also have a Bosch unit that looked original, except for two things: It was missing the cooling shroud, and when I first pulled it out, I found a sticker on it that says "Bosch Remanufactured".
02-13-2006, 10:35 PM
#134
Rennlist Member
I'm about done with this. The root of the problem is rotor RPM. As of now, there are 3 options:
1) Take it and get my money back in the morning.
2) Discover a replacement alternator pulley that I can put on the crank without altering where the other pulleys sit, modifying or effin' around that is at least 7" in diameter
3) Sell the "work in progress" to someone who has a large enough crank pulley (significantly larger than 5").
With a 2:1 pulley relationship, the rotor only turns at 1400RPM. That's simply not enough. With the engine at 1000 RPM(as it warmed up and speed decreased) it was putting out plenty of current, 14V. I didn't try to load it down & take measurements much, since what I cared about was idle and when it got there I had nothing. I like my idle @ 700RPM, thank you very much. I found out that in a typical application these alternators run ~3x crank speed. If you can do that, you're welcome to pick up the torch -- but I just don't see that as a reasonable option.
Out of curiosity, toofast & 928fixer, what is the diameter on your crank pulleys?
Bosch -- here I come.
1) Take it and get my money back in the morning.
2) Discover a replacement alternator pulley that I can put on the crank without altering where the other pulleys sit, modifying or effin' around that is at least 7" in diameter
3) Sell the "work in progress" to someone who has a large enough crank pulley (significantly larger than 5").
With a 2:1 pulley relationship, the rotor only turns at 1400RPM. That's simply not enough. With the engine at 1000 RPM(as it warmed up and speed decreased) it was putting out plenty of current, 14V. I didn't try to load it down & take measurements much, since what I cared about was idle and when it got there I had nothing. I like my idle @ 700RPM, thank you very much. I found out that in a typical application these alternators run ~3x crank speed. If you can do that, you're welcome to pick up the torch -- but I just don't see that as a reasonable option.
Out of curiosity, toofast & 928fixer, what is the diameter on your crank pulleys?
Bosch -- here I come.