TheSamba.com :: View topic - 71 bus alternator bad? gen-light on, pls help?

Mon Jul 21, 2008 1:41 pm

This is my first vw, and I've had it for like 2 days.

The engine starts, dies (without pedal) because the idle isn't set right, but the alternator doesn't seem to be charging. I tested the battery and it reads at 12.3V w/ bus off; 12.2V w/ bus on.

The red generator light in the dash is also flickering. It has an alternator w/ an externally mounted regulator. Alternator actually says VW on it (may have come from a bug?) Two screws that secure the regulator to the alternator are missing (haven't been able to find replacements).

I won't drive it because the engine overheats.

I would really appreciate any help!!

Thanks

Tue Jul 22, 2008 10:05 pm

Is your voltage measured at idle or while the RPMs are increased?

Wed Jul 23, 2008 6:30 am

Welcome,
Are you sure you have an alternator and not a generator? Post some pics, I've never seen a regulator mounted directly on the unit (12v anyways), it's usually on the firewall or internal.
What makes you think the engine overheats? Do you have a Bentley or idiot manual? Have you done a tune up and valve adjust? How's your fuel lines? All the tin and seals in place? any road visible from inside the engine compartment?

Wed Jul 23, 2008 6:54 am

Something doesn't sound right here. We need pics. The only VR's that were mounted to generators were for the 6 volt Busses and Beetles. All others were either mounted to the firewall on the passenger side behind the oil bath or in some other location?!? I can't offer suggestions on alternators, I retain the 38amp generator on mine, the VR is located where it should be, that is on the firewall. As far as your curb idle, what rpm's are you seeing with an appropriate meter? You say it dies if your foot is not on the pedal. If your curb idle is too low, a gen warning light will flicker; your VR is sending a signal to your dash warning light that proper charge is not in effect. I may be wrong on this however, I never profess to be right on.

Wed Jul 23, 2008 7:33 am

Is the idle cut off solenoid on the carb working correctly?

It should be wired to the "+" or "15" side of the coil and should daisy chain to the electic choke. Put the key in the "on" position, and remove the crimped connector at the solenoid. You should hear it "click". You want it to work 8 times out of 8.

It needs to be attached firmly to the carb but do not reef on it.

Wed Jul 23, 2008 9:34 am

I've attached some photos so you can see what I'm talking about.

Caleb, I tested the voltage with the engine running somewhere in the range of 1500 rpm (since it won't run without throttle).

Busdaddy, I'm pretty sure it's an alternator (please see pics). I'm not positive it's overheating, but when I first bought it and drove it for about 5 minutes I noticed the flickering of the gen-light and the engine started smoking (I think due to oil burning on the crank case or heads, something...). I have a Haynes manual but it doesn't say much on the topic. The motor was recently tuned and the valves look good. Fuel seems ok.

Jody, yes, the curb idle's too low... had a hard time adjusting it though. It has a 34 Pict 3 carb on it. I'm going to mess with the adjustment some more tonight. I'm hesitant to "warm up the motor" though if something serious is wrong with it.

Randy, is the "cutoff solenoid" the same as electromagnetic cut off valve? Sorry, I'm not sure which part you're talking about.

Thanks everyone

Wed Jul 23, 2008 9:42 am

The electromagnetic cut off is that horizontal cylinder type part thats atached towards the base of the carburator on the left side looking at the carb, and has a wire conected to it. It also was the reason my 34 pict 3 wouldn't idle. if you can find a plug that will thread in the hole that comes out of you can test to see if thats it. I think I used one of those big plastic phillips head interior screws.

Wed Jul 23, 2008 10:01 am

Hmm.. definitely an alternator, the box on top is strange though, it may need brushes or another regulator, make sure all the connections are tight but don't get your hopes up. Although you can replace brushes and regulators in place.
The idle issue could be the solenoid, it's worth your time to pull off that carb and check all the jets in it though, not very often a new carb is jetted close to what a bus needs.
Your preheat pipes don't look like they get hot, between this and the cheapo air filter your idle may suffer too, fuel economy for sure.
That chrome fan shroud is asking for overheating problems, very poor quality and fit and usually no vanes inside to distribute the air correctly, start shopping for a genuine VW doghouse shroud.

You need to do some more reasearch on the overheating, with that shroud we know you have no thermostat or flaps so they cant be stuck shut. You will want to look at the front of it at the fan intake, check the fan for rags or other blockages and eyeball the gap between the fan and the intake rig on the shroud. Reach around there and try turning the fan too. It may just be leaky valve covers dripping on the exhaust but check it out anyways. If you don't have an oil temp gauge either get one (money well spent) or get a meat thermometer from Wal-mart for now with a long probe and sample the oil in the dipstick tube.

Thu Jul 24, 2008 5:45 am

Well here's my take, and others may agree/disagree:

First, get your fuel filter out of the engine compartment, it belongs after the tank outlet and before the firewall, and make sure there is a rubber grommet in the firewall tin where the metal part of the fuel line passes through. Make sure the arrow on the filter points towards the carb.

Can't really be sure from your pics, but your carb looks off kilter, leaning to the left, like it's butting up against the alternator, preventing an even seal on your intake. There may be a vacuum leak there. Also I can't be sure if all the carb's moving parts on the right side are not working as they should, that looks like a really tight fit up against the alternator body. That air filter is not helping, you should source an orginal oil bath for the '71's.

I'm not sure what manufacture the 34-3 is but it appears to be brand new. If it's a Kafer Pierburg, they have been known to be crap out of the box and need major adjustments/re-jetting for Bus to finally operate properly. Your distributor may be an orginal DVDA, but I can't tell from the pic. If so, there is another vac port that should either be capped off, or a vac line should be attached there to the capped plug on the carb.

On your alternator, it looks like you have a generator pulley, I may be wrong though. Generators are initially shimmed with 4 shims between the two wheels and 3 on the outside. It looks like there's more on the outside. But whatever works I guess, just as long as the belt is within specs and tightness and and you can sight a perfect straight line from the pulley to the rear engine pulley. You don't want your pulley too far out or too far in. If that's the case, you have to adjust the mounting of your alternator, or configure something else. I can't offer suggestions on the electric, but I can say I've never seen an arragement like that for an alternator.

Your oil filler stand assembly does not appear to be vented from what I can see from your pics. I may be missing something however. There should be a vent hose coming off the top somewhere that should either be hooked up to a breather box or into you air filter. If it's not vented at all then your getting excessive crankcase pressure and it will blow oil in unfortunate places. Like I said, more than likely there is a vent tube that I just can't see from the pics, but then again anything's possible with today's aftermarket parts and what previous owners do to the engines.

The aftermarket fanshroud as suggested should be given the heave-ho. It's not cooling your engine properly. You may be lucky to have original German cylinder tin covers, these evenly divert cooling air over the heads. I seriously doubt you have the flaps and a thermostat.

Best of luck, hope this helps

Thu Jul 24, 2008 8:38 am

First, thank you all for the continued help.

The electromagnetic cutoff valve is working properly, based on the "click test" with the ignition on. I managed to get a steady, but slightly faster than normal idle working after I warmed up the engine with my foot slightly down on the accelerator pedal for a few minutes. After that it seems to idle ok (although not ideally). I imagine a cold start idle is still going to have problems.

I will look for a better air filter or an oil bath type. I have to pull the carb off to change the alternator, so I will adjust that again later with the new filter.

In terms of wiring on the existing Motorola alternator, there is a B+ going from the alternator body direct to the battery. The other two connections are on the plastic external regulator and each of those two red wires is grouped together with other wires and run through firewall holes out of the engine compartment on the right side toward the front. I'm not sure which is which (i.e., which goes to gen warning lamp and frankly no idea where the other one goes...) Does one go to the starter?

A local bug-formance shop has a bosch alternator in stock. I think my best bet is to just replace? I'm going to attempt the swap without pulling the motor. It looks like I'll eventually need to pull the entire motor though to install a black doghouse style fan shroud? There doesn't appear to be any way to do this with the motor in, because the chrome curves down and sits above the heads.

Also, while it was running yesterday I did some looking, and it appears that the main oil leak (causing smoke issue) is on the left side valve cover dripping on the exhaust. Is this generally caused by a bad gasket, or is it something more serious? I'm going to replace the gaskets there and on the carb.

The blue wire you see in the pics actually runs from the coil to an oil pressure switch that sits just below the distributor? I originally thought that was going to the gen warning lamp - but that's not the case...

Jody, I will check all the vacuum lines you suggested, and oil filter stand venting.

Other than that, I just hope the coil is all wired up properly. The wires are not color coded properly. There's no brown ground wires, the blue wire doesn't go where it typically would, etc.

To be continued...

Fri Jul 25, 2008 12:20 am

Go up to the top here and you'll see "Technical" to the right. Click on that. Then click on "wiring." Then seclect "type 2." Then scroll down and look for "1971." There are 2 pages you can pull up. The first page is the front of the Bus, the 2nd is the rear. Really nice in color diagrams. Add these to your "favorites."
The wire coming off your oil pressure switch was originally blue with green stripes. It could be any color now, but should not be hooked up to your coil!!! It should go directly to your oil warning light in your dash gauge cluster. I bet if you get up under the dash and look you'll see the original colored wire going into your oil warning light bulb socket, but anything's possible.
Keep in mind these diagrams are for the Generator, not for the alternator upgrade. Although the OP switch is still wired the same. You may want to try the "search" for something like "alternator conversion" and see what you find. I'm pretty sure changes have to be made when adapting the alternator to the fanshroud, so you may want to consider doing all that when you find a good fanshroud.

Fri Jul 25, 2008 8:12 am

I picked up a couple machine screws at the hardware store to secure the ext. regulator on the alternator down (where the screws were missing). It's still a little loose so I'm going to get some locking washers or a different type of screw, but the generator light went off and the battery appears to be charging at around 13.7 - 13.8 V now!

Also, I took off the valve covers and cleaned them up real good. The gaskets on there were a rubber type applied with a sealer of some type. Cleaned all the crap out, put in new cork gaskets, and now the valve covers are virtually leak free, eliminating the major smoking issue.

Idle seems to be working now, but I'm sure not ideally. I took it for a 10 minutes test drive after I did everything, and it drives fine. A little bit of smoke is still burning off the back end of the exhaust, probably due to a combination of oil still being on there from the previous leak, and a little leak from the oil sump plates/plug that I'm going to replace.

I'll look into the wiring for the oil switch. I ordered a Bosch AL82N alternator... it'll be here next week (go figure, now that my existing one works). But when I replace the fan shroud I might just throw that in.

Thanks everyone!!!

Fri Jul 25, 2008 9:36 am

Good to hear things are coming together for you, you might want to try disconnecting the brake booster line from the manifold and capping the manifold temporarily (large braided line on lower left below carb), if your idle improves you may need new booster lines or booster work. Remember you have no power brakes while performing this test so plan ahead for stops.