Amazon: 1965 B18 Alternator conversion

[65 Canadian]

Hello friends,
And greetings from Canada.
The previous owner of my 1965 Volvo Amazon had a mechanic,who for reasons unknown ground out the holes of both the Generator and bracket.
Long story short - both are buggered and lining up the pulley's is tricky to say the least.
I've decided to convert to a alternator set up.
Its a early version B18 so I've ordered the conversion bracket.
My question is ?
What alternator to choose ?
And I need a little help with that one.
I don't plan on running a big sound system.
In fact the only thing I plan on adding is fog lights.
I'm hoping someone can suggest a proper amp alternator.
That will boost the amps enough for my needs, and be reliable charging the battery.
Without having to change anything concerning the fuse box.
Also is it better to go with the internal voltage regulator.
Or go with a external voltage regulator set up.
Any help would be greatly appreciated.
Thanks,
Shayne

[Ron Kwas]

Shayne;

" for reasons unknown ground out the holes of both the Generator and bracket." ...the simple reason is likely that they were worn oval by themselves (typical!), and were enlarged to fit larger pivot bolts.

"I've ordered the conversion bracket." ..."What alternator to choose ?" ...this is a function of which bracket...Bosch or Delco...I don't believe you ordered it from me (suitable for Delco), because if you did, general Alt requirements plus PN recommendations would be included with installation instructions (a good conversion kit, IMO, would not leave one hanging and on their own...!)

"...big sound system." ...anything reasonable (like up to a couple of hundred Watts) will not draw any increased current high enough to impact conversion Alt output...

"...fog lights." ...in the conversion I offer, I recommend going to a ~60A rated Alt (not higher!). This will power significant loads (like 2X55W, notice the Wattage total here is in the similar range of the sound sys also!), still have plenty of output with which to keep Bat well charged, but still have good reliability. (As a reference: 12V X 60A = 720W)

"...fuse box." ...it is always recommended when increasing the current which can flow, to refurbish or at the very least check FB for corrosion and voltage drops, which will cause I2R heating...doing anything less (or nothing at all) is setting the situation up for failure of next weakest link!

"...internal voltage regulator. ...or external..." ...any Alt worth installing when doing a conversion, whether Bosch or Delco, will have an internal VReg...do not even consider an Alt with ext. VReg!

See also: https://www.sw-em.com/altkit.htm

Cheers

[65 Canadian]

Thanks Ron,
I appreciate the great advice, and info you supplied here.
I've emailed my parts guy at vintage import parts to see the compatibility of the bracket.
And may be in touch.
Thanks again.
Shayne

[richo122]

Used a new OMX Diahatsu G10 45amp internal reg. alternator, 3" x 7/16" UNC bolt for the bottom mount, machined some spacers, used the stock alternator bracket and a 11A0865 belt.
Wiring only modified to run the IGN exciter wire up to the fused (left) side of the fuse box, otherwise stock wiring utilised.
Used some of Ron Kwas' excellent paste and thoroughly cleaned the fuse box.
Were I literate enough to post photos, I would.

[jimbo1593]

regarding the alternator issue.
Probably one for Ron.

I think the idle on my amazon is worse since fitting a 55A alt vs the dyna on my friends amazon. Under load, say rear screen heater, lights and wipers, revs really drop as the alt loads up. not so much on the dyna car, at the expense of flatting the battery i presume.

What do you think Ron?

[Ron Kwas]

Jim;

I can immediately think of two ways an Alt might affect the Idle...
1...electrically, somehow, in that lack of output is decreasing the buss voltage as the Bat goes flat, which would in-turn make itself known through Ign issues (AMP Ind ON and other indications nowithstanding...)...but that is pretty unlikely in your case...most of the time the Alt serves to pull the buss V up with its output, so again, any elec effects would be rare and wierd and unlikely... and...
2...mechanically, in that whatever additional elec load(s) are ON result in additional current being drawn from Alt, which in-turn reflects this mechanically onto the driving belt, and in-turn Crankshaft...so I would not be surprised if you're drawing a high Alt output current to run a big elec load (like your rear screen heater), it might very well noticeably affect the Idle.
...note that before an Alt with a higher output capability was installed, and big elec loads were beyond what Gen was able to supply, that current was supplied by Bat, and so was not a load which was reflected on the Generator or Crankshaft or Idle...

If during high elec Loads is the only time you are noticing this, you can simply tickle your Idle speed up just a touch at the Carb(s) to compensate, (or do this manually with your foot on the throttle)...otherwise, just understand that it is quite a normal symptom of what is happening and nothing to be concerned about. If the idle is dropping to the point of stalling the engine, it might be adjusted a touch lean at idle also...

I expect in military versions like the BV202, where vehicle might be static and engine might be run to supply the communication suite, they would have a high idle control, similar to what civilian versions have with the Choke...(but without simultaneous enrichment, as it is not needed). The BV engine at idle is WAY out of its optimum load range and so cannot supply as much power as the comm suite might need...

Cheers

[jimbo1593]

thx Ron, helpful as ever.
part of the prob is i run a K cam, so the idle doesn't like to run too low, i'm not yeg decided if I will revert to C cam at some point.
tempted to say that if dynamo was still fitted i would prefer having to charge battery every so often and not have revs dropping.
just me i guess.

[Ron Kwas]

...that would be the reason to increase the Idle setting...

[Derek UK]

Basically, if the red light is out it's charging. I would do some checking with a volt meter/ multimeter on how the charging rate varies with revs under increasing loads as you switch things on. In theory everything runs off the battery when fully charged, and the generator, dynamo or alternator, tops it up as needed. Consider it to be a water tank that needs topping up as required as you use up the water. Maybe the battery is past it's best? Check and clean the earth lead to body connection as well as the positive lead at the starter. Clean the battery connections. A 900-950 rpm idle should be fine.

[Ron Kwas]

Derek;

"everything runs off the battery when fully charged, and the generator, dynamo or alternator, tops it up as needed." I must try to adjust your understanding of this a bit (...a nice way of saying I disagree with this general assertion, but I'll try to explain)...because the Voltage of even a fully charged Battery will (almost) never (under normal operating conditions) be as high as the output Voltage of the Alternator (Chg Sys), and since voltage differences always determine which direction current flows, the source with highest voltage in the Vehicles Elec Sys will source power for loads, and that is normally the Chg Sys.
The "H" diagram may help to understand this:

...notice direction of current at gauge can be Charge or Discharge, and it is the voltage of the two sources in the system which determines this direction...the source (Cheg Sys OR Bat) with the highest voltage will supply power to the Loads...and as I note earlier, that is typically the Chg Sys/Alt...BUT if for instance Chg Sys output is low because RPMs are low, or Loads are so high that Alt output is insufficient to power all loads, its voltage will drop to near that of the Bat, so Bat will start to contribute...what I mean to note by this is that this is not a hard switching point but a gradual, one supplying, then the other sharing, then the other fully supplying, occurrence...

Hope that helps, Cheers and Merry Christmas!