75 BJ with SBC V8 and a 78 FJ Loom 🙃🤪

Joined
Aug 4, 2022
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united kingdom
Hi all, my first post on MUD and new to the Cruiser World having done my time with Land Rovers 🫢. Im learning fast but some help would be amazing… Im based in the UK and for my sins I have purchased a 40 series truck fitted with a Chevy Small Block, she lasted approximately 2 miles before the wiring loom went up in smoke. Long story short what I have is an imported LHD diesel truck which was fitted with a Chevy V8 by a US based company called CustomPower Group inc (who nobody has heard of), the wiring is, or I should say was, very messed about with. No fusible links, just direct heavy wire connection between alternator amp meter and battery cable tied to the already rough 1975 loom. Hence all the smoke when the live wire fell off the back of alternator onto the engine whilst driving her home.
Turns out not many 40 Series trucks in the UK or EU so I’ve settled for a 1978 ‘2 piece’ LHD FJ petrol loom which joins together just on the cabin side of the firewall before it passes through. BJ-FJ wiring had some notable differences so make the loom conversion easier I managed to get a full set of new/old stock accessory switches and indicator switch. Im pretty handy but I’m definitely not an electrical expert, Ive pulled out the old burned loom inc all the 24v section that was still in there and fitted the loom and new switches. Connected all the obvious stuff but come to a stop. I’ve managed to source a new/old stock Toyota FJ ‘yellow label’ Alternator and Regulator but I’m thinking I should probably re-wire the charge circuit to cope with the GM alternator (also a winch fitted) and wondering if anyone has a kit for this or am I on my own here?

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pbgbottle

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I bypassed that amp meter. On my v8 conversion it started to smoke one day also if you have the BI40 24 volt cluster there is a voltage dropper on the circuit board bolted to two posts on the gauges I removed that voltage dropper and just made a jumper wire I ran the 24 volt gauges with my 12 volts they worked. Also needed a 12 volt wiper motor and blower for the defrost
I can splice the Gm alternater into the Toyota loom. Works fine. How big is that alternator ,maybe you don’t want to do that.
 
Joined
Aug 4, 2022
Messages
2
Location
united kingdom
I bypassed that amp meter. On my v8 conversion it started to smoke one day also if you have the BI40 24 volt cluster there is a voltage dropper on the circuit board bolted to two posts on the gauges I removed that voltage dropper and just made a jumper wire I ran the 24 volt gauges with my 12 volts they worked. Also needed a 12 volt wiper motor and blower for the defrost
I can splice the Gm alternater into the Toyota loom. Works fine. How big is that alternator ,maybe you don’t want to do that.
Hi Pdgbottle, thanks for the reply. Maybe whoever wired up the Chevy motor already removed the dropper as the Amp gauge as it was previously wired up, couldn’t say if it was working as I only covered 2 miles from purchasing it and didn’t look at it. In fact it seems ALL the charge was going through the gauge as there was no bypass or shunt. Im not sure how to identify the GM alternator, does this pic help?

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Coolerman

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Jan 5, 2004
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Paint Lick, KY
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www.globalsoftware-inc.com
That is a GM 10SI 12V, 61 Amp, internally regulated alternator. No need for an external alternator. Here is a connector kit with the diode you need:

GM 10SI
The split wiring harness you showed a pic of is not for a 1978 FJ40. Well at least its not a USA 1978. That split style harness would have been on a 1979 or later FJ40 here in the US.

The later harness and Amp meter can handle the 61 amp alternator, but if you plan to add any accessories that draw high current you should add an aux fuse panel to the truck and not hack up your FJ40 harness.

If your harness does not have a fusible link I might be able to build you one if you can show me the connector on the main harness it would plug into.
 

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