New truck in the drive

[Shifty]

Looks good! 

[Dr_Snooz]

I printed up these filler blocks to locate the radiator where I need it.





Painted up.

[Dr_Snooz]

[Dr_Snooz]

I need to buy a CNC machine. Then I can make these out of aluminum.

[Dr_Snooz]

Here's the final rad setup.



It's solid.

I have this circuit breaker for the trailer brake.



I don't like having live posts sitting out there for anything to short on, so I designed a cover to protect it.





And some new parking lights.

[Shifty]

Nice fiddly-work!   

[Dr_Snooz]

I've never really made a loom before, and I'd like this to look nice when I'm done, so this is taking forever.

[Dr_Snooz]

The headlight harness I built with my crummy eBay crimpers came apart when I removed the core support. After much had scratching, I think I know how to put it back together again. I have a set of new crimpers coming.

[bd]

• Strip away a suitable length of wire insulation such that the bare wires penetrate to the center of a butt splice (see 'C' in upper image) or completely through a parallel splice (see lower image).
  
  
• Thoroughly burnish exposed copper wire strands until shiny to remove all surficial oxidation, allowing for even solder flow and adhesion.
  
  
• Firmly crimp using uninsulated, tinned, brazed-barrel copper butt or parallel splices to create a permanent and mechanically stable connection.
  
  
• Solder using electrical grade 60/40 or 70/30 rosin core solder to seal against subsequent oxidation and ensure a permanent and stable electrical connection.
  
  
• Shrink seal using marine grade, adhesive lined, dual-wall polyolefin heat shrink to insulate and reject moisture and corrosive dust intrusion.

[Dr_Snooz]

Thanks bd. My crimpers were designed for smaller gauge wire than I used on my headlight harness. My crimps just weren't up to the job, especially around the relay connectors where I had a few parallel splices. I never had a problem on the road, but when I disassembled everything, the crimps failed.

I could use some guidance on wire sizing. I want to get a 150A alternator to support the high draw fans. I bought a 1/0 wire from eBay for that purpose, and this monster showed up.



It's the right size per NEC, but it's impractically large. I've noticed that a lot of the factory wiring is undersized also. Nothing's burned up yet, so what am I missing here?

[ehjorten]

I am sure BD will have better information, but for 150 A alternator, you will never be outputting 150 A continuously, it will only be for maybe a brief period of time, but even assuming you are outputting 150 A, you would be able to support that with a 6 AWG wire at nearly 5 feet of length with a 2% voltage drop. It really depends on the length of the wire.

When I rewired my '69 Chevelle long ago for a CS130 alternator, I ran two 8 AWG wires, which is equivalent to a 5 AWG. It is probably overkill, but it was easier to crimp terminals and route two smaller wires than to deal with one very large gauge wire.

[bd]

A 150-amp alternator charge lead should be ~5' long.  An alternator will push maximum output for 30-40 seconds, at most, before tapering down to <60%.  For a 150 amp alternator, 60% is 90 amps.  So, hypothetically, the alternator will produce fewer than 90 amps routinely.  For your circumstances, a 4-gauge SGX cable is adequate for 80 amps continuous output with a ~1% voltage loss (0.14-volt) across the 5' run (3% loss is the OEM standard).  In contrast, a 2-gauge cable is gross overkill, yielding ~0.15-volt loss @ 150 amps continuous.  If your alternator generated >70% routinely its life would be dramatically shortened!

For comparison, a 10' long 1/0 cable will carry 300 amps continuously with voltage loss limited to ~3% or ~0.4-volt loss across the cable in a 12.6-volt circuit, which is the minimum specification for a Class 8 truck diesel starter and super heavy-duty for a LD diesel starter.

[Dr_Snooz]

Thanks guys. So basically, if I do a voltage drop calculation with a 3% loss, that will get me where I need to be? I'm coming from residential wiring where the requirements are quite different. I know I'm missing something because GM was using a 10G wire for the 105A alternator, and 16G wire for the headlights. Just trying to figure out how to do things the right way.

[bd]

Acceptable voltage losses depend on the type of load and duty cycle.  Typical OEM low- to moderate-load, moderate to high duty-cycle primary circuits (e.g., lights, radio, blower fan, battery charging circuit, radiator fans, power windows, etc) are based on 3% loss.  Ultra high-load, low duty-cycle starter circuits are based on 5% to as much as 7% losses.

My personal preference during a wiring repair or rewire varies with the type of appliance, duty cycle, repair cost, thermal exposure, space/flexibility constraints, and my experience, generally targeting 1% - 2.5% loss; ~4% for cranking circuits.  Opinions will vary with the electrician.  I nearly always employ GXL or SXL insulated wire.

[Dr_Snooz]

I'm still farting around on this rad install. The wiring is all done and nothing caught fire when I connected the battery, so that's good.



I had to move the heater hose routing around since the new rad doesn't have a heater hose provision.



According to Summit, this Griffin CU-70013 is a "direct-fit" for my truck. It's nothing of the kind, so I don't know why I was surprised to find that the nipples are larger than those on the factory rad, but I was. Now I'm trying to figure out how to make that all work. I ordered some universal hoses. One was the longest available, but still too short. The other couldn't make the dog-leg twists of the factory hose. So now I'm on the order parts -> wait a week to get them -> be disappointed -> order more parts merry-go-round.