Bulkhead Connector Bypass Step by Step

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XP29
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Post by XP29 »

Thanks, had a read through. It was just I'm finding 14.8 seems to be the threshold for when it's over charging when I've been searching. With my meter I'm still getting 14.8 but I took a run out to where I got the alternator, he put his Snap-on unit on and it was getting bang on 14.8 and just under with no load, dropping slightly with load put on (lights/heater). He said the readings were ok and just keep an eye on the battery.
1966 Charger, 383 4bbl, 4 speed manual trans, Sure-grip, original paint.
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morgan
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Post by morgan »

Sounds right to me.
The cheapo-chinese-in-car-voltmeter I run shows about 12.8 off and anywhere between 14.8 and 15.1 running - I'm not expecting 100% accuracy from the tool but its in the ballpark. Not wildly overcharging but clearly alternator doing its work. Yours sounds fine to me. So long as its a couple of volts higher when running its close enough for jazz.
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XP29
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Post by XP29 »

Thanks Morgan, I'm finding so many mixed messages of that 14.8 is fine and overcharging!
1966 Charger, 383 4bbl, 4 speed manual trans, Sure-grip, original paint.
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Post by XP29 »

Double post :oops:
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Post by morgan »

Ive been through EXACTLY what you have - it becomes all consuming and in my case I certainly got to the stage where I over thought it.

If you meet these 3 criteria (Car runs, +2Vish, ammeter bypass mod done) then its a win.
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Dave81
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Post by Dave81 »

XP29 wrote:Thanks Morgan, I'm finding so many mixed messages of that 14.8 is fine and overcharging!
14.8 should be fine when driving.

Most voltage regs I've got have a max voltage of 14.88V.
If they are working and earthed properly you should never see more than that. 15V would be my comfortable limit. If your seeing 16 plus id be concerned about boiling the battery and all the other associated issues.

This is the reason I put a voltmeter in the car. Mine Bananarama! 18 until if I found the shorting issue. Now I look down when driving and its hovering around the 14 mark........= Happy Camper and confidence! :thumbright:
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Post by XP29 »

Cheers guys, yes I work myself into a worry if I think it's not spot on. I'll keep going and just keep an eye on the battery and any signs of overcharging/gassing up.
1966 Charger, 383 4bbl, 4 speed manual trans, Sure-grip, original paint.
petebryan
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Re: Bulkhead Connector Bypass Step by Step

Post by petebryan »

Going back to Steve's original post re the bulkhead bypass, I'm trying to work out how difficult this all is for my novice-level skills. Can I check how much you had to take apart in the cabin to get the job done and how difficult it was? I'm guessing the steering wheel came off? And did you have to lower the steering column before you could get the instrument cluster off to get to the Ammeter (think I read somewhere else that this was part of the procedure)?

thanks!
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Re: Bulkhead Connector Bypass Step by Step

Post by Pete »

petebryan wrote: Tue Apr 14, 20 12:00 am Going back to Steve's original post re the bulkhead bypass, I'm trying to work out how difficult this all is for my novice-level skills. Can I check how much you had to take apart in the cabin to get the job done and how difficult it was? I'm guessing the steering wheel came off? And did you have to lower the steering column before you could get the instrument cluster off to get to the Ammeter (think I read somewhere else that this was part of the procedure)?

thanks!
A lot depends on the model of car usually "A" Bodies you have to drop the column to remove the Binnacle.

It's been a while since I have done a "B" Body, so I can't really remember.

Due to a fire as a result of the Ammeter wiring, I had to remove the complete A/C Unit and dash pad and instruments to do the job on an "E" Body.
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Dave999
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Re: Bulkhead Connector Bypass Step by Step

Post by Dave999 »

the easiest way is to get a length of fat cable... same thickness as battery cable (actually 1/2 that would do, its not running the starter and will see no more than 40 amps with the standard alternator). with 2 eyes one at each end, ebay provides any length you want..Big stereo power supply cable works as well and is nice and flexible.

run it from the alternator stud, over or under the radiator or across the front of or through the K frame (tie it in with cable ties) and round to the stud on the starter relay, relay bolted to inner wing up front near battery. sleeve it with fat rubber tube over the sharp bits. leave everything that was connected, connected, and just add this second wire.

that way when the alternator is doing its thang the current takes the easy route, your new wire, rather than go through the bulkhead.

your ammeter stops working i.e measures nothing...but provided it was ok before, you have achieved a fix that won't melt the bulkhead connector....it does however leave the ammeter live which if it has been melted at some point or the cables are loose leaves some risk of a short at a later date.

it works perfectly well and is better than nout...usually used when a 60+ amp alternator is fitted to a car with 36 amp wiring, like yours and mine :)

previously power went up to the bulkhead through ammeter and back through bulkhead to battery... i.e there is a loop running from alternator through the ammeter and dash back to the battery via the stud on the starter relay, and this fix just circumvents it

Dave
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Re: Bulkhead Connector Bypass Step by Step

Post by morgan »

I went through all this pain and came up with an alternative roughly based on what Dave999 suggests. Its not such a bad job.

The really hard bit is finding the damn splice in the loom - really its a dash-out job - and its one that I didnt fancy - I gave up trying to find the thing.
So what I did was came up with an alternative to take the 'running load' off the bulkhead connector.
The details/diagram are here - viewtopic.php?f=6&t=46698 (Scroll down for the adapted madelectric diagram)

You still have to get behind the ammeter to bypass it.
You still need fusible links to protect everything from overload (They were like $5 from ebay US I think - madelectrical sell them too)
Make sure your bulkhead connectors are nice and clean and not getting hot.

At some point, in a perfect world, I'll find the main spice and bypass but for now this offers overload protection and removes a big chunk-o-risk.
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Re: Bulkhead Connector Bypass Step by Step

Post by Dave999 »

i found the main splice

and i never want to see it again

on an aussie A body about 5 inches from the point where the wiper switch connects in

buried in the middle of the loom where if it overheats it can melt the insulation on just about every other circuit...
i doubt it would overheat, 4 wires crimped and joined by a toffee sized chunk of lead solder

turns out the problem i was looking for at the time was 12 inches up from the battery, not under the dash at all...

also learned that once you get deep under that black tape the cheap sods just used any wire to make up for a shortage of 1 colour or other...all nicely soldered and taped, and yet anything too long was zigzagged up and down to fit.....makes no sense.... but still....

looks like 1 loom modified for a range of different cars with instruments and switches in wildly different places....once bound up who is to know..

2 rolls of non tacky loom tape later... all was back as Mr Chrysler intended and i moved from making a mess under the dash to fixing the actual problem under the hood.
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Re: Bulkhead Connector Bypass Step by Step

Post by petebryan »

Many thanks for responses Pete, Dave and Morgan; very helpful and appreciated.

Pete W: thanks; should have said, I've got a 1970 Cuda 383 (have now added that to my profile). When you did this job to your E-body, did you have to move the steering column too to get to the Ammeter and/or the wiring? Did you do the full MadElectric approach or a variation like Dave /Morgan?

Moving on to Dave and Morgan's responses, you've both described that identifying the spliced wire within the loom is the toughest part and means a world of pain and way beyond my appetite / ability! That's put me off the full MadElectric approach.

My understanding is that Dave's proposal is the simplest solution, in that it gives a big wire for the main current to go through to the battery (via starter) directly, albeit with the ammeter circuit still in place,and through the bulkhead connector.

Morgan's variation seems to be one step on from Dave's in that it removes the ammeter by joining up the wires currently going across it. Morgan - how easy did you find it it to get at the instrument panel - can you just unscrew the instrument cluster without anything else needing to move first?

I very much like both approaches and am tempted to go the additional mile that Morgan suggests to remove the risk around the ammeter, and run the smaller residual risk around the bulkhead connectors remaining in place, given that current through the bulkhead connectors must me much lower after adding the big alternator-battery wire.

That said, the context of all this is that I'm installing an electric fan after many attempts to fix a persistent overheating problem in traffic jams. [I know that many don't like those at all but decision made!]. The fan will draw 16-19 amps, and I suspect I won't have enough power from the existing alternator particularly because it's likely to be at idle that the fan will be running. I'm therefore expecting to have to upgrade the alternator too, though haven't yet worked out exactly how much additional power from a new alternator I'd need, or any of the specs around that. So if I go that route, is there anything in either of your suggestions that you would worry about if there's a more powerful alternator producing more current? I'm guessing the answer has to be 'no' in that the additional current's going down the new big wire from alternator to battery (via starter relay), so the additional current required for the fan doesn't go up the through the bulkhead circuit? Does that make sense? Or does it completely depend on the wiring of those fans (I've got a wiring diagram for that -can post that also if that helps with the question!).

And I guess the fuseable link is there to protect the wire through the connectors if the power is higher than expected.

As I say though, I really am a novice at all this so any thoughts are welcome!
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Re: Bulkhead Connector Bypass Step by Step

Post by Pete »

[quote=petebryan post_id=638764 time=1587062461 user_id=14277]
Many thanks for responses Pete, Dave and Morgan; very helpful and appreciated.

Pete W: thanks; should have said, I've got a 1970 Cuda 383 (have now added that to my profile). When you did this job to your E-body, did you have to move the steering column too to get to the Ammeter and/or the wiring? Did you do the full MadElectric approach or a variation like Dave /Morgan?


I did the mod before it was documented and common practice. I took the Column out, the Instrument Binnacle out, and also the A/C unit and the complete frame and dash pad.

The damage to the loom was so great that the whole lot had to be replaced, but I am a trained Digital electrician, so not hard, just tedious. Also the repeated installations and checks were hard work as the dash is bloody heavy!!!
Pete Wiseman; Cambridge.

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Re: Bulkhead Connector Bypass Step by Step

Post by morgan »

Aw, I gotta say it...
That said, the context of all this is that I'm installing an electric fan after many attempts to fix a persistent overheating problem in traffic jams. [I know that many don't like those at all but decision made!]
It not that I dont like electric fans (mine used to have one, and I have been VERY tempted myself). I know the pain, I've had overheating probs but you've got to look at it like this - the car was designed to run in the Texas desert 50 years ago without overheating. The UK climate shouldnt worry it.
I'm not saying dont fit it, go for it, BUT at best it will mask the problem. Better to find out why.

The weak spots on the setup are typically (from my own experience)
- The Rad itself. They are old now. I went for a big ally aftermarket, some prefer original looking - you can get them re-cored and they can even put way more cores in now and still look stock. So make sure the rad is good.
- A good shroud and fan man enough for the job. I had a rubbish fan and no shroud for YEARS. This was foolish - fan needs to actually draw the air.
- Water pump. Its a cheap upgrade, looks stock and shifts a LOT more water than stock. Only just done this myself (there is a thread somewhere). Tech has moved on and your pump is likely old.
- Timing. Timing timing timing timing. Now I run purely mech advance so struggle here, but if you can run vac-advance it will bring temp down a lot. Wonky timing creates heat.

Get those 4 things right and your cooling system should look after you. If I am reading it right a stockish 383 shouldnt have trouble cooling. So unless you are doing something wild with it I'd respectfully suggest you have a gremlin in there somewhere...
I feel your pain though. I frequently threaten mine Basil Fawlty style...

Edit - Ha - here, read this. It will sound familiar. :) viewtopic.php?f=6&t=58548
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