patrickstars 1983 242 4.8L/AR5 swap - Page 12

patrickstar · 02-23-2021, 03:18 PM

Quote:

Originally Posted by Harlard

Bet it's something dumb like the low wattage light bulb signal missing.

I believe the alternator harness has a resistor(?) built-in to mimic the "low wattage bulb". The ECU was showing a consistent ~14.7ish volts while driving and cruising. I'm wondering if either the battery is bad or if my battery cables are routed wrong somehow...

patrickstar · 02-25-2021, 04:01 PM

Who all has relocated their battery to the trunk? I am curious about wire size and routing, especially V8 swapped cars

Duder · 02-25-2021, 06:08 PM

Quote:

Originally Posted by patrickstar

Who all has relocated their battery to the trunk? I am curious about wire size and routing, especially V8 swapped cars

I haven't actually carried this out yet but I'm going to see if an E36 stock battery cable will work. In those cars the battery is in the passenger side buttcheek area essentially, and they have a nice high quality cable running through the cabin up into the engine bay. Should work for a 240 but again I haven't done a test fit or anything yet. I want to say it's 0 gauge (single aught) stranded cable but I can verify if you're interested.

patrickstar · 02-25-2021, 07:53 PM

Quote:

Originally Posted by Duder

I haven't actually carried this out yet but I'm going to see if an E36 stock battery cable will work. In those cars the battery is in the passenger side buttcheek area essentially, and they have a nice high quality cable running through the cabin up into the engine bay. Should work for a 240 but again I haven't done a test fit or anything yet. I want to say it's 0 gauge (single aught) stranded cable but I can verify if you're interested.

Those come with a distribution block up front as well, right? Probably would have worked better than the homebrewed setup I've got.

I really think I need to bump up the main power cable and rework the battery ground cable.

Duder · 02-25-2021, 10:40 PM

Quote:

Originally Posted by patrickstar

Those come with a distribution block up front as well, right? Probably would have worked better than the homebrewed setup I've got.

I really think I need to bump up the main power cable and rework the battery ground cable.

Yeah there is a junction block / jumper cable connection point near the firewall on the passenger side. The chassis has a battery tray there too, maybe some of the cheaper specs didn’t have the trunk mounted battery, but I know the 325i did.

I have one of these cables somewhere and looked for it today but couldn’t find it in my parts stash. If I get my hands on it soon I’ll let you know.

Edit: lots of BMWs have the battery in the trunk, so there may be a better battery cable to look at for 240 use. E34, E46, E39, etc. etc.

2turbotoys · 02-25-2021, 11:04 PM

I will be doing the battery relocation, and you should use some huge wire for sure. I figured it out but have to find the notes on it, think it was 00 gauge, copper wire, not that aluminum with copper coating crap.

patrickstar · 02-27-2021, 06:54 PM

So I did quite a bit of testing today.

Battery is getting ~14.7v while running. Doesn't seem to have a parasitic draw anywhere. Battery was good, tested it and replaced it with a new one. Car was still doing the same thing.

I'm starting to think its a heat soak issue with the starter. It only does this while hot, when cold the car cranks with no hesitation. I'm running an aftermarket starter, Hooker 8501 clones, no heat shield on the starter. Im thinking I'll order one and give that a shot.

culberro · 02-27-2021, 08:05 PM

If the starters not working when it’s hot, sounds like you may have a bad solenoid that’s getting jammed up when it’s heat soaked. Starters are pretty simple in operation...

patrickstar · 02-27-2021, 08:20 PM

Quote:

Originally Posted by culberro

If the starters not working when it’s hot, sounds like you may have a bad solenoid that’s getting jammed up when it’s heat soaked. Starters are pretty simple in operation...

The starter might be suspect, it was a cheapo O'Reilly/Autozone/Napa starter.

The positive cable from trunk to starter is undersized anyway, so I am thinking I'll order new cables and a heat shield and see what that does for me. Might beef up some of my grounds as well

2turbotoys · 02-27-2021, 09:34 PM

My brother had a 2 gauge cable in his Corvette battery relocation and it was no where near big enough.

culberro · 02-28-2021, 12:29 PM

Cable sizing is very interesting, I just went through this on an EV project at work.
You have to balance voltage drop, heat generated in the wire, constant current, peak current, and size and weight of the cable.

That being said 2awg should be more than fine. It has a continuous amp rating of more than 200 amps. I’ve used 8awg for rear mounted battery setups without issue. Peak currents aren’t that high high with a starter. You can run them through a 150amp fuse/breaker.

The issue comes when you have poor crimps and corrosion, or the starter spins the motor over too slow (usually a combination of corrosion in the wires and all the connections).

What Patrick is dealing with is a starter that won’t actually spin anything when hot. It has nothing to do with the cables, and everything to do with the starter and most likely the solenoid.

patrickstar · 02-28-2021, 01:52 PM

Quote:

Originally Posted by culberro

Cable sizing is very interesting, I just went through this on an EV project at work.
You have to balance voltage drop, heat generated in the wire, constant current, peak current, and size and weight of the cable.

That being said 2awg should be more than fine. It has a continuous amp rating of more than 200 amps. I’ve used 8awg for rear mounted battery setups without issue. Peak currents aren’t that high high with a starter. You can run them through a 150amp fuse/breaker.

The issue comes when you have poor crimps and corrosion, or the starter spins the motor over too slow (usually a combination of corrosion in the wires and all the connections).

What Patrick is dealing with is a starter that won’t actually spin anything when hot. It has nothing to do with the cables, and everything to do with the starter and most likely the solenoid.

I was hoping to talk to you about this when you grab the door cards today, this has been my thought process too. I only installed the 2awg because a friend suggested it. He's running the same setup in a LSX s13 and has never had issues.

I will mention that the starter does want to spin when its hot, but cranks too slow to do anything. It has the exact characteristics of a dying battery, but the battery is charging and has good voltage.

patrickstar · Yesterday, 07:53 PM

Tackled cutting my own 5-panel gaskets. Went to Hobby Lobby, picked up a 12x18" 5mm EVA foam sheet, a silver sharpie and a x-acto knife. Came out better than I expected. Next big interior project is going to be building a set of plain black doorcards via Dereks (Vol242vo) method.

I was planning on taking my girlfriend for a drive in it today, but wanted to throw my new taillights in first. I installed them but they need some work. Need to clean all the contacts up and test the brake light switch, I think it may need replacing.

02-25-2021, 11:04 PM	#281
2turbotoys Salaminizer Join Date: Nov 2007 Location: Reading pa	I will be doing the battery relocation, and you should use some huge wire for sure. I figured it out but have to find the notes on it, think it was 00 gauge, copper wire, not that aluminum with copper coating crap. __________________ Feedback thread https://forums.tbforums.com/showthread.php?t=144924 1978 242, 5.3 L33 1979 242, MS, R brakes 2006 V50 T5 AWD @ 17 PSI

02-27-2021, 08:05 PM	#283
culberro Ronald Culberbone III Join Date: Feb 2010 Location: Portland, OR	If the starters not working when it’s hot, sounds like you may have a bad solenoid that’s getting jammed up when it’s heat soaked. Starters are pretty simple in operation... __________________ Cult Person. Pissing in your Kool-Aid.

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02-25-2021, 04:01 PM	#277
patrickstar Board Member Join Date: Feb 2015 Location: Vancouver, Washington	Who all has relocated their battery to the trunk? I am curious about wire size and routing, especially V8 swapped cars

02-27-2021, 06:54 PM	#282
patrickstar Board Member Join Date: Feb 2015 Location: Vancouver, Washington	So I did quite a bit of testing today. Battery is getting ~14.7v while running. Doesn't seem to have a parasitic draw anywhere. Battery was good, tested it and replaced it with a new one. Car was still doing the same thing. I'm starting to think its a heat soak issue with the starter. It only does this while hot, when cold the car cranks with no hesitation. I'm running an aftermarket starter, Hooker 8501 clones, no heat shield on the starter. Im thinking I'll order one and give that a shot.

02-27-2021, 09:34 PM	#285
2turbotoys Salaminizer Join Date: Nov 2007 Location: Reading pa	My brother had a 2 gauge cable in his Corvette battery relocation and it was no where near big enough.

02-28-2021, 12:29 PM	#286
culberro Ronald Culberbone III Join Date: Feb 2010 Location: Portland, OR	Cable sizing is very interesting, I just went through this on an EV project at work. You have to balance voltage drop, heat generated in the wire, constant current, peak current, and size and weight of the cable. That being said 2awg should be more than fine. It has a continuous amp rating of more than 200 amps. I’ve used 8awg for rear mounted battery setups without issue. Peak currents aren’t that high high with a starter. You can run them through a 150amp fuse/breaker. The issue comes when you have poor crimps and corrosion, or the starter spins the motor over too slow (usually a combination of corrosion in the wires and all the connections). What Patrick is dealing with is a starter that won’t actually spin anything when hot. It has nothing to do with the cables, and everything to do with the starter and most likely the solenoid.

Yesterday, 07:53 PM	#288
patrickstar Board Member Join Date: Feb 2015 Location: Vancouver, Washington	Tackled cutting my own 5-panel gaskets. Went to Hobby Lobby, picked up a 12x18" 5mm EVA foam sheet, a silver sharpie and a x-acto knife. Came out better than I expected. Next big interior project is going to be building a set of plain black doorcards via Dereks (Vol242vo) method. I was planning on taking my girlfriend for a drive in it today, but wanted to throw my new taillights in first. I installed them but they need some work. Need to clean all the contacts up and test the brake light switch, I think it may need replacing.