CMP Electrics

Lauren Child · #1 05-01-12, 15:50

Hiya,

I've started looking at my F22's electrics. I had a dodgy horn that turned out to be not enough voltage getting to it, and then I had trouble starting her which flattenned the battery.

While I polished the contacts and got the horn working again, only about 4volts was getting through to it, which got me thinking about the sluggish starting. With the battery out for charging I've done a bit of investigating on the wires.

I've found some loose connections, but the cable used seems to be smaller than I was thinking it should be. It looks like 60mm2 (with a small section of 40mm2).

Did she have 00 gauge originally? If so that's about 70mm2.

Assuming that makes sense, and yes I'm also looking at the earth straps around the place, can I get a bit of advice?

Is the wire sizing that significant?
Is there any easy trick to getting at the switch and starter motor?
What size of ring terminal do I need for them and the engine case connection?
Is sluggish starting normal? She seems to slowly turn the engine over, with one or two moment of "whoosh" and one or two moment of "stop, I've had enough"

Thanks!
Lauren

Richard Farrant · #2 05-01-12, 19:48

Hi Lauren,

As you say, all the earthing points need cleaning for good contact, but if it is still on 6 volt, then the battery cables should be significantly larger than you would use for 12 volt. Actual cross section/area size escapes me are this moment.

regards, Richard

cletrac (RIP) · #3 05-01-12, 20:43

The battery cables should be about as big around as your little finger. What's that in metric?

Lauren Child · #4 05-01-12, 21:08

Thanks chaps, She is indeed still 6 Volt.

Little finger size is maybe a bit bigger than what she has, depending on who's pinky you are looking at

Ken Hughes · #5 06-01-12, 00:31

Hi Lauren,run a new heavy battery cable from the earth end of the battery earth chassis mount,to your bell housing near as possible to the starter motor.
I had advice from Alex Blair on this site,and it works a treat!!,just like 12v.
Do that first before anything else as that will eliminate any earthing problem.
My F30 was having the same trouble as you are having and this fixed it.

Lynn Eades · #6 06-01-12, 02:09

If you can, buy cable with lots of fine strands, rather than a cable with a few heavy strands. Welding cable is good because it employs many fine strands. It remains flexible, and with its good cross section, a great current conducter.
I suggest you follow closely what Kenny has suggested. It is well known that many Jeeps(amongst others) have suffered this same problem.

Phil Waterman · #7 06-01-12, 17:23

Hi

Lynn and Ken's point about the welding cable are on the mark. Adding a ground cable from the battery ground to the chassis to the engine will cure a lot of problems. I've gone over to generally making my own cables using heavy welding cable or heavy fine wire cable from electrical supplier. While your at it get the lug ends from them I like to crimp the lugs on to the cable and while they are nice and clean solder them as well for the best electrical conductivity.

Be sure though that when running your power side of the cable that you use cable clamps to keep the cable in place. Check your routing to be sure of any points were it rubs against anything. One problem with the welding cable that I have encountered is that the insulation is little softer than I'd like and is prone to wearing through. I had a cable fire because of this on a new installation, my own fault didn't have enough cable clamps.

When I replaced the cable after the fire I slid a section of hose over it at the wear point.

Cheers Phil

Ken Hughes · #8 06-01-12, 18:00

Clamping and insulating the cable is a good point Phil.

Lauren Child · #9 06-01-12, 19:32

Thanks folks!

I had spotted the welding cable and wasn't sure, but I'll give it a go with some conduit in the important places

Any ideas for the best way to get at the switch and starter motor? The switch in particular looks like it's in a particularly awkward spot.

TTFN
Lauren

Ken Hughes · #10 07-01-12, 04:26

Hi Lauren,by switch do you mean the soliniod down in the chassis area aft of clutch and brake pedal mount?,or the dash starter button?

Lauren Child · #11 07-01-12, 12:04

Quote:

Originally Posted by Ken Hughes

Hi Lauren,by switch do you mean the soliniod down in the chassis area aft of clutch and brake pedal mount?,or the dash starter button?

The solenoid down on the frame

It looks to be pretty awkward to get to.

Ken Hughes · #12 07-01-12, 19:12

Yes Lauren,that solenoid is dam awkward to get at,i dont think there is an easy answer,but hey someone here may have one,you never know.
I just kept at it till i got it off.cheers.

paul Lincoln · #13 10-01-12, 00:19

Lauren,
We run our Fords on 6V and, while they are never going to fly on the battery, they do the job with good cables and CLEAN earth connections. What we have found is that OPTIMA batteries are the absolute "Dog's". They can power the vehicle in second gear if it won't start. We have even flattened the battery and, in the time it took to make and drink a cup of tea, it had built up enough power (unaided) to throw her over and start it up! They cost over £100, but we won't consider anything else. David, on 01953 881330 is our friendly supplier and will give you a good deal if you mention my name. He also does brilliant quick release battery terminals in red and blue. Ideal for home made wires and can be removed in a second to render vehicle safe at a show. Paul.

Lauren Child · #14 11-01-12, 01:05

Thanks - I had been pondering the Optima batteries but the smaller capacity put me off. At the moment I have a big-ass 160Ah truck battery, but these top out at around 50Ah. Given the benefit in technology though I may have to reconsider when this battery gives up on me (assuming it hasn't already

)

I got the new cable through today (ouch copper is expensive) and it looks more up to the job so now I just have to find the time (and more importantly, the "get-up-and-go") to fiddle around out in the cold.

Ken Hughes · #15 11-01-12, 07:11

Hi Lauren,those optima batteries are good,we were restoring a 1936 Ford that had one fitted,and with sitting around for 6 months it still had plenty of cranking power.
The ford was in our workshop for 3 years and the battery was only recharged once during that time.

Phil Waterman · #16 11-01-12, 18:24

Hi All

Lauren your original question as spawned an interesting discussion.

What has been peoples experience with the Optima batteries concerning the following:

Post corrosion

Charging rates encountered on the CMPs with the High Amp charge rate regulators

Good high grade regular batteries seem to last 4-5 years in my trucks and then one day they just seem to stop holding a charge. Or their cranking voltage drops off steeply. One of the problems I have noticed on the last couple of batteries is that though they will crank the engine over for a long time they drop below about 4.5 volts very quickly like 20-60 seconds. This is a problem because below 4.5 v the ignition spark is pretty weak.

Cranking time to start is really important if the carb is dry and you have only a mechanical fuel pump.

Cheers Phil

paul Lincoln · #17 11-01-12, 20:21

I would guess that we have had an Optima battery on one of our F30s for 5 years. It is still as good as new and there is no corrosion on the terminals. We use the quick release clamps so we can disconnect when we put it away for winter. My other three 12 cabs all have Optima batteries and so does my Jeep. I will be putting one on my next Jeep project too.
My supplier is not too far from you in Norfolk (UK).

Lauren Child · #18 10-06-12, 17:48

This week I finally got the weather and time to swap out the battery cables. It's made a *huge* difference. Starter now cranking 2-3 times faster. I used 70mm2 high-flexibility cable (very fine cores in the wire).

Ken Hughes · #19 12-06-12, 08:48

I am glad we all could help.

Lauren Child · #20 16-06-12, 17:04

Can I check how folks are routing the cable down to the solenoid?

I've followed the routing of the old cable, across the clips by the twisty grease doodah, around the edge of the edge bay to the handbrake area and then down close to the doghouse spring clip immediately above the solenoid.

With a bit of wobbling the cable has moved close to the exhaust manifold (actually to the point of touching an old earth cable that was about to get very hot....) hence this is clearly not the best routing.

There's a smaller diameter cable loom running through some metal clips in the area that look battery cable sized - are these supposed to be for the battery cable?

Stew Robertson · #21 17-06-12, 03:14

The battery cables run right along the frame, inside the frame

Stew

Tony Wheeler · #22 19-06-12, 18:51

Quote:

Originally Posted by Lauren Child

Can I check how folks are routing the cable down to the solenoid?

Hi Lauren,

As Stew says, the standard battery cable route to the solenoid is along the inside of the RH chassis rail, as in the pic below. However I notice in your first post you have an F22. I'm not familiar with the F22, but from your description it sounds like it has a battery box inside the cab, like the FGT. If that's the case, you may get some answers if you post this as a FGT question.

Cheers,
Tony

Lauren Child · #23 22-06-12, 00:24

It does indeed have the battery box inside the cab, on the opposite side of the cab to the solenoid, hence routing the cable across the back of the engine bay and down.

It may be that this is just one of the oddities with my vehicle and there's no good route given the full cab. I hadn't considered that most CMPs have the battery box out by the step.

Bob Estabrooks · #24 25-06-12, 05:44

I have been starting my 15 FCMP A for 20 years plus. It is 6 V. But I have a 12V in the toolbox and a 12 V selenoid attached to the frame just behind the 6v. This 12 V only needs to be charged 2- 3 times a year. If I am out for an extended time an the 12 V runs down, the 6V with a fresh recently run engine will start on the first tap. A dry carb rasies hell with a current 6 V battery

Bob

Phil Waterman · #25 25-06-12, 20:34

Hi All

Engine starting on 6 or 12 volt, either or approach. Being a bit of a purest I have retained the 6 volt electrical system on all three of my CMPs. Being blessed with easy starting Chevy engines the 6 volt has not let me down very often. Generally only when they have sat for a long time or in very cold weather or when something else was wrong that more volts might or might not have helped.

But like Bob Estabrooks one of my trucks is set up to start on either 6 volt or 12 volt. When I installed the 261 engine which was designed for 12 volt I did have some concern that the 6 volt would not be able to do the job. But as the C60S has a 12 battery for radios, lights in the box and water system, I installed a selector switch which allows me to connect just the starter to 6 or 12 volt battery. So if the engine doesn't catch on the 6 volt a flip of the switch and the 12 volt spins the engine over.

Only draw back is that the charging system will recharge the 6 volt battery.

Cheers Phil

Cheers Phil