2.5TD glow plug amps?

In article , Andrew T. writes

HBOL says they should be Champion CH70 wired in parallel. Earlier engines have series-wired ones (Champion CH63), but I can see why that would be deprecated: if one fails you lose the lot. The other good reason on cold days is that operating the glow plugs for a few secs conditions the battery (warms it, mainly), so that if you do the sequence: plugs, wait five secs, then starter, it'll start more easily, possibly.

BUT... I've had two ignition switches go on TDs with parallel glow plugs. Per factory, the entire current goes through the steering column switch and slowly wrecks it, so a relay would be sensible!

I think if you allow 60A that ought to be enough (180 Watts per glow plug), but I've Googled and I can't find a current rating for them. Champion's web site is truly horrible...

Hope this helps, but it probably doesn't :-(

,

With my owners handbook in front of me it tells me its a 10 amp fuse

DieSea

In article , DieSea writes

Presumably that's for serial wiring?

It _must_ be more than that for parallel plugs, surely? The high current contacts inside the steering column switch are for more than that, and they burn out (I took a failed one apart to find out what had happened).

Skim-reading it, I can't find a fuse shown in the HBOL wiring diagram circuit for the glow plugs. It goes straight back to the ignition switch. There is a ballast resistor shown in the series-wired variant.

Again looking at the OM it tells me that its fuse 17 and 10 amps

It then goes onto say that fuse is for the glowplug and starter motor

Perhaps it means the starter motor and glowplug relays ??

The only reason I'm looking at the fuse diagrams

I'm trying to dump the wrong radio code I put in when I blew a fuse un Scotland over the weekend

DieSea

Just to muddy the waters a bit, I've got a Champion CD which lists their CH63 (an 11 volt unit i.e. for parallel connection) from June 1983 for both the 2.25 and 2.5 engines. The series heater plug (nominally 1.7 volt) is their CH45 listed as being for the 2.25 engine to 1983.

Martin may be able to help.

I don't know to be honest but IIRC the 2.5 NA & TD use a timer relay and it's quite big physically. I would expect it to be rated around 40/60 amps (possibly higher) which is what someone has just suggested. Is this the one that's just been converted to a TD in the last couple of weeks? because, if so, it might not have the standard relay. Good idea to stick one in anyway if it's burning the switches. I can look it up tomorrow though.

Book of diesel data here says 11A per glow plug in parallel, and says nothing about the series ones, but somewhere in the depths of my memory

35A rings a bell.

Hello Everyone,

Thanks alot for all the replies, much good info, when I said wired in series I was perhaps wrong.... what I meant was that there is one wire going from one plug to the next and so on, so this would be parallel... wiring them in series would be rather tricky I suppose, if done in the same manner as resistors are wired in series. Yes, it is the "new" conversion from V8 to TD, I was planning just to put in a beefy relay and aux switch and not using the ignition switch at all (except perhaps to power the relay), together with separate fuse. I have some 40amp relays lying around so I'll try one of these, and try to dig out the ammeter from the shed.

Thanks alot! Andrew

Which, presumably, would give you around 8.75A, or 100W (approx.) per glowplug. About right at a guess.

I still think series wiring sounds like a bad idea, but it must have been done that way for a reason - anyone know why?

In article , Andrew writes

HBOL: 10J engines (up to 1984), clearly shown as wired in series, with a quite different graphic for later, parallel-wired glowplugs.

But I share your skepticism: this is going into the box, along with spiky carpet grippers, dual-mass flywheels, and big Q-max punches without bearings: just because you could imagine it doesn't mean...

... talking of which, and veering wildly off topic, does anyone know a good source of supply of either rectangular punches or fly press tooling for small rectangular holes? I'm trying to fit some Ericsson keys tidily, and the old cheat of a round hole with a switch guard has failed (I've run out of switch guards :-( ). Wonderful switches for the job - can't beat the tactile feel of them - but a right PITA to fit. Everything I've seen so far is either too big or requires a second mortgage.

Buy a decent timer for them - it'll save a lot of hassle and grief. Something like the first in the below link would be perfect (aside from the vendor being 12000 miles from you).

Are you reading the previous post right? If they take 11amps current, then four of them will take 44amps (the figure that was originally requested), and at 12v, that's 528watts.

It worked alright for a long, long time and is still doing so on my old Series2. Probably just the technology of the time but easy to test if it goes wrong. With that little bulb wired across the resistor after a few seconds the resistor gets hot, it's resistance gets higher, more current tries to flow through the bulb which starts to glow giving you a rough guide to what's happening. If it initially glows brightly, it tells you there is a short cicuit and if it doesn't light at all then there is an open circuit (e.g glow plug failure or bad connection), but if it glows dimly then everything's usually ok.

Martin

The ones on my 2.5n/a pull about that (tested with an ammeter)

In article , Oily writes

If he meant 35A for the series ones, probably not!

I thought he meant 35A for the four together, in parallel. Champion rate them at 11V incidentally, presumably allowing for the battery voltage drop on load.

Yup.

Yes, I can see that. It still means that if one plug fails you lose the lot. OK, you will know what's wrong, but you won't know which one and the engine won't start easily, if at all. You also can't bypass the faulty one even if you find it, without risk to the others from overvoltage.

With parallel glowplugs, even if one, or even two go, you can most probably still start the engine, and you could disconnect one or two if you needed to.

Makes you wonder why there's no relay then :-(

Would've thought RS would do them, but oh yea you did say 2nd Mortgage!

OK, at lunchtime I eventually found my clip-on ammeter (not sure of accuracy), a good battery and jump leads (the engine is sitting on the garage floor). Ammeter clipped on + jump lead, connected up and it went off the scale at 75a! so I tried just 1 plug and it gives 25a. Tested each one separately and each gives same result.

100 amps all in?? seems alot, but on a couple of web-sites I found when googling "glow plug wiring" several people suggested using a starter solenoid.

But really it can't be 25a each can it? I'll have to find another meter.

Cheers, Andrew

In article , Andrew writes

(a) yes, it could be.

(b) no, it probably wouldn't be, because that load would drop the voltage *significantly* (Champion rate at 11V), so the current will drop too.

That doesn't mean you won't see a big switch-on surge current tho.

A starter solenoid is the safe route, IMHO, although making off the terminals nicely might be awkward (load circuit designed for _big_ wire).

If the glow plugs in question are supposed to be wired in series that's in the ballpark for an individual plug.