improving disco 3.9 petrol ignition system

3.9 disco engine already has an electronic dizzy, or should have anyway! What exactly is the problem? Badger.

"Badger" wrote in message news:cbfctm$kec$ snipped-for-privacy@newsg1.svr.pol.co.uk...

The early ones, like my '95 (US) are old style distributors. I think they changed with the change to 4l.

kip

On or around Fri, 25 Jun 2004 02:16:23 GMT, "Kip Kniskern" enlightened us thusly:

if it's a points-and-condenser distributor, then the electronic one is a straight swap. You'll also need the amp unit if it's the kind with a remote amp. some electronic ones have the amp on the distributor itself.

There's nothing "old style" about the distributor in a 3.9, it's an electronic unit without contacts. The comparison you are making is to a distributorless ignition as fitted to the 3.9 when they changed it's marketing name to 4 litres (the engine capacity is the same).

It's probably possible to fit the later system to a 3.9 but I suspect the cost would be prohibitive.

There are a number of replacement engine management systems out there which will control both fuel and ignition available commercially or "open source". Take a look at

for example. The Megasquirt'n'EDIS project uses a sensor ring on the crankshaft to drive both ignition and injection doing away with the distributor altogether. There are versions of the project that are ignition only. Of course you need to be ceratin that the distributor is the cause of your problems before embarking on this kind of modification otherwise you could end up spending a lot of money and still have the same problem !

cheers

Dave W.

I was just about to say that! You beat me to it.

Yep, you'd need all the electronics to provide advance / retard, knock sensors, cam sensor, crank sensor etc. etc. More hassle than it'd be worth IMO, better to fit an aftermarket system such as DTAor similar.

Wise words.

Badger B.H.Engineering, rover V8 engine builders.

On or around Fri, 25 Jun 2004 11:21:37 +0000 (UTC), Dave White enlightened us thusly:

IME, the electronic distributor is a reliable bit of kit. The only one I had die was due to a rotor arm going short-circuit between the top and the post.

Whats wrong with the standard 3.9 ignition apart from crap leads? Mine has done sterling service since fitting magnecors.

Nothing, unless you want to do silly wading... far be it from me to put someone off doing it though :-)

I have to confess, I have a MegaSquirt'n'EDIS sat on the dining room table and have just finished attaching a sender ring to the crank pulley. Sometime in late July I'll be "binning" the standard fuel injection and distributor.

Whilst I've been running a custom set of Magnecore leads for the last few years they have done me proud but as soon as the water gets above distributor level I start getting problems, usually with water vapour getting inside the cap despite positive pressure, silicone etc...

Disposing of the distributor and air flow meter seems like the way forward now... I've never been 100 percent confident that the air flow meter is water proof and getting rid of it altogether makes the snorkel pipework a bit simpler.

Why you would go to these measures in a vehicle that isn't expected to have to cope with water levels higher than the bonnet is beyond me though ! As you say, there's nothing wrong with the standard distributor if it's got some decent HT leads on it.

cheers

Dave W.

You were asking for flow rates for 3.9 injectors a few day ago, did you get an answer yet?

If not, a mate of mine came up with the figure 108cc/min@2.5 bar - take that as it comes, I'm not sure whether that's right or not.

I'd be interested in hearing how your MegaSquirt installation goes, can we have pictures when it makes it into the vehicle?

Regards

William MacLeod

No, I didn't....

Thanks, I'll tap those figures in and see what happens :-)

At some point in the (not too distant) future I'll be putting a few pages up about the vehicle and it's various mods. I've taken a series of pics as I've gone along. I'll post a URL once something meaningful appears.

cheers

Dave W.