MOT emissions for an LPG classic

I built the Velleman kit for my old 997 mini, but found that I still had points bounce. IIRC there are some ballast resistors in the circuit, just increasing the value sorted it.

My LPG VW Sharan is all computerised, I'm sh*t scared of something going wrong :-)

Paul

: I built the Velleman kit for my old 997 mini, but found that I still had : points bounce. IIRC there are some ballast resistors in the circuit, just : increasing the value sorted it.

I didn't modify the circuit, but I did change the mechanical design a bit: fitting the thing in a die-cast alloy box with the heat sink on the outside.

I'm not a great fan of fitting these things to "normal" cars - I take the view that, for example, my Herald ignition worked fine when the car was built and if it isn't workingfine now I should find the problem, not just pump more volts at it. LPG is different: it definitely needs more oomph to ignite it, and the DS ignition is pretty marginal even on petrol...

: My LPG VW Sharan is all computerised, I'm sh*t scared of something going : wrong :-)

Just wait till you annoy it. It'll vent the tank to the interior via a pipe it's keeping secret, wait a minute for a decent fuel-air mix and then trigger a couple of sparks.

To modify the old joke: parachutist with failed main and reserve is plummeting towards eath, meets a bloke coming up. "Do you know anything about parachutes?" asks the one. "No" comes the reply "Do you know anything about LPG conversions?"

Ian

"Paul Collins" realised it was Fri, 3 Sep 2004 18:52:29 +0100 and decided it was time to write:

Points bounce...

I think my Spitfire 1500 may be suffering from that. Sometimes, when it gets over about 3,500 rpm, it just won't go any further and effectively loses power. It doesn't always happen, but when it does, it's usually at the same number of revs, irrespective of the selected gear. Fuel pump and filter are new, carbs are not worn, well adjusted and filled with the right oil, points gap is spot-on.

Any solutions, apart from going optical/electronic?

New points? There's nothing intrinsically wrong with points apart from the fact that they wear out.

Worth changing the capacitor too.

"Dave Plowman (News)" realised it was Fri, 03 Sep

I don't think the points have done more than 3,000 miles, at most, but I'll try that tomorrow.

If it's intermittent I'd be looking at something sticking. That could be the advance weights in the dizzy. Points, even well buggered ones, aren't going to bounce at 3500rpm. Another classic cause of not wanting to rev is broken valve springs but again that's not an intermittent thing.

In the fuel supply it could perhaps be a bit of crap in a line somewhere, maybe the float bowl, or too low a float level, or a dodgy fuel pressure regulator.

snipped-for-privacy@aol.comNoEmails (Dave Baker) realised it was 03 Sep 2004

Thanks for the suggestions.

The car has been much too reliable for a tinkerer like me, so I'm glad to have a few things to check. ;-)

A fuel pressure regulator on a Spitfire 1500?

There's one built in to most carb fuel pumps and who's to say an additional one hasn't been fitted?

Once in a while you can come across a faulty set that do strange things, and if the capacitor is starting to fail.....

: Incidentally, I fitted a Velleman kit ignition amplifier from Maplins : a month or two after the LPG conversion. It made a huge improvement, : and I very strongly recommend them to anyone thinking of LPGing a : classic.

Though I have just had to take the damn thing out as it started drawing fourteen amps, overheating and, to put it mildly, buggesring up the ignition system. All very odd - it has been in there for ten thousand miles faultlessly and there is no sign of any blown components.

Ian

Yes, I've seen a dodgy capacitor acting as a rev limiter too.

The other thing worth checking is the little wire that connects to the points. Metal fatigue is not unheard of.

Jim

Lucas points don't bounce at 3500 rpm unless you are revving your Spifire to 9,000+ RPM you just won't encounter it, from your description you have have fuel suppy problem most likely due to black gunge inside the tank, this was a well known problem on BL and Chrysler UK vehicles in the 1970s it was caused by the tank manufacturer painting the inside of the fuel tanks. From about 76 simple mod was introduced to combat this a screen filter was fitted inside the fuel tank on the end of the suction pipe. To an extent this fillter is self clearing as the gunge falls off when the vehicle is parked overnight but if your tank is realy badly gunged it won't do any good.

It might also be an idead to check the distributer base plate is earthing properly and that the condensor wiring is correctly fitted and the condesor screwed down to the base plate tightly.

Was getting similar problems on a freind's stag, a couple of garages had looked at it but couldn't sort it. The problem was a worn baseplate and I replaced with a newtronic ignition (on its own base plate)and the car ticked like a swiss watch. Now it starts on the button hot or cold and runs smoother. If you change get a set of new leads, as the extra kv and dwell angle will soon highlight and deficiencies in old ht leads.

They can't have been much good. A dwell meter will show this straight away.

Just what I thought, particularly as both of these garages are supposed to be old car freindly.

Usually diagnosable by the Triumph badge! It's a very common fault.

The problem was not the baseplate in (AC Delco) 'Triumph' distributors but the shaft bearing.

As well as the bearing, and the baseplate, and wear on the hinge pins, and the hinge pin rivetting falling out.