Hot Starting Issue

[beebee246]

Can you tell us what ignition setup and plugs you have in place?
If you keep the throttle fully open while starting, how long does it take for the engine to catch?

Hi ALH,
Thanks for your reply. Just got back from a week away, without any method of getting on line, so apologies to you, and all respondents for tardy response.
I have a SUPER 4 coil (the standard Superformance replacement for the original), standard Dinoplex ignition box, and I was using Bosch WR5 DP (single electrode) platinum plugs (which I have in BS1319, and they work well), but I have swapped those for Bosch W5 DTC (triple electrode platinum), which made no difference. As you will probably have gathered from my previous replies, the car doesn't catch (at all). It will not start (or fire) when hot. And I don't mean super hot, I just mean after a short run in normal UK temperatures. Yesterday I drove it 5 miles, and switched it off on my drive. To get the car into my garage, I had to "chug" it in on the starter motor (I know, not recommended).That's after I'd left it 30 minutes to cool; It still wouldn't fire.

[alh]

Hi Brian,

the Super4 ignition is actually a clone of the early seventies Bosch TSZ, the output is exactly the same as a points and coil ignition, e.g. not really sufficient for running the Dino engine. I would recommend getting something with more output, as example a MSD 6A/Blaster 2, a Crane XR3000 or a high power Bosch conversion. (All of these can be fit into a Dinoplex AEC101 or AEC103 enclosure).

With the Super4 in place, you could short-circuit the ballast resistor of the Bosch red coil while starting (this is the primary reason why there is an external resistor). To test if this approach works, short circuit the grey white Bosch ballast resistor with a wire, then try to start the car. Remove the short circuit wire after the car has started (else the coil overheats after some minutes).

If this works well, you might want to add the components/wirings as in the circuit diagram below. This short circuits the ballast resistor every time you turn the starter, enabling a hotter spark. I recommend NKR BPR7EIX spark plugs for the Dino engine and a transistor ignition setup.

Bosch Coil resistor bypass.png (24 KiB) Viewed 10412 times

Best,
Adrian

[beebee246]

Hi Adrian,
Many thanks for your reply, and advice. My next opportunity to look at the car is this weekend, so I'll follow your advice & let you know how I get on,
Thanks, Brian

[Dario]

Maybe you have already done this, but if you have a chance, a good place to start is to look at the plugs when it's not starting: are they moist with gas or bone dry? If it's the latter, definitively a fuel supply problem (carbs, vapour), if they are moist, then look to the ignition side. If (like mine before I rebuild the carbs) they are black and wet, then fuel/air mixture fouling the plugs...

good luck, not much fun to be stuck at the gas station waiting for the engine to cool!

Dario

[beebee246]

Maybe you have already done this, but if you have a chance, a good place to start is to look at the plugs when it's not starting: are they moist with gas or bone dry? If it's the latter, definitively a fuel supply problem (carbs, vapour), if they are moist, then look to the ignition side. If (like mine before I rebuild the carbs) they are black and wet, then fuel/air mixture fouling the plugs...

good luck, not much fun to be stuck at the gas station waiting for the engine to cool!

Dario

Hi Dario,
Didn't get chance to look at the car yet. The plugs were dry when I pulled them, so suspect fuel vapourisation. Going to go through the carburation later this week,
Thanks,
Brian

[Dario]

Hi Brian, I've been thinking about your hot start issue. Vapor lock could be an easy culprit, but it shouldn't be a real problem in our Dinos: the Fuel pump is below the gas tank, away from engine heat. Also, we have a recirculating fuel line that keeps the fuel constantly running in the fuel lines, which keeps them cool. (I'm guessing the setup is the same for 2L and 2.4L cars.) This leaves us with the carbs, which are in the fully open position when you try to start the engine hot. Therefore, it is something with the float level (controls the amount of gas to the jet), or the supply to the main jets (are your std or have they been swapped by a PO?). You should be able to force gas to the engine by pumping the accelerator pedal. Does this give you a few pops when you crank the engine? If not, are you pump membranes in shreds? I would also look at the static advance when your engine is hot (i.e. at idle): maybe the weights get stuck or something and this makes starting difficult when turned over by the starter motor.
good luck and keep us posted,

Dario

[Tobi]

Also, we have a recirculating fuel line that keeps the fuel constantly running in the fuel lines, which keeps them cool. (I'm guessing the setup is the same for 2L and 2.4L cars.)
Dario

2400s have a recirculating fuel line, 2000s don't. That's why they also need a pressure controoler.

[Dario]

I stand corrected! I would guess the spark plugs would be dry if they were hot enough to prevent condensation of the fuel. I would also check if there is a smell of gasoline from the exhaust when it's not starting...

[beebee246]

Hi Brian,

the Super4 ignition is actually a clone of the early seventies Bosch TSZ, the output is exactly the same as a points and coil ignition, e.g. not really sufficient for running the Dino engine. I would recommend getting something with more output, as example a MSD 6A/Blaster 2, a Crane XR3000 or a high power Bosch conversion. (All of these can be fit into a Dinoplex AEC101 or AEC103 enclosure).

With the Super4 in place, you could short-circuit the ballast resistor of the Bosch red coil while starting (this is the primary reason why there is an external resistor). To test if this approach works, short circuit the grey white Bosch ballast resistor with a wire, then try to start the car. Remove the short circuit wire after the car has started (else the coil overheats after some minutes).

If this works well, you might want to add the components/wirings as in the circuit diagram below. This short circuits the ballast resistor every time you turn the starter, enabling a hotter spark. I recommend NKR BPR7EIX spark plugs for the Dino engine and a transistor ignition setup.

Bosch Coil resistor bypass.png

Best,
Adrian

Hi Adrian,
We changed the wiring to your suggestion, although we bypassed the electronic ignition, and have temporaily gone with a points and 12v coil. The hot starting is much improved (and the cold starting also), so must've been a weak spark issue. I now have a rev counter that bounces around all over the dial!. Do you think that I'd have the same spark strength if I go get the car rewired over to the Dinoplex again.
Thanks, Brian

[Dinoswede]

Beebee246;
If you rewire your ignition back to include the Dinoplex again and get a non-starting Dino,when hot, you must have an issue with your Dinoplex.
My original large Dinoplex gave up some years ago, without any indications of upcoming problems. After having the Dino parked for 1 hour, after a
longer drive, it just would not fire up. After swiching over to the emergency mode, it fired up promptly. When opening the Dinoplex box, already
the strong smell of burned electronic components was reason enough to look for a replacement...

Dinoswede