Engine stalls but will restart (so far)

[Raynewalk]

Anyone encountered this. Series 1 V8 BW35

Engine accasionally cuts out. Will turn over and so far has always restarted after a few attempts. Seems to occur only when idling or running slowly
and possibly when the engine is hot, although it is by no means over heating. If it is fuel vapourisation then I am getting worried about summer performance! Car runs beautifully otherwise, starts easily and idles smoothly.

Thanks for your help...

[rockdemon]

could just need a tune?

[devilsplaymate]

Hi.
My V8 auto S2 BW35 used to stall if i braked too hard to a stop. This was caused by the idle speed being set too low. I took it up to around 600 - 650 RPM and it solved it.

Glen.

[JVY]

I would start with basics like making sure idle speed is set correctly, static ignition set up properly and carb idle mixtures set correctly (i.e. "tune" as rockdemon put it").

[Raynewalk]

Thanks for the advice. It is not under braking. I was expecting a flood of responses about fuel vapourisation but if they are not prone to that then good news. I'll let you know how I get on. The problem I have with the car is that it is restored and in great condition but I have none of the build records and have no idea what was done when. I changed the oil at the weekend and the filter had a date 11.1.11 written on it. The oil was pretty black though. It now has Millers.

cheers

Greg - must add my avatar

[rockdemon]

They are prone to fuel vapourisation but i think you'd have to provoke it hard to happen at this time of year!

Rich

[chrisyork]

Hi Gregg

Not sure we've seen you on the forum a lot before, have I missed giving you a welcome?

Your problem could be quite a number of things. They do suffer from fuel vaporisation, but your symptoms don't sound classic for that problem.

So starting at the beginning, we need to know a few more things about the car. Is it still running the original fuel system with mechanical pump? Or has it acquired an electric one at some point? If so what type, where mounted and is the mechanical pump still in place and / or in use? Are you running the original ignition system with points and condensor? If not do you know what type of system is fitted? Has the coil been changed? Has the feed to the coil been changed? They have a ballasted feed as standard which delivers around 7V to the coil. That is boosted to 12V during starting by switching out the ballast resistor (hidden in the loom) via the starter motor.

So pending results on that.....

You'd expect fuel vaporisation to set in after a long fast run and then standing in traffic for a few minutes. The car then needing around a half hour cooling off before it would start again. A lot of people cure it by fitting an electric pump with varying degrees of common sense and competence as to the actual installation. It can also be sorted by fixing the underlying problem! Poor engine tune will make things worse. So also will a common cooling system problem - a blocked outlet from the carb "tower" at the top of the inlet manifold. You should be able to see coolant from here pumping into the top of the radiator.

As likely is an ignition problem. If you are still on points it is worth knowing that there have been some duff batches of capacitors around which can give truly bizarre and inconsistent symptoms. So too could a coil on the way out. Both tend to misbehave more when hot. And could well fail just enough to stop the engine at low revs but not enough to inhibit restarting. The entire ignition system on a V8 is close to the mark - it's all abit too much for a straight enlargement of the standard Lucas 4 cyl system to cope with 8 cylinders. Keeping the distributor cap and rotor arm pretty new is essential as is using the highest possible quality of ignition leads - nobody's yet come up with a credible alternative to Magnecors. Some sort of boost system for the coil is also a good idea - there are various sorts of fully internal to the distributor electronic systems, systems with the electronics bolted to the outside of the distributor and fully external amps and capacitor discharge systems.

But of course it could simply be that the carbs are set a bit rich (or even a bit weak!). Why not try doing a plug cut to find out what's really going on from that point of view? Drive steadily with the engine under load (say at 60 mmph?). Then simultaneously kill the ignition and knock the transmission into neutral. The engine then stops instantly from loaded running and when you pull plugs, their colour will truly represent how the engine has been running.

Hope that's more the sort of response you were looking for!

Chris

[stina]

But of course it could simply be that the carbs are set a bit rich (or even a bit weak!). Why not try doing a plug cut to find out what's really going on from that point of view? Drive steadily with the engine under load (say at 60 mmph?). Then simultaneously kill the ignition and knock the transmission into neutral. The engine then stops instantly from loaded running and when you pull plugs, their colour will truly represent how the engine has been running.

If your gonna play those sort of games have a good look in the mirror first , and for god sake don't turn the key right back , locked steering at 60 wont be much fun

[chrisyork]

Hi Stina

Gregg's is an S1, so doesn't have a steering lock. But traffic conditions are. of course, a priority!

Chris

[1396midget]

locked steering at 60 wont be much fun

It's really not much fun, happened to me in the midget when the throttles stuck open. Managed to unlock it again without major incident, but new pants were almost required.

But you shouldn't need to charge about with the engine off if it only happens at idle. One thing to check might be float chamber seals, if it's not quite sealing that can cause cutting out at low rpms.

[DaveHerns]

Hope his brake servo is working properly if he cuts the engine at 60mph !

[V8P6B]

They are prone to fuel vapourisation but i think you'd have to provoke it hard to happen at this time of year!

Rich

Mine had a breakdown with fuel vapourisation today... Got it going again just as the breakdown truck arrived...

[Raynewalk]

Thanks for your various diagnosis. It has happened twice more, on the same run. A local stop/start journey this time. Took almost 10 minutes before it decided to start. I am still torn between fuelling and electrics. I am still getting to know the car. It has a mechanical fuel pump and has electronic ignition. The HT lead from the Luminition 'coil' was a tad loose but that could have been from my poking around in the dark when it stalled the other night. Anyway it is seated home properly now. All looks well in the distributor.

On the fuel front I am adding octane boost (Castrol valve master) I know there is considerable debate about whether the V8s need this at all. Once again I know the car has been restored but unfortunately have no build plans or photos so I do not know how the engine is set-up. The engine has clearly been in bits because the gaskets are spanking clean. I think this problem is occuring more when the fuel is nearer to empty. Maybe my mix is out or there is some debris?

[Raynewalk]

GRrr. Still happening. More frequent now. I only have to go a couple of miles. To be precise about the symptoms:-

1. Engine cuts dead, doesn't splutter to a halt. Ignition light out (inhibitor in drive)
2. Ignition on in neutral or park. Engine turns over but will not restart. Does not cough or nearly catch
3. Random fiddlying with ignition leads and removing/re-inserting dashpots
4. After several minutes, when it feels like it, fires instantly and cleanly. Runs smoothly, until....

[harveyp6]

You need to take two spanners to crack the fuel pipe open at the filter, and a spark tester to check for a spark, at the time that it breaks down, otherwise you're looking for a fault that's not there when it's running, or messing about blindly when it stops.