Driving on 3 cylinders

[windydubber]

Ok for reasons to long to go into I need to drive my van 20-30 miles on three cylinders. Why three? Well one spark plug has popped out and needs re threading.

My question is, what is the general consensus on driving one cylinder down. Can I do any damage other than to the environment?
Cheers

[itchyfeet]

Drove a car coast to coast in Australia on 3 cylinders once, before I fixed the duff valve.
I'd just do it, it will be fine, no racing though, be gentle.

Had a friend who drove through europe with an Aircooled thread knackered, kept pushing it back in the hole with tape around it every time it poped out.

[ghost123uk]

Yeh, go gentle and no harm should result.

A mate of mine bought a used motor for his Bay. One of the plugs was like yours but had been secured in place with high temperature LocTite. He had a hell of a job getting it out to properly Helicoil it !

[windydubber]

Brilliant! That's exactly what I needed to hear! You've made my day!!

[ghost123uk]

Aside = I stopped to help a biker on the hard shoulder of the motorway once. He had a "proper" 70's Triumph Boneville twin. It had holed a piston and was pumping oil into the exhaust. My solution was to take the tappet covers off the offending cylinder, completely remove the (simple) adjusters and then removed the 2 pushrods. The valves then obviously would not operate at all and he set off home (from near Preston to Blackpool) on one cylinder. I drove with him until he pulled off the motorway, got a thumbs up as he left

[windydubber]

I wish I had that level of expertise. Maybe one day!

[silverbullet]

I would try the tape technique. Two turns of masking tape should do it but make sure the plug is right in to give it a fighting chance.

[BOXY]

You don't want to be trying it without a plug screwed in. Without a plug all that lovely petrol & air mix will be squirting out into the engine bay. I prefer to keep my petrol inside the engine.

[silverbullet]

Better to back off the rockers and take out the pushrods for the duffer as suggested, at least the unburnt mixture wont catch fire in the exhaust...

[itchyfeet]

You don't want to be trying it without a plug screwed in. Without a plug all that lovely petrol & air mix will be squirting out into the engine bay. I prefer to keep my petrol inside the engine.

Surely with no spark plug it won't suck air fuel mix through the carbs, it will suck the path of least resistance which is fresh air through the spark plug hole.

no squirting with carbs

[BOXY]

You might be right, but the positive pressure at the plug hole won't be any higher than in the carb will it? The pressure in the carb might even be slightly higher if the air box intake gets a little bit of forced induction from air coming through the side vent?
I know years ago I drove a Renault 5 L about 10 miles after it launched a plug and there was definitely petrol and carbon sprayed on the inside of the bonnet.

[windydubber]

Some of you may have seen my post asking if I could run on three cylinders! Well I decided to go with the majority and risk it!
She took a bit of effort to start last Thursday but when she fired up she managed to get us the thirty miles to Silverstone for the Grand Prix! Left the campsite yesterday and drove her the 10 miles to the garage. What a brilliant vehicle! Even when she's not well she manages to give us a good time!!
Now to wait for the verdict from the mechanic!!

[Dazco]

Good to hear it managed to do the run.

[windydubber]

Just heard from the mechanic! He was able to helicoil the head rather than replacing it! This is probably the difference between us doing our big summer trip or small summer trip!!
Just the other 99 jobs to worry about now!!

[moggymorgan]

Good news,you can enjoy the summer months now