Butterfly screw in inlet manifold

TeZZaP · 19th July 2023, 11:09 AM

I was nearly home when the engine started to roar. I killed the ignition and coasted to a stop, I assumed it was a problem with the accelerator pedal linkages, but when I checked it was the lower spindle/butterfly on the carb being stuck open.

Once back home and with the carb off I could see that one of the brass screws that secures the butterfly to the spindle was missing, presumably into the inlet manifold or even sucked into a cylinder… so, my current plan is to use a vacuum cleaner to rig a small tube that I can poke into the manifold and hopefully suck out the screw, and if nothing comes out I’ll do the same thing in each cylinder via the spark plug hole.

I’ve also ordered a small camera that I can poke into the cylinders/manifold to visually check for damage.

So… has this happened to anyone else? What are the risks if I can’t get it out? Will it just get sucked out into the exhaust?

**1950landy** · 19th July 2023, 11:26 AM

What is the screw made of, one of these magnets may do the trick if it's steel.
s-l1600 magnet1.jpg 515Wx515H-TO15615-1magnet.png

**p38arover** · 19th July 2023, 02:05 PM

Aren't the screws brass?

**JDNSW** · 19th July 2023, 02:21 PM

Screws are brass. But very unlikely to cause any issues if sucked into the engine - perhaps mark the top of the piston at worst. (not on a Landrover, but I have had one go through my chainsaw without issues)

Magnet wont pick it up, but a bit of blutack on a rod probably would, or perhaps a three finger pickup tool.

**RANDLOVER** · 19th July 2023, 03:44 PM

It seems there may not be much to find if the screw went in the cylinder, as brass melts between 900-1000 C and petrol flame temp is 2000-2500 C.

TeZZaP · 20th July 2023, 06:30 AM

Unfortunately I’m away for a few days, but will report back at the weekend when I get a chance to investigate further…

**gromit** · 20th July 2023, 06:47 AM

Originally Posted by RANDLOVER

It seems there may not be much to find if the screw went in the cylinder, as brass melts between 900-1000 C and petrol flame temp is 2000-2500 C.

Aluminium melts at a lower temperature but the pistons don't melt.

As JDNSW states it's unlikely to have done any damage if it got sucked into a cylinder apart from a mark on the piston. Worthwhile seeing if it's still in the manifold though, could still be usable.

Colin

**RANDLOVER** · 20th July 2023, 04:15 PM

Originally Posted by gromit

Aluminium melts at a lower temperature but the pistons don't melt.

As JDNSW states it's unlikely to have done any damage if it got sucked into a cylinder apart from a mark on the piston. Worthwhile seeing if it's still in the manifold though, could still be usable.

Colin

You make an excellent point, shows how good the cooling system on a Land Rover is.

TeZZaP · 25th July 2023, 01:28 PM

Sorry for the delay, was waiting on new probe camera.

Nothing came out of the inlet manifold nor the cylinders using the vac, but the probe camera did spot this on top of the cylinder #1 piston…

Image-1.jpg

So I’m guessing the screw has either been obliterated or smashed flat and the gone out via the exhaust valve!

No sign of damage to either the walls of the cylinder or the valves/seats, so I’m guessing all’s good in the end!

**p38arover** · 25th July 2023, 02:14 PM

It's left an imprint of the thread.

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