Compression Question

[Ancient Mariner]

If the glowplug was removed and replaced with an extended plug with 5mm diam hole thru the guts and a valve fitted would it pass enough gas to inhibit combustion? Time for my medication:D

[JDNSW]

Probably not, but one has to wonder what this is for? It would presumably be possible to make a fitting where the actual valve was very close to the combustion chamber, to minimise the actual volume added to the combustion chamber.

John

[Ancient Mariner]

John I have been thinking compression braking but think as you do that 5mm bore will not bleed off enough compression .The 90mm of 5mm bore would be a killer:( but if the valve could limit it to 25mm I think I could live with that


Thanks Noel

[Blknight.aus]

At low rpm on a cold engine yes, a hot engine at high rpm no

If you were thinking of using it to inflate stuff it will work but you'll get diesel fumes past it.

If you were thinking by of using it as a compression brake that will also work, what you need to do is install a switch that disables the engine brake at idle, when the clutch is depressed or when the rack is in other than the no fuel positions.


The simplest way to closely achieve this would be.

Fit a brake pedal switch and bracket to the clutch use that to energise a relay.
Take power from the nor.ally closed position of the relay and drive that through another relay controlled by a tacho that cuts the power to the brake setup if engine rpm is under 950rpm.

From the normally open position. switch wire up a feed that puts up a warning light where you can see it that lets you know that the compression brake is on.

That way you get a warning that your about to drop the clutch against full engine braking

Edit, changed first sentence to hot engine at high rpm no