A recent threat got me thinking. The exhaust components on my boat are pretty close to some wiring in the engine compartment. I was thinking about wrapping the exhaust with some insulating material, but was concerned that this might raise the internal temperatures, particularly in the mixing elbow that might promote earlier carbon fouling or some other undesirable consequence. Having done so, I consider replacing the elbow a distinctly undesirable consequence.
To Insulate or Not
- Thread starter wufibugs
- Start date
Your mixing elbow should be running somewhere between cool to cold if it's clear. I would suspect that if the elbow ever became hot enough to affect the wire (rated for 105 deg. C.) you would see an overtemp problem with the engine as well.
Take a look after several hours of heavy motoring to see if there's a heat problem.
wufi, the inmsulation protects what's OUTSIDE from the heat inside the pipe, NOT what's inside the pipe. The temperature change with or without insulation INISDE the pipe wouldn't change any, if at all.
Protect what's outside the pipe, add insualtion.
Protect what's outside the pipe, add insualtion.
The wiring that has to go through the engine compartment passes over the current insulation which reflects heat back. Guess Ill just put a second layer of insulation over the wiring at the rear of the compartment. Thanks, Ralph and Stu.
In a water injected exhaust system the temp of the exhaust gas would not be able to get over 212 unless there was a cooling water restriction. Kind like the pot of water boiling noodles, even on high the water just boils at 212
if you can touch the wiring near the heat source, and hold onto it, it isnt too hot....
unless you are right at the exhaust manifold near where it exits from the head, the exhaust elsewhere should never be hot enough to damage a wire.... that is IF you have just a couple of inches of space between the wiring and manifold. just a couple of inches away should keep the wiring cool enough to hold on to at any time....
sometimes, if the wiring loom runs directly over the top of the hot manifold without enough clearence, the constantly rising heat can damage the wires, but if the wire runs beside it or below it. there is very little to worry about.... as the heated air rises away from the manifold, it is constantly bringing cool air up from the bottom to replace it, which passes over the wiring keeping the wires cool enough to touch even though they are very near the heat source...
unless you are right at the exhaust manifold near where it exits from the head, the exhaust elsewhere should never be hot enough to damage a wire.... that is IF you have just a couple of inches of space between the wiring and manifold. just a couple of inches away should keep the wiring cool enough to hold on to at any time....
sometimes, if the wiring loom runs directly over the top of the hot manifold without enough clearence, the constantly rising heat can damage the wires, but if the wire runs beside it or below it. there is very little to worry about.... as the heated air rises away from the manifold, it is constantly bringing cool air up from the bottom to replace it, which passes over the wiring keeping the wires cool enough to touch even though they are very near the heat source...
Richard, the only part that gets hot enough to damage the wires is the (usually) rusty part that goes aft of the cylinder head and the exhaust elbow. It is about 6" long and 2" wide. In this picture, it is the kinda silvery/rusty part, just below center of the picture. The rest of the exhaust (elbow, cylinder head, rubber hose) is water cooled and will not be above 120F if the water is flowing. If the wires aren't touching the silvery rusty part,and are more than a couple or three inches away, they are fine.
