Heat Shrink Tubing protects encased wires from damage Options

[JeffBowlsby]

The heat shrink tubing used on our cars' engine bay wiring collects and routes individual wires for convenience, protects the wires from physical abrasion, dirt and fluid contamination, and most importantly heat exposure. The internal wires have a thin wire insulation further protecting the concealed copper wires and preventing internal shorts, as long as the wires remain pliable and the insulation does not crack.

One consequence of heat if it gets too high, is that it can melt, even char the outer Polyolefin HST casing, within limits. I recently repaired Ted Piersons (TRP) original FI harness that was charred in certain locations and was delighted that the damage was limited to the outer casing and did not reach the internal wires which generally requires a replacement harness. If the outer casing is damaged, hardened, cracked, even charred, its time to replace it to save the internal wiring. Consider it a preventive maintenance item. Automotive engine bay wiring harnesses are not capable of being 'life of car' equipment, they are a maintenance replacement item. Replace damaged casing and other worn out or damaged components such as the rubber boots and wire terminals, and you will greatly extend the service life of the harness.

Heat exposure is arguably the most damaging exposure and common Polyolefin HST protects against heat up to about 195 degF. Higher performing HST is available rated to almost 400 degF, but its generally overkill for 914s.

[TRP]

The heat shrink tubing used on our cars' engine bay wiring collects and routes individual wires for convenience, protects the wires from physical abrasion, dirt and fluid contamination, and most importantly heat exposure....

... I recently repaired Ted Piersons (TRP) original FI harness that was charred in certain locations and was delighted that the damage was limited to the outer casing and did not reach the internal wires which generally requires a replacement harness.

True story! The shrink tubing did its job quite well. When I sent the harness to Jeff it was clearly 'brown' and stiff in a few areas where it had been exposed to some high temps over the years; luckily the wires inside were in great shape! There were a few areas where the heat shrink had been cut back or compromised, the wires in those areas needed to be replaced. The newly repaired harnesses from Jeff are perfect.

Thanks Jeff for tuning up my harnesses! They look SPECTACULAR.

Ted

[wonkipop]

love these scientific posts. (IMG:style_emoticons/default/beerchug.gif)

[Root_Werks]

Reminds me I do have a bunch of that drain pipe looking wire loom stuff in the engine bay on my 914. It gets super soft when warm.

What would a layman like myself use to loom wires in the engine bay? Would I have to buy something solid and pull wires through? Or is there a product that is "split" so it can be installed over wires?

(IMG:style_emoticons/default/idea.gif)

[JeffBowlsby]

I know even new cars use the corrugated split tubing but most engine bays are fully protected from weather, where 914 engine bays are weather-exposed. All functionality considered, split tubing has limited usefulness on a 914.

Its convenient and is available at all FLAPS, but is always 'too big' for the wires inside, making it look clunky and foreign in our engine bays. Joining sections requires molded junctures that look like a plumbing system, not a wiring harness. It likely does provide some degree of heat protection, but it fails to protect the internal wires from the evils of fluid and dirt contamination.

For me split tubing for 914s is a Hard Pass, except as a replacement for an identical OEM part in a newer vehicle where the engine bay is weather-protected.