Solution to Brittle Wiring Harness Cover Under Plenum

[BamaDrewski]

I did a valve cover gasket replacement job a couple of weeks ago. While I was in there, Toyota has a bunch of wires running across the top of the engine (under the plenum) which is covered by a square looking plastic cover. After 12 years of engine heat, that plastic "cover" broke like an egg shell. I was thinking there had to be a better solution for protecting the wires than this stupid piece of plastic. So, I researched "hi-temp silicone tape" and came up with something called "Rescue Tape." (I bought it at a local BassPro Shop in the boat section) This stuff is incredible. It is self fusing, has an incredible 950 PSI Tensile Strength, insulates 8,000 Volts per layer, withstands 500° F degrees of heat and remains flexible to -85° F! (-60° C). SO, I wrapped the entire wiring harness in red "rescue tape" making sure it was nice and snug. When I put everything back (plenum) I decided to run a zip tie through a small hole I drilled in the plastic timing belt cover and I "suspended" the newly wrapped wiring harness so it does not rest on the engine itself. SO FAR, WORKS LIKE A CHAMP!

 

[Qyota]

Nice work! I look forward to doing this soon, as I still need to do my driver side VCG.

 

[SliderNH]

Yeah that plastic is super brittle. Good Mod! Thanks for sharing!

 

[calisurf]

thanks for the post, I am gonna give this a try. Doing a valve cover job right now and I also broke the egg shell cover myself.

 

[Rock_Rat]

Replacing brittle harness

Nice job [MENTION=25434]BamaDrewski[/MENTION]. Having done this quite a few years ago I have a few suggestions.

The fusion tape is good as long as you get the high heat and oil resistant type. Personally, I think the better option would be to use poly loom around the harness after it's taped and DO NOT put any holes in your timing cover.

Just purchase zip ties and clamps from Napa and use the existing bolts to secure the harness to the engine.

Trim the ties (my photos don't show where I trimmed them) and bend the clamps upward to ensure the harness doesn't rest on the engine anywhere. Here's what I did a few years ago.

The poly loom, zip ties, and the clamps keep everything VERY secure! No fears of wires chafing anywhere while going off road. You don't want ANY movement in this harness at all.

If you need to secure wire bundles, I also recommend you use a cable tie mount for your "zip" ties. Here's a link to images on google for Cable Tie Mounts. They make so many different types. When it comes to running wiring for off road lights, winch, amp or whatever, the cable tie mounts provide you with that secure professional installation. I have a couple bags from panduit.

 

[jeremyc74]

Just FYI, that stuff is also available in black if you prefer a more OEM look.

 

[ian1006]

I did valve cover gaskets about 3 weeks ago and that cover literally crumbled. I used poly wiring loom, zip ties, black electrical tape.

 

[Rock_Rat]

Just FYI, that stuff is also available in black if you prefer a more OEM look.

Agree! The next time I go in there, I'm going to replace it all with black. I think it will look a lot better. All I had at the time was the high temp orange.

 

[jeremyc74]

Agree! The next time I go in there, I'm going to replace it all with black. I think it will look a lot better. All I had at the time was the high temp orange.

Yeah, it's good stuff! I've wrapped more connectors with this stuff while I was in the Marine Corps than I even care to think about. :bowl:

Here's a listing on Amazon:
http://www.amazon.com/010476-Self-Vulcanizing-Super-Fire-Tape/dp/B000MY55F4

And in the related items there's also another good item if you're going for an OEM type repair....German engineered electrical tape! :frisky:
(The Germans overthink everything, but this is actually good stuff!)

http://www.amazon.com/Tesa-Black-Hi...263_img_2?ie=UTF8&refRID=09VK1FYDKFXS4R4P03M6

That might even be a little cleaners.

 

[BamaDrewski]

Nice job [MENTION=25434]BamaDrewski[/MENTION]. Having done this quite a few years ago I have a few suggestions.

The fusion tape is good as long as you get the high heat and oil resistant type. Personally, I think the better option would be to use poly loom around the harness after it's taped and DO NOT put any holes in your timing cover.

Just purchase zip ties and clamps from Napa and use the existing bolts to secure the harness to the engine.

Trim the ties (my photos don't show where I trimmed them) and bend the clamps upward to ensure the harness doesn't rest on the engine anywhere. Here's what I did a few years ago.

The poly loom, zip ties, and the clamps keep everything VERY secure! No fears of wires chafing anywhere while going off road. You don't want ANY movement in this harness at all.

If you need to secure wire bundles, I also recommend you use a cable tie mount for your "zip" ties. Here's a link to images on google for Cable Tie Mounts. They make so many different types. When it comes to running wiring for off road lights, winch, amp or whatever, the cable tie mounts provide you with that secure professional installation. I have a couple bags from panduit.

Thanks for shout-out RockRat! I thought about the polyloom when I decided on the self-fusion, high-temp tape. I was concerned the poly loom would not be able to tolerate the heat. Either way - this approach is much better than the brittle eggshell plastic that came stock on our rigs.

Great photos of your engine man!

 

[mtbtim]

When i did the job on [MENTION=102606]infamousRNR[/MENTION] truck, I taped the plastic wiring loom with HVAC foil tape before prying on it to get the driver side valve cover out. Taping it beforehand keeps it together even if it cracks, which it probably will. This way, you prevent a bunch of plastic bits flying all over the top of your engine, or worse yet, dropping onto the top of the head while you're removing your valve cover.

Here's the video [MENTION=102606]infamousRNR[/MENTION] and I made for the Valve Cover Gasket job.

<iframe width="560" height="315" src="https://www.youtube.com/embed/N5fAXAuGozI" frameborder="0" allowfullscreen></iframe>

 

[toverturf]

I just did this job and yea that drivers side one was super brittle for me. I just taped it up with some green painters tape because that's all I had on hand before I moved it around. It's definitely broken into a ton of pieces under it haha. Just left that tape on there when I put everything back together. Wish I saw this thread before hand because I probably would have ordered some of that silicone tape before doing the valve cover gaskets.

 

[BamaDrewski]

I just did this job and yea that drivers side one was super brittle for me. I just taped it up with some green painters tape because that's all I had on hand before I moved it around. It's definitely broken into a ton of pieces under it haha. Just left that tape on there when I put everything back together. Wish I saw this thread before hand because I probably would have ordered some of that silicone tape before doing the valve cover gaskets.

That painter's tape could be a hazard. It is not designed for high heat and it will dry out quickly with engine temps and could actually start to scorch/burn. I'd get that off and replace it with the rescue tape ASAP. This is just my opinion of course.....

 

[toverturf]

That painter's tape could be a hazard. It is not designed for high heat and it will dry out quickly with engine temps and could actually start to scorch/burn. I'd get that off and replace it with the rescue tape ASAP. This is just my opinion of course.....

Yea I think i'll order some rescue tape then and get it put on there.

 

[2TH4IST]

My drivers side cracked when I did my vc gaskets. I used some 1/2" fire sleeve (for hydraulic hose heat protection). Slit it and zip tied it around the loom. Great abrasion and heat protection.

 

[3bears]

yep...had to do mine too ...used rescue tape
driver side is the worst....guess heat really traps in there.

 

[octanejunkie]

Nice job [MENTION=25434]BamaDrewski[/MENTION]. Having done this quite a few years ago I have a few suggestions.

The fusion tape is good as long as you get the high heat and oil resistant type. Personally, I think the better option would be to use poly loom around the harness after it's taped and DO NOT put any holes in your timing cover.

Just purchase zip ties and clamps from Napa and use the existing bolts to secure the harness to the engine.

Trim the ties (my photos don't show where I trimmed them) and bend the clamps upward to ensure the harness doesn't rest on the engine anywhere. Here's what I did a few years ago.

The poly loom, zip ties, and the clamps keep everything VERY secure! No fears of wires chafing anywhere while going off road. You don't want ANY movement in this harness at all.

If you need to secure wire bundles, I also recommend you use a cable tie mount for your "zip" ties. Here's a link to images on google for Cable Tie Mounts. They make so many different types. When it comes to running wiring for off road lights, winch, amp or whatever, the cable tie mounts provide you with that secure professional installation. I have a couple bags from panduit.

I was going to use SBC chevy wire loom standoffs to support my wrapped harness (wire harness tape and high-heat loom) but the cable clamps look easier lol

 

[twolfe278]

Wiring Harness

FRAGILE’ That must be French. Just bought a 2000 Limited with 226k. The 1- owner never replaced anything. This mod helped me tremendously on my VCG job. It all fell apart even while taped like Tim suggested. I thought…oh snap. Found this and voila! Thanks a ton everyone. What a resource this forum is. I’m going to replace timing belt, water pump, and radiator also. Should I do that after valve covers before reinstalling air box etc? Didn’t know if there was a benefit to doing it all at the same time.

 

[gh25_]

I used the 3m friction tape but the Tesa tape is also really good. Some car brands use the specified tesa cloth harness tape from the factory. The 3m stuff is equally as good which is what I used. Above the valve covers & plenum area doesn't get very hot considering. I've measured various parts of my engine when it's hot. If I remember correctly that area it's about 110 - 130 deg. F. Only my driver cover got destroyed. After I got the rest of the old plastic cover off I first wrapped the bare harness in just standard electrical tape. Then after that I wrapped the whole harness in I believe it was 3/4" sized dorman wire conduit. After that I wrapped the whole thing in the 3M' friction tape to incase it all. Been about 7 months since I did it and it's been working great for me and looks good too. I know this is an old thread but it might help someone anyways haha.

3M #3407NA

Tesa #51036

 

[shadow247]

I just did the VC on 2 different 3.4. Mine is a 2001 4RUnner with 220k miles, garage kept and babied. The other one was a 1998 Tacoma 4x4 with some HARD miles on it.

My wiring and loom was super pliable and soft. I don't think I could have broken those plastic pieces if I tried. Only 1 ear was torn for the mount, and that was done by the TOyota dealer that had been in there previously.

The Tacoma was just a bunch of bare wires. Whoever had been in there before mangled up the harness covers and loosely wrapped the wires in electrical tape that was falling off. I rewrapped everything in Tesa tape and cleaned it up the best I could.

I was full expecting a mess on my 2001, but I guess I got lucky. After reading all the threads, Timmy's video, etc... I was pleasantly surprised.