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How are manufacturers and individuals handling cat shield rattle?

Discussion in 'Gen 3 Prius Accessories and Modifications' started by Georgina Rudkus, Jun 17, 2021.

  1. Georgina Rudkus

    Georgina Rudkus Senior Member

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    I recently came across this video of a Gen 3 cat shield made by Miller Cat installed on a Prius, and I am not impressed with the design. I can, however, see how the design might be problematic in promoting rust.



    Shipped flat, the trailing edge of the shield is apparently laser cut with slots that allow the installer to easily bend it upward to provide support and clearance from the car's floor pan.

    There's where the design becomes problematic. Laser cut edges are rough and contact the steel floor pan vertically. As the car is driven over time, the rough edge is likely to quickly"saw" through the paint and into the steel substrate and expose it to rust. Basically; an unintended consequence.
     
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  2. xliderider

    xliderider Senior Member

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    Run a flat file over the edges to knock down, or even put a small radius on the laser cut edges, problem solved.

    Posted via the PriusChat mobile app.
     
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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Feedback to Miller Cat manufacturer might lead to them doing this. (y)
     
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  4. black_jmyntrn

    black_jmyntrn Senior Member

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  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Thanks for that. (y) Would be worthwhile to hit all the drilled holes with something like Fluid Film? Maybe do the same to all riv-nuts and fasteners too.
     
  6. black_jmyntrn

    black_jmyntrn Senior Member

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    Not really. I've installed a Gen 2, Gen 3, and Gen 4 Miller Cat shield(I need to post the Gen 2 and Gen 4, I have had technical issues lately), with each of them having no rattle. If an installer didn't install one riv-nut properly and the rattle "could" happen, the install would have to be botched for it to rattle. They even include foam strips that are strategically placed.

    The thought of "the rough edge is likely to quickly"saw" through the paint and into the steel substrate and expose it to rust." is plausible but a reach IMO. I mean, if someone didn't have a lift and installed the shield laying on their back, I could definitely see an improper installation happening.
     
  7. Georgina Rudkus

    Georgina Rudkus Senior Member

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    A new Miller Cat Gen 3 install video;

     
  8. farmecologist

    farmecologist Senior Member

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    Hmm in that video the three 'fins' are supposed to be bent downwards at a 45 degree angle. Someone F'ed up on the install. :whistle:
     
  9. lech auto air conditionin

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    One little trick to cut down on rattling and loose rivet installation when installing that kind of cat shield.
    Of course for proper installation is key number one. But like we do in helicopters when you’re riveting together any of the body panels with rivets.

    Apply epoxy to your rivets when installing brush a thin coat of epoxy over the head of the rivet just like an aircraft or helicopters.

    Because of the extreme vibration that aircraft go through and temperature changes expansion and contraction rivets have a tendency to loosen up. This is why it’s aircraft industry standard to do a epoxy coating on installation of rivets.
     
  10. Georgina Rudkus

    Georgina Rudkus Senior Member

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    I use the Miller Cat method with rivet nuts but no foam strip, spacers or rear vertical flange. My method is to make two radial bends on the trailing edge of the front shield. The rear profile has an upside down "trapezoid" shape that clears the rear contact point of the catalytic converter should the plate remain flat.

    The M6 Torx security screws are then fastened stainless steel neoprene backed conical "crush" washers under their heads.

    The opposing bends made over a 2x4 adds a strengthening structure to the plate and totally eliminates any "oilcanning" effect.

    The manufacturers prefer to ship the plate flat. The pre-bent plate would provide no problem in a flat cardboard box, if the box is made with a few extra inches on each side. The resulting "bulge" would not impede shipping and handling. And, and deformation occurring from shipping is easily bent back by hand by the recipient.
     
  11. Boojoo007

    Boojoo007 Junior Member

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    I just had my shield installed on my Prius C 2011 . There is a noticeable rattle now, kind of annoying but should I be concerned about the noise or just leave it be?
     
  12. ASRDogman

    ASRDogman Senior Member

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    You should go back and tell them it rattles, and to please fix it so it doesn't rattle.
     
  13. Boojoo007

    Boojoo007 Junior Member

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    thanks, I’m going back . I looked under and noticed not all the bolts were put in compared to the images on the website. I’m not happy!
     
  14. lech auto air conditionin

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    Properly installed Sheilds do not rattle
     
  15. Georgina Rudkus

    Georgina Rudkus Senior Member

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    Here are photos of the bends that provide clearance and stiffness to eliminate all rattles and contact with the catalytic converter. 212305_IMG_1237.jpg 212306_IMG_1244.jpg
     
  16. WickedV

    WickedV Junior Member

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    The manufacture is not Toyota and other than protecting your cat from getting swiped, not certain they are bothered.
    Can rectify the issue "if" you have one, by placing some, also from Amazon, yes I know I have an issue lol, Aluminum Heat Shield Protection with Fiberglass and Self-Adhesive Backing Heat Barrier 2 Sq Feet (12x24 Inch) , cut and place it on the shield and sandwich it next to the cat or what ever else may be rubbing on the guard.Acts like a cushion. Helps if you dimple the guard at the contact point first and if the issue remains, then install the heat barrier material. Dependent on how your cat and it's piping was made by Toyota, it may all be generic but not all cats collide with the shield.
    Seriously it's not "Miller" as the manufactures problem, it's the person who installed the shield and their lack of incite to see a possible issue and do nothing to rectify it.
    Personally I use the Cat Security/ cat guard variant, my cat rubbed on that too initially.

    Oh and forget the rivets, nice in theory, but they may cause vibration too, best to riv nut the thing on and use security screw in fasteners.
     
    #16 WickedV, Dec 15, 2021
    Last edited: Dec 15, 2021
  17. Boojoo007

    Boojoo007 Junior Member

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    I went back another time and it was still making bad noises. Finally they found they forgot a part, which I suspected the whole time.
     
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