Bushing vs Grommetts

[AviatorJ]

I'm doing a modification that may require some holes into the webbing. Typically I've used snap bushings, but I've also used rubber grommets as well. Is there a reason to use one over the other? Bushings I think of protecting from the sides of the hole. Grommets I think of more a snug fit.

[Jesse]

I greatly prefer snap bushings. If you want a snug fit, or don?t want movement in the hole, a little rtv can make up the difference.

[AviatorJ]

Thanks Jesse

[RV3bpilot]

I used some rubber grommets in the engine compartment and they soon were destroyed by the heat. I was trying to protect my spark plug cables. The snap in bushings will hold up better near heat, but not exhaust heat of course...

[az_gila]

Originally Posted by RV3bpilot

I used some rubber grommets in the engine compartment and they soon were destroyed by the heat. I was trying to protect my spark plug cables. The snap in bushings will hold up better near heat, but not exhaust heat of course...

Some of this may be the difference between h/w store parts and mil-spec parts.

If you want to use them around the engine you need the red colored ones...

a. Rubber, nitrile black. Shore A 60. Temperature range is -45? to +250? F.
b. Rubber, silicone brick red. Shore A 60. -150? to +500? F

They will be MS 35489 grommets, with the red ones having an "X" at the end of the part number. I've seen the red ones mostly as surplus, but SkyGeek has a few, with the Lycoming -19X one being over $100

[arffguy]

I bought some MS35489 black grommets for my engine compartment. In six months they were shot. If you find a source for the "red ones" I would sure like to know what it is. Thanks.

[TX7A]

Originally Posted by arffguy

I bought some MS35489 black grommets for my engine compartment. In six months they were shot. If you find a source for the "red ones" I would sure like to know what it is. Thanks.

https://www.mcmaster.com/#rubber-gro...hings/=19lvvlj

[RV3bpilot]

Thank you Gil and Sam... I will be replacing my old cheap natural grommets with some good ones..