Side sills…. do they rust?

[Shannon Whitehead]

#292951

The side sills are aluminum, so while they won’t rust, galvanic corrosion is definitely a concern that needs to be taken into account. If you are really concerned, just do a Google search for a galvanic corrosion chart and come up with something like this:

The OEM screws for this application are some sort of coated mild steel, and they are sheet metal screws. If you replace them, they need to be either sheet metal screws or you need to use some sort of threaded insert, as was discussed here:

http://driveviper.com/forums/threads/7713-Side-sill-fasteners?highlight=threaded+insert

I just got done doing this to mine, and I used 1/4″-20 stainless steel screws and fender washers. If you use the 1/4″-20 rivnuts, you’ll need a 25/64″ drill bit to enlarge the holes in the body, and I’d highly recommend buying the tool shown a little further down in that thread (not a cheapie). Also, if you use the 1/4″-20 fasteners, they’ll be slightly too big for the holes in the body panel, so you’ll need to hog them out a bit with a Dremel or the like. If you don’t do this, you’ll end up hating life…trust me on this one. Other than that, it is a pretty straightforward exercise, and you should never have to worry about them again. I’m not a huge fan of sheet metal screws, and apparently neither were the Dodge engineers…on the 2013+ Vipers, they use threaded inserts for this application straight from the factory.

[sssammm]

#292956

I used hard rubber 1″ washers, spreads the load really well

[Shannon Whitehead]

#293031

sssammm said:
I used hard rubber 1" washers, spreads the load really well

This is what I said to myself in my mind as soon as you mentioned your issue. Never done it myself, but my reflex reaction was exactly this. Though if you are worried about reaction between the aluminum, would stainless screws work (more expensive but not 100 bucks for them, I don’t think? Or how about nylon? They don’t need to torqued ultra tight do they? If not, the plastic variety might give you the the hold you need with no concern about corrosion. Provided they don’t get much sheer force. I haven’t looked at mine so not certain.
Good luck.

[viper04blk]

#293043

good idea…. i will do that

I want to use m6x1x20 as thats what the original spec size is….i dont want to drill and tap the thing to a different size of bolt. I will track down a bolt based on the specs in that chart. Thanks for the info!

[Shannon Whitehead]

#293075

Vprbite said:
This is what I said to myself in my mind as soon as you mentioned your issue. Never done it myself, but my reflex reaction was exactly this. Though if you are worried about reaction between the aluminum, would stainless screws work (more expensive but not 100 bucks for them, I don't think? Or how about nylon? They don't need to torqued ultra tight do they? If not, the plastic variety might give you the the hold you need with no concern about corrosion. Provided they don't get much sheer force. I haven't looked at mine so not certain.
Good luck.

IMO, the galvanic corrosion issue we’re talking about here is not an issue. For this application, you need something stronger than nylon…there’s a fair amount of flex to the side sills, so it does require some clamping force to get the panel back in place where it is supposed to be. I’m just finishing up swapping in some high flow cats, so I’ve now had both sides off on my own car. Personally, I don’t like the original sheet metal screws going into the blind holes…there just isn’t much thread material there on the frame side. Personally, I think the rivnuts are the way to go, but it does require full removal of the side sills so you can drill the holes out and set the rivnuts. It made sense doing it while I had the sills off for the exhaust project, but probably wouldn’t pass muster if you were just trying to address the fasteners.

Just something to think about, but not something I would lose sleep over. Ultimately, I didn’t want those sheet metal screws backing out and falling off…they’re directly in line with the rear tires, so there’s a pretty good chance you’d end up with a flat tire it if happened. None of mine were loose, but I don’t think the sills have ever been off the car since it was built.

[Shannon Whitehead]

#293290

That was what I wasn’t too sure of. So if it does flex, why not just a hard rubber washer? And then locctite it if you are really concerned about it.

[sssammm]

#293292

Ive used the 1″ rubber washers, 3mm thick on two Vipers, they are hard rubber but still flexible
and keeps the screwhead off my paint, and tightens up nicely

[Shannon Whitehead]

#293306

sssammm said:
Ive used the 1" rubber washers, 3mm thick on two Vipers, they are hard rubber but still flexible
and keeps the screwhead off my paint, and tightens up nicely

This would have been my first thought. But I’ve never had to do it so I am speaking theoretically, I guess.

I think just the fact that you care is good. Which means whatever you choose will probably be fine because you will make sure its tight and probably check it after a few drives and see if it’s still all good, which it probably will be. Then you will rest easy. I honestly think just the effort goes a long way here.

Does anyone who has more than a chemistry minor, which I tripped and fell into because a physiology degree takes you one credit away from a chem minor, know more about the galvanic corrosion? That chart is helpful. But is there anything that acts as a catalyst for the reaction that would matter here? Such as living in a humid climate or near salt water air? I would think salt water air would provide a good medium for those electrons to jump across. Though, wouldn’t the corrosion be more likely to cause the nut and bolt to seize together than to corrode away completely? At least in the time frames we are dealing with here. In 5000 years I don’t think it matters much. Or would living in a dry climate slow that reaction to such a pace that it ceases to matter?

My plan is to switch all screws, bolt and fasteners over to solid gold to avoid corrosion. I just need to rob FT Knox first or become a Sauid Prince. Never mind that solid gold is effectively play dough under stress. It won’t corrode and will look cool. 🙂

Happy fastening, OP.

[sssammm]

#293311

Oh yes, I forgot, I stripped all the screws and repainted them then baked them to harden the paint

[Shannon Whitehead]

#23032

I have swapped out my exhaust and I am now putting back together my car. The bolts on the bottom of the side sill have been removed once before me (assuming for inspection when entering Canada). The paint is scratched off underneath of the head of the bolts that hold the side sill onto the car. The bolts themselves were messed up, so I am replacing them with new M6x1x20 bolts.

Here are my questions …… is there anything special about the factory bolts??? I am using zinc plated bolts from the bolt store. The factory bolts would cost me 100 bucks to buy all 14… the bolt store ones are 3 bucks, and fit just fine.

Will this scratched off paint make rust? or is aluminum fine for this?

Are the factory bolts aluminum as well? I know dis-similar melts touching each other can make corrosion.

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