Hell hole repair, Recommendation Options

[watsonrx13]

Well, worked on the passenger's side of the engine compartment today. I removed the battery tray and started cleaning the hell hole. There's only a few small holes in the side wall and one small hole in the firewall.

Question: Should I cut out the side wall and replace with a patch panel, butt-welded or try to weld up the holes?

BTW, the white showing through is a piece of paper taped on the back side so the holes would show up easier.

[dmenche914]

Lucky you, that is not all that bad of a hell hole. Mine even went as far as requiring the motor mount replacement! It appears you only have surface rust, and some pin holes. In this case, I would save all the original metal.

Clean all the rust, either blast, or chemically remove it (naval jelly works, put saran wrap over the jelly coated surface over night (so it will not dry out) it may require several applications, and scraping, but it does work)

Then neutralize the remaining metal with a phosphoric acid treatment, followed by a primer, then fill the pin holes with filler, and paint. Should last a very long time if you killed the rust. (ie decade or more) I have used this technique on cars (non-cosmetic areas, like engine bays,and floors) It works very good if there is only little rust pitting, with a few pin holes. I would not use this method on a fender top, or anything that must be perfect.

Other option is to cut and weld. If you do this, it will still not look factory without some filler, unless a very talented welder put lots of time into it (ie money) This is the "best method" but it depends what is best for you, what you want to spend, and use of the car (ie conours winning rare factory six 914 verse the daily driver four cylinder that you commute in.

Now you could go for a less than invisable metal patch, but it is still more work than the clean and paint method, and may not last any longer, But in the case from what I could determine from your photo, a metal patch would be over kill for some small pin holes
However if the rust is any worse, or covers a large area, or is rusting from behind the panel, then metal replacement is really the only way to go if you want the repair to last more than just a few years, or compromise strutural strength.

Anyway, at least be thank full your rust is not like many others rust in this area. heck, a thick coat of paint might fill in the small pin holes so no filler is needed. If that is the case, bow down to the idle of the 914 and offer up a case of holy synthetic oil, for the idle of the 914 has smiled on you and given you near rust freeness.

dave