Guys,
I'm wanting to install rivnuts for the two wings.
My question is how deep, or thick is that piece of frame I would have to drill into ? Is it thin enough for it to hold the rivnuts that I have when they expand ?
If anyone has experience with this, and can show a pic of what they used, I would be grateful.
Thanks in Advance.
Craig

 

Craig, What I have found in cutting the rear off of one of my tubs to make the back of the El CaPorscho conversion is that the frame component of the unibody construction of the 928 is made up of an inner and outer formed sheet metal component with a heavy frame rail inside of it. The inner and outer sheet metal is just the same as all the body metal, but the inside frame rail is about 12 or 14 gauge steel--pretty heavy.

Here is a picture of what I have cut into just inside the right door which shows the inner frame component exposed. I suspect that the same type of construction is used where you are hoping to put the rivnuts, but I am not sure where they will go so I can't tell about the structure at that point.

I hope this helps.

 

Yes, Jerry, thanks it really does. Will allow me to get the rivnut (that I have) in there and 'bring it down' so it can/will expand in the backside of sheet that you had exposed. I think it will work.

 

If you mean the wings that go from the front of the rear bellypan up to the frame rails/floor stiffeners , the steel plate there is no more than about 1.5mm thick. I have used rivnuts to secure these wings after the original holes became too worn to retain the original and then larger self taping screws. Worked no problem at all other than the effort required to operate the rivnut gun at an odd angle.

 

I've also used rivnuts on the belly pan and the front frame section were the front pan mounts. Installed about 3 years ago and they still hold tight. Attached is a pic of the belly pan but I never could get a good pic of the front frame area. As an FYI I bought metric rivnuts so I can use a standard MM bolt to attach everything.

 

Yes, I did too.
I don't have a rivnut gun. I'm going to try to tough it the old fashion way. If it proves not possible, I'll have to get one. I think it will be possible, just tough.

Thanks Guys. Really appreciate it.

 

Once the original holes had worn out too much, I enlarged them to take up square plastic inserts (about 5x5mm) into which the original sheetmetals screws fit. I did this with the "wings" on the front end of both the front and rear belly pans.
I got mine from a VW dealer but I guess they are fairly standard stuff. Upside is that if these plastic parts fail, you can easily replace them with new ones. Also no risk of contact corrosion there.

my 0.928 cents

Kurt
_________
90 S4 satin black matallic

OC charter member

 

From memory, the frame section there is less than .125. I replaced all the speednuts (Tinnerman nuts for the purists) with RivNut-style (actually 6mm Nutserts) inserts for the front pan into the frame. I made a new aluminum cross-bracket that attaches to the frame on both sides, hangs down and runs across at the joint between the mose and the front pan. There are Nutserts in the bracket that hold the front of the front pan up maybe 1/2" higher than original, with screws that pass through the plastic nose section there. Dropping the pan now leaves the cross-bracket in place, with just the 5 screws coming down.

 

Quite the set up. The cross bracket is beyond me. I'm just going put in the two rivnuts, use an M8 bolt with lock washer.

 

Here's a steel 8/32 nutsert for the front 'feet' of the rear belly pan that Dr. Bob helped me install a few years back. It was very easy drilling into the frame rail. Were I to do it again I'd use an M6, just to keep it metric.

 

Well Rob,
I hope that my rivnut insertion looks as level and clean. I'll be working in a tighter area, but it should work out.

 

The Nutsert tool I use has a socket-head capscrew as the driver pilot. I find a good grade-8 (or equivalent)capscrew for the duty, and put just a --little-- lube on the threads. In tight spaces like the frame horn, I use a good Allen driver on an extension to drive the screw, Allen tool end through Nutsert holder. Then you can drive it and keep it straight with a small ratchet comfortably below the car. No muss, no fuss, and no blood donations, and much easier on the wrists.

For those playing along at home, the rear edge of the belly pan is "supported" with spring-steel tabs that dangle from the bottom of the radiator support. The outer end is drilled through, and a tinnerman nut is latched around the hole to receive a screw from below. My 'improvement' is in response to the constant flexing that happens whenever you get too intimate with a parking stop, or in my case with the apron into my driveway. The flexing was enough to crack the original long 'ears' that support the front of the front belly pan, so making the full aluminum support brace for the front let me pull the pan up a little, and support it better in its better position.

 

I plan on toughing it with a closed end ratcheting wrench on the tightening nut, and holding the bolt with socket and extension to set the rivnut. I've mimed the motions in the space and it should work when I get to it.

 

I want to do this at some point, but baulked at rivnut gun prices. Reading this made me realize I don't need the gun! Old fashioned way M6 is the plan! Thanks guys.

 

I use the tool too often (really!) to put it into the community pool for loan-out. If anybody in the L.A. area wants/needs to set some, you are welcome to use the tool here in sunny Glendale. On the lift if you need it.