16 replies to this topic

[OUBob]

So I have a few holes in the floor of my si. No biggie, right? Been surfin the site for a bit now, haven't seen any threads really answering my question.


Is anyone familiar with the construction of the floors near the rockers and torsion bar mounts? I need to replace some sheet metal, and it appears there may be multiple layers in the area. Is there a body construction diagram?

Before anyone tells me it is too far gone and starts telling me to scrap it and asking for parts, it is still structurally sound enough to not flex over train tracks and to support its own weight when jacked up. The rust is not to the rockers or torsion bar mounts yet, but is nearing.

I guess what I want to know is: can I cut out the bad and just weld in good? Or do I have to go one layer at a time?

[kaymo]

as long as you weld structure back in properly, metal is metal. just make sure to kill all that cancer so u dont do it twice. if it looks rusty, it probably is lol

[Stuckey85si]

I agree with kaymo. I have cut out and repaired 3 different spots in my floor boards. I simply cut out the bad,welded in 16 gauge metal, sealed it with a seam sealer then painted it.

[OUBob]

So no special construction details? Its all just sheet metal down there? Now I'm curious what would happen if I were to get to the rocker seam, or under that big bolt at the rear of the torsion tube. I guess just put it bach together the way it was.

This would be great news, and will put another 3g back on the road after ten years.

[EuphoricBlue]

http://www.astralkno...rx/crxwork.html
This was my little patch job. It was my first and my goal was just to learn, not to actually stop the rust. It will come/is coming back on mine.

But regardless. I've seen the construction XD The floor pan is a single sheet of stamped steel. If you look under the car where the torsion bar mounts, what's welded to it there is all there is.
At the front corners you have the drains/structure. They have covers glued to them.
And, of course, the rocker is a hollow structure that has a thick reinforcement inside it. But until you get right to where the floor meets the rocker it is all 1 layer.

You can kind of see the internal structure here:

This is the back, but the same thing happens in the front around the jack points.


But really, just don't get too aggressive. It's all pretty simple in there. Cut just deep enough to get through the layer and anything you may nick below it you'll be able to easily mend with a little weld.

Edit: The big bolt at the end of the torsion tube is deceptive. It really just holds the rear of the bar from vibrating around too much. It doesn't really see any load there.

[OUBob]

http://www.astralkno...rx/crxwork.html

Edit: The big bolt at the end of the torsion tube is deceptive. It really just holds the rear of the bar from vibrating around too much. It doesn't really see any load there.

Massively good info.
What I am taking from this is: I can pull the torsion tube bar rear mount off and work around it. Also, Take the sheet metal to the rocker and weld just as it was.

Also: Can I purchase Floor pan pieces? It appears in this thread http://www.redpepper...e...50706&st=45 this is what has been used.

Edited by OUBob, 06 February 2012 - 04:15 PM.

[kaymo]

if i am not mistaken, those are hand beaten panels. i do not believe replacement metal is available for our cars. remember, this is not an NSX... its just sheet metal (thin at that)

the rear torsion bar tube mount (the two 12mm bolts) is just to keep dirt out of the torsion bars, and to keep the end of the tube from bouncing around. the weight of the front of the car actually transfers up the tube to the subframe of the car, the end cap has no weight loading.

[OUBob]

Doesn't that end hold the torsion bar in place? Wouldnt there be a torsional stress from the torque of the torsion bar?

Also, wouldn't mass production create the need for stamped pans? I could see them being hand made on the NSX, but to crank out 10 million Civics?

[kaymo]

it holds the end of the tube from bouncing around. the actual torsional stress goes up the tube to the height adjustment bolt.

if the cup held torsional stress, it wouldnt do very well since its simply a rubber cup that slides over the end.

i meant the panels in that person's thread were hand made, not the ones from honda. panels from honda are going to be new old stock only good luck with that

[EuphoricBlue]

On a side note, a floor pan is a floor pan. Source one out of a 4G in a scrap yard. Cut patch metal out of it as needed. Hell, I used bits of my damaged MR2 hood as filler metal for the floor pans and rockers. Metal is metal.

As for the torsion bars, the torsional load is actually applied on the bolt at the subframe. The front of the tube has a lever with a stud going through it and a nut on the stud.
The nut adjusts ride height and captures the torsional load.

The cap at the back end of the torsion bar tube is just that, a cap. They are a bit snug to get off, but once you get them off you find out it's exactly as Kaymo describes, a cap with a rubber cup in it that slides over the end of the torsion bar. It doesn't locate the bar in any way, just stops it from vibrating, smacking the floor pan and making noise.

[1styearSI]

i have the perfect fix!!!buy my RUST FREE 87 crx si FOR 1800 check out the fs section for pics of the car and all the parts that come with it!

[OUBob]

i have the perfect fix!!!buy my RUST FREE 87 crx si FOR 1800 check out the fs section for pics of the car and all the parts that come with it!

^ That would be Great! Just trade me for my rust box w/original drivetrain already removed and you can keep your drivetrain too! Thats actually not a bad price.

Ive been out with the wire wheel on the angle grinder. It just destroys rust. These holes got BIG. But it doesnt remove the pock marks and discoloration underneath. I assume I need to see bare, bright steel before I paint. What have you guys used to remove the remaining rust? I imagine I cant just hit it with the grinding wheel.

[hondaguy72]

Cutting out the pitted sections is the preferred method. If you are unable to do this you may be able to save the pitted sections by using encapsulating paints. I've had fairly good results with using POR15. It's basically super glue with pigment. Once it's bonded to the metal no air or moisture can penetrate it effectively stopping the rust.

If you do end up using the product make sure to buy the product in small quantities. It's hard to store once opened and it does not take much to do large surfaces. One pint could probably coat an entire lower chassis!

http://www.por15.com/

[OUBob]

So there is no need for primer with this stuff? Just hose it on then undercoat it? It seems this can be effective with minimal rust removal. If I take the time to grind out as much rust as possible, then apply this stuff, I assume I will be protected for quite some time.

[hondaguy72]

No primer. Surface prep includes removing scale and grease. Acetone or wax and grease remover both work equally well. Pitting is preferred as the product does not like to adhere to smooth metal. It would last a very long time. I would suggest at least two coats, possibly three.