side frame rust through/rot

FC_fan · 05-13-2009, 07:05 PM

car: 1986 rx-7 N/A

well I have 2 trouble spots.

one is on the drivers side. the rear of my rocker is rusty and the last 6"-7" of the side frame is gone/ needs to be replaced (that includes as far as I need to cut back onto solid metal). looks the rocker has been bondo'd over by the previous owner. anyway, I was thinking of using a carbon fiber I-beam to put inside the side frame as it would be light weight and strong. what do you guys think? I will be spraying metal ready and POR-15 all over the area inside and out to try and prevent further rusting as well.

The second is on the passenger side on the corner right behind the front wheel well and under the front fender. the entire 6"x6" section is swiss cheese and distorted from jacking weak metal I think (my pinch welds under the car are all bent from jacks too on both sides of the car). I don't know how I should fix that section. it looks like a pretty complicated area. maybe build a small metal "box", coating the inside with POR-15 (just in case, don't want it rusting from the inside out). then put that small "box" in that corner and weld it up good to all the surfaces it touches. I'm not sure if that would be that best way to go about it.

I'm open to ideas are direct me to threads who have dealt with this problem. I have to fix it, these cars are rare around VT. My brother (89 FC) has a parts car in demo derby condition but these sections are almost as bad as mine so I think fabrication and creativity is the way I need to go. thanks guys.

FC_fan · 05-14-2009, 04:55 PM

anyone got any ideas?

firzen · 05-15-2009, 09:40 AM

I think some pictures would be useful.

I'm sure that others here might balk at a restoration since the damage sounds extensive. That and since FCs are not yet too rare in the market and another one can be easily acquired for less money, you should really consider your options.

classicauto · 05-15-2009, 04:12 PM

Just use metal, its the easiest way. Getting to creative on a rust repair if you're not experienced with sheet metal work can usually lead to discouragment on the project becuase the learning curve is steep.

Ditch the CF idea IMO. Just get some sheet metal, patch where you need to, and do some body work.

Also, the rocker sections are avialable from mazda new at fairly reasonable price. They actual rocker piece does not include the rear section where the rocker becomes the wheel well (behind the door). That piece comes on the factory quarter panel. So keep that in mind...

As for the pinch welds/damaged jacking points. Best thing is to bang them back out, and assess the rust damage. They might be ok to be ground off and coated, but you won't know until you get them straight. There's alot of ways to undo the dents to the heavier metal.....anything from tacking washers to the dent and using a slide hammer, to using ACTUAL stud gun/slide hammer....some times you just need to get creative on that stuff though.

need RX7 · 05-15-2009, 04:40 PM

My first FC has similar rust, I gave up on trying to fix it and bought a shell from Texas. If you have experience in welding and fabricating, I'd say go for it. I don't have either of those though, so I took the easy way out. Pics would definitely help.

FC_fan · 05-15-2009, 11:41 PM

well, I have a metal/fab guy who will help for free

. They part I am most concerned about is that side frame section, not the rocker panel itself unless the side frame rail is referred to as the rocker. I don't think it is though. I will finally be getting the 7 on to some wheel ramps this weekend so I will try and take pics. I have some horrible quality/angle pics but they might not help you guys understand it all that much. I'll post them up now anyway. check back on sunday night and I might have the better pics from the bottom of the car up here.

you guys know about POR-15? look it up if you don't. I will be using that and metal-ready (made by same company) to take care of the rust in those areas. then I will be using it on the entire bottom of the car after wire brushing and sanding a little. the rest isn't bad, just surface rust where the old protective coating is flaking off.

first 2 is the drivers rear rocker area, 2nd 2 are my front fender area.

RETed · 05-16-2009, 04:25 AM

I wouldn't bother and throw that chassis away...

You claim the car is rare, but I think it's more the fact that you're not willing to look farther for a better chassis.
Chassis' are cheap.
Just look at the classifieds, eBay, or Craigslist - just to name a few options.
Sure, it's not in your neighborhood, but how much does it cost to truck the car to you?
I mean I live in Hawaii, surrounded by water, and I'd be willing to pay good money for a good chassis - it's still going to cost $1,500 from the east coast shipped to my door, but I would be willing to pay for it.

The pics look like the unibody is compromised.
I wouldn't bother with trying to "fix" it.
Cage the car and be done with it.
If the hole bothers you, then just cover it up.
Trying to fix it and getting back the original strength of the unibody is a PITA and basically takes a certified auto body person to take care of the repairs - read: BIG BUCKS.

-Ted

classicauto · 05-16-2009, 07:46 AM

Yeah thats pretty bad rot.

You'd need to remake the inner rocker/floor, the support (center piece that joins to the pinch weld) and outer rocker.

And thats only the areas you can see right now. Where is else is there corrosion that isn't too far behind that? Or not rotted through yet. It would be a good learning experience for rust repair though

but thats a big patch job.

Even looks like your door seam is nearly ready to bust open

FC_fan · 05-18-2009, 08:22 AM

well, Apparently someone I was introduced to is looking for a tuner. He was going to get a prelude or integra but he is interested in my car. I told him about the rot and rust and said I was looking to get $1500 for it (left room to talk down). He said he'd think about it. So maybe I'll sell this car and try and find an actual T2 and then sell my T2 motor once I'm done rebuilding it. We'll see, I'm showing him the car this friday so fingers crossed I get a decent offer for it.

and before anyone says anything, I already know $1500 is a high price for the condition the cars in. I'm just trying to get a decent amount I can put towards another FC so its more of a wishful thinking kinda price.lol. it does drive great and strong though

firzen · 05-18-2009, 07:29 PM

Yeah, that rust is pretty bad- don't bother restoring it unless you're rich, have a lot of time, and know professionals that are crazy enough to help you.

I say part out the interior if yours is still good, sell all the unnecessary stuff and race that thing at LeMons.

FC_fan · 05-19-2009, 07:49 AM

LeMans!!! It's a N/A 13B, a crx with an intake and exhaust could take it!lol. Well, I was told that if it were caged it should be fine BUT I have a 5 month old daughter and need the 2+2 seats so that would interfere with the cage. The guy thats interested might put a cage in it and we'll fix the rust at least and fiberglass over the holes. The engine runs super strong and the transmission shifts okay, could use a clutch though in the future. I could probably make more parting it out but thats more time and work. I'd rather have someone try and save the car personally.

djmtsu · 05-19-2009, 12:10 PM

Quote:

Originally Posted by FC_fan

LeMans!!! It's a N/A 13B, a crx with an intake and exhaust could take it!lol. Well, I was told that if it were caged it should be fine

He said LeMons, not LeMans.

There is quite a difference!

FC_fan · 05-19-2009, 03:06 PM

what's LeMons then?

djmtsu · 05-19-2009, 03:31 PM

http://www.24hoursoflemons.com/

FC_fan · 05-19-2009, 10:21 PM

^ OMG! that's awesome, I would love to do that but I don't have the money for safety equipment and my 7 cost $1500 (was fiberglassed over the sections now failing). there is a $500 limit for car price. I think my 7 is still a little too good for that LeMons race anyway though. someday I'm gonna do that though! thanks for the link, way better then a demolition derby by far!

05-13-2009, 07:05 PM	#1
FC_fan The Newbie Join Date: May 2009 Location: Vermont iTrader: (0) Posts: 27 Rep Power: 0	side frame rust through/rot car: 1986 rx-7 N/A well I have 2 trouble spots. one is on the drivers side. the rear of my rocker is rusty and the last 6"-7" of the side frame is gone/ needs to be replaced (that includes as far as I need to cut back onto solid metal). looks the rocker has been bondo'd over by the previous owner. anyway, I was thinking of using a carbon fiber I-beam to put inside the side frame as it would be light weight and strong. what do you guys think? I will be spraying metal ready and POR-15 all over the area inside and out to try and prevent further rusting as well. The second is on the passenger side on the corner right behind the front wheel well and under the front fender. the entire 6"x6" section is swiss cheese and distorted from jacking weak metal I think (my pinch welds under the car are all bent from jacks too on both sides of the car). I don't know how I should fix that section. it looks like a pretty complicated area. maybe build a small metal "box", coating the inside with POR-15 (just in case, don't want it rusting from the inside out). then put that small "box" in that corner and weld it up good to all the surfaces it touches. I'm not sure if that would be that best way to go about it. I'm open to ideas are direct me to threads who have dealt with this problem. I have to fix it, these cars are rare around VT. My brother (89 FC) has a parts car in demo derby condition but these sections are almost as bad as mine so I think fabrication and creativity is the way I need to go. thanks guys.

05-15-2009, 04:40 PM	#5
need RX7 Clean S4 Nutswinger Join Date: Mar 2008 Location: Sterling Heights, MI iTrader: (0) Posts: 485 Rep Power: 17	My first FC has similar rust, I gave up on trying to fix it and bought a shell from Texas. If you have experience in welding and fabricating, I'd say go for it. I don't have either of those though, so I took the easy way out. Pics would definitely help. __________________ -Ted -1986 Mazda RX7 Sport [DD/beater]: engine finally let go at 205k. parts car status. -1986 Mazda RX7 base [resto-mod project]: S5 n/a swap in progress.

05-19-2009, 03:31 PM	#14
djmtsu My minds tellin' me no... Join Date: Feb 2008 Location: Murfreesboro, TN iTrader: (10) Posts: 4,043 Rep Power: 21	http://www.24hoursoflemons.com/ __________________ 1976 Mazda Cosmo RX-5 1976 Mazda Cosmo RX-5 2003 Toyota Tundra TRD 2015 Toyota 4Runner SR5

05-14-2009, 04:55 PM	#2
FC_fan The Newbie Join Date: May 2009 Location: Vermont iTrader: (0) Posts: 27 Rep Power: 0	anyone got any ideas?

05-15-2009, 09:40 AM	#3
firzen Rotary Fanatic Join Date: Mar 2008 iTrader: (2) Posts: 231 Rep Power: 17	I think some pictures would be useful. I'm sure that others here might balk at a restoration since the damage sounds extensive. That and since FCs are not yet too rare in the market and another one can be easily acquired for less money, you should really consider your options.

05-18-2009, 08:22 AM	#9
FC_fan The Newbie Join Date: May 2009 Location: Vermont iTrader: (0) Posts: 27 Rep Power: 0	well, Apparently someone I was introduced to is looking for a tuner. He was going to get a prelude or integra but he is interested in my car. I told him about the rot and rust and said I was looking to get $1500 for it (left room to talk down). He said he'd think about it. So maybe I'll sell this car and try and find an actual T2 and then sell my T2 motor once I'm done rebuilding it. We'll see, I'm showing him the car this friday so fingers crossed I get a decent offer for it. and before anyone says anything, I already know $1500 is a high price for the condition the cars in. I'm just trying to get a decent amount I can put towards another FC so its more of a wishful thinking kinda price.lol. it does drive great and strong though

05-18-2009, 07:29 PM	#10
firzen Rotary Fanatic Join Date: Mar 2008 iTrader: (2) Posts: 231 Rep Power: 17	Yeah, that rust is pretty bad- don't bother restoring it unless you're rich, have a lot of time, and know professionals that are crazy enough to help you. I say part out the interior if yours is still good, sell all the unnecessary stuff and race that thing at LeMons.

05-19-2009, 07:49 AM	#11
FC_fan The Newbie Join Date: May 2009 Location: Vermont iTrader: (0) Posts: 27 Rep Power: 0	LeMans!!! It's a N/A 13B, a crx with an intake and exhaust could take it!lol. Well, I was told that if it were caged it should be fine BUT I have a 5 month old daughter and need the 2+2 seats so that would interfere with the cage. The guy thats interested might put a cage in it and we'll fix the rust at least and fiberglass over the holes. The engine runs super strong and the transmission shifts okay, could use a clutch though in the future. I could probably make more parting it out but thats more time and work. I'd rather have someone try and save the car personally.

05-19-2009, 03:06 PM	#13
FC_fan The Newbie Join Date: May 2009 Location: Vermont iTrader: (0) Posts: 27 Rep Power: 0	what's LeMons then?

05-19-2009, 10:21 PM	#15
FC_fan The Newbie Join Date: May 2009 Location: Vermont iTrader: (0) Posts: 27 Rep Power: 0	^ OMG! that's awesome, I would love to do that but I don't have the money for safety equipment and my 7 cost $1500 (was fiberglassed over the sections now failing). there is a $500 limit for car price. I think my 7 is still a little too good for that LeMons race anyway though. someday I'm gonna do that though! thanks for the link, way better then a demolition derby by far!