How to shrink a floor pan

[Mckrack]

Does anyone know how to shrink a floor pan when it's buckling. When I get in the car and put my feet down on the drivers side it buckles. Someone told me it needs shrinking. I think the floor pans although they were installed properly by the person that sold the car to me are aftermarket and not original.

Please chime in and if you don't know could you give me some names and email addresses of some people in FLA I could email. Does anyone know of anybody near Boca Raton. I can travel with the car as far as Orlando or maybe Tampa area.

Thanks

[JimmyZ]

Determine if it is a replacement pan and not a failing old pan. The stock floor pans have a 1/16" thick asphalt-like melt sheet applied to the metal. They also have several removable rubber drain plugs. Even the fine aftermarket ones I've seen don't have the holes for the plugs.

Is your frame rail extension installed underneath? If the frame rail extension isn't there than there is no reinforcement therefore things will flex. It might also be a cracked weld from improper prep. (Unlikely)

If the FR extension/channel is there and all of the welds are holding then here are some options...

You could either use the torch and cool method or cut out some excess in the middle and reweld the seam. (Not over the FR extension/need access to repaint) It is probably beyond using a shrinking hammer or shrinking dolly. With these methods you will need to repaint the affected area of course. The torch and rag cool method would prob be best cosmetically IMO.

I live in Orlando (Winter Park) but it would probably be cheaper to take it by a body shop and flip the guy a $20 to shrink it with a torch. (If that's what's called for)

Jim

[hls30.com]

... I think the floor pans although they were installed properly by the person that sold the car to me ...

Thanks

MCkrack,

You are being too kind.

If they were installed properly, you quite simply wouldn't be having that issue. This problem shows the floor is one place you have proof a hobbiest and not an expert worked on your car-I hope you don't find any more!

While I am no expert, in the 17 floor panels I have welded in, it sounds like either your floor wasn't fitted patiently and properly before welding or maybe the installer didn't begin with spot welds around the area. I have had that situation-my spot welds were too large with my first floor pan and the heat moved things around before I had the entire circumference of the repair stabilized-when the several checks with a level showed it was off, I cut it out and started again, verifying with the level as I went. That floor and every one since has been rock solid.

Hopefully the panel can be warped into the stressed situation that will keep it in the position stepping on it places it into so it won't be noticeable to you.

Fortunately that floor issue is only important if you are going for 300 points and someone is serious about your having to earn them. Enjoy the car and quit sweating the little stuf.

Will

[brushie1320022]

I have been a welder for 20 years and you dont shrink by a torch. Atorch only expands the metal and it gets warped. Shrinking metal is hard. Cold does shrink metal. But it has to be a very cold stream to shrink it. Dont know if this helps but thought i would tell you

[JimmyZ]

My welding experience is not as great. I had a MIG job for a few years and have some TIG time as well. Nowdays my welding is for hobbies such as the Z and plane.

As for shrinking with a torch, I've done it a few times with a wet rag. A lot of the old bodyshop books describe methods for torch shrinking. I wouldn't try it on something thin and visible like a Z's hood. Seems that the trick is to avoid putting in too much heat. Shrinking with any accuracy is definitely something that takes practice. For fun I've taken a few "oil cans" out of some flat panels. Never did it on anything visible or critical though. It's easier to replace a hood than to shrink an oil can out of it. It can be done though.

My bodyshop buddy has a stud welder which can be employed for shrinking. (Special attachment on head) This is simply an electric version of the heat and cool principle. (Wet rag still needed for cooling)

I was trying to avoid a mechanical means of shrinking for appearance sake. It would be easy to go nuts with a shrinking dolly/hammer but the metal would be marred horribly. It would also be easy to stretch the metal further by hammer forming (against a block w/recess) a channel to reinforce and "take up the slack". Neither method is acceptable to me but it might be if your sanity was on the line.

There is also a shrinking disk for a grinder but I don't think it's worth buying for just a floor pan.

Check out pg 198..

http://www.delmarlearning.com/samplechapters/dl_display_sampchap.aspx?isbn=0766813983&cid=12

My 2c

[Mckrack]

I appreciate the help.The pans are not OEM or Charlies pans he makes up there in Canada. The pan buckles whetre my feet go only on the driver side. The body guy says he knows how to fix it. Of course the undercarriage redstoration is complete soi now he will probably have to remove all undercoating and start over. I have copied and pasted your responses to him in an email. I will see what he has to say. Thanx for the help.

On a side note HLS inferred that the pans were not installed correctly becaus he mationed that I was being too kind. Well if you saw them you would think that they were. I don't know crap happens doesn't it.

[geezer]

I have used a combination of heat and dry ice to eliminate oil canning, but never on a finish panel. Not a problem in this case, but be real carefull using heat on a assembled car.

[hls30.com]

I

On a side note HLS inferred that the pans were not installed correctly becaus he mationed that I was being too kind. Well if you saw them you would think that they were. I don't know crap happens doesn't it.

Mckrack,

I wasn't trying to be mean to you in plainy saying they weren't installed right-If I had paid a professional to put them in and had that issue the car would going be right back to the guy, and he would be taking care of the entire situation his unprofessional work caused. I was just saying a professional would have made sure the floors were right before they left the shop-after all, his reputation is at stake. A typical hobiest wouldn't know to check his work with weight or levels-that is a difference between welding only one set of floors and having the experience of doing a couple in complete restorations. Looks can be decieving without experience-in this case, they were.

You said the PO had the floors done, please don't take my fair evaluation of the work he had done as an attack on you-it was only ment to alert you that there may be other things in your car that were done similarly. If you are as anal about your car as a I am about mine, finding and correcting them will give you piece of mind.

I appologize, I didn't mean to be offensive with my comments.

Will

[Mckrack]

I didn't take it that way. No problem. I don't know who did the work since I bought it from someone that way. I guess I will have it taken care of one way or another. Quit frankly if when I finally get to sit in the car if the sound deadener prevents the floor from flexing then I won't do anything. When I was at the shop the other day I pressed on the floor and it did buckle but now behind where my feet are sort of under the seat. I may get lucky. Will keep yo posted. No pun inteneded.

[TVollnogle]

Here's a link to the Autobody Store forum where I recently asked a question about fixing an oil-canning door caused by previous damage which wasn't properly repaired. I tried some of the suggested techniques, which solved my problem. The most effective method I found was spot heating with a torch, using a dolly and hammer to "shrink" the metal, then quenching with water.

http://autobodystore.com/forum/showthread.php?t=4094

Len, who sponsors the site, used to do a lot of Z work. He said back in the

'70s he had a lot of them in his shop yard since he did all of the repair work for one of the dealerships in the his NJ area.

Hope this is of some value.

Terry

Grand Rapids, MI

'70 240Z #3212

[a7dz]

Another thought is to just glue a doubler to the oil can as a stiffener. Do it on airplane skins quite often. No heat no discoloration quick and fast.

[Mckrack]

Glue a Doubler, what to stiffen it yup. somehow don't think that is going to work.