Hood 'Oil canning' problem.
 

Well not technically oil canning. That apparently implies a raised area, and a lower area.
The whole hood skin feels very thin. When you push down between the edge of the hood and one of the braces it wobbles down, and bulges up between the brace and the centre rib. The hood is up at my panel guys shop, and he's not overly happy about it. I took up the new hood brace pads and put them in yesterday to see if it would help, but it just raised the area where the braces are, but didn't help the 'wobble' at all.
So is this normal? I can't just shoot down the road and see the neighbour boys one down here!
I have searched on here but didn't find anything specific, but did see a couple of comments about how thin these hoods are.
My hood had just a tiny bit of rust on the leading edge, and a couple of pinholes above the battery area. And a couple of area's of surface rust, kinda weird, but like it had rusted under the paint. I have had it sandblasted, but the general feeling is that hasn't caused/affected the hood at all.
Appreciate your thoughts on this matter! I won't tell you how rare/expensive another second hand hood is down here. With the money already tied up in this one I really need to make it work.

Re: Hood 'Oil canning' problem.
 

In my experience, hood wobble can be greatly reduced or eliminated with proper adjustment of the front two hood bumpers, hood latch, and hinges so the hood sits firmly on the rubber bumpers that line the fenders. If the hood latch and front two bumbers allow the hood not to make contact with one or both of the front two bumpers, the hood will shimmy like no tomorrow when on the road. I know this from personal experience. Good luck.

Re: Hood 'Oil canning' problem.
 

As stated above, make sure your hood is aligned correctly, good hinge springs and all that. Once you have all the bumpers adjusted, there's several different options to help reduce the "tinny" look and feel of the hoods. One is the original stripped insulation that runs just under the bracing. That's the best look. Other options are to add new car style felt looking inserts between the braces, or to install some dynamat stick on type insulation. In some high profile builds I've seen X style bracing added in the large areas on both sides to effectively eliminate all shaking. I've seen all methods used effectively when done correctly. Unfortunately without adding extra bracing, they don't 100% eliminate the problem, but it most likely won't be an area of concern once finished.

Re: Hood 'Oil canning' problem.
 

the hood on my truck was so flexible I really couldn't D.A. the old paint off it without it flapping up and down so I wound up having it media blasted instead and block sanded it gently after bondo and primer...and that was an O.E. one...I imagine an aftermarket one would be even worse with thinner metal...its just such a large low crown panel with very little support...the strips I bought are pretty worthless...if you have the room to slide them in they aren't touching or supporting anything....might try to put some sort of seam sealer in there instead,just haven't gotten to that point yet

Re: Hood 'Oil canning' problem.
 

cleszkie/lefty, I hear what you are saying, but what I'm still dealing with is what volksworld is more talking about. Just appears to be really thin. (It's an O.E. hood).
Anyone else? What does your hood feel like when you push on it? I thought you could have a party up there, but it feels like you'd end up with some serious dents if you sat on it!

Re: Hood 'Oil canning' problem.
 

i took winshield urethane adhesive and put it in between the braces and the skin and now it sounds solid no tin can

Re: Hood 'Oil canning' problem.
 

Ill tell you what not to do. I once saw a hood where the sprayed. Spray foam inbetween the hood skin and braces :D

Re: Hood 'Oil canning' problem.
 

http://i290.photobucket.com/albums/l...DSC02272-1.jpg

that's a picture of mine-when I'm driving the area along the peak of the bonnet about 1 foot back from the front is shimmering up and down constantly and it does move quite abit.
from the research I've done, its quite common and can only be fixed by putting in more braces under the skin ie one joining the two diagonal ones together and then some tight fitting packing between brace and skin.
I don't care enough about it too worry about fixing it-too busy driving it.

hello from rotorua by the way!

Re: Hood 'Oil canning' problem.
 

Hey Mark,

Thanks for the feedback. So just to be clear, if you push down on the hood half way between the outer edge and the brace, and half way front to back, does it push down really easily (feels really thin) and at the same time raises the bonnet skin up between the brace and centre of the hood? My panel beater is still skeptical that this is normal! Your thoughts are appreciated.
Quite the garage full of cars you got there! And Hi from the South Wairarapa.

Re: Hood 'Oil canning' problem.
 

I had the same issue on my OEM hood, I welded a horizontal brace in the center between the 2 long braces that run from the front to the back of the hood. The underside of mine I painted satin black, I then used black silicone to fill the gaps between the sheet metal and all braces. looks great and it is now solid.

Re: Hood 'Oil canning' problem.
 

Hey BillHilly,

Vic used a type of expanding foam between his hood skin and the frame underneath, in his thread he talks about it, it starts at the last post on the page of this link:

http://67-72chevytrucks.com/vboard/s...563833&page=35

Hope that helps you, Vick has been a wealth of information for me.

Re: Hood 'Oil canning' problem.
 

Not stock, but it sure works. A piece of L channel steel between the supports...nothing massive, just adds support, and stops that damn flapping!

Re: Hood 'Oil canning' problem.
 

Over the yearsi have seen several original 69-72's that had a brace installed in this same spot. IIRC, it was made of 1/4" or so round rod, flattened on the ends where the original front to rear braces are and had a rubber "donut"over the rod in the center channel "groove" of the hood. I wonder if these were a dealer oltion or what. I have never thought to take a photo of one.

Re: Hood 'Oil canning' problem.
 

Hmmm... mine is solid like a rock, and presuming they were all the same thickness, I'd strongly recommend you check the insulating strips between the hood frame and the sheetmetal.

They should not only be in place but also glued in with something like weatherstrip adhesive. That should firm it up.

Re: Hood 'Oil canning' problem.
 

Thanks for chiming in beetle.

Thanks Swamp, can't get that down here, but Fulson (?) do something similar.

Thanks Lou.

I'm leaning that way..

We were all singing a similar tune, then in stepped davepl! Just kidding, this is the feed back I was after. Dave, I took my new set of brace foam support things up to my panel guy and slide them all in, but it made no real difference. At this stage, my cheapest option is to probably make a centre brace and try some additional foam. I'll let you know how I get on.

Re: Hood 'Oil canning' problem.
 

The problem is the straight-up front of the hood. It creates an area of lower air pressure across the center of these hoods. My advice is to switch to a 67/68 front clip. These are more aerodynamic!
:lol::lol::lol:

JK!

Re: Hood 'Oil canning' problem.
 

Yes, instead of being a brick, they are a brick with a very slight bevel on one of the short sides :-)

Re: Hood 'Oil canning' problem.
 

HA!!! Pretty much.

Re: Hood 'Oil canning' problem.
 

BillHilly,
I hope you got everything worked out. Can you posted an update and photos of what you ended up doing, please!

Re: Hood 'Oil canning' problem.
 

Hey PDXk5, I should have come back and cleared things up shouldn't I! I had my hood up at my friends panel shop and they weren't very happy with it, to say the least! Anyway, there is only one other truck of this era in the valley here, so I rang the owner up and he graciously drove it straight around.
His hood was identical to mine. Very thin to the touch etc. So mine suddenly became ok! The biggest issue is going to be that mine has alot of heavy pitting and the panel boys are concerned about what the bog will do when they apply it. Should find out in a few weeks when we do it... I'll try and come back and tell you how it went. Oh, and we've got a tube of 'anti flutter foam' to try instead of the foam strips.

Re: Hood 'Oil canning' problem.
 

You could just heat shrink it, very carefully Would not be seen when finished and looks completely stock.

Re: Hood 'Oil canning' problem.
 

This was one of the first things I worked on, annoying seeing the hood look like a hurricane was going on. I'm cheap, and had some scrap square tubing and some woodworking tools. LOL If I ever want to restore to Pebble Beach concours standards, easy to remove.
http://cdn.ipernity.com/200/17/24/41...20cc1e.640.jpg

Re: Hood 'Oil canning' problem.
 

I have just added extra layers of foam to the braces and fixed the problem

Re: Hood 'Oil canning' problem.
 

Working on mine now... with what I'm doing I had to cut the braces off and move them more outward... so I'm having to tie them together with some cross bracing... and after that I'm sure I will still have to stuff some sort of foam padding between the skin and braces...

Here's a sneak peak of what I'm doing...

Re: Hood 'Oil canning' problem.
 

How on earth did you get that suff between the braces and skin?

Re: Hood 'Oil canning' problem.
 

I ran a bead of black rtv between my hood skin and the braces.

Re: Hood 'Oil canning' problem.
 

When is the Chevy Pickup class at Pebble Beach this year, I can never remember... :-)

Re: Hood 'Oil canning' problem.
 

LOL!! Most of those cars are so opposite of what I like. I don't know what people see in them.


Says the guy with the rusty old Chevy HAHA.

Re: Hood 'Oil canning' problem.
 

theres supose to be some insulation between the supports and the underside of the hood. even if its there it will have shrunk to a point where it serves no purpose. you could shim it up in some way that it supports the hood from below again. or find some similar material to replace it.

my 72 has the same problem, not bad enough to fix but maybe down the road...

Re: Hood 'Oil canning' problem.
 

Hey, they started a Hot Rod class several years ago, never know. LOL

How about SEMA quality?

Re: Hood 'Oil canning' problem.
 

I took some cloth inserted rubber (sort of like the rubber pads you mount under the bed to frame attaching points, and that took care of my "Oil Canning" My painter actually was having a devil of a time blocking my hood and asked me if there something missing, I told him to stop right there, and I'd be right over, five minutes later, he was good to go.......

here's a link:

http://www.brotherstrucks.com/67-72-...tinfo/HBSP072/

Ben
:metal: