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Just Some Dude in Jersey
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Discussion Starter · #1 ·
How does water, dirt, media blasting stuff, etc. get out of the bottom of the GT fresh air intake system and the door hinge area? Outside air gets drawn in through the cowl screen, wiper motor cover, and maybe several other places, it then flows sideways and down both sides. Some of the air can come out the vents on the sides of the dash and the rest can go straight down to a large cavity at the bottom outsides of the footwells and can come out the footwell side vents. But, those vents are 2"-3" above the bottom of the cavity. On my GTX car, while I was fixing it up, I found the bottom of that cavity had 3" of mud/sand in it. It was a mutha to get it out with vacuuming and blasting water in there and sucking it out. My project car also has mud in the bottom of that cavity. Water can also get down into that cavity, especially if you are too aggressive with hosing or powerblasting. If you have your whole car media blasted inside and out and in the fresh ait intake at the cowling, the media stuff can get down into that cavity. That mud will hold water and rot the car. How does water normally drain from there? I might need to drill a hole somewhere to let it out. Also, how does water, dirt, media blasting material, etc., that gets into the door hinge area, get out? That area is right next to the aforementioned cavity where the footwell vents are. Are they connected?? Are the the same cavity? I don't see a drain hole anywhere. If I have a blaster dude blast that hinge area, does the whole cavity behind it fill up with grit, walnut shells, or whatever particles are in the media blasting stream? I suppose if your car was on a rotisserie you could flip your car sideways or upside down and stuff in those cavities might come out. Any clues?
 

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You have summed up the major problem with these cars. I do not recall specifically how that stuff was originally intended to exit, my guess being there were drainage channels to allow water to escape, but these would pack up with dirt and, coupled with the fact that rust prevention science was nil back then, the result would be that your car would be eaten away from the inside. The big problem is that, not only do you end up with cosmetic damage, but structural parts get eaten as well. Going back to my days as a make-ready mechanic in a dealership in the 1960s during a summer vacation from school, I recall that dealer-applied undercoating was a popular option and I would not be surprised if the tar we applied did not stop up some of those channels. Her are a couple of pics of my car a few years ago when I was having the body work done, showing what you can find beneath even good-looking skin.
DSCN6501.JPG DSCN6642.JPG
 

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Just Some Dude in Jersey
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Discussion Starter · #4 ·
Yeah, this issue seems to be a design flaw according to European guys on Facebook.

I'm going to have to get a flashlight and shine it inside the side panel vent, then look to see if that cavity connects to the cavity behind the hinges. I presume it does not.

One thing I could do is to cut a 1/2" wide slot straight down from the vent holes to the rocker where that cavity ends, then I could blast water in there to wash out the dirt/grit/whatever. Then spray some paint in there to try to seal up the inevitable rust that might be forming in there. I think on my GTX I got that area pretty well cleaned out and brushed POR15 in there as best I could. Rustoleum 2X is very much like POR15 in acting like a rust encapsulator.

I haven't posted on this site how dreadful my hinge areas are on my new car after cutting all that gullwing mod metal out. They are NASTY, I can't even bolt the door hinges on properly. That area needs blasting, but that will surely fill up the cavity behind the hinge mounting with a mountain of grit. I'm thinking that I could use a 3/4" hole saw I have and drill a hole at the bottom of the doorway hinge mounting plate, just above the rockers, to allow me to fish and flush the debris out of there.
 

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Solo II is fun in a GT!
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This might be a good justification for getting a bore scope.
 

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1970 Opel Gt - Purchased July 1972 - Chartreuse - restored - 3000 miles as of 02-16, 2021 -
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Bore scope - got one myself to check out the inside of my gas tank now I have a second use for it
 

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This might be a good justification for getting a bore scope.
The one that plugs into my cell phone was like, $8 on Ebay. 10' long cord, LED ring around the lens to see what you're poking at.

If you've got amazon prime, free 2-day, $7: https://www.amazon.com/Endoscope-In...ld=1&keywords=borescope&qid=1607980973&sr=8-7

To clean the mud out, I used duct tape and small hose from an air mattress inflator to seal up to my shopvac, can worm it around through the panels there.

Once the mud's out... sounds shitty but, perhaps dump water into it and see where it comes out. Vacuum out the water if it doesn't, leave a heater on to make sure it evaporates after.

I thought there were little slot spaces like the rockers have, to perform drainage but now I'm not so sure.
 

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1970 Opel Gt - Purchased July 1972 - Chartreuse - restored - 3000 miles as of 02-16, 2021 -
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Following the thought process but a little different area, if you flip your lights half way and look on the left, passenger side, there is a crevice beside of the fender, up high. While working on the lights this week I thought about what happens to the water that inevitably ends up finding its way into the cevice, is there a drain port for that - I have not seen one. Also everytime I turn on my fan I get blasting media comming out of the defroster - I assume that will eventually pass. I guess next time I take off the instrument panel, what the hay just might as well remove the dash and have a go with that heater box. Maybe not.
 

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Just Some Dude in Jersey
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Discussion Starter · #10 ·
I've used this stuff to rust proof internal areas:
Excellent Gary! That's just the ticket I was hoping to find. I had meant to ask if there was a simple rust encapsulation product that came in a spray can for tough to access areas. You read my mind! :)
 

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Just Some Dude in Jersey
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Discussion Starter · #11 ·
One of the most useful Opel books you can have is the "Illustration Catalog" that dealerships used to have. They show exploded views of just about every part and device of various models. There is nothing better when you're trying to figure out how many washers or layers of pieces make up a certain item and how the heck stuff like body panels are put together. An interesting observation is that all the pics of GT body stuff seem drawn in an entirely different, simpler, more artistic way, whereas, cars like Mantas, Kadetts, etc. have excessive detail and a more industrial look. This appears to be the result of GTs' having had their bodies designed by that French company, Brissoneau(?), whereas, all other models had their bodies designed in Germany. If you've ever had the misfortune(Ha!) of having owned GT's all your life and then acquired a Manta, you would think that two entirely different companies made those cars. They have no similarity in design philosophy in regards to the body.

They pictures are arranged kind of cockamamie and not every body panel for GT's is shown and I found one of the pics below in the Cooling Group(the pic showing the front fenders), other pics came from the separate Body and the Sheet Metal Groups, even though they show the same category of body panel parts. The GT stuff seems to be printed as an afterthought at the end of each section.

So, I was curious to see if I could find an exploded view of the panels that comprise the lower flow through vent chamber and the door hinge mounting area. These are the pics I found and notations I made regarding those areas:

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