Bog in the roof

[Calaber]

If there's rust in a roof, it won't be in the area where there's just the roof skin, it will be along the upper edges of the screen or the sides in the gutter. Both areas are susceptible to rust in cars and would be fairly considered as structural.

 

[Trevor loves holden.]

Cut it out and put a sunroof in it, that's if its in the spot.

 

[vc commodore]

Roof skin is not structural. I can understand the A, B and C pillars along with the bracing along the roof line front to back and side to side as being structural but the roof skin just keeps the rain off your head.

If the roof skin was structural, then doors wouldn’t need intrusion bars because the structural skin would protect the occupants.

But I’d bureaucrats see i5 as structural, then it’s structural

A roof is structural....When they build a convertible version of a car, they strenghten the chassis, to cope with the lack of strength, above the pillars....

Do a little research on what's involved, from an engineering stand point on how the chassis has to be strengthened before lopping the lid of a car and what the consequences are of not strengthening the chassis prior to lopping the lid off, or even lopping the lid and using the vehicle without the necessary chassis work. Might help you understand it a little better

 

[vc commodore]

Cut it out and put a sunroof in it, that's if its in the spot.

Good in theory but in the long run it introduces more rust issues....

 

[Skylarking]

A roof is structural....When they build a convertible version of a car, they strenghten the chassis, to cope with the lack of strength, above the pillars....

If you look at how a roof is constructed, you should realise the framing between the pillars front to back and side to side provides the strength. It’s what Holden calls the structural roof bow. When the roof is lopped off to creat a convertible, such strength is lost and needs to be regained by adding extra structural members to the body below the waist line...

In a sedan, the roof skin is just that, a skin that covers the roof bow. And according to Holden, the roof skin is made of a medium grade steel so more than likely provides less of a structural element that the roof bow itself. How much the roof skin adds to the roof bow strength, I don’t know... but it’s not the main structural element.

Here is a Holden presentation PDF that describes the VE design, read it, you may learn something.

Do a little research on what's involved, from an engineering stand point on how the chassis has to be strengthened before lopping the lid of a car and what the consequences are of not strengthening the chassis prior to lopping the lid off, or even lopping the lid and using the vehicle without the necessary chassis work. Might help you understand it a little better

I can throw the same comment back to you to do a little research but you’d probably find it a little insulting.

As an FYI, I tend to research as needed and usually do so to a higher level than most would bother. I also don’t have difficulty understanding complex engineering issues. Though it’s been a long time, I’m sure I’d cope with doing the math on structural loading if required. Can’t be bothered though...

So I doubt I need guidance on issues of roof skin structural integrity based on a feeble comparison of a sedan to a convertible. But thanks for your input

 

[vc commodore]

If you look at how a roof is constructed, you should realise the framing between the pillars front to back and side to side provides the strength. It’s what Holden calls the structural roof bow. When the roof is lopped off to creat a convertible, such strength is lost and needs to be regained by adding extra structural members to the body below the waist line...

In a sedan, the roof skin is just that, a skin that covers the roof bow. And according to Holden, the roof skin is made of a medium grade steel so more than likely provides less of a structural element that the roof bow itself. How much the roof skin adds to the roof bow strength, I don’t know... but it’s not the main structural element.

Here is a Holden presentation PDF that describes the VE design, read it, you may learn something.
I can throw the same comment back to you to do a little research but you’d probably find it a little insulting.

As an FYI, I tend to research as needed and usually do so to a higher level than most would bother. I also don’t have difficulty understanding complex engineering issues. Though it’s been a long time, I’m sure I’d cope with doing the math on structural loading if required. Can’t be bothered though...

So I doubt I need guidance on issues of roof skin structural integrity based on a feeble comparison of a sedan to a convertible. But thanks for your input

I can tell you from experience, with Regency Park (which is where the defect will have to be removed), they WILL knock the car back for any signs of bog in the roof....They WILL insist that the offending section be removed, a new piece welded in and only have a protection coat of primer over the new section, so they can see it was welded into place.

Going back a few years back, I had the pleasure of putting a car through this inspection, where it had a sunroof fitted and some surface rust showing, where the vinyl roof section had peeled away from it... This is exactly the procedure I had to go through to have the defect removed....And the car was a Valiant, so the roof metal was thicker than the modern Commodore...

I had also seen the results of a VH and VK Commodore having the roof lopped at the top of the pillars.....The cars bent like a banana in the guts....

So yes, I could do some internet research, but I prefer my real life experiences and I will provide those experiences to those that require it, so they can decide whether to take the advise or kick it to the kerb

 

[Skylarking]

@vc commodore, I’m not disputing that the authorities have their standards before they pass a vehicle for registration.

I’m also not questioning that there are some rather dodgy repairs being attempted by back yarders and the regulators have reason for what they do.

I’ve just questioned whether a roof skin with some bog will compromise the structural integrity as I suspected the roof skin was not structural. The engineering answer to that question depends on what condition the main structural parts of the roof bow are in. Why bog was used and where and what it may be hiding. Having said that, engineering can be irrelevant when bureaucrats are involved

Pity @Darth Milz hasn’t come back with more info on roof condition and why bog was used as things could have been more focused, but meh

My issue was that roof skin doesn’t automatically equal roof structural member and your implication that I don’t know what I’m talking about and need to research more before posting was just insulting.

I’ve also helped mates remove and repair roofs as part of a vehicle restoration, so I’m familiar with how much strength an old vehicle body has without the roof attached to the body. But that wasn’t part of the discussion, it was just your justification for an insult.

There is no need to be insulting to convey your experiences. Obviously you’re free to post your thoughts but not to insult. There is already too much of that going on in these forums at times.

In any case, let’s move on, though I do hope you had a look at the Holden presentation PDF as i found it rather interesting. As it has some nice sketches of the VE roof bow and the steel types uses, maybe you would too

 

[Trevor loves holden.]

Vic roads roadworthy regulations:

Section I Body and Chassis :

General The structural components of all vehicles must be sound and free from cracks, damage, faulty repairs or modifications, rust, deterioration, distortion or any other condition which could lead to structural failure of the vehicle or adversely affect the performance of safety related features.

Skin of a roof is not structural only the cross members are.

The body and fittings of all vehicles must be free from any damage, which might increase the risk or severity of injury to any occupant, pedestrian or other road user. The body must also be free of any damage likely to allow the entry of exhaust gases into the passenger area. All seals at body openings necessary to prevent the entry of exhaust gases into any passenger area must seal effectively. Floors including floors in load areas must be in a sound condition. Floors in passenger areas must be free of loose material or objects or tears, or incorrectly fitted matting, or covering likely to interfere with the driver’s ability to safely operate the vehicle.

All the roof has to do is keep gases and protect the driver from outside elements, I wounder how convertibles go with soft tops for a roadworthy?

 

[vc commodore]

Vic roads roadworthy regulations:

Section I Body and Chassis :

General The structural components of all vehicles must be sound and free from cracks, damage, faulty repairs or modifications, rust, deterioration, distortion or any other condition which could lead to structural failure of the vehicle or adversely affect the performance of safety related features.

Skin of a roof is not structural only the cross members are.

The body and fittings of all vehicles must be free from any damage, which might increase the risk or severity of injury to any occupant, pedestrian or other road user. The body must also be free of any damage likely to allow the entry of exhaust gases into the passenger area. All seals at body openings necessary to prevent the entry of exhaust gases into any passenger area must seal effectively. Floors including floors in load areas must be in a sound condition. Floors in passenger areas must be free of loose material or objects or tears, or incorrectly fitted matting, or covering likely to interfere with the driver’s ability to safely operate the vehicle.

All the roof has to do is keep gases and protect the driver from outside elements, I wounder how convertibles go with soft tops for a roadworthy?

Handy posting this up when the car is in S.A, which interperates rules differently in this area

 

[Skylarking]

^ just highlights that SA bureaucrats have no real clue when it comes to engineering.

Won’t help the OP as he has to deal with the SA bureaucrats