Re-engineering a pop top...

[giraffeinbath]

I need to do something with the Canterbury Pitt style pop top fitted to our ’68 Devon.

I’ve heard Devon used these early on prior to them developing the their own 2 part pop top that people would normally associate with Devon conversions. I don’t know for sure whether that is true, but I’d be interested to know if anyone is familiar with their Devon conversions history. Given the way it’s been fitted though I'd assume this one was most likely added by an enthusiastic DIY owner along the way at some point, let's just say there’s room for improvement as it’s not been executed well and the makeshift fittings have fallen to bits over the years rendering the pop completely unusable.

There are no parts available off the shelf for this so I need to re-engineer it myself, it shouldn’t be rocket science but it's taking some thinking about the best way to do it. If anyone has any advice or pics of how they might have repaired/improved their pop that would be helpful, particularly the frame and the way it's been integrated into the roof. Obviously these are different to most as they don't have the 'foot' to attach the raising mechanisms as would be the case with a convension Devon roof or a westy, it's literally just a rectangular hole cut into the sheet roof metal.

I’d like to incorporate the ability to put some boards across the width to have an extra bed up there which wouldn’t have featured on the original, and possibly the addition of some struts to hold it up in addition to the standard frame.

Not exactly a specific question, just a call upon group experience if you have anything to share as Google hasn’t proved much help with this one...

 

[ozziedog]

Hi bud, good to hear from you. I’m not sure what you mean by ‘foot’ but I’m guessing that you mean the up stand that surrounds the hole in the roof. If so, the early Devon roofs had this at about an inch and a quarter to an inch and a half high and this was just a section of the roof folded / beaten / tortured back as the hole was formed then four little gussets tacked Into the corners for a bit of strength and to fill in where there simply wasn’t enough metal. This also stopped rain penetration when driving. On the later Devon roof after 75/76 the fibreglass monocoque style this lip height was reduced considerably to about a quarter of an inch and possibly as much as a half an inch. It really didn’t warrant a large upstanding like the first one. The engineering of this is well renowned as can opener and hammer beating technique and is full of sharp edges etc etc. With the early roofs they were side hung so needed the extra perhaps because of the spring fixing points whereas the later ones were supported front and rear so had the additional benefit of roof braces / supports / ribs close by. If that’s not what you mean then disregard all that ^^^ baloney up there. I’ve heard from more than one old chap source, that there were frequent coalitions from various UK conversion companies from new depending on what a customer wanted as in a Devon interior but a different pop top. This was also pointed out that a van on a forecourt second hand could be modded to a customers spec to get a sale because most wanted a pop top and as a sales tool, the van could then be supplied with the exact top that the customer fancied, as an after market extra . Ive got a 1970 early with a steel roof panel from a 72 Devon which had the two part roof and crinkle cut fabric which was an absolute genius idea for upping and downing your top, just a shame about the ally flat roof issues. So I’ve got that roof panel but fitted a much later Devon top 75/76 onwards which is all fibreglass. This has a 3/4” ally box section attached to the roof with bolts fibreglassed into the roof cap. Straight along each side and curved front and rear. The suspension of it is front and rear but almost to the corners and has hinged props to keep it rigid, again in the corners front and rear. The suspending on both of their roofs starts with a stout steel plate to pivot the springy arms from.

Ozziedog,,,,,,,,,,,send some pics bud

 

[giraffeinbath]

Thanks Ozzie, it was some years ago that I came over to yours to take a look at your van when posing the same question, I'm no further along!

Find attached a few pics, they're not great but it such a long time ago that the pop actually worked digging up images is easier said than done. As you can see all the lift brackets were very home made (out of 70's tubular framed garden seats maybe?) and have long been consigned to the metal recycling so I don't have anything original to copy.

The other thing you can't see here is how the canvas is pulled into a weird upside down trapezium shape due to the difference in size of the top and bottom mounting points of the canvas, so I want to relocate the bottom monting sop it sits directly below the top mounting to keep it all square, which should also stop the canvas being the means to funnel all the weather straight into the roof aperture.


Obviously it should lift both ends, but the rear support had already broken at this point...

















So in summary I'm really trying to work out 2 things;

• How to lift and hold up the pop top
• How to attach the canvas directly to the roof

...and both with the minimum of new holes drilled into old metal...

I quite like the way these guys are using crossed struts front and rear to lift and support the top in the video below.

Obviously they have the benefit of having worked the struts and fixings into their own bespoke cap and fibreglass base, I'd have to screw them directly onto the roof panel and support it from underneath somehow plus it may be a squeeze fitting it under the old pop but I like how the whole setup is unencumbered by internal poles and supports.

​

It's the route I'm inclined to start exploring, my only concern is how strong it would be longitudinally to the van as it's a lot of weight held up by some fairly small foot brackets.

Again this isn't so much of a direct technical question, more of a call for a second opinion...

 

[ozziedog]

Your current supports look to be roughly into the four corners so that set up shouldn’t be a mahoosive issue when you consider yours looks to be well sculpted to produce the said longitudinal support by design. I’d possibly loose your ply cover panels to check you can get a decent fixing for the lower end of the struts. Your link looked very much like a Sopru but I’ve only ever seen side supported / hung Soprus before and they’re an Aussie conversion. If you went that way, it wouldn’t be an issue to have piano style props in each corner internally to provide the stability when camped alla the later Devon roofs. Not sure you can do your props externally because of the space and the fibreglass slope mightnt let you get a decent fixing strengthwise, and looking for strength areas , if you went internal with your props, you could get a decent fixing at the slope to flat roof abutment where you could fibreglass a single inch box section to the roof or perhaps two box sections with your struts supported between them. I just can’t see the space required under that slopey bit. If you wrapped the lower section of the bellows around inch square batten and stapled it to the hidden far side, with perhaps three or four fixings pre drilled per side with a modern flexible adhesive to seal and finish it. Do you have an upstand around your hole at the moment? It’s hard to tell from the pics.
That pop top is very similar to the original one that was fitted to my van. The two arme to the supports were a tad longer and they overlapped each other and that kept the support there. I can see that you’re wrestling with conundrums at each turn of events. Another option might be to throw a wad at it and let someone like Space Roofs do the whole thing start to finish and grin and bare it and just enjoy it once done. You’ll forget about the cost when you’re pulling up and it just works and it’s nice and easy.

Ozziedog,,,,,,,,,you could also keep pondering for another decade or so

 

[67panel]

Mmmmmm or is it a Viking roof??? Have seen one with that type of bar to hold it up but it was a loooooooooooong time ago so dont remember what. Now I would remake /redesign the end brackets from thin wall steel tube bent to shape with a locking system to hold them upright as long as the fixings in the roof panel were good.