Cutting, drilling, welding van body: Compromised strength?

wanderingturtle · 01-07-2014, 05:20 AM

Are there concerns about loss of strength when cutting, drilling, or welding the body of a van? How much of the structural integrity is in the body?

Specifically, I have a 1994 G30. I want to swap to captain's chairs, which will require drilling. To repair rust around where the doghouse sits, I have an 87 Vandura that will donate some floor, requiring cutting and welding. I'd like to make access panels in the floor for storage, fuel pump access, extra batter storage, etc. And I'd like to maybe put in a sunroof.

I will be hauling kids so structural integrity is a concern.

I did search but didn't have any luck.

86Scotty · 01-07-2014, 08:53 AM

I would say no, not in the small ways you are talking about. Holes for seats, etc. are not going to matter. Small access doors in floor or body for fuel pump or a small storage compartment won't matter either IMO. Just look under the van and make sure you aren't cutting any lateral supports of any kind. I am not familiar with the GM vans but the Fords are incredibly strong and aren't even affected by the spare tire hanger/subframe piece being removed. There are several threads on doing that if you are talking about rear underfloor storage.

Have you posted this on a GM van forum (if there is one)? About 95% of folks on here have Fords but that's just because there are so many more of them and they are more popular for conversion.

Good luck

Ford_6L_E350 · 01-07-2014, 09:34 AM

If the welds are good, it will be as strong as ever after floor section is replaced.

Mike

E350 · 01-07-2014, 11:30 AM

For the Fords I believe there is an upfitter TSB or build sheet which says to disconnect the batteries and at least the PCM if you are going to Mig, Tig or Arc. I would search for something like that for your van. Frying the computer would not be good.

wanderingturtle · 01-09-2014, 03:03 PM

Quote:

Originally Posted by 86Scotty

I would say no, not in the small ways you are talking about. Holes for seats, etc. are not going to matter. Small access doors in floor or body for fuel pump or a small storage compartment won't matter either IMO. Just look under the van and make sure you aren't cutting any lateral supports of any kind. I am not familiar with the GM vans but the Fords are incredibly strong and aren't even affected by the spare tire hanger/subframe piece being removed. There are several threads on doing that if you are talking about rear underfloor storage.

Have you posted this on a GM van forum (if there is one)? About 95% of folks on here have Fords but that's just because there are so many more of them and they are more popular for conversion.

Good luck

What about large doors in the floor for storage?

I'll look into chevy van forums. Although I think that people on here might be more experienced with cutting up van bodies. It does make me a bit nervous to be around a bunch of ford people, though.

wanderingturtle · 01-09-2014, 03:18 PM

Thanks, I'll be sure to disconnect the computer and battery before welding.

What about cutting large holes in the floor, for large access to storage?

I've looked at some other forums. I thought the people here might be more experienced with cutting up van bodies.

Although I do feel a little nervous being in a room full of Ford people..

carringb · 01-09-2014, 05:56 PM

One thing to keep in mind is the pre-'95.5 Chevy vans are Unibody, so the body is structural. A agree that good welds will maintain strength, but if you plan on having a large open hole, structural integrity is something to think about. I have never seen GMs guidelines for modifying the body (Ford makes them available, but that doesn't help you).

That said... The conversion van industry seemed pretty keen on putting holes wherever they wanted. I've never seen a van buckle during use, but I have seen some conversion vans that did not hold up well in a collision due to its modifications.

86Scotty · 01-09-2014, 06:06 PM

Quote:

Originally Posted by wanderingturtle

Thanks, I'll be sure to disconnect the computer and battery before welding.

What about cutting large holes in the floor, for large access to storage?

I've looked at some other forums. I thought the people here might be more experienced with cutting up van bodies.

Although I do feel a little nervous being in a room full of Ford people..

Lol, we're not Ford people, though, necessarily.

I would guess most of us fall in to them because there are so many. Youre stretch Chevy is pretty cool, and kind of rare where I live.
If you like cool modified Gm/Chevy's then check out Accrete and Spoolin's builds. Just run a search for them.

And Welcome to the addiction!

JWA · 01-10-2014, 04:26 AM

Another aspect of modifying a Chevy van body is maximum consideration towards which body panel is cut and re-welded, special emphasis on the welding process. If your '94 G30 is indeed the unibody construction you can greatly diminish its structural strength by using improper welding repair.

If there's little information about cutting or removing parts of the floor for access doors etc its most likely due its not a common practice. Add in the unibody aspect with its special repair techniques and we're talking potential problems that affect crash worthiness. Ford's are body-on-frame where load bearing is handled by the frame which makes cutting larger parts of the body away much much less a concern.

Seat installation where new holes are drilled shouldn't be an issue. Cutting a hole in the floor for under storage via an access door would be another matter.

The van conversion industry did pretty much ignore many safety concerns for a number of years---I believe 2003 brought about significant changes and requirements via new FMVSS's.

All this being said I'd be hesitant to greatly modify a Chevy van floor or remove big chucks for convenience---it could impact safety and structural integrity.

Chance · 01-10-2014, 10:04 AM

Sprinters and ProMaster are also unibody in construction, and their bodies get modified with openings. Windows are an obvious addition, but more significant is cutting out a large part of the roof to add a penthouse roof. Most of these vans have a frame so they are not completely unibody in design. As long as the frame rails are not rusted or cut through, small openings in the body should be OK.

It's also possible to reinforce for any material that is removed, making the finished product even stronger than the original. In my opinion the devil is in the details.