Are the inner walls of an MCI bus REALLY part of the structure?

[Oregonconversion]

I have heard both sides... I am not sure if I should remove these walls or not....

If I do take them off, do I have to put them back? If so how?

[Ednj]

can i start
I think you remove more structural stability from removing the seats then those panels.

[JackConrad]

   I have heard both answers, but never an answer from an MCI engineer or someone I felt was qualified to give an answer based on actual enginnering data.
   We took our inner panels off when we had the coach sprayfoamed. We did not put them back on. We installed 1/2" B-C plywood using urethane construction adhesive and #10 sheet metal screws at the same spacing as the OEM rivets (in new holes).  No problems in 42,000 miles.  Just our way, YMMV  Jack

[Nick Badame Refrig/ACC]

I have heard both views also.

I know for a fact that the upper vertical beams on the side walls move a bit from body stress. Not much, but they do move.

If you do remove them, a simple diagonal gussett at each end of the coach within the box channels will keep everything stable.

Jack has installed plywood which most do, and is also a good substitute but, the gussett would put less stress on the wood.

Good Luck
Nick-

[Airbag]

A bus is a semi moncoque structure meaning the skin is part of the strength. Now what part the inner skin plays can only be answered by an engineer. If I had to guess I would say the outer skin makes most of the music and that is why I'd never substitute smooth skins for corrigated skins. Now all you smooth siders out there can flog me for saying that.  I tend to go with the stock configurations as much as possible with buses and airplanes. I figure the manufacturers payed guys with white shirts and skinny black ties with pocket protectors and slip sticks big bucks to engineer something and who am I to say it's OK to change it?

[belfert]

Has anyone ever called MCI to ask this question?  Do they still have engineers from that era? 

The corrugated metal sides may simply be the style of the times and not necessarily a structural element.  If smooth sides had been the style during that era that may have been what they would have used. 

One thing I like about MCI is that they have several of the engineers who designed the Dina on the tech support staff who can answer questions about the Dina.  They even copied and shipped me a set of Dina wiring diagrams at no charge when the book MCI sold me didn't match my 1995 model.  (The wire numbers had changed.)

[edroelle]

I built my MCI 8 similar to Jack.

I did not remember the inner surface being held on by structural rivets.  I thought the thin aluminum was held by pop rivets.

I installed 3/8" wood inner panel

Ed Roelle

[luvrbus]

I watched Marathon convert MCI's when they first started and they removed the inner panels and never reinstalled them     good luck

[alltech]

I worked with an engineer that use to work for MCI and when I looked at removing mine he said it depended on the year of MCI. On the buses with the exterior skin riveted on through the middle of the of the sheeting as on the MCI 7,8,9's it is the exterior sheeting that is part of the structural integrity and the sides act like a tension truss to move the load to the axles. On the 102C3's it is the interior that forms the box truss that is the part of the structure. The exterior sheeting on the 102C3's exterior sheeting has very little to do with the structure.

The local Big Rig collision here in Calgary specializes in Repairing MCI bus from all over Canada and the USA he says that if you are removing either inner or outer skins you should block the center of the  coach to prevent it from sagging in the middle. Apparently he has had to repair buses from other shops that have removed the wrong skin and compromised the integrity of the frame.

Good Luck

Ross