MCI Engine Mounting rail repair

[Fredward]

While I have the engine out of my MC-5 I plan to plate the inside of the rails to increase the overall strength and to compensate for some damaged and broken pieces. So I plan to make a triangular piece of plate steel and weld it on the inside of each rail from the front where it attaches to the vertical frame running all the way back to the rear where it will be very small. I also figure this will help support the trailer hitch for when pulling the toad or a light aluminum trailer. I know these things were not designed for trailering so I"m not going to put any significant hitch weight on it.

I just want to beef up the structure a little to compensate for occasional hitch weight and make up for some cracked and broken pieces.

Is there any reason (cooling?) not to plate off the rails on an MCI?
Fred

[Stan]

I don't see any reason not to do the plating. You have to V out any cracks and weld them before you plate over them. The critical thing is welding the plate to the existing structure. Doing it wrong can cause heat affected zone  stresses (cracks) .

[edroelle]

Rather than cutting triangles, I would suggest plating the entire side.  When I did mine on my MCI 8, I saw no access concerns.  Also, since moisture will  lay around, and assuming you correct most oil leaks, I would suggest using stainless steel to limit corrosion.

Ed Roelle
Flint, MI

[Tom Y]

Fred, I looked at a 9 used for Greyhound that had plates on the sides. I was told Greyhound wanted them that way. I can't remember but I think it was on the outside of the rails.  Tom Y

[Dallas]

I pretty much have to agree with Ed.

I'm working at the present time on a 102C3 doing a repower with a high HP 8V92.

The engine cradle mount rails on this particular coach have been cracked in at least 6 or 8 places on each side, repaired poorly and have cracked again at the same spots and in 4 or 5 other places on each rail.

My fix is going to be to clean and "V" all the existing cracks, weld them up and then plate with plate and angle Iron.

I'll be using mild steel to do the plating with because, it's stronger than the stainless and these old coaches won't get enough mileage to make a difference.

Dallas

[Fredward]

Ed,
Thanks for the response and I definitely intend to plate the entire side. One great big triangle! The front, drivers side motor mount may have a clearance issue so we may need to cut a quarter inch off but thats what torches are for!

Our local bus garage also endorses plating the rails. They say that it is a common procedure with older MCI.

FRed

[Tom Y]

Fred, The other thing they had on the hound was bolted between the rails about 2/3 back if I remember right. This would help also.  Tom Y

[NJT5047]

NJT MC9s have the same crossover.  That means that Nimco has them all over...if anyone wants one. 
I've had the engine out of my 87 MC9 and there were no frame rail cracks...nor was there any evidence that the frame rails had ever been repaired?? 
Seems likely that lower operating speeds and smaller engines had some benefit after all.   
Fredward, I got some really bad news regarding your drive axle...someone's installed it
backwards!   
JR

[mikelutestanski]

Hello:    Having the same problem with my MCI 7; even had some rot on one of the rails. so  what to do?
         Well we decided to change all the steel pipes with 1 inch square stock 1/8 inch thick or so.  So taking out each piece one at a time we replaced and welded the entire set on both sides front to back.   The top rail was replaces near the rear where the salt had corroded it out.  the main bottom rails were covered with a steel strip 2" by 1/4 by whatever length required to fit.   The whole section was primed and painted..   This mod has been in place for 10 years approx 50k miles and works fine..  no subsequent cracks and my hitch is suspended from this and we hauled a 24 foot car hauler fully loaded to Florida when we moved at least 5 times    3000 miles each trip.
     So this works in my opinion.   
       Now FYI   MCI had a kit that was offered for 7,8,9,and other buses that consisted of (2)   1/8 inch plates that were tacked onto the rails top to bottom front to rear  to deal with this problem..   the plates were steel and not stainless as they were up in the compartment supposidly out of direct contact with spray?
     MCI recommends that the cracks be repaired but my experience with this kind of cracking and the thin metal pipes involved has been that it always reoccurred; therefore we elected to go with the heavier square tubing. Where stainless was involved we used stainless wire to bury the steel welds to prevent cracking of the adjacent stainless   ie   you need to use stainless rod or wire to attach steel to stainless.       
     I have include a picture of the rail assembly that shows some of the details   unfortunately my new cradle for the L10 is also there.   That has been finished and painted since this pix  but some of the square tubing can be seen.
      It may seem like I don't agree with the plating idea but I do...Any reinforcement is better in my opinion .  using stainless for this may not be necessary unless you have an abundance of stainless laying around.  then the only problem is welding technique to make sure nothing cracks later..  Having said that what we did; a complete replacement of all the steel piping  between the upper and lower rails was strong enough to do what was required in our case..     
     REMEMBER  YOU HAVE TO BE COMFORTABLE WHILST SITTING IN THE DRIVER SEAT ABOUT WHATEVER WORK AND MODIFICATIONS YOU HAVE DONE TO YOUR COACH.   MY WIFE  THE BOSS HAS ALWAYS SAID DO WHAT MAKES YOU FEEL RIGHT BECAUSE YOU ARE SITTING IN THE DRIVER SEAT AND ARE THE PILOT.  IF I AM HAPPY THEN SHE WILL ARRIVE SAFELY AND HAPPY.     
    FWIW   happy bussin   mike   

[Lin]

I had some serious cracks on the right side engine carriage and leg.  I do not do that sort of work, so a mechanic has been working on it.  The cracks have been welded over before.  He has cleaned them out, re-welded them, smoothed them out and plated over the areas.  The 3/16 stainless  tube from beneath the rails has been removed (it was crushed and distorted in several places probably from bottoming out and/or attempts to jack up the bus!) and replaced with a 3/8 steel channel from the back to the leg.  It looks massively strong now.  One thing you might consider when doing your plating is use plug welds also.  They look like they go a long way to increasing strength.