New to forum, MCI question

[roadkill]

Hello all and thanks for having me.  I recently purchased a 1972 MCI M7 Challenger.  This bus started off its life from the factory as an RV and appears to have been renovated around 20years ago but is certainly showing its age.  It has a good drivetrain with the original (I think) 8V71 and Allison transmission.
My hope was to only renovate the interior because I believed all other systems were working.  I picked it up after dark and drove it 150 miles back home, everything went well except that when I started all the clearance lights, brake lights etc were working, by the time I got home the only lights that were working were the headlights (which I believe were converted to 12v)

I was hoping that maybe someone on this forum had a wiring diagram, especially for the junction block at the drivers seat.  There is a lot of hacking on the wiring but I'm hoping enough of it is original that I can trace the problem. I have spent hours looking for this wiring diagram online and have yet to see one.

Any help would be appreciated, and I'm sure I will have many more questions in the future, after creeping this board for awhile it looks like this is right where I need to be.

[richard5933]

Is the conversion done by Custom Coach? If so, I can help with the wiring on the house side of things.

The running lights? I say that there is a 99% chance that you ground connections issues. Haven't seen an old vehicle yet where bad ground connections didn't create all sorts of electrical problems, especially intermittent ones.

You might also have greed crud/corrosion on the terminal board causing bad connections.

Before you start cutting things apart, strongly suggest you get the manual and wiring diagrams. Lots of manuals available here: https://www.busconversionmagazine.com/product-category/bus-manuals/

[chessie4905]

Two things. Check your oil level regularily, as they do use oil. Especially so you know how much it uses per 500 to 1000 miles. Never allow engine temp to get over  205 to 210 max. Too many of these engines have been overheated because owners don't  realize they can't  get as hot as a car engine without damage. Overheating can crack heads and take temper out of piston rings and score cylinder walls.
Use proper spec. 40W oil only. Always carry one or two gallons with you. Truck stops don't  carry it anymore. Carry a set of fuel filters and a gallon of fuel to top them off before installing. Have a tool or tools to replace fuel filters. Welcome to our group. Oh, and a roll of paper towels.😉

[roadkill]

How would I be able to tell if it was converted by Custom Coach? I am not seeing any badging anywhere.
I am also certain it is grounding issues, I was fiddling with wiring and now have all lights except turn signals, but I think that might be switch issues.

Are there any suggestions for cleaning the terminal board? all those non-insulated contacts scare me lol

on another note, does any one know what type of oil goes in the gear box that drives the squirrel cage fans above the engine? the ones that cool the radiator, the site glass appears to be empty

thank you for all the replies

[richard5933]

How would I be able to tell if it was converted by Custom Coach? I am not seeing any badging anywhere.
I am also certain it is grounding issues, I was fiddling with wiring and now have all lights except turn signals, but I think that might be switch issues.

Are there any suggestions for cleaning the terminal board? all those non-insulated contacts scare me lol

on another note, does any one know what type of oil goes in the gear box that drives the squirrel cage fans above the engine? the ones that cool the radiator, the site glass appears to be empty

thank you for all the replies

A few pictures of the interior and I might be able to offer a guess if it's a Custom Coach, especially the layout of the house control panel and the way the cabinetry is done. There would have been a badge on the nose and tail of the bus as well, but sometimes those are removed.

The non-insulated contacts shouldn't scare you if you shut down the power first. Shut down both the chassis and house batteries, and for good measure shut down shore power just in case.

I like a product called DeOxit. They have a number of variations but I've been using DeOxit D5 and a small wire brush. Sometimes it's necessary to pull out the 600 grit wet/dry to use in conjunction to remove really bad corrosion, but usually a brush with the D5 takes care of it. Tedious work doing them one by one, but it does help.

Ground wires can be found all over the bus, including behind some of the light fixtures themselves, behind the headlights, adjacent to terminal boards, etc. You'll have to snoop around and see what you've got.

I've got no suggestions on the oil but it should be in the manual.

[Dave5Cs]

Oil for the fan gear box is ok with 40 or 30 weight. I use 40 and then only have to carry one oil for engine and gear box for squirrel cages.
Most time the Custom Coaches have brown Formica everywhere and MCI front badge will say Cruiser or Land Cruiser.

[hogi6123]

It's hard to tell the difference between the oil above or below the sight glass, you really should first insert something into the filler hole to determine the actual level before adding oil.  A zip tie or long thin screwdriver should work well for this.

[buswarrior]

Get yourself something to use as a dipstick, there have been many a fan gearbox sight glass look empty, when it is full.

Big big mess, when it pukes it out, fans inhale it, and spray it all o ver the engine room. That's a day wasted cleaning...

Happy coaching!
Buswarrior

[ol713]

     Hi;
        I also have an MC-7 and the diagrams.  Let me know if you need the diagram for the light circuit.  I have the diagrams
        in paper form.  I guess I can copy them and send them to you via snail mail.
                                              Good luck     

[luvrbus]

They have a 15 amp self resetting fuse in the panel under the drivers window check it.MCI wiring will vary from bus to bus it depends on the serial number and how it was ordered  lol I hate tracing wires when one was ordered with grounding relays makes a person wonder WTH  were they thinking

[RollingLiving]

We also have...and, in fact, live in...an MC-7.  Love it!

Everything above, said about the lights, is accurate.  But I might suggest that, before you dig too deeply, you go to NAPA and get proper 24 volt bulbs for the clearance and tail lights.  We have another 24 volt bus and a prior owner had put 12V bulbs in all the fixtures.  So, of course, they all burnt out quickly...leaving just the headlights, like happened to you.  And since they get too hot, they melted the tail light lenses too.

[RJ]

Hello all and thanks for having me. 

Name?? -

Welcome to the madness. Being a busnut is incurable, but it can be controlled!

Hopefully this link will work, it will take you to a Facebook page that has a .pdf file listing all of the current CORRECT oils to be used in your 2-stroke 8V71 engine, as well as part numbers for both the oils and NAPA Gold filters, both oil and fuel. ICYMI, NAPA filters are made by WIX, a well-known and respected company in the filtration industry.  The filters will usually be in stock at your local NAPA store, but you'll have to order the oil, tips on how are in the .pdf.

https://www.facebook.com/groups/609135379253771/files

FWIW & HTH. . . 

[windtrader]

Thanks for the reference, RJ. I was very surprised to see the notation that Rotella barely is under the ash limit of 1%. I had always held that Delo, Delvac, ad Rotella were all fine but based on this information Rotella is a second choice.

[luvrbus]

Thanks for the reference, RJ. I was very surprised to see the notation that Rotella barely is under the ash limit of 1%. I had always held that Delo, Delvac, ad Rotella were all fine but based on this information Rotella is a second choice.

Don the ash was based years ago and Detroit has never changed the spec the primary fuel for Detroits was No 1 fuel a light fuel that fuel is no longer here unless you buy kerosene.Delvac is my favorite but don't worry about the ash content with the bio diesel of today,Back when we were running the heavy red off road fuel we had to use a oil with !.24 ash to make the TBA numbers jive,there is more to oil besides the ash content it is all in the manual lol and don't be shocked if you have a old manual that tells you Detroit recommends  15/40 and any kind of water except ditch water,40 and 50 single w oil is important   

[service _guy]

Hi all.
I am also new to the forum, I have been tasked with sorting out some electrical issues with a buddies coach, its a 1969 MC-7 Custom Cruiser factory conversion.
Biggest problem we really don't have the correct manuals, so not exactly sure how the electrical system works to be 100%
We never can get the reading lamps that are all along the bus to work, they are just below the curve in the ceiling, all the lamps have switches on them, but we can't get them to work.
I will have some other questions, can I post up here for help?
I have a number of pics of the interior.
Is there some kind of manual that explains the house/coach/shore/generator power selection and to get the systems to interact correctly?
Thanks
Dave