North Florida Bus Conversion
C. Fred Hobe
|Tips on helping your engine run
When I installed my new motor, an 8V71 Turbo with N 80 injectors, I found that pulling a car at any speed over 65 caused my temperature to climb. By opening the back doors and leaving them open I could run 70 to 75mph without much heating problem at 95 degree out side temp. I bought the two lower panels from International Bus Parts that are ventilated, cost $320. As the upper panels are painted I went to an air conditioning shop and was given the sides off a whole house house unit. I cut the ventilators off the unit and weld it to the top door panels . This opening is about 21 by 11 inches and the two ventilators fit just right. I then cut the door skin to fit the opening and painted to match . These upper panels cost nothing and will let out more hot air than what I could have got for another $300. I think that it looks real cool and at a big saving. If you dont want the S.S. at the bottom you can save big. Try it if you are having any heat problems you may like it.
Tips on helping your engine run cool - High Speed Pulley
As more and more converters go to bigger motors on MCIs it becomes very hard to cool the motor with out a lot of expensive parts. I have given some tips and here is one more that will be a big help, and at a modest price. The MCI 7 and 8 have a 8.5 pulley on the squirrel cage fans. The 9 has a 8 inch which is not very much better. You can get a 6.5 from Granger or and good bearing and drive shop. The thing that you cant get is the tapered shaft that will fit the fans shaft. You have to buy a straight shaft that is ¾ inch and take it to a machine shop and have the taper and the key way cut into it. I took the original pulley and they matched the taper. Now it is exactly as the original was. It cost me $50 to have this done.
The 6.5 pulley is the only size that you can go to as
the C belt which is on the coach is 124 inch. The next size smaller is 119 inch which will
work on the 6.5 pulley. It seems that they come in 5 inch differences at this big size.
The difference is about 500 RPM faster at running speed. This will pull in a lot more air
and not destroy the squirrel cage fans, if they are in good shape.
If anyone is interested in having a high speed pulley, I'll make them available for $250.00. And I guarantee it to lower your temp 10 degrees. I also send instructions on how to install it right.
On the two squirrel cage fans there are four rubber or
plastic shrouds that cause the fans to pull in max air. These need to be replaced on most
old coaches. The way to tell is to look inside. If the shroud does not come to the center
of the fan it needs to be replaced. The new ones will come very close to the fan. They
cost about $30 each at international bus. But the best ones you can have made at a local
tin shop. Have them made so that they come to the center of the fan blades. Another way to
tell is to feel them if broke they will have a rough edge on them. Also seal the door on
the fans so that no air can be sucked in around them. Also make sure that air cant
be pulled around your radiators.There is a small hole in the center of each fan were there
was a cold weather adjustment. I plate over this so that all the air comes out the bottom.
When you are working on the fans make sure that you clean them. They will have years of
dirt on them and a good cleaning will make them move more air. While you are cleaning, go
to an air conditioning shop and buy a gallon of condenser cleaner. Spray on your radiator
and wash off. You will be surprised on how much cooler it will run.
For this you will have to have a tin shop make it, if you dont have a Break and a roll and shear. Remove both of the screens and take them to your tin shop. Have them make and weld the scoops to the outer frame of the screen. It should rap around the back of the screen 4 inches as this get out in the front were the air can be forced in. Have the scoops stick out 3 to 31/2 inches. The bottom and the top should be closed so that all the air is forced in. If your screens have that soft alum. wire in them have it taken out and replaced with S. S. expanded metal . It is very tough and looks good. Below you will see two types, one has rolled face and the other is made at a 45% flat on top design. Both work real good and dropped my operating temp 10 degrees in real hot weather. They have no effect when idling.
The plastic inlet rings that make the squirrel cage fans work to there maximal, from
ABC bus cost $140.00 and only last a few years. Then they start to crack and go bad. A
better way to do the same thing is to have a tin shop make up four inlet rings out of 20
gage galvanized metal. Cost was $15.00 each, with a saving of $80.00. And they will last
the life of the coach. Below is a photo of the cones that I had made. The rubber one were
on the coach for just over two years and about 30,000 miles. The heat had cracked them.
The reason that I found this out was that the seals were leaking and I had to remove both
blowers two change the seal. I didnt want to install the rubber inlet rings that
werent going to last.
Tip on building for future
Tip on how to fix the cable on
MCI 7 and 8 baggage door lift cables
Cost about $3.00. New one from ABC over $15. This will save
you from taking the guard off the side of the coach and about an hour in time. More if you
have built in cabinets and other things in the bays as most do. So cut them out before you
build them in. Take a philips screw driver and put in the end of the cable and pull it
down in the hole that it fastens to and lower the door about 6 inches, Now put a pair of
vice grips on the cable up at the pulley, Raise door and put pin in clevis. And you are
done takes about 5 minutes.
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