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MCI 102-C3 coach to RV - Engine Bay

MarkObtinaro said,

Using PVC is actually a very clever way in which to isolate, protect, and to move electricity, water, high pressure oil, and high pressure air from the back of the bus to the front of the bus and back again.

I still hope you get the cooling system on your coach figured out. The dual radiator setup on a C-coach with the 8V-92 with an automatic was just adequate on warm days on reasonable hills. Get the ambient above 90* and the slope more than 5% and you were going to overheat. And that was when the buses were new. Be aware that on automatic transmission equipped buses the driver's side radiator was almost 100% tasked to cool the transmission leaving only the curb side radiator to cool the engine.

When Kasseboher/Setra started selling buses in North America they installed 8V-92's in them. To deal with the extra heat those engines generated Setra installed an auxiliary radiator with two or three electric fans. Even with the almost doubled radiator cooling capacity over the Eurospec Setra coaches the 8V-92 equipped Setras would still over heat on a hot day on a long uphill grade.

The advent of the D-coach and the single radiator was a big improvement. Going from the 8V-92 to the Series 60 was the biggest improvement for the cooling system.

I know some of the model -12's had larger radiators than some of the C-coaches. Just like the -8's were bigger than the -7's and the -9's were bigger than the -8's. But all of the -5, -6, -7, -8, -9, -10, and -12 models had the twin radiators and they all overheated if the grade was steep enough and/or the ambient temperature was hot enough.

Many operators that routinely pulled big hills, like the buses that traveled over Donner Pass, installed water sprayers that would shoot water onto the radiators to speed the heat transfer. It worked fairly well but the downside was if you didn't use distilled water over time the radiators would get clogged with mineral deposits.
 
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PVC was the way to go. Cheap, very light, fits perfectly, and a load of fittings to accommodate the variance in materials I'm shoving through them. Since I'm running rubber, polyethylene, and nylon through them, plastic should eliminate any wear from scuffing.

I have a few general thoughts on the cooling. Stuff to muddle with once I have a floor in. So far as I can assume, I won't be using the OE twin radiators that it has now. Did some research on the MCI and Setra buses prior to our purchase since we had an opportunity to snag a Setra at auction for cheap. I noticed that supplementing the twin rads still wasn't adequate. Whenever the time comes to try out what I end up with, we have three hefty mountain passes nearby to test it on. Three out of four routes out of this valley require that we ascend at least a couple thousand feet. Check out Wolf Creek Pass in Colorado. That's a killer.
 
MarkObtinaro said,
JNHEscher said:
I have a few general thoughts on the cooling. Stuff to muddle with once I have a floor in. So far as I can assume, I won't be using the OE twin radiators that it has now. Did some research on the MCI and Setra buses prior to our purchase since we had an opportunity to snag a Setra at auction for cheap. I noticed that supplementing the twin rads still wasn't adequate. Whenever the time comes to try out what I end up with, we have three hefty mountain passes nearby to test it on. Three out of four routes out of this valley require that we ascend at least a couple thousand feet. Check out Wolf Creek Pass in Colorado. That's a killer.​
I am really curious as to what direction you are heading for cooling. Prevost and Eagle both had only one large side mounted radiator to cool their 8V-92 equipped buses. But both of them required the use of miter boxes to turn the power 90* to make the fans turn. And like the squirrel cage gear box, using a gear box to turn fans eats up a few HP and adds to the cooling issue. And like the MCI's, if the hill is steep enough, long enough, and/or the ambient temp is hot enough the Eagles and Prevosts overheated too.

I suppose what makes me so curious is up until the advent of the cool running Series 60 no OEM that built rear engine buses ever made a bus that didn't over heat. I include rear engine school buses and rear engine transit buses in buses that overheated as well. And if all of those OEM's couldn't figure out a way in which to cool the 8V-92 down when it got hot outside I really would like to see your solution.

I am not trying to be snarky or disrespectful. I am just very curious.
 
MarkObtinaro said:
I am really curious as to what direction you are heading for cooling. Prevost and Eagle both had only one large side mounted radiator to cool their 8V-92 equipped buses. But both of them required the use of miter boxes to turn the power 90* to make the fans turn. And like the squirrel cage gear box, using a gear box to turn fans eats up a few HP and adds to the cooling issue. And like the MCI's, if the hill is steep enough, long enough, and/or the ambient temp is hot enough the Eagles and Prevosts overheated too.

I suppose what makes me so curious is up until the advent of the cool running Series 60 no OEM that built rear engine buses ever made a bus that didn't over heat. I include rear engine school buses and rear engine transit buses in buses that overheated as well. And if all of those OEM's couldn't figure out a way in which to cool the 8V-92 down when it got hot outside I really would like to see your solution.

I am not trying to be snarky or disrespectful. I am just very curious.
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Understandable, as I realize any RE vehicle design has had its cooling woes. I certainly appreciate your knowledge that has brought on such curiosity. The main reason I went for a Pirate thread was because of the top-notch constructiveness and criticism. I am slowly building ideas to work with when the time comes to put this system back together.
 
MarkObtinaro said,

Back in the day Flixible put the radiators up high with a big scoop to funnel air flow through the radiator. It worked, sort of, with the Buick straight 8's but became inadequate when a 4-53 was put back there.

Gillig and Kenworth used what they called high capacity air scoops up on the roof to get more air to flow through the radiator. It worked with the lower HP engines but came up short with bigger HP engines on hot days on steep grades.

Thomas has put the radiators on their rear engine buses down low on both the curb side and the driver side. They have put them as high as the bottom of the windows. They have used hydraulic fans, miter boxes, and belts to turn fans. Under 200 HP they did okay. Under 250 HP they did okay except for the really hot days. Over 250 HP and they overheated on hot days on steep grades.

GM put their engine in transversely with the radiator "in front" of the engine in the driver's side lower rear quarter. They didn't overheat that often but the biggest engines offered from the factory in a GM parlor car was the 8V-71 with HP ratings in the 300-325 HP range.

What all of the OEM's ran into is the fact that you are trying to move air from a low pressure area into a high pressure area. Unlike in a front engine where you are moving air from a high pressure area to a low pressure area. Getting air to flow through a radiator in a rear engine bus is difficult at best.

Crown in their buses with the amidships engine solved the problem by putting in one of the largest radiators in a bus I have ever seen. They are about almost 5' wide, 2.5' tall, and more than 8" thick. The fan was usually a direct belt driven affair that was placed at the rear of a plenum that really sucked air through the core of the radiator. When the shutters open and air is being sucked through it will suck just about anything else through as well. The only Crowns I know that had overheating issues were due to radiator cores that were all crudded up, the tubes were so packed with mud no air could get through, or someone increased the HP beyond a reasonable amount. Remember, Crowns were available with Cummins Big Cam engines with HP ratings of 450+ HP (I have actually seen a 475 HP Crown 10-wheeler that had a 13-speed Eaton Fuller Road Ranger with double overdrive--that bus didn't slow down for ANYTHING!)
 
MarkObtinaro said:
What all of the OEM's ran into is the fact that you are trying to move air from a low pressure area into a high pressure area. Unlike in a front engine where you are moving air from a high pressure area to a low pressure area. Getting air to flow through a radiator in a rear engine bus is difficult at best.​
That hits the nail on the head with what I was explaining to my dad the other day while we were standing in the back of the bus. I was showing him where the radiators were and how the miter box was set up to run the two squirrel cages and that I thought it was a little backwards to be trying to pull air into the bay through the radiators when there's typically a vacuum induced at the rear corners of buses and 18-wheeler box trailers and the vortexes that follow. I mentioned that I could possibly take advantage of the suction. Still, with a hard load on the engine while going uphill in the dead heat of a southwestern summer, there's not going to be enough static airflow as the load increases and speed decreases.
 
87manche said,

I think you'll end up with a bevy of solutions.

get the radiators and fans as well sorted as you can, but probably have to do meth or spray water to keep the engine cool for those 5 minutes of hill climbing.
 
87manche said:
I think you'll end up with a bevy of solutions.

get the radiators and fans as well sorted as you can, but probably have to do meth or spray water to keep the engine cool for those 5 minutes of hill climbing.​
I think so too. And spray will be easy. The hydronic floor will contain roughly 20 gallons as well which I'll set up to be an emergency coolant reserve with a solenoid valve and smallish flow so as not to crack the heads or block.
 
bigun said,

With no knowledge on the subject I must ask why not suck cooling air from under the bus, other than the chance of road debris getting into your radiators?
 
[486] said,
bigun said:
With no knowledge on the subject I must ask why not suck cooling air from under the bus, other than the chance of road debris getting into your radiators?​
under is low pressure, almost as much as the rear

also there is the ground there with a foot of clearance if that, so straight flow to the center of the core is kind of obstructed by the ground, around the edges would be okay
 
bigun said:
With no knowledge on the subject I must ask why not suck cooling air from under the bus, other than the chance of road debris getting into your radiators?​
That's part of my plan. I haven't mentioned the wind tunnel yet because of the amount of details. Basic description is that there's fresh air intake holes on the nose of the bus that supply air in some part of the driver's air and passenger's air and the tunnel it passes through is in the cold air return where all our conduits are going. I could build a couple doors that allow lots of air flow to enter the front, cool as it passes through the tunnel, and blow directly at the engine. Creating scoops that utilize the negative pressure at the rear corners of the bus would help draw cool air through the tunnel. I'll get some pics of that up soon
 
Man, do I love the smell of fresh fittings. These arrived this morning. I'm revamping the fuel transfer lines to eliminate all pipe threads. I'm not a fan of pipe threads. 'Nuff said. I'll have to rethread a few of the NPT ports, but that's easy. This setup will consist entirely of o-ring boss and SAE flare connections.

There's some Vibrant, Fragola, and Jiffy-Tite in there. A real nice Vibrant Performance flap-style check valve that functions waaaay better than the OE valve. I hadn't ordered a new filter mount, yet, as I'm tossing between an Earl's with a ¾-16 stud and the only mounts I can find that have the factory 1-12 stud size which are a bit costly. One of Faria Engineering's mounts is a perfect match, but runs $170. A smaller, ¾-16 primary filter will probably be just fine.

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CarterKaft said,
JNHEscher said:
Man, do I love the smell of fresh fittings. These arrived this morning. I'm revamping the fuel transfer lines to eliminate all pipe threads. I'm not a fan of pipe threads. 'Nuff said. I'll have to rethread a few of the NPT ports, but that's easy. This setup will consist entirely of o-ring boss and SAE flare connections.

There's some Vibrant, Fragola, and Jiffy-Tite in there. A real nice Vibrant Performance flap-style check valve that functions waaaay better than the OE valve. I hadn't ordered a new filter mount, yet, as I'm tossing between an Earl's with a ¾-16 stud and the only mounts I can find that have the factory 1-12 stud size which are a bit costly. One of Faria Engineering's mounts is a perfect match, but runs $170. A smaller, ¾-16 primary filter will probably be just fine.​
I hear you on the pipe threads but if you use the correct sealant (not pipe dope) it's not near as much of a problem. I use the anerobic Loctite style now and all my worries are over, 540, 542, 545, 5452 etc.

How are you porting the old npt for o-ring thread?

My suggestion on diesel fuel filtering is buy the most common filter you can. You want to be able to find a new filter in Bug Tussle, Texas or Beaverlick, Kentucky. IMO you also want a filter you can just spin off and throw away. A cleanable screen element is acceptable for a primary first line of defense but will need to have a removable canister not an inline.
 
Although proper sealant works on NPT, I thought it'd be nice to be able to disassemble and assemble any line or fitting without having to apply a sealant. That and the occasional pain of a pipe thread fitting that needs to be clocked in a certain position that gets tight 180° off.

I had spent a few days measuring fittings, port sizes, hoses, etc. and then laying out all the NPT and AN specs so that I could match thread sizes as closely as possible. Thread pitch matches between NPT and the similar straight-cut thread on all but the -12 o-ring fitting I'm putting on the tank. The -12 will be 2 threads off over an inch as compared to the 3/4NPT. I just use a straight tap to ream the NPT ports with lots of lube and very gradual cutting. It's worked for me numerous times. Plenty easy in brass and aluminum.

I'll be choosing the most common filter between various parts stores. I went into Napa to check on their 3118, which is their equivalent to the factory primary. They had 21 in stock at their Alamosa store. I'm going to have them pull up their deepest 3/4-16 options that match to OE specs and cross-reference them. Might even see if Wal-Mart carries something. Can't beat 24-hour parts availability.

Crappy pic, but it shows the filter adapter for the primary. I was curious what it looked like and was a bit surprised to see that it's a thick wall with a 1/2" ID. A 3/4-16 filter with reasonable capacity will be just dandy. The Earl's 3/4-16 filter mount has an 1/8"NPT gauge port on top that would be perfect for burping the system if I ever open up the lines or need to after a filter change.

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Puzzling. There's supposed to be two -8 barbs and two -4 barbs. Despite being made in China, I've never had a problem with Vibrant Performance fittings. Their 21004 is supposed to be -4 hose end to -4AN female. It has a -4 nut on a -6 barb. I'll be ordering a Fragola to replace it along with the new filter mount.

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Braided hose from Raceflux turned out nice. I need to order the -4 hose yet. Kinda wanted to assemble the -8 first to be sure everything went together right.

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Great success. We're mostly packed for moving and still haven't gotten keys to the new place so I'm pacing around the house as I usually do when I'm bored. The fuel line stuff was sitting in an open box, so I went for it.

I tried to put this return line together several times and fought it every time. Ordered some decent cable cutters so I could make all our battery cables and get a clean cut on this -4 hose. Wrapped some painter's tape around it inside out, made the cut, lubed it all, stuck the fitting in my Koul Tool and shoved it right in while being able to slide the tape back as it entered. One more task checked off while we wait. Now if I could just get a straight -4 fitting that is what is says it is.

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That works great on the stainless braid. This nylon braid uses some super fine threads that fray really easily. Cable cutter did a nice job.
 
Hory scheiss. I only had to order every single -4 hose end Summit offers in order to find one out of all of them to fit the braided nylon correctly.

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The Russell hose end didn't fit, either. Nut was too small for the braid. My last option was the barbed Fragola end. The return line is low pressure, so I shouldn't encounter any problems.

My dad arrives with the Kenmore 41002 combo tonight. I'm hoping I can get back to the bus to finish making it driveable again. We've officially moved into the Fort Garland place and my wife got the call to start working at Memorial hospital central in Colorado Springs shortly. We'll then find a place up there to finish out the build and possibly have room for some friends who are also converting a bus. Not long before we can get out of this damn valley.
 
I suppose the thread will be pictureless for a while. Uploader is still dead.

I purchased a 7x16 Micro Mark (Chinese) lathe a while ago. $800 plus some extras for that versus the total in quotes I got from the local shop for $780 to turn or thread a few small items. Might as well blow nearly the same dollar amount on the gift the keeps on giving.

One piece that needs some mods is the Vibrant Performance check valve for the return fuel line. A restrictor with an 0.080" ID needs to be in place and I don't see the floppy rubber flap holding up in the long run. I have tooling on the way to complete the task.

From Mcmaster Carr, en route, I have some 1/2-13 brass set screws (only need one) that I'll turn down and thread to 3/8-24 and drill to 0.078"ish with a 5/64" bit. The check valve I can tap directly with a 3/8-24 tap. Also, a couple conical springs to try out with the 3/8" ball bearing a grabbed at Ace Hardware today that fits perfectly. I'll use whichever spring achieves close to 2 pounds of pressure on the ball.
 
I loathe mobile versions of websites, but if it works to continue with pictures, then so be it. Didn't care for the Tapatalk app, either.

Here's the check valve I'm working with. It holds pressure very well, though as you can see, the valve itself is not the best for continuous duty on a thirsty diesel. That rubber would rip before long. The cylindrical spring just holds it in place. So in place of the rubber, a check ball fits right in.
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McMaster parts came in. The lightest spring puts about 3 pounds against the check ball. I'll leave it be for now and see how the engine reacts to it. Likely no difference as the restrictor is there to maintain something like 30-75psi.

My apologies for any sideways pictures. The mobile version of Pirate is rotating them when I submit a post. Can't seem to do anything about it.

I have the brass set screw all set up in the lathe and no tooling. It was scheduled to arrive today, but for whatever reason, UPS gave to a post office and don't know where it went from there.
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Found my tooling and had a little fun on the lathe. I had thought about making a press-fit restrictor before, but wasn't too keen on the idea. Went for it with a one thou interference fit and got a 0.079" bore drilled in it with a 5/64" bit. Perfectly snug fit. The check valve is done.

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On a roll tonight. Turned down this adapter so that the fuel filter o-ring would seat properly. The wrench hex was a little too thick and stopped the filter right as the o-ring touched the filter mount flange.

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Made the official decision this morning to go electric on the water pump. Two or more Meziere pumps for redundancy and to be sure that I somewhat match the stock pump flow range. The cooling topic was discussed here a while back. Whatever radiator I end up choosing will likely be some central mount. I tore out all the factory radiator piping to get going on the swap.

With the heated floor and engine sharing the coolant, I can run one water pump for the floor when the engine is off. Meziere has plenty of options that would be a great unit for the floor. The cold return off the floor will be passing through the engine block. This makes using any one of the electric pumps for the floor an easy setup.

Gage (my oldest) and I pulled the stock water pump off to check it out. Pretty easy task. Stuck it back on to keep the 20-30mph winds from blowing dirt into the gear case. Not sure if I ever mentioned how almost all the coolant pipe couplers had been replaced with some universal silicone hose. They all fit too loosely and leaked. Several even had as many as three hose clamps on each end. Glad to be simplifying the system.

I’ll be yanking the radiators out when the wind dies down again. It’s blowing hard enough again to end up bending some doors off their hinges.

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Rads weren’t too difficult to extract. I did, however, stand there for the longest time contemplating how to hoist them out of their holes. I’d rather not herniate my disc for like the 20th time. Ended up dropping the spare tire below and prying at each radiator until they dropped onto the tire. Perfect landing each time. Another load of copper and brass for the scrap yard, I believe.

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