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Old 11-17-2016, 08:57 PM   #11
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That is a really cool old bus!! I love the look. Can't wait to see more pics.

Originally Posted by cowlitzcoach View Post

The Fuel Pincher never came from the factory with a turbo. Putting a turbo on is not generally thought to be a very good idea as the bottom end and the pistons can't take the added pressure. It was designed as a low cost entry level diesel engine that was to be used and then thrown away.

Cowlitz, I agree with you except the factory turbo setup. This is a pic of a genny at my work with the 8.2 with factory turbo. Also, the local fire department had a rescue truck for years, and it also had a factory turbo.

20161117_143927 by Hvbuzz, on Flickr
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Old 11-17-2016, 10:53 PM   #12
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A tale of two belts:

So as I mentioned above, Apollo has a strong young engine. I've worked on tractors and backhoes before, but this is my first bus and I am still getting comfortable with diesel mechanics. That said, when I bought the thing on the other side of the state, I bought two brand new batteries, and the engine turned over on the first turn of the key.

I got about 45 minutes down the road when I lost communication with my buddy in the trail vehicle and so we pulled off at a rest stop. It was only then that I noticed that the temp gauge was is 214 and there was steam pouring out of the engine compartment.

We soon discovered that the belts that are connected to the hydraulic pump had snapped and Apollo's hydraulic cooling fan was no longer turning. The belts are apparently size AX60. They run from the main oil pump, around that eccentric bearing, and then around the pulley on the hydro pump. On this maiden voyage, we were lucky enough to have extra belts in one of the storage compartments. We changed the belts and made it all they way home (another 4 hours) with no other issues.

Since this trip we have been throwing those two same belts about every 500 miles. It only happens on the highway. Sometimes they will take out the alternator belt as well, but not always.

This picture shows the ends of the belts but the flat side of the belts looks pretty worn. One time, there looked like there was melted rubber on that eccentric bearing. I took the bearing off and took it to some truck repair places in Portland, but everyone I showed it to says that it seems to be fine.

So, I absolutely think you kind commenters are correct in that I am having belt alignment issues. The main oil pump pulley seems to have 5 possible slots for belts. I think all the belts are in the right slots, but I am not positive. Furthermore, while the hydro pump seems secure , it looks light it might not be lined up perfectly with their corresponding pulley slots. It almost looks like it is bent forward towards me as I'm facing it.

Here's my best try at taking a picture straight down the belt line

I worry that the belt to the alternator may not be the right size. I think I have a 25-7640 on there now, but I have written down somewhere that 25-16003 might be the right size. Maybe you can see in the labeled photo that the alternator is adjusted as far out as possible. Even more of a concern is that the alternator belt seems loose and is dancing around perilously close to the eccentric bearing while the engine is running. Any beltheads out there that can teach me about belt sizes??

I guess the main thing I'm hoping to figure out is how to measure belt alignment more carefully. I like the idea of measuring with a straight edge, but I don't quite know how to accomplish that.

Thanks again for all the support and advice. I've read through all your comments and will be trying to update you all as I start working on the various systems that you have given me such valuable advice (grammar, eek). More to come -Jon

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Old 11-18-2016, 10:21 AM   #13
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Year: 1946
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That's quite a collection of belts! And unless they are aligned and tensioned just right, I can easily see how they could go south in a hurry. I would be suspect of the position of the hydraulic pump based on what is taking place. You "might" be able to shim that rascal but if the bracket is too far out of whack it may or may not help.

And, is the eccentric spinning freely? I just recently read a thread on a diesel site where the chap had similar mysterious issues. Took him months to finally figure out that his tensioner, which would turn just fine when cool, was locking up and seizing, but only after it got hot.

Best of luck with it.
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Old 11-18-2016, 10:43 AM   #14
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Year: 1935
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Engine: 317 ci/tid / Isuzu
I can recall a million years ago when Chrysler was using dual belts to turn their A/C compressors. They would pitch their belts unless the belts were a matched pair (they were sold only in pairs at the time). Someone smarter than me will know if matched belts are required on your set up. Also, I think Tango is probably right about the tensioner . I've seen dual belt tensioners heat and seize. I've also seen tensioners with worn bearings "tilt" on their rotational axis enough to make one belt looser than the other.

Let us know what you finally discover. Jack
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Old 11-18-2016, 10:58 AM   #15
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Also..."V" type belts tend to be much more demanding than the flat, grooved style when it comes to alignment. The 8 row that Cummins uses are very stable even if off a smidgen.

At least it doesn't make a 90 degree bend like the old Corvairs. You couldn't keep a belt on those things for fifteen minutes.
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Old 11-18-2016, 04:12 PM   #16
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Alright man this is just a thought from looking at your pictures?
Let's follow the belt left from the alternator.
It looks like it is in the second groove of the next pulley/shiv on the next /top pulley/shiv and in the third groove on the bottom/crankshaft pulley/shiv? The other thing I see is that it looks like your alternator has a pulley to accommodate two belts instead of one.
. Just an observation from pics but I think your belt needs to be moved forward one groove on the crankshaft pulley?
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Old 11-18-2016, 07:53 PM   #17
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"Apollo" - 1967 Gillig conversion

Wow! I'm super thankful for all this info!! Thanks Alan for making sure I get my lingo straight.

Makes me curious about what's actually happening inside that engine. Any help you all could offer in terms of identifying this engine and tracking down schematics would be greatly appreciated!

Hoping to dive in to some belt work tomorrow. Thanks again!

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Old 11-18-2016, 08:04 PM   #18
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Location: Gonvick MN
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Year: 1975
Chassis: Gillig
Engine: Cat 3208t/10 speed transmission
Roger may be right.
It appears from your pictures that the belts might be in the wrong grooves.
It's hard to tell.
Put a straight edge across the front of the hydraulic pump pulley down to the crank pulley ( what you are referring to as the oil pump).
This will help you to see where the belts should be.
With a setup like yours ( and mine) that is sort of homemade, deciding how to route the belts is just one of the many challenges.
Keep up the good work.
Keep us updated.
Remove hence to yonder place....
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Old 11-18-2016, 11:09 PM   #19
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1. Get your belts sorted out, NOW! The consequences of broken belts could be your engine dying from oil starvation or overheating, or you dying from ineffective brakes because of low air pressure.
2. Have accurate and trustworthy gauges for coolant temperature and oil pressure, ideally also connected to alarms and lights. Speedhut makes some that would work well; I've put in two Speedhut gauges for coolant and transmission temperatures, and they work well.
3. Your engine should ideally have shutdowns for low oil pressure, high coolant temperature and low coolant level - if so, make sure they all work as intended, and if it doesn't have them you should try to install some. You may be able to connect them to a fuel shutoff Skinner valve, maybe?

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Old 12-12-2016, 05:26 PM   #20
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Getting rolling again:

Hi, everyone! I appreciate all your advice and am trying to experiment with the belts and routing soon. It's been stormy here in Oregon and haven't really been able to dig in recently.

I'm trying to fix my biggest air leak, my low air pressure switch. It is a bendix LP-3 style. I believe this one is set to 60PSI. It is the two-pole variety. The supply line seems to be two 1/4" copper lines, going in to a T-junction, which the actual switch screws into. The switch itself seems to be the male side, and has 1/2" threading.

I see the numbers 223 stamped on both the top and bottom, as well as 8067 on the top metal plate, and 239100-a on the bottom, near the threading.

Could anyone help me verify that the part in the following link might be a good replacement? There seems to be many options for this exact style of switch and I don't know how to get the exact part I need:

Looking forward to getting Apollo on the road again. Not too excited to have to fill up the diesel when he's rolling just hoping to only have to buy this part once, and not having to deal with returning it over and over until I get the right one.

I look forward to more updates to follow shortly.


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