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 C7 and blowby
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 10/30/2015 :  09:02:25 AM  Show Profile  Reply with Quote
2005 Blue Bird AAFE with about 165,000 miles on the original C7. Bus runs like a bat out of he**, no miss and never skips a beat.

It got all 6 injectors replaced in July of 2014 due to hard starts and a miss that nobody could track down. Compression tested like that of a new engine at that time. Hard starts and the miss were cured.

The last few years it's had a lot of blow by, but now it's excessive to the point that you don't even want to stand by it when it's on high idle. It used 3 quarts of oil last week (280 miles) and looks like about 2.5 this week at the same miles.

My gut tells me its broken a ring or two or ten. I still want to believe it's just the air compressor or turbo.

Any guidance? If it needs an engine, it needs an engine...I have to keep it. How have you guys pin pointed Cat failures?

The ones I've been personally involved with were clear cut and consisted of a nasty miss when it was the common broken ring(s), or popping back through the intake (roller lifter failure).

tigger2
Advanced Member

USA
469 Posts

Posted - 11/02/2015 :  11:21:01 AM  Show Profile  Click to see tigger2's MSN Messenger address  Reply with Quote
We have had several of our early C7's break the rings and score the liners without power complaints, the last one dropped debris on the crank and took it out as well. The engine has to be sleeved and re-bored to std. and rebuilt.
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 11/03/2015 :  08:06:10 AM  Show Profile  Reply with Quote
Just for laughs I'm sending an oil sample for analysis. I think we have a Christmas break project on our hands though.
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bwest
Administrator

United States
3820 Posts

Posted - 11/03/2015 :  11:43:01 AM  Show Profile  Reply with Quote
I'll bet the oil analysis won't show anything. I've been told if you can see the debris in the oil, the lab can't pick it up. Something about having to be small enough to be burnt to be detected. I'm not sure how they do an oil analysis.
Anyway, My money is on a broken ring. Probably number 5. Don't ask my why, I don't have a clue as to why they do it. However, I have had four in my fleet of 17 develop broken rings. Two had 145k (within 77 miles of each other), one had 140K, and the other had 207K (didn't fix this one).
LOL, this is the reason I like this job, you just never know what is going to happen next. The best part is, I get to try and prevent the problem by changing methods and purchases from the onset (go propane!).

Bryan
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 11/03/2015 :  11:57:54 AM  Show Profile  Reply with Quote
The C7 would probably make a good boat anchor, along with the VT365. Other than that, I see no use for them.

On that note, it's going to be 48 tonight...I gotta plug in 3 of the 7 Cats!
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bwest
Administrator

United States
3820 Posts

Posted - 11/06/2015 :  11:53:01 AM  Show Profile  Reply with Quote
365 yes, I can deal with the C7. It's no where near as complicated as the VT365.

Bryan
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second.flood
Top Member

USA
640 Posts

Posted - 11/06/2015 :  12:07:43 PM  Show Profile  Reply with Quote
My BB salesman told me that BB is going to offer a gasoline engine soon.
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BJ Henderson
Advanced Member

USA
280 Posts

Posted - 11/07/2015 :  05:52:23 AM  Show Profile  Send BJ Henderson an AOL message  Reply with Quote
Can you do compression test? That would be what I would do at this point. Plus, check that turbo, like you said. Compressor, too.

We have two of the 2005s in our fleet, pretty reliable engines for the most part.

CMTT,CMAT,CMBT
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 11/07/2015 :  07:47:36 AM  Show Profile  Reply with Quote
Yes, Blue Bird says they will be selling gasoline buses again...but Blue Bird says a lot of things that never make it beyond a few units.

Id like to do a compression test but it'll have to wait til time allows. Y'all know that feeling.
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bwest
Administrator

United States
3820 Posts

Posted - 11/10/2015 :  05:32:54 AM  Show Profile  Reply with Quote
Compression test on a 3126? I'm not sure that is possible. Might be mistaken but I've never done one.

Bryan
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 11/10/2015 :  06:29:09 AM  Show Profile  Reply with Quote
http://www.mytoolsforyou.com/automotive-tools/STR-TU-15-43.html

Not saying I'd endorse that particular brand of tool or anything, but there is an adapter to do the test. Local dealer has one.
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 12/04/2015 :  4:23:31 PM  Show Profile  Reply with Quote
Right you were bwest...oil was like that of a new engine across the board.

Anybody think I'd be able to see anything cylinder wise if I dropped the pan and barred the thing over?
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bwest
Administrator

United States
3820 Posts

Posted - 12/10/2015 :  08:32:36 AM  Show Profile  Reply with Quote
Yep, check number 5.

Bryan
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 12/10/2015 :  09:09:51 AM  Show Profile  Reply with Quote
Going to have to do that when time allows. Will report back.
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 01/27/2016 :  07:42:14 AM  Show Profile  Reply with Quote
An update for anyone who cares...167,xxx miles...

Bus developed a miss and the blowby got so bad that you couldn't stand to be within 15 feet of the bus. It also started drinking oil. Since the bus is in great overall condition, we decided to have a reman installed.

I would like to have done it in-house, but both my guys were off the first half of January and my previous surgeries ruined my heavy lifting/shoving/pulling abilities for good. Oh well...miserable job anyways...worth the money to hire out!!!!!

We should have the bus back next week.
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BrokenBus
Active Member

10 Posts

Posted - 01/27/2016 :  08:18:42 AM  Show Profile  Visit BrokenBus's Homepage  Reply with Quote
Will they do a tear down on the old engine to see what the problem was?
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 01/27/2016 :  09:12:17 AM  Show Profile  Reply with Quote
For a fee they would. I'm not paying for it.

Reviva and Jasper both say they are seeing cylinder distortion on the cores coming in. Might explain the high rate of ring failures.
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bwest
Administrator

United States
3820 Posts

Posted - 01/29/2016 :  05:26:31 AM  Show Profile  Reply with Quote
Found this; https://www.youtube.com/watch?v=bUVjJibTLLQ
Wonder if Jasper is measuring with the stress plate?

Bryan
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 01/29/2016 :  07:07:19 AM  Show Profile  Reply with Quote
Great video! I'm told that both companies R&D included the stress plate factor (they called them torque plates) and that the remans are honed with the plates installed. I'm told that anyways.

I do wonder is #5 is just more apt to warp due to some block construction characteristic.
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bwest
Administrator

United States
3820 Posts

Posted - 01/29/2016 :  1:57:46 PM  Show Profile  Reply with Quote
quote:
Originally posted by Thomasbus24


I do wonder is #5 is just more apt to warp due to some block construction characteristic.



Could very well be. It make a little more sense than just thinking it's random anyway.

Bryan
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bluebirdvision
Top Member

USA
1081 Posts

Posted - 01/30/2016 :  7:54:16 PM  Show Profile  Reply with Quote
Kill all the C7s. LOL

Facebook Page: Blue Bird Corporation Fans
https://www.facebook.com/home.php?sk=group_212311114614&ap=1


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bwest
Administrator

United States
3820 Posts

Posted - 02/01/2016 :  06:34:37 AM  Show Profile  Reply with Quote
quote:
Originally posted by bluebirdvision

Kill all the C7s. LOL



The government tried to do that once! Remember drilling the hole in the bocks?

Bryan
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 02/01/2016 :  2:11:28 PM  Show Profile  Reply with Quote
EPA clean diesel grant funding?

That is a total joke. I look into it every year and the only eligible buses are the reasonably clean running ones. My old smoke belchers don't qualify.

You litterally could not replace a nasty old 3208 or VT225, but by gummy, that C7 can get junked! It's all for the children, you know.
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bwest
Administrator

United States
3820 Posts

Posted - 02/03/2016 :  06:26:37 AM  Show Profile  Reply with Quote
quote:
Originally posted by Thomasbus24

EPA clean diesel grant funding?

That is a total joke. I look into it every year and the only eligible buses are the reasonably clean running ones. My old smoke belchers don't qualify.

You litterally could not replace a nasty old 3208 or VT225, but by gummy, that C7 can get junked! It's all for the children, you know.



Don't get me started, my friend! People put these grants together who have no clue what is going on in the real world. They would save time, money, and lungs if they'd get a bunch of us together in a round table discussion on these topics. lol

Bryan
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Thomasbus24
Administrator

USA
4544 Posts

Posted - 02/03/2016 :  08:02:09 AM  Show Profile  Reply with Quote
That would be a lot of hot air and CO2 emissions at that meeting! I could tell them a thing or 6.
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bwest
Administrator

United States
3820 Posts

Posted - 02/03/2016 :  08:24:06 AM  Show Profile  Reply with Quote

Bryan
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