Read about the Great Fleets Across America
Subscribe

School Bus Fleet Magazine Forums
School Bus Fleet Magazine Forums
Home | Profile | Register | Active Topics | Members | Search | FAQ
 All Forums
 Professional Garage
 Enter Forum: Professional Garage
 C-7 blow by
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

Wobbler62
New Member

2 Posts

Posted - 05/29/2013 :  4:10:26 PM  Show Profile  Visit Wobbler62's Homepage  Reply with Quote
I have a C-7 with 2000 miles on it and it shows excessive blow by from the draft tube. I would like to know how to test crank case pressure and what it should be. I would also like to test compression and what it should be. Is there something else I should look at. I cannot believe that there is much wrong internally with a 2000 mile engine even if it is a Cat.

Mechan1c
Top Member

USA
696 Posts

Posted - 05/29/2013 :  7:19:09 PM  Show Profile  Reply with Quote
Steady stream, or puffing like a single hole?

Year? S/N? What's it in?

2K seems a bit low?? What's the story behind this? CATs don't smoke unless somethings really gone south. If it's got excessive blow by, did it happen all at once, or has this been something gradual?

Have you checked for overheat events? The reason I ask is I had a bus that the de-rate function had not been set, and it had gone through a bunch of overheats, and severe overheats without the shop knowing. These overheats led to a severe case of cylinder scoring and blowby that was so bad we couldn't run the bus. It drove just fine, but it smoked like an early 3208 on a cold morning!
Go to Top of Page

Wobbler62
New Member

2 Posts

Posted - 05/30/2013 :  2:38:36 PM  Show Profile  Visit Wobbler62's Homepage  Reply with Quote
Thanks for your speedy reply.
In answer to your questions: 1. It has a steady stream of smoke. 2. The serial is: FMM18721 and 2006 is MF year, and it is in an MTV military cargo truck. 3. There have been no overheat events.
There
Someone also suggested that if it is over full on oil that could cause the appearance of blowby so we lowered it to just below the add mark and took it on a 100 mile loaded run to see if it helped. It did not.

Any help will be appreciated,
Go to Top of Page

C.HARDY
Advanced Member

354 Posts

Posted - 05/30/2013 :  3:03:39 PM  Show Profile  Click to see C.HARDY's MSN Messenger address  Reply with Quote
I had Internationals with T444Es that smoked through the draft tube since brand new. Dealer said some just smoke more than others......I wonder if thats a military truck if it did alot of idling?

"Hardybusman"
Go to Top of Page

Wolf0r
Top Member

USA
2179 Posts

Posted - 06/11/2013 :  12:11:14 PM  Show Profile  Reply with Quote
I would have an oil sample looked at. Only 2000 miles on a 2006, how many times has the oil been changed?

“The good thing about science is that it's true whether or not you believe in it.”
Neil deGrasse Tyson
Go to Top of Page

bwest
Administrator

United States
2324 Posts

Posted - 06/11/2013 :  1:18:00 PM  Show Profile  Reply with Quote
Yeah, the 2,000 mile thing has me really stumped. Unless... Now I'm wonder about stuck rings. There should be lots of blow by and lots of smoke from the exhaust if the rings are stuck.

Bryan
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
 


School Bus Fleet Magazine Forums © 2013 School Bus Fleet Magazine Go To Top Of Page
This page was generated in 0.12 seconds. Snitz Forums 2000