Tahoe & Suburban The power, space, and brutal towing ability make the Tahoe and its longer sibling, the Suburban, arguably the best full size SUV's on the market today.

2013 Chevrolet Suburban
Platform: GMT 400, 800, 900

07 Suburban a Qt low 3000mi after oil change

Old Apr 26, 2010 | 12:06 AM
  #11  
cam3439's Avatar
CF Active Member
 
Joined: Jan 2010
Posts: 128
Likes: 0
From: TX
Default

I see what you're saying with build up of pressure in the crank with blow-by, and don't these engines come with some type of windage tray already? I'm pretty sure the oil gets sucked up through the PCV valve due to vacuum from the engine running and especially at higher rpm's.
Reply
Old Apr 26, 2010 | 3:52 PM
  #12  
73shark's Avatar
Administrator
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2006
Posts: 11,337
Likes: 194
From: KC, MO area
Default

The PCV (Positive Crankcase Ventilation) system is to burn blow-by gases instead of venting to the atmosphere like the old road draft tubes did. There should be very little, if any, oil in the blow-by. Since the PCV usually sucks from the valve cover, high rpm will create a lot of mist in that area and thereby put some oil into the PCV system, therefore the need for catch cans. A unmodified street driven vehicle shouldn't require a catch can.

Not sure if there's a windage tray or not. One would hope so.
Reply
Old Apr 27, 2010 | 7:38 PM
  #13  
cam3439's Avatar
CF Active Member
 
Joined: Jan 2010
Posts: 128
Likes: 0
From: TX
Default

The engine is healthy and all, but when he put that catch can on he was pretty surprised on how much oil he was catching. He plans on adding a supercharger onto it, but hasn't yet. What about the AFM? I somewhat know how it all works with the lifters and all, but do the lifters still pump oil up the rods on the deactivated pistons? And if so, what's the oil pressure through the rods when they're deactivated? I think that the lifters are deactivated by oil pressure, but don't know all the specifics.
Reply
Old Apr 27, 2010 | 8:22 PM
  #14  
73shark's Avatar
Administrator
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2006
Posts: 11,337
Likes: 194
From: KC, MO area
Default

If I had a motor that was still in the 5 yr/100K warranty and it was sucking oil in the PCV system, I'd have it sitting in the dealer's service bay 'til it was good.
Reply
Old Apr 27, 2010 | 8:50 PM
  #15  
in2pro's Avatar
Administrator
 
Joined: Apr 2008
Posts: 7,573
Likes: 47
From: Austin, Texas
Default what is a windage tray?

A windage tray is usually a stamped piece of sheet metal that is mounted between the crank shaft and the oil pan. On slow revving i.e. stock applications there benefit is slight. However race and high RPM applications claim that they actually free up more horsepower. When the crankshaft is rotating say at highway speed a horizontal vortex of swirling air is generated.

The oil in the engine that was pumped up high and residual from the crank assembly is draining back to the oil pan gets caught in this vortex and is spinning too. Some estimate that anywhere from 1 to 3 quarts of oil can be caught in this vortex. Which leads to why a wind-age tray is such a great thing. (1) this much swirling oil acts like a small load on the engine and robs HorsePower. (2) with that much oil NOT in your oil pan at High RPM you could have a potential oil starvation

A windage tray acts like a scraper and removes the oil from the vortex letting it drain back to the oil pan. It does not actually touch the crank shaft.
Reply
Old Apr 27, 2010 | 8:56 PM
  #16  
MDTAHOE's Avatar
Super Moderator
Professional Mechanic
 
Joined: Nov 2008
Posts: 2,950
Likes: 5
From: Bowie, MD
Default

Most of the time on a vehicle with a good converter you will not see the smoke come out of the tail pipe.
Read this it may explain some
https://www.carchex.com/goss/article...rter-confusion
Reply
Old Apr 27, 2010 | 9:14 PM
  #17  
in2pro's Avatar
Administrator
 
Joined: Apr 2008
Posts: 7,573
Likes: 47
From: Austin, Texas
Default

Thanks Anthony and I have to say I like the following quotes from the article..

"Converters are excellent for reducing emissions but create substantial confusion among motorists possessing “enough knowledge to be dangerous.” "

"This makes it possible for an engine to consume alarming quantities of oil without a trace of exhaust smoke"
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
89scottsdale
Silverado, Sierra & Fullsize Pick-ups
4
Nov 29, 2014 9:15 PM
pervitizm
Tahoe & Suburban
1
Jan 22, 2010 9:35 PM
MC
TrailBlazer
1
Aug 24, 2007 10:27 PM
larry_chip
Tahoe & Suburban
6
Apr 24, 2007 11:46 AM
digdug
Tahoe & Suburban
7
Feb 4, 2007 3:08 PM


Thread Tools
Search this Thread

All times are GMT -5. The time now is 3:28 PM.