Smoking Turbos - EXPLAINED Check Valves, Oil Drains, Crankcase Ventilation - Dodge SRT Forum
 
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 03-24-2008, 10:43 AM Thread Starter
Supporting Vendor (Gold)
 
Ben@AGP's Avatar
 
Join Date: Mar 2003
Location: Arizona
Posts: 7,419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Lifetime Premium Member
Smoking Turbos - EXPLAINED Check Valves, Oil Drains, Crankcase Ventilation

If you have a car that resembles a James Bond tricked out SRT-4, please take the time and check this out.

A turbo drains its oil from gravity, nothing more and nothing less. If there is any restriction in the turbo's drain path back to the pan, oil will build up in the center housing. This oil is going to take the path of least resistance and will leak out of the turbine's side piston ring and turn into blue smoke coming out of the exhaust.

Most of your friends are going to tell you that you have a blown seal, and that your turbo needs to be rebuilt. 99% of the time, there is nothing wrong with the turbo. We get turbos in the shop everyday for rebuild because of the mysterious "blown seal" theory that lingers around every intarweb forum that deals with any turbo vehicle. These turbos are perfectly fine, and don't need a rebuild 99% of the time.

I'm putting this explaination together to help all of you save time and energy before you feel the need to send a turbo back to us for rebuild.

Lately, we've noticed a trend with some of the available "check valves" in this market that some shops are selling. Moreso, there are part numbers floating around this forum from industrial supply companies that many people are buying and installing. Most of these check valves will not work properly to allow enough crankcase venting so the turbo can sufficiently drain.

We've done some testing here with a local car and we were able to figure out what was going on. The very popular 1/4"NPT check valve has a .200" valve that is insufficient in allowing the engine to pull enough crankcase pressure when in vacuum. This extra crankcase pressure under vacuum conditions will cause the turbo to leak oil past the piston ring and results in blue smoke out your exhaust. Get rid of this size check valve as all your are doing are causing more problems for yourself.

That same company offers a check valve with 3/8" NPT ports and the valve size is .460". This valve is FTW, period.

We put the 1/4"NPT check valve on the car, let it sit at idle for 30 minutes. After about 20 minutes, the car started smoking, and got progressively worse over the next 10 minutes. Keep in mind, this is on a car that never smoked before. We then installed the 3/8" NPT check valve on the car and let it idle for 30 minutes. No smoke at all. We then put the smaller check valve back in, and instantly started smoking again.

Please make sure you know what you're doing, and don't just listen to everyone else. If you have questions, any of us here at AGP can answer them.


WEBSITE | EMAIL | YOUTUBE | FACEBOOK | 480-983-6083
Ben@AGP is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old 03-24-2008, 10:44 AM Thread Starter
Supporting Vendor (Gold)
 
Ben@AGP's Avatar
 
Join Date: Mar 2003
Location: Arizona
Posts: 7,419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Lifetime Premium Member




WEBSITE | EMAIL | YOUTUBE | FACEBOOK | 480-983-6083
Ben@AGP is offline  
post #3 of 5 (permalink) Old 09-28-2008, 10:27 AM Thread Starter
Supporting Vendor (Gold)
 
Ben@AGP's Avatar
 
Join Date: Mar 2003
Location: Arizona
Posts: 7,419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Lifetime Premium Member
To add a little bit to this thread. You should only be running a properly sized check valve (like the one above) if and only if you're removed the factory PCV. You should never, ever never, never, ever run a check valve in conjunction with the factory PCV. You've now added an additional airflow restriction on probably the most important system of your engine.

Additionally, there is no need to run a check valve. If you have a properly functioning PCV, an additional check valve is going to:

1. Best case senario - do nothing for you.
2. Worst case senario - cause your car to smoke under many different conditions.

If you do not have a properly functioning PCV, buy a new one. They're cheap at the dealer.


WEBSITE | EMAIL | YOUTUBE | FACEBOOK | 480-983-6083

Last edited by Ben@AGP; 02-09-2010 at 02:03 PM.
Ben@AGP is offline  
 
post #4 of 5 (permalink) Old 02-09-2010, 01:59 PM Thread Starter
Supporting Vendor (Gold)
 
Ben@AGP's Avatar
 
Join Date: Mar 2003
Location: Arizona
Posts: 7,419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Lifetime Premium Member
To add a little bit to this thread where we've seen cars smoking from improper installation of your oil drain lines. Here are a few tips.

* The oil drain line needs to be a minumim of .600" ID at its smallest point.
* Never use any AN fittings of -10 or -12. AN fittings neck down well under .500" ID
* Home Depot brass fittings connected to your drain flange will also neck down well under .500" ID
* The oil drain line needs to be verticle and must follow a direct path to the factory drain port in the bottom of the block.
* The oil drain line needs to be inspected to make sure it is still internally to dimension. We have seen oil drain tubes deteriorate on the inside, while appearing perfectly acceptable on the outside. Check your drain, you will be amazed what you see.
* Do not ever use any silicone sealant on the oil drain flange. This silicone will ball up, and become a restriction in the drain line.

These drain restrictions can often be fixed very easily with little time, and little money. Make sure that you stay on top of these points, because failing to follow these guidelines can and will lead to premature turbo failure.


WEBSITE | EMAIL | YOUTUBE | FACEBOOK | 480-983-6083

Last edited by Ben@AGP; 09-16-2010 at 11:25 AM.
Ben@AGP is offline  
post #5 of 5 (permalink) Old 09-21-2010, 09:25 AM Thread Starter
Supporting Vendor (Gold)
 
Ben@AGP's Avatar
 
Join Date: Mar 2003
Location: Arizona
Posts: 7,419
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Lifetime Premium Member
1st thing to determine if your turbo is smoking because of bearing wear or if the turbo isn't draining properly.

1. Check your turbo for shaft play. Standard bearing turbos should have anywhere between .005" and .015" radial play (up down) and anywhere between .001" and .003" axial play (in out). If your turbo has anymore than this amount of play, chances are that your wheels are contacting the housings, and your turbo is in need of a repair by a qualified turbo repair facility that can help you determine what caused the turbo bearings to wear. If you don't fix what's causing your bearing wear, it will continue to happen.

Common causes for bearing wear:

Oil Contamination = microfine particles present in your oiling system that are fed through the turbo's oil feed port and wear grooves into the shaft, bearings, and bearing housing. Just because you say "Well I changed my oil and my filter" doesn't mean that your engine is clean of debris that will cause a turbo failure.

Oil Starvation = lack of sufficient lubrication causing the bearings to wear because of material on material contact. Oil starvation can be caused by poor oil pump clearances, removing of balance shaft assemblies improperly, going to big oil filter kits, restricting oil supplies, and using oil that breaks down too quickly by not having proper levels of ZDDP.

Oil Coking = overheating of the oil or not having the proper oil for your application. Overheated oil turns to carbon, and carbon will end up turning your turbo bearings into black, rock hard pieces of material that will not allow oil to properly pass through. This is caused by too thin of an oil, or an oil that doesn't have proper levels of ZDDP, or caused by not water cooling your turbo.

More stuff on it's way...


WEBSITE | EMAIL | YOUTUBE | FACEBOOK | 480-983-6083
Ben@AGP is offline  
Sponsored Links
Advertisement
 
Closed Thread

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome