Blow By.....

Prof

Prof

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I am getting some rumblings about driver side blow-by in boosted engines.

If you don't have it, great.

This thread is being started to see if we can address this issue on a pure technical level. Please provide your experience with the V10 and its blow-by issues, if you have had them.

If you have addressed this issue with other engines, that input would also be appreciated.

If you don't have experience with this issue, we would appreciate your careful observation of the thread but please, let's see if we can focus on this one issue.

I have it bad. I have talked to Sean Roe, Justin and Joe Donovan about it...and all of them have seen it in several trucks...I expect it is a bigger problem than we really know.

So if you have addressed it, post up, if you have perspective on causes, solutions, or consequences please post them...this is a really sticky and messy issue to me.
 
Prof,

Where is yours comming out of? Oil filler cap? Rear vent driver side? Passenger side?

I presently am not having any problem since the Catch can install!
 
roy ive got boomers valve covers on my motor with the breathers. ive noticed a little on the passenger side but really have looked real hard at the drivers side since its located at the rear of the engine. will give it a closer look this afternoon when i get home to see what it looks like and let ya know. i would assume with all the valvetrain action going on in these motors it would be more blow by than a normal engine. just my opinion.
 
I wish I could be more help but all I know is this. I have it in my Viper and was told if I put a Roe on it I would most likely mess up alot of things. I would call Sean Roe, or I can call my Viper tech. The catch can should help, but it may end up being a more serious problem.
 
What year Prof? In the '04's the breather is on the back-side.
When the 05's came out they moved it to the front.
Seems under WOT the oil will get-out of the breather. :mad:
They have several answers out there for this problem.

Quick
 
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The problem is with poor crankcase evacuation on these engines. Especially on a boosted engine. Your blow-by gases are pressurizing the crank case, which is cause oil to get pushed past seals and gaskets. The only way to fix it is to install a serious crankcase evac system. A good crankcase evac system will improve ring sealing and will actually increase horsepower.

This problem is not with just the Viper engines. I have seen it on many engines, with the turbo four bangers being the worst. I had to install a catch can on my wife's SRT-4 to catch all the oil from the PCV hose. It was filling up the intercooler.

-Muzzy
 
I had some major problems with blow by and low oil pressure, we re-built the motor with new bearings and rings... both problems solved.
 
BigRed460 said:
I had some major problems with blow by and low oil pressure, we re-built the motor with new bearings and rings... both problems solved.
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That is why my Tech is going to rebuild my engine before any FI, man I wish it was easier but. By the time the engine is done, hopefully ear end, it will be stronger than stock and putting close to 540rwhp!
 
I noticed a little bit of blow by on my Viper (with Roe S/C) before I installed Justins catch can (actually Justin installed it for me, lol).

Since adding the catch can I have had NO issues with it.
 
Did you call up Amy and talk about the Blow by issue?
 
prof., woodys engine did this before i rebuilt it. the motor ran good but had the oil problem. What i found when i tore it down was 3 pistons cracked in the ring gap area. The rings were not broke. After the rebuild every thing was ok.
 
Great input...I had someone do leak down test here...and they were of the opinion that due to the minimal piston dome thickness that the heat cannot be dissipated and that that the rings suffer since they are so close to that thin dome.

One of the reasons I am going to forged pistons...

Anyone else got ideas and/or experience with this?

Roy
 
I think all of the engines with stock pistons will at some time suffer from the blow-by issue...there are a lot of people out there that have worked with this problem...for some reason, it has never really been surfaced...as I have spoken with engine builders that have lots of experience with our trucks...everyone has seen this issue crop up more than once.
 
Prof said:
I think all of the engines with stock pistons will at some time suffer from the blow-by issue...there are a lot of people out there that have worked with this problem...for some reason, it has never really been surfaced...as I have spoken with engine builders that have lots of experience with our trucks...everyone has seen this issue crop up more than once.
Click to expand...
Whats Roe's solution to it or is it... Forged internals?
 
No one has done enough research to be definitive in their diagnosis or Rx. I'm in hopes that this thread will spark some ideas that will work...it is my approach to go with forged rods and pistons...better pistons and new rings...and we will see if this is a permanent solution.

If you look at the back of a stripped viper block and a stripped LS 7 block one of the things that jumps out at you is the venting to the crank case...LS 7's had some issues with blow-by and they have moved to the venting...

I think that the piston issue is the real cause...look at the minimal amount of metal there is between the first ring and the piston dome, in a Viper engine...IMO there is just not enough metal to avoid some heat related issues...and the rings are the least capable, and closest part to the heat issue...add FI and the natural rotation of the engine drives all the pressure up under the piston skirt (sound nice eh?) on the drivers side...and then in the process of looking for relief...those heated rings become the weak point...

But hell, who am I, just a worn out teacher that lets others do the hard things on my engines...
 
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Prof said:
No one has done enough research to be definitive in their diagnosis or Rx. I'm in hopes that this thread will spark some ideas that will work...it is my approach to go with forged rods and pistons...better pistons and new rings...and we will see if this is a permanent solution.

If you look at the back of a stripped viper block and a stripped LS 7 block one of the things that jumps out at you is the venting to the crank case...LS 7's had some issues with blow-by and they have moved to the venting...

I think that the piston issue is the real cause...look at the minimal amount of metal there is between the first ring and the piston dome, in a Viper engine...IMO there is just not enough metal to avoid some heat related issues...and the rings are the least capable, and closest part to the heat issue...add FI and the natural rotation of the engine drives all the pressure up under the piston skirt (sound nice eh?) on the drivers side...and then in the process of looking for relief...those heated rings become the weak point...

But hell, who am I, just a worn out teacher that lets others do the hard things on my engines...
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sorry PROF , but i cannot follow why natural rotation of our engines would build up pressure on drivers side .... :confused: :confused:
 
[SIZE=-1]Blow-by occurs when the explosion that occurs in your engine's combustion chamber causes fuel, air and moisture to be forced past the rings into the crankcase. Your engine's rings must maintain an excellent fit in order to contain the pressure. [/SIZE][SIZE=-1]As rings and cylinder liners wear away they are less capable of maintaining this seal. Consequently as a car ages the amount of blow-by that occurs can increase. [/SIZE][SIZE=-1]Soot and deposits left over from incomplete combustion that collect on the rings can also inhibit their seal worsening blow-by. [/SIZE][SIZE=-1]Blow-by inhibits performance because it results in a loss of compression. When the expanding gases slip past the rings they cannot as effectively push the piston down and make the vehicle go. As a result the car will have less horsepower. This also results in a loss of fuel economy. [/SIZE]

http://www.misterfixit.com/blow-by.htm


Well, here's the story. The crankcase, that which contains the crankshaft and connecting rods, is the bottom side of the engine - you can see the bottom of the pistons from under there. Compressed fuel and air mixture burns in the cylinder on the top of the pistons. When the rings become tired and worn they allow some of this compressed and burning mixture to leak past and escape into the crankcase. That is called "blow by".
In old engines that blowby simply vented into the atmosphere via a tube called a crankcase vent tube. The EPA found bad stuff in that blowby gas and mandated that the engines must suck up that stuff and burn it to render it harmful in some other way. In came the PCV which stands for Positive Crankcase Ventilation, named after the then head of the EPA Pierre Positive.
This system makes the engine suck the junk out of the crankcase via the PCV Valve into the intake manifold and back thorough the system. Welll, if that system is sucking the junk out, there must be a source of air to go into the crankcase else you would just implode the engine and the oil pan would collapse. Soooo, they ran a tube from the top of the valve covers to a source of clean air so that dirt would not get sucked into the crankcase. (note: the valve cover covers the valve train but that is also part of the crankcase - air and blow-by move readily between those zones in the engine.) The source of clean air which was chosen is the air cleaner - makes sense, except for the fact that the air doesn't go thorough the air cleaner filter, so they put a little kotex-like pad in there to clean the bugs and stones out of the air.
Remember now, the air is supposed to flow from the air cleaner's pad thorough that hose and into the valve cover, circulate around the crankcase and get sucked out via the PCV Valve. When the blow-by becomes so excessive that the PCV Valve system can't remove it, it has to go somewhere! Else the crankcase pressure would become excessive and the engine would explode. The place that it goes is back thorough the hose to the air cleaner - THE WRONG WAY!!! Of course it carries any oil in the valve cover back with it and that's what you mop up two or three times a month or week if it's really bad. Bottom line?? It's time for a new box of kotex or an engine overhaul, whichever is cheaper. (there is one other solution - see below)
If you do find oil in your air cleaner it may well be that your PCV valve is stuck closed and is therefore not sucking the blow-by out of the crankcase but rather, it is blowing back into the air cleaner. Make sure to check the PCV Valve before overhauling your engine!!
Click to expand...
 
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