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Crankcase Pressure Issues

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Old Nov 19, 2014 | 12:01 AM
  #61  
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Originally Posted by KLO29
What do you think is going on with the gaskets? Right now I pull no vacuum on the backside of the PCV valve. If I remove valve and hook back up it seems to work fine. I'm wondering if the valave is needed. Or can it be removed and I connect hoses straight through?
its either the headgasket or it a cracked head..

if the headgasket is blown or leaky into the oil passageways (usually towards the top by the lifter/pushrod area), it will pressurize the crankcase and push seals out

a failed pcv system will not push seals out on its own...you might get some leaks...bit not blown out like you are experiencing...especially naturally aspirated...might be a little different if you were forced induction

and a failed head gasket or a cracked head will not necessarily show an issue at lower rpm's, it may only show itself at WOT when cylilnder pressures are the highest



also, a vacuum pump setup would be greatly beneficial if everything is correct, but its pointless if you have head or gasket issues.
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Old Nov 19, 2014 | 08:24 AM
  #62  
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I mentioned earlier in this thread to connect a pressure gauge to the crankcase and drive it hard then see when the pressure rises up to levels that could push a seal out.
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Old Nov 19, 2014 | 09:05 AM
  #63  
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I don't know why you have a check valve on it. My '04 LS1 did not have any check valve from the factory. I know the older LS1s had extra stuff. Your picture hose routing looks correct. Take the valve off, run plain hoses and give it a try. It still could be your rings though are letting through too much blow-by.
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Old Nov 19, 2014 | 11:20 AM
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Originally Posted by svede1212
I don't know why you have a check valve on it. My '04 LS1 did not have any check valve from the factory. I know the older LS1s had extra stuff. Your picture hose routing looks correct. Take the valve off, run plain hoses and give it a try. It still could be your rings though are letting through too much blow-by.
Crankcase Pressure Issues-pcv-set-up.jpg

here is a diagram on what my readings are for the vacuum test.. is this correct or is the PCV valve faulty. this is a brand new set up I recently purchased
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Old Nov 19, 2014 | 11:21 AM
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Originally Posted by KLO29
Attachment 477691

here is a diagram on what my readings are for the vacuum test.. is this correct or is the PCV valve faulty. this is a brand new set up I recently purchased

I took the reading from the hose not the valve cover typing can be mis leading
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Old Nov 19, 2014 | 11:58 AM
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If you posted it, I may have missed it. What did your leak down and compression test show? I'm really leaning toward a possible ring issue. Maybe even upside down.
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Old Nov 19, 2014 | 01:09 PM
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Originally Posted by Sales2@Texas-speed
If you posted it, I may have missed it. What did your leak down and compression test show? I'm really leaning toward a possible ring issue. Maybe even upside down.
i was told 2-5% not sure if there is a proper procedure on how to do it. should the motor be Hot or cold? I asked a while back but never got a response
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Old Nov 19, 2014 | 01:12 PM
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Originally Posted by Sales2@Texas-speed
If you posted it, I may have missed it. What did your leak down and compression test show? I'm really leaning toward a possible ring issue. Maybe even upside down.
the compression test was 150 PSI
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Old Nov 19, 2014 | 07:07 PM
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Originally Posted by KLO29
i was told 2-5% not sure if there is a proper procedure on how to do it. should the motor be Hot or cold? I asked a while back but never got a response
2-5% doesnt sound correct...
its usually 8%-10% or more depending on how the rings are set up
more commonly 10-15%

you have to do it hot
and there is a leakdown tester...
its basically a pressure gauge in a box

you put pressurized air into it and zero it out, then you put the other side of it into the cylinder....
it will read 0-100% leakage on the gauge

you always zero it with nothing connected because you need 0% leakdown to be maximum pressure in the tester
anything that escapes(your leakage in the cylinder), will show less pressure in the tester, and the needle will move towards higher percentages.

I can post pictures and demonstrate later tonight if you want to see how to do it...I'm sure I have a motor somewhere I can use as a dummy test.
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Old Nov 19, 2014 | 08:04 PM
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Originally Posted by soundengineer
2-5% doesnt sound correct...
its usually 8%-10% or more depending on how the rings are set up
more commonly 10-15%

you have to do it hot
and there is a leakdown tester...
its basically a pressure gauge in a box

you put pressurized air into it and zero it out, then you put the other side of it into the cylinder....
it will read 0-100% leakage on the gauge

you always zero it with nothing connected because you need 0% leakdown to be maximum pressure in the tester
anything that escapes(your leakage in the cylinder), will show less pressure in the tester, and the needle will move towards higher percentages.

I can post pictures and demonstrate later tonight if you want to see how to do it...I'm sure I have a motor somewhere I can use as a dummy test.
That would be awsome no hurry cars not being driven
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Old Nov 19, 2014 | 09:59 PM
  #71  
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Both the leak down and compression test where performed by a speedshop that deals specifically in LS motors. they have built some real fast cars. None which have ever had this issue. I didn't have them do my Motor and now I regret it. He has been helping me out
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Old Nov 19, 2014 | 10:14 PM
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Originally Posted by KLO29
That would be awsome no hurry cars not being driven
Here is a Basic Leakdown test

for reference, the engine I used is a built LS1 with rings Gapped for Turbo and this motor has not been Run yet...all parts are brand new and no "break in" has been done yet...it has only been turned over by hand, and this is at approximately 50* ambient shop temperature


start with the Tool itself...no air connected...
you can see here its basically a gauge, and a regulator ****, a few hoses, and an adapter to use the spark plug hole





Connect the Air to it, put the Spark plug adapter in the Hole, but do not connect the two together yet...

Turn the **** until it reads ZERO



then make sure the cylinder you want to test is at Bottom Dead Center and connect the Hose to the Spark plug adapter

the total leakage will be shown on the gauge



this value is pretty normal for a completely cold, brand new, never been run motor, built for Turbos.
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Old Nov 20, 2014 | 10:41 AM
  #73  
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Originally Posted by soundengineer
Here is a Basic Leakdown test

for reference, the engine I used is a built LS1 with rings Gapped for Turbo and this motor has not been Run yet...all parts are brand new and no "break in" has been done yet...it has only been turned over by hand, and this is at approximately 50* ambient shop temperature


start with the Tool itself...no air connected...
you can see here its basically a gauge, and a regulator ****, a few hoses, and an adapter to use the spark plug hole





Connect the Air to it, put the Spark plug adapter in the Hole, but do not connect the two together yet...

Turn the **** until it reads ZERO



then make sure the cylinder you want to test is at Bottom Dead Center and connect the Hose to the Spark plug adapter

the total leakage will be shown on the gauge



this value is pretty normal for a completely cold, brand new, never been run motor, built for Turbos.
awsome I have barrowed my buddies leak down tester. I plan on working on this over thankgiving weekend I'll reply back with my findings.

I do know I told the engine builder I never plan on running nitrus, Turbos, Super charger on the car. I wonder if he made it So tight that it scratched the cylinder walls?
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Old Nov 20, 2014 | 11:37 AM
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Originally Posted by KLO29
the compression test was 150 PSI
Seems like it might be a little low. Was it done hot? Did you check every cylinder?
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Old Nov 20, 2014 | 10:29 PM
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I will run the leakdown test again, I did it hot as I remember burning my arms. I have a Matco setup similar to the Snap On setup in the pics above.
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Old Jan 18, 2015 | 11:51 PM
  #76  
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did you ever find a solution to your oil blow by problem?
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Old Jan 18, 2015 | 11:53 PM
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also, I found a lot of oil in my intake and recently installed a catch can and blocked off all ports on the valve covers, and at throttle body. I have the ls6 valley installed. is this ok
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Old Jan 19, 2015 | 09:41 AM
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Originally Posted by rholdcroft99
did you ever find a solution to your oil blow by problem?
No, I'm going to take another look at this. I'm thinking about installing a breather setup to vent both sides of the engine. I feel if this engine weren't sealed up good, it wouldn't make the power that it does? I've done compression checks, leak down test, and everything seems great.

This engine had an LS6 valley plate, but the block wasn't trimmed enough and it somewhat squished the PCV tube on the underside of the plate. I reinstalled the stock one and stock routed PCV tube along with a catch can.

Seriously thinking about tying both rear valve covers together into another catch can with a breather and venting the oil fill cap.
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Old Jan 20, 2015 | 09:42 PM
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Haven't done a dang thing. I put a breather on oil cap and drove it a few times since the first time we posted the question. Haven't gotten on it maybe tomorrow see how the breather does.
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