Blowby? / possible blown intake gasket
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Joined: Jun 2005
Posts: 237
Blowby? / possible blown intake gasket
Fellow CZ8 members,
I have spent many weeks researching, reading, and looking for a definitive answer to this issue - please don't think I skipped over reading the loads of threads on this topic. I'm not being that lazy
Here goes:
I have a 1993 LT-1 Camaro that has been rebuilt and currently has less than 600 miles on it. We recently added a supercharger to our setup a Vortech V-1 with a stock pulley( we think it is about 8psi) Once we added the supercharger we have been having many issues - oil pouring out of the PCV U-Turn on the drivers side of intake ( 1993 ). The dipstick has not blown out. We have a breather in the pass. valve cover. The supercharger blew out the rear RTV seal of the intake. Today we spent the day cleaning up and replacing the intake with new gaskets and new RTV. Currently the RTV is drying. Tomorrow when we start it we will have the Supercharger belt off to make sure everything is happy in terms of leaks.Once we verify there is no problems running N/A we would like to connect the supercharger but are afraid it will blow out the rear RTV again. We don't know what we are doing wrong. We have a breather in the valve cover. A lot of people suggest a catch can off the pass valve cover.. and yes that makes sense to be - but I cannot see how that is venting the engine any different than a breather or open. We obviously do not want to blow another seal and redo the procedure as I don't need to remind you about the adventures to get to the 9/16 bolts that hide from universals and want to hurt your knuckles
Please help - Thank you in advance
-Brad
I have spent many weeks researching, reading, and looking for a definitive answer to this issue - please don't think I skipped over reading the loads of threads on this topic. I'm not being that lazy
Here goes:
I have a 1993 LT-1 Camaro that has been rebuilt and currently has less than 600 miles on it. We recently added a supercharger to our setup a Vortech V-1 with a stock pulley( we think it is about 8psi) Once we added the supercharger we have been having many issues - oil pouring out of the PCV U-Turn on the drivers side of intake ( 1993 ). The dipstick has not blown out. We have a breather in the pass. valve cover. The supercharger blew out the rear RTV seal of the intake. Today we spent the day cleaning up and replacing the intake with new gaskets and new RTV. Currently the RTV is drying. Tomorrow when we start it we will have the Supercharger belt off to make sure everything is happy in terms of leaks.Once we verify there is no problems running N/A we would like to connect the supercharger but are afraid it will blow out the rear RTV again. We don't know what we are doing wrong. We have a breather in the valve cover. A lot of people suggest a catch can off the pass valve cover.. and yes that makes sense to be - but I cannot see how that is venting the engine any different than a breather or open. We obviously do not want to blow another seal and redo the procedure as I don't need to remind you about the adventures to get to the 9/16 bolts that hide from universals and want to hurt your knuckles
Please help
- Thank you in advance -Brad
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Joined: Jun 2002
Posts: 798
From: San Jose, CA
It will blow the RTV out because even stock the seal would get blown out. That's the second biggest curse of the LT1. The first was the ring lands on the pistons would crack with just mild boost (5 lbs).
Back during the LT1 days I saw brand new cars sitting on the showroom floor with oil soaked tranny pans. I bought and still own a '97 lt1 which was repaired once by a good shop but it was blowing out within the first week of repair even with no boost. You should have gone LS1 if you wanted a great strong reliable engine. Maybe if you put a breather on the left side cover as well? I just think it was a horrible design to begin with just like the pistons (way too thin and weak metal between the rings).
Hal
Back during the LT1 days I saw brand new cars sitting on the showroom floor with oil soaked tranny pans. I bought and still own a '97 lt1 which was repaired once by a good shop but it was blowing out within the first week of repair even with no boost. You should have gone LS1 if you wanted a great strong reliable engine. Maybe if you put a breather on the left side cover as well? I just think it was a horrible design to begin with just like the pistons (way too thin and weak metal between the rings).
Hal
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
It will blow the RTV out because even stock the seal would get blown out. That's the second biggest curse of the LT1. The first was the ring lands on the pistons would crack with just mild boost (5 lbs).
Back during the LT1 days I saw brand new cars sitting on the showroom floor with oil soaked tranny pans. I bought and still own a '97 lt1 which was repaired once by a good shop but it was blowing out within the first week of repair even with no boost. You should have gone LS1 if you wanted a great strong reliable engine. Maybe if you put a breather on the left side cover as well? I just think it was a horrible design to begin with just like the pistons (way too thin and weak metal between the rings).
Hal
Back during the LT1 days I saw brand new cars sitting on the showroom floor with oil soaked tranny pans. I bought and still own a '97 lt1 which was repaired once by a good shop but it was blowing out within the first week of repair even with no boost. You should have gone LS1 if you wanted a great strong reliable engine. Maybe if you put a breather on the left side cover as well? I just think it was a horrible design to begin with just like the pistons (way too thin and weak metal between the rings).
Hal
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Joined: Oct 2002
Posts: 1,194
From: Albuquerque, NM.
I've had my car 14 years and have NEVER blown out an intake gasket, weather it was stock, modified with N/A bolt on's, or when i put 14psi to it. I know it's been a hit and miss historic problem on the LT1's, but not on every LT1 and strange how it happened right after you put boost to it. If you blew out the gasket after you put the charger on, then your probably pressurizing the crank case and causing it. Obviously this has varying causes, cracked lands, rings, hole in piston, large ring gaps, rings not seated, valve cover vent line not connected to the suck side of the charger vs into the throttle body (this is the 1st thing i'd check) etc.. When most talk about the catch can, there probably talking about the vent line from your valve cover that normally goes into your TB ( i believe its that way also on a 93') going into a catch can/oil seperator, then into the suck side of your charger. The TB port would then get pluged. If you don't do this, you will then pressurize the crank case. The other items can be checked with either a leakdown test or a compression test. Best to verify you don't have anything going on in any of your cylinders.
What did you set up the ring gaps to? They should be larger then stock for boost, but not huge on only 8psi. Also, you wont always blow out the dip stick. I had 2 cylinders with cracked ring lands. When it happened, it never blew out the dip stick in my case. But, have also had turbo buddies running large ring gaps that blow it out if they don't tie it down. Think it just depends on the setup. You'll just have to go through the normal checks if your VC vent line/PCV isn't plumbed incorrectly. Hope the info helps. Keep us posted...
Ken R.
What did you set up the ring gaps to? They should be larger then stock for boost, but not huge on only 8psi. Also, you wont always blow out the dip stick. I had 2 cylinders with cracked ring lands. When it happened, it never blew out the dip stick in my case. But, have also had turbo buddies running large ring gaps that blow it out if they don't tie it down. Think it just depends on the setup. You'll just have to go through the normal checks if your VC vent line/PCV isn't plumbed incorrectly. Hope the info helps. Keep us posted...
Ken R.
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
I've had my car 14 years and have NEVER blown out an intake gasket, weather it was stock, modified with N/A bolt on's, or when i put 14psi to it. I know it's been a hit and miss historic problem on the LT1's, but not on every LT1 and strange how it happened right after you put boost to it. If you blew out the gasket after you put the charger on, then your probably pressurizing the crank case and causing it. Obviously this has varying causes, cracked lands, rings, hole in piston, large ring gaps, rings not seated, valve cover vent line not connected to the suck side of the charger vs into the throttle body (this is the 1st thing i'd check) etc.. When most talk about the catch can, there probably talking about the vent line from your valve cover that normally goes into your TB ( i believe its that way also on a 93') going into a catch can/oil seperator, then into the suck side of your charger. The TB port would then get pluged. If you don't do this, you will then pressurize the crank case. The other items can be checked with either a leakdown test or a compression test. Best to verify you don't have anything going on in any of your cylinders.
What did you set up the ring gaps to? They should be larger then stock for boost, but not huge on only 8psi. Also, you wont always blow out the dip stick. I had 2 cylinders with cracked ring lands. When it happened, it never blew out the dip stick in my case. But, have also had turbo buddies running large ring gaps that blow it out if they don't tie it down. Think it just depends on the setup. You'll just have to go through the normal checks if your VC vent line/PCV isn't plumbed incorrectly. Hope the info helps. Keep us posted...
Ken R.
What did you set up the ring gaps to? They should be larger then stock for boost, but not huge on only 8psi. Also, you wont always blow out the dip stick. I had 2 cylinders with cracked ring lands. When it happened, it never blew out the dip stick in my case. But, have also had turbo buddies running large ring gaps that blow it out if they don't tie it down. Think it just depends on the setup. You'll just have to go through the normal checks if your VC vent line/PCV isn't plumbed incorrectly. Hope the info helps. Keep us posted...
Ken R.
Thank you for your reply - very informative!
"valve cover vent line not connected to the suck side of the charger vs into the throttle body (this is the 1st thing i'd check)"
I do not have my valve cover vent connected to the suck side of my blower... how do i do this. I have the air filter directly on the supercharger intake ( no dryer vent tubing ) I guess i need to plumb into the filter or somthing.. what size airline should I be using to connect the valve cover to the suck side... if i connect that do you think my issues will go away?
Thanks again!
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Joined: Jun 2005
Posts: 237
Ken,
Thank you for your reply - very informative!
"valve cover vent line not connected to the suck side of the charger vs into the throttle body (this is the 1st thing i'd check)"
I do not have my valve cover vent connected to the suck side of my blower... how do i do this. I have the air filter directly on the supercharger intake ( no dryer vent tubing ) I guess i need to plumb into the filter or somthing.. what size airline should I be using to connect the valve cover to the suck side... if i connect that do you think my issues will go away?
Thanks again!
Thank you for your reply - very informative!
"valve cover vent line not connected to the suck side of the charger vs into the throttle body (this is the 1st thing i'd check)"
I do not have my valve cover vent connected to the suck side of my blower... how do i do this. I have the air filter directly on the supercharger intake ( no dryer vent tubing ) I guess i need to plumb into the filter or somthing.. what size airline should I be using to connect the valve cover to the suck side... if i connect that do you think my issues will go away?
Thanks again!
-EDIT - perhaps I should wait and put an oil/water sep inline
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Joined: Oct 2002
Posts: 1,194
From: Albuquerque, NM.
Let me ask you this, do you have a large line going from the side of your throttle body into the top of one of your valve covers? If so, then your pressurizing the crank case. I'm not exactly sure if that was different from 93' to 94' and up cars, but i would imagine it's there. If you wanted to do a quick check on that, you could disconnect that line at the throttle body and cap the throttle body port. If not, then that will be a big vacuum leak. Leave that line disconnected and see if you still have the oil out the pcv or a blown intake gasket. If you wanted to hook that up to the suck side, then you would probably need to do a hard pipe setup on the suck side with the filter on the end of that, and put a port for the line hook up on the hard pipe. I'm using the stock size line on mine from the valve cover to the intake side and i'm running it through an air compressor air/oil seperator from Lowe's. The catch can's work basically the same way.
Ken R.
Ken R.
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Joined: Jun 2005
Posts: 237
Let me ask you this, do you have a large line going from the side of your throttle body into the top of one of your valve covers? If so, then your pressurizing the crank case. I'm not exactly sure if that was different from 93' to 94' and up cars, but i would imagine it's there. If you wanted to do a quick check on that, you could disconnect that line at the throttle body and cap the throttle body port. If not, then that will be a big vacuum leak. Leave that line disconnected and see if you still have the oil out the pcv or a blown intake gasket. If you wanted to hook that up to the suck side, then you would probably need to do a hard pipe setup on the suck side with the filter on the end of that, and put a port for the line hook up on the hard pipe. I'm using the stock size line on mine from the valve cover to the intake side and i'm running it through an air compressor air/oil seperator from Lowe's. The catch can's work basically the same way.
Ken R.
Ken R.
One questions - what is different about running the Valve Cover open vs. putting to the suck side. - I guess it will pull the pressure out and throw it out the bypass valve?
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Joined: Oct 2002
Posts: 1,194
From: Albuquerque, NM.
I guess preference in some cases. It will releave the pressure in there. Even with a seperator, you may get some oil residue from time to time on the intake side of the charger. If you run just a breather, that will work also, but eventually, the breathers get saturated and is some pressure does vent out there, it tends to blow the oil off the breather and into the engine compartment or eventually starts leaking off the breather once saturated. There actually is a lot of posts out there about the various setups and others experiences. Hopefully one of them works for you. If you ever see lots of smoke coming out of your breather one day, be sad. I was sad one day, then a new set of pistons, rings, rod bearings and some sweat and tears, and i was happy again.
Ken R.
Ken R.
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Joined: Aug 2006
Posts: 1,497
From: Orem, UT
Just in case there's any confusion,
No vacuum is created on the 'suck side' of the turbo/blower.
To pull vacuum you would need a restriction (much bigger than the air filter... think throttle blade). Atmospheric pressure simply 'replaces' the air that is consumed by the compressor, Just as your intkae manifold is at atmospheric pressure under WOT even though your engine is consuming a huge volume of air.
The intake pipe will always have atmospheric pressure in it (possibly minus a small amount due to parasitic loss), but not less (aka vacuum).
Tapping a hose into the intake pipe will draw blowby out throught a pseudo-venturi action, but again it won't suck it out.
No vacuum is created on the 'suck side' of the turbo/blower.
To pull vacuum you would need a restriction (much bigger than the air filter... think throttle blade). Atmospheric pressure simply 'replaces' the air that is consumed by the compressor, Just as your intkae manifold is at atmospheric pressure under WOT even though your engine is consuming a huge volume of air.
The intake pipe will always have atmospheric pressure in it (possibly minus a small amount due to parasitic loss), but not less (aka vacuum).
Tapping a hose into the intake pipe will draw blowby out throught a pseudo-venturi action, but again it won't suck it out.
Last edited by MikeGyver; Apr 9, 2009 at 02:52 AM.
Thread Starter
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Joined: Jun 2005
Posts: 237
Just in case there's any confusion,
No vacuum is created on the 'suck side' of the turbo/blower.
To pull vacuum you would need a restriction (much bigger than the air filter... think throttle blade). Atmospheric pressure simply 'replaces' the air that is consumed by the compressor, Just as your intkae manifold is at atmospheric pressure under WOT even though your engine is consuming a huge volume of air.
The intake pipe will always have atmospheric pressure in it (possibly minus a small amount due to parasitic loss), but not less (aka vacuum).
Tapping a hose into the intake pipe will draw blowby out throught a pseudo-venturi action, but again it won't suck it out.
No vacuum is created on the 'suck side' of the turbo/blower.
To pull vacuum you would need a restriction (much bigger than the air filter... think throttle blade). Atmospheric pressure simply 'replaces' the air that is consumed by the compressor, Just as your intkae manifold is at atmospheric pressure under WOT even though your engine is consuming a huge volume of air.
The intake pipe will always have atmospheric pressure in it (possibly minus a small amount due to parasitic loss), but not less (aka vacuum).
Tapping a hose into the intake pipe will draw blowby out throught a pseudo-venturi action, but again it won't suck it out.
Registered User
Joined: Oct 2002
Posts: 1,194
From: Albuquerque, NM.
So you don't think "drawing out" and "sucking out" is the same thing? True it is a venturi type setup, but all a venturi does is creat a sucking action. It would be the same as running lines from your valve covers to your collectors but on a much smaller scale and not going back through the blower.
Ken R.
Ken R.
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Posts: 237
So today I went out to see if our intake gasket job worked.. it did.. but for some reason no we are blowing ungodly amounts of smoke out the tail pipes while driving...
This did not happen before the install - I did find a small piece of aluminum in the oil galley when I doing the intake job... This motor has less than 1000 miles on it and has never been raced... I have attached a link for the ALDL data from my moats data log.
http://www.bradleymurphy.net/April10.adl
Please Help...
Thank you in advance.
This did not happen before the install - I did find a small piece of aluminum in the oil galley when I doing the intake job... This motor has less than 1000 miles on it and has never been raced... I have attached a link for the ALDL data from my moats data log. http://www.bradleymurphy.net/April10.adl
Please Help...
Thank you in advance.
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
So today I went out to see if our intake gasket job worked.. it did.. but for some reason no we are blowing ungodly amounts of smoke out the tail pipes while driving... This did not happen before the install - I did find a small piece of aluminum in the oil galley when I doing the intake job... This motor has less than 1000 miles on it and has never been raced... I have attached a link for the ALDL data from my moats data log.
http://www.bradleymurphy.net/April10.adl
Please Help...
Thank you in advance.
This did not happen before the install - I did find a small piece of aluminum in the oil galley when I doing the intake job... This motor has less than 1000 miles on it and has never been raced... I have attached a link for the ALDL data from my moats data log. http://www.bradleymurphy.net/April10.adl
Please Help...
Thank you in advance.
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
Okay... I think I did something stupid - In replacing my Intake manifold (1993) I broke the stock " U-Turn" for the PCV valve... I replace it with a short piece of gas line... UNDER FURTHER INVESTIGATION... i see the line was kinking- I am 95% sure that is what the smoke was from .. i will test this is in morning.. I am sorry for the freak-out but i thought there was a hole in my engine... ( there still may be ) I will follow up in the AM.
Nope - Still blowing smoke .... crud...time to take apart the engine