Blowby? / possible blown intake gasket
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
We are talking a lot of smoke - and if this is any clue to anything..
I am getting oil smoke out the pass side valve cover on accel as well as oil smoke out the PCV opening on the driver side ( of the intake (1993) ). I dont know if this helps .. I wil still be pulling plugs for investigations..
Thank you all
I am getting oil smoke out the pass side valve cover on accel as well as oil smoke out the PCV opening on the driver side ( of the intake (1993) ). I dont know if this helps .. I wil still be pulling plugs for investigations..
Thank you all
Registered User
Joined: Jan 2001
Posts: 657
From: Farmington Hills, MI
tritonium,
To see this much smoke from the valve cover and out of the exhaust would indicate to me that there has been a mechanical failure. Blowing out engine seals and getting vapor form the valvecovers would mean you are pressurizing the crankcase. Excessive blowby into the case via broken piston.
Metal pieces in the valley = no good. A leak down test would tell you for sure which cylinder while you have the plugs out.
What type of pistons did you use for the rebuild and what is you static compression? On a boost motor, all it takes is ONE time going lean to do this especially with a cast piston.
To see this much smoke from the valve cover and out of the exhaust would indicate to me that there has been a mechanical failure. Blowing out engine seals and getting vapor form the valvecovers would mean you are pressurizing the crankcase. Excessive blowby into the case via broken piston.
Metal pieces in the valley = no good. A leak down test would tell you for sure which cylinder while you have the plugs out.
What type of pistons did you use for the rebuild and what is you static compression? On a boost motor, all it takes is ONE time going lean to do this especially with a cast piston.
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
tritonium,
To see this much smoke from the valve cover and out of the exhaust would indicate to me that there has been a mechanical failure. Blowing out engine seals and getting vapor form the valvecovers would mean you are pressurizing the crankcase. Excessive blowby into the case via broken piston.
Metal pieces in the valley = no good. A leak down test would tell you for sure which cylinder while you have the plugs out.
What type of pistons did you use for the rebuild and what is you static compression? On a boost motor, all it takes is ONE time going lean to do this especially with a cast piston.
To see this much smoke from the valve cover and out of the exhaust would indicate to me that there has been a mechanical failure. Blowing out engine seals and getting vapor form the valvecovers would mean you are pressurizing the crankcase. Excessive blowby into the case via broken piston.
Metal pieces in the valley = no good. A leak down test would tell you for sure which cylinder while you have the plugs out.
What type of pistons did you use for the rebuild and what is you static compression? On a boost motor, all it takes is ONE time going lean to do this especially with a cast piston.
hello,
Thank you for your post -
I do not know how to do a leak down test - I will google that.
I agree it is a mechanical failure - the thing i don't understand is none of these symptoms were prevalent before we fixed the intake manifold leak - there was no smoke just oil leaking out the rear intake seal.. i guess bizarre coincident.
I know i used forged Eagle Pistons. The compression was kept very close to stock. If memory serves me right 10:5:1 ? Thank you for your reply.
Registered User
Joined: Jan 2001
Posts: 657
From: Farmington Hills, MI
Here is an example of a leak down tester.
http://store.summitracing.com/partde...5&autoview=sku
In your case, a compression tester might give you the info you need by comparing all 8 cylinders. A leak down will give you more info though by showing you a percentage of leakage in each cylinder. Usually cylinders that are 5% or less are ok. Then you can figure out where the leakage is - past the rings, past the intake or exhaust valve, or past a head gasket.
Hope everything works out for ya,
-Scott.
http://store.summitracing.com/partde...5&autoview=sku
In your case, a compression tester might give you the info you need by comparing all 8 cylinders. A leak down will give you more info though by showing you a percentage of leakage in each cylinder. Usually cylinders that are 5% or less are ok. Then you can figure out where the leakage is - past the rings, past the intake or exhaust valve, or past a head gasket.
Hope everything works out for ya,
-Scott.
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
Here is an example of a leak down tester.
http://store.summitracing.com/partde...5&autoview=sku
In your case, a compression tester might give you the info you need by comparing all 8 cylinders. A leak down will give you more info though by showing you a percentage of leakage in each cylinder. Usually cylinders that are 5% or less are ok. Then you can figure out where the leakage is - past the rings, past the intake or exhaust valve, or past a head gasket.
Hope everything works out for ya,
-Scott.
http://store.summitracing.com/partde...5&autoview=sku
In your case, a compression tester might give you the info you need by comparing all 8 cylinders. A leak down will give you more info though by showing you a percentage of leakage in each cylinder. Usually cylinders that are 5% or less are ok. Then you can figure out where the leakage is - past the rings, past the intake or exhaust valve, or past a head gasket.
Hope everything works out for ya,
-Scott.
Thank you for the information - I will be pulling plugs and doing a compression test first - what is the numbder it should be ? - of is it measured in variation between eaach cyl?
Registered User
Joined: Jan 2001
Posts: 657
From: Farmington Hills, MI
tritonium,
No prob. The actual value you get from a cranking compression check will vary and depends on a lot in the setup like compression ratio and valve timing. As an example, you might be looking for 160-185psi. The object is to look for a low cylinder(s). The lowest cylinder should be within 10% of the highest.
-Scott.
No prob. The actual value you get from a cranking compression check will vary and depends on a lot in the setup like compression ratio and valve timing. As an example, you might be looking for 160-185psi. The object is to look for a low cylinder(s). The lowest cylinder should be within 10% of the highest.
-Scott.
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
tritonium,
No prob. The actual value you get from a cranking compression check will vary and depends on a lot in the setup like compression ratio and valve timing. As an example, you might be looking for 160-185psi. The object is to look for a low cylinder(s). The lowest cylinder should be within 10% of the highest.
-Scott.
No prob. The actual value you get from a cranking compression check will vary and depends on a lot in the setup like compression ratio and valve timing. As an example, you might be looking for 160-185psi. The object is to look for a low cylinder(s). The lowest cylinder should be within 10% of the highest.
-Scott.
Registered User
Joined: Jan 2001
Posts: 657
From: Farmington Hills, MI
You'll need an adapter with a 14mm thread and tapered seat. I've actually never done a comp. check on a LT1 so I don't have a P/N. Maybe someone else can chime in here or you could ask (search) in LT1 tech.
Both Golen and VRE have good reputations and buying a complete shortblock makes a lot of sense in some cases. Both 383 and 396 are 0.030" over bore. The difference is in the stroke.
-Scott.
Both Golen and VRE have good reputations and buying a complete shortblock makes a lot of sense in some cases. Both 383 and 396 are 0.030" over bore. The difference is in the stroke.
-Scott.
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
You'll need an adapter with a 14mm thread and tapered seat. I've actually never done a comp. check on a LT1 so I don't have a P/N. Maybe someone else can chime in here or you could ask (search) in LT1 tech.
Both Golen and VRE have good reputations and buying a complete shortblock makes a lot of sense in some cases. Both 383 and 396 are 0.030" over bore. The difference is in the stroke.
-Scott.
Both Golen and VRE have good reputations and buying a complete shortblock makes a lot of sense in some cases. Both 383 and 396 are 0.030" over bore. The difference is in the stroke.
-Scott.
Thank you once again - I hope do not need to buy a new short block but it is good to know there are options. I will search around for that adapter kit.
Brad
Thread Starter
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Joined: Jun 2005
Posts: 237
I am wondering is there any electronics or pots that i could have hooked up incorrectly on the intake to make the car run with so much smoke -- this was not happening before we re did the intake manifold ( unless some1 threw a wrench into an intake port while i was at work) eek. any electronics ?
Thread Starter
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Joined: Jun 2005
Posts: 237
I have pulled 6 out of the 8 plugs. the last two on the drivers side - I can only get them out from the bottom due to my headers. The 6 I have taken out do have a good amount of oil on the threads - however there is no oil on the firing pins.. I have attempted to take photos but my camera cannot focus well in all light conditions... grr I will work on the photos - But it has oil on the threads Brown/Black ceramic fire part, black fire pin ( not oil - more charred) - then a black suit ( maybe oil) on the part it sparks against - same on all 6 I have pulled so far... i think the oil on the threads is from the leaking intake manifold driping down the block. but who knows - once again a lot of oil in the threads.
Edit - Got a decent picture
www.bradleymurphy.net/plug.JPG
Happy Easter
Edit - Got a decent picture
www.bradleymurphy.net/plug.JPG
Happy Easter
Last edited by tritonium; Apr 12, 2009 at 12:51 PM.
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Joined: Oct 2002
Posts: 1,194
From: Albuquerque, NM.
Your plugs may look normal, even if your broke. Like was said above, it sounds like your broke. I'm gonna guess broken piston(s) or ring(s). Another quick check is if you have an air compressor, screw the line in the cylinder after bringing that piston to top dead center and pressurize it (like you do when you pressurize the cylinder for removing your valve springs if you've ever done that), and listen for air. If you hear air out the valve cover, you have cylinder leakage, out the throttle body, intake valve issues, out the exhaust, exhaust valve issues.
You can pick up compression test gauges at autozone and such. They usually have the adapters to fit the spark plug hole. I usually pull the gauge off the rubber line, then get it started in the spark plug hole, then you can spin the rubber air line to thread it the rest of the way in. That way you don't have to get a socket or wrench in there until u need to snug it down. But if you buy that, then you might as well just compression test it. Like boosted said, the target numbers might vary a bit depending on the setup, but you'll know pretty quick which cylinder is dead because that number will be way down compared to other good cylinders. Just hook up the gauge, disconnect the coil, then have someone crank it for about 5 seconds or so while you watch the gauge and see what each cylinder psi peaks at. Like i said, you'll know right away. But, at this point, it doesn't look good. A lot of us have been there....
Ken R.
You can pick up compression test gauges at autozone and such. They usually have the adapters to fit the spark plug hole. I usually pull the gauge off the rubber line, then get it started in the spark plug hole, then you can spin the rubber air line to thread it the rest of the way in. That way you don't have to get a socket or wrench in there until u need to snug it down. But if you buy that, then you might as well just compression test it. Like boosted said, the target numbers might vary a bit depending on the setup, but you'll know pretty quick which cylinder is dead because that number will be way down compared to other good cylinders. Just hook up the gauge, disconnect the coil, then have someone crank it for about 5 seconds or so while you watch the gauge and see what each cylinder psi peaks at. Like i said, you'll know right away. But, at this point, it doesn't look good. A lot of us have been there....
Ken R.
Thread Starter
Registered User
Joined: Jun 2005
Posts: 237
Your plugs may look normal, even if your broke. Like was said above, it sounds like your broke. I'm gonna guess broken piston(s) or ring(s). Another quick check is if you have an air compressor, screw the line in the cylinder after bringing that piston to top dead center and pressurize it (like you do when you pressurize the cylinder for removing your valve springs if you've ever done that), and listen for air. If you hear air out the valve cover, you have cylinder leakage, out the throttle body, intake valve issues, out the exhaust, exhaust valve issues.
You can pick up compression test gauges at autozone and such. They usually have the adapters to fit the spark plug hole. I usually pull the gauge off the rubber line, then get it started in the spark plug hole, then you can spin the rubber air line to thread it the rest of the way in. That way you don't have to get a socket or wrench in there until u need to snug it down. But if you buy that, then you might as well just compression test it. Like boosted said, the target numbers might vary a bit depending on the setup, but you'll know pretty quick which cylinder is dead because that number will be way down compared to other good cylinders. Just hook up the gauge, disconnect the coil, then have someone crank it for about 5 seconds or so while you watch the gauge and see what each cylinder psi peaks at. Like i said, you'll know right away. But, at this point, it doesn't look good. A lot of us have been there....
Ken R.
You can pick up compression test gauges at autozone and such. They usually have the adapters to fit the spark plug hole. I usually pull the gauge off the rubber line, then get it started in the spark plug hole, then you can spin the rubber air line to thread it the rest of the way in. That way you don't have to get a socket or wrench in there until u need to snug it down. But if you buy that, then you might as well just compression test it. Like boosted said, the target numbers might vary a bit depending on the setup, but you'll know pretty quick which cylinder is dead because that number will be way down compared to other good cylinders. Just hook up the gauge, disconnect the coil, then have someone crank it for about 5 seconds or so while you watch the gauge and see what each cylinder psi peaks at. Like i said, you'll know right away. But, at this point, it doesn't look good. A lot of us have been there....
Ken R.
Thank you once again for your informative response! I really appreciate it.
No, things do not look good.. I will try the air compressor test and compression test ( if i can get it in there) . I will let you know how the air compressor test goes ( If you get this post soon - How do you make sure the piston in a specific cyl is at tdc? lets say cly 2. - Thank you and sorry about the rookie questions
I just cannot figure ut why the smoke started directly after the intake manifold gasket replacement.. makes no sense to me. a coincidence>
Thanks again .
Brad