LT1/LT4 Tech 1993-1997

Vacuum leak

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Old Nov 13, 2023 | 07:04 AM
  #1  
32rdstr's Avatar
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Default Vacuum leak

Got the engine (95) from eBay so really don't know much about it's history. Cleaned it up, sand blasted the intake and fired it up. No smoke but did not run right. Found out I had a vacuum leak on the intake to head area. Decided to replace the gaskets and when I took the bolts out I discovered the problem. When I put an intake on I always use flat washers to help with clamping. Turns out the washers were to big because there is a recess around the bolt holes on the intake. This caused the flat washers to become "coned" and give a false torque reading. Success (or failure) is in the details.

Now for the PCV system. Not to sure about how things are set up on my engine. There is a hose running from the passenger side valve cover to the throttle body but the PCV on the other side of the intake is blocked off. The connection for the PCV hose under the throttle body is also blocked off with a screw in plug. Is this normal?
 
Old Nov 17, 2023 | 10:18 PM
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can you post a picture, this is how it should be. the other hose on the passenger side allows air from the intake to go into the motor to keep air flowing through the engine.
http://shbox.com/1/pcv_pipe.jpg

 

Last edited by craby; Nov 17, 2023 at 10:21 PM.
Old Nov 24, 2023 | 07:25 AM
  #3  
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Thank you Craby. sorry but can't really get a good picture of the area under the throttle body. It's just a screw in plug that's there and the port on the left side of the intake is capped. How will this affect the engine?

On a side note I noticed Craby posted a sticky regarding Opti Sparks. The price of a new one is all over the board. Some at $800 and others at $99. Of course the name brands are higher such as Accel @ $370 and MSD @ $650 but Summit also sells one from Speedmaster for $100. You get what you pay for SOMETIMES works but I wonder about the performance of the not-so-pricey units. Any input would be nice.



 
Old Nov 24, 2023 | 08:51 AM
  #4  
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Originally Posted by 32rdstr
On a side note I noticed Craby posted a sticky regarding Opti Sparks. The price of a new one is all over the board. Some at $800 and others at $99. Of course the name brands are higher such as Accel @ $370 and MSD @ $650 but Summit also sells one from Speedmaster for $100. You get what you pay for SOMETIMES works but I wonder about the performance of the not-so-pricey units. Any input would be nice.
Some of the expensive ones have issues and you sure don't want a cheap one,best bet is either GM Performance or MSD and a new pigtail with it.
 
Old Nov 24, 2023 | 11:34 AM
  #5  
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I don't think gm is making the performance dizzy anymore. checkout summit unit. at least you know if it fails soon they will replace, rock auto also has some but not sure of the quality.
https://www.summitracing.com/search/...3Adistributors
https://www.rockauto.com/en/catalog/...stributor,7108
 
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