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What the hell? I torqued the manifold to the proper in/lbs specs and 2 passes in the proper order. When I was doing my oil pressure sending unit I took the intake on and off like 8 times so I know I didn't screw that up. I practically had the procedure memorized.
Gaskets are what I thought were high quality ultra power. It's like they pushed themselves put. This explains the vacuum problems. I suppose I should reinstall new gaskets and rtv the outer edge? Or do I need to get a new intake?
I can swap it for an LS7 intake, will that work without a tune?
No an LS7 intake won't fit and no RTV and new gaskets won't work to fix this. You have cathedral port heads on the LS1/LS6. Same for LS2 (so any of those 3 intakes will work the LS6 being the better of the 3). Or upgrade to a FAST and new TB. The LS7 intake is for rectangle port heads. Same as the LS3. So these 2 are a no-go.
You likely had a backfire cause that. Or the gaskets were bulging and you didnt realize when you torqued the intake down. Either way the intake is shot and you may want to check for issues with the engine. If it was runjing fine before your R&R with those new gaskets odds are good you had a bulge or bulging gaskets when you torqued the plenum down. Boom!
No an LS7 intake won't fit and no RTV and new gaskets won't work to fix this. You have cathedral port heads on the LS1/LS6. Same for LS2 (so any of those 3 intakes will work the LS6 being the better of the 3). Or upgrade to a FAST and new TB. The LS7 intake is for rectangle port heads. Same as the LS3. So these 2 are a no-go.
You likely had a backfire cause that. Or the gaskets were bulging and you didnt realize when you torqued the intake down. Either way the intake is shot and you may want to check for issues with the engine. If it was runjing fine before your R&R with those new gaskets odds are good you had a bulge or bulging gaskets when you torqued the plenum down. Boom!
Thank you for taking the time to explain. The motor seems to be acting fine aside from the vacuum inflicted problems and I only just noticed this when explaining how some things worked to my wife. There was an event where I had a loose battery connection cause the engine to lose voltage and caused a couple of pops that sounded unusual, but this was at idle RPMs, so I hopefully escaped significant damage. I see no change in its behavior. Crossing my fingers the motor will be okay until it takes its throne as a restoration project in my future barn.
Would the budget replacement be an LS2 intake? I am not looking to power it up currently.
You need a new intake manifold. I just don't see how any "fix" will work to save that one. Your best budget fix is acquiring another LS1 (97-00) intake manifold. A later year intake manifold LS1/LS6 (01-04) would be an upgrade, but they are pricier.
LS2 intake manifold will fit your heads, but you will need an adapter for your throttle body, or an LS2 throttle body with some tuning. It's generally regarded that the LS2 intake manifolds are nothing special.
LS3/7/A/9/4 Intake manifold will not fit your heads.
Thank you for taking the time to explain. The motor seems to be acting fine aside from the vacuum inflicted problems and I only just noticed this when explaining how some things worked to my wife. There was an event where I had a loose battery connection cause the engine to lose voltage and caused a couple of pops that sounded unusual, but this was at idle RPMs, so I hopefully escaped significant damage. I see no change in its behavior. Crossing my fingers the motor will be okay until it takes its throne as a restoration project in my future barn.
Would the budget replacement be an LS2 intake? I am not looking to power it up currently.
No, an LS2 intake would not be a budget replacement. You need an LS1 or LS6 intake. And unless you are going to have the car re-tuned you need to put back the same version you took off
In my honest opinion,, The difference between an LS-1 & LS-6 manifold would not need tuning. The computer can compensate for the difference in air flow characterizes between the two. That being said, If you swap on something entirely different, (fast or LS2),, That change may benefit from retuning.
Everyone is correct,, YES,, That manifold is trashed. The gasket groove is compromised and will never be reliable again. Then again, what caused it to break?? If it were ME, I would install the manifold on the heads WITH OUT GASKETS / SEALS and insure that it sits FLUSH on the heads with out bolts, doesn't rock or have any major gaps anywhere. If the manifold cant sit flat on the heads, those gaskets / seals will extrude out of the groves. and never properly seal.
Normally, the LS Manifold does not and should not require ANY goop to seal it. I have had excellent results with the grey OEM material O Ring Seals. They fit and seal excellent.
Can you pull the intake manifold and show us a pic of the sealing groove and sealing surface?? Something is fishy! It may NOT be broken . Just need to be able to see it to make a solid recommendation.
Maybe someone didn't put both dowels in one head, and "eyeballed" it. Which would do what Bill said, that the manifold would probably rock. If you bought it used, you never know.....
Can you pull the intake manifold and show us a pic of the sealing groove and sealing surface?? Something is fishy! It may NOT be broken . Just need to be able to see it to make a solid recommendation.
Originally Posted by Markolc1981
You need a new intake manifold. I just don't see how any "fix" will work to save that one. Your best budget fix is acquiring another LS1 (97-00) intake manifold. A later year intake manifold LS1/LS6 (01-04) would be an upgrade, but they are pricier.
LS2 intake manifold will fit your heads, but you will need an adapter for your throttle body, or an LS2 throttle body with some tuning. It's generally regarded that the LS2 intake manifolds are nothing special.
LS3/7/A/9/4 Intake manifold will not fit your heads.
A LS2 intake will likely make more than an LS1 but dynos showed less than an LS6. You can drop an LS2 intake on and adapt the factory TB IMO without tuning to get back on the road. A LS2 throttlebody will take some tuning and an adapter harness.
The gasket should fit in the grooves of the intake snugly. I've had intakes off plenty of times, never had a gasket fall out. It looks to me like the gaskets lost their placement in the grooves in the intake when you placed the intake on the motor but, that is speculation. Agreed with Bill see if the intake seats down flat, if the grooves aren't damaged, some new GM gaskets if you can get them should do the trick. If the intake isn't holding the gaskets in the grooves, I'd get another intake.
If you have an LS1 intake, the LS6, LS2 and aftermarket intakes take some minor mods to update. 2001 and newer LS1s received the LS6 intake from the factory.
Thank you for taking the time to explain. The motor seems to be acting fine aside from the vacuum inflicted problems and I only just noticed this when explaining how some things worked to my wife. There was an event where I had a loose battery connection cause the engine to lose voltage and caused a couple of pops that sounded unusual, but this was at idle RPMs, so I hopefully escaped significant damage. I see no change in its behavior. Crossing my fingers the motor will be okay until it takes its throne as a restoration project in my future barn.
Would the budget replacement be an LS2 intake? I am not looking to power it up currently.
If the LS2 is a budget intake, there's a good reason; it is the worst flowing cathedral intake of the 3. DO NOT go with an LS2 intake. I remember back when GM Hi Tech Performance was around, they did some testing and were really surprised that the factory had dropped the ball that hard on the LS2 intake. The LS2 also has a 90mm TB, IIRC, which REALLY makes it look like dog crap, because it should bury the other 2, but fails miserably. As Johnny said, LS6, FAST, or even MSD. BTW, on the LS7, the MSD is the winner by a substantial margin. I dont know if that is the case where cathedrals are concerned......
Can you pull the intake manifold and show us a pic of the sealing groove and sealing surface?? Something is fishy! It may NOT be broken . Just need to be able to see it to make a solid recommendation.
Thank you to everyone for your replies. It helped me make a decision on what to do. I bought an LS6 intake that apparently came off an 01 to 02 f-body. From what I have read this was a good iteration for the LS6 intakes. Car is up and running like a champ. No hiccups and I did not need to shave down the ribs. I tried my damnedest to get the greased-up coolant crossover pipes to touch and could not save for one tiny spot. Thanks again everyone!
Gaskets destroyed my intake manifold?
