I purchased a NPP controller that requires me to remove the tip off the vacuum source located at the back of the intake manifold. I have tried without success to remove the tip. It is so tight between the intake manifold and the cowl that I removed the passenger side coil pack rack to get more room. I can touch the tip but it won't twist off. I bought the recommended X-Acto knife to cut it off but can't get the knife to the tip. There is just not enough room for my hand and the knife to get around the plastic blade next to the tip and be able to use the knife. Any suggestions for those that have removed the tip??

 

I remembered an old plumber's trick to cut PVC pipe when it is in a hole and you can't get a saw to it. I used nylon twine to saw through the tip. I cut a piece of twine about 30" long, wrapped it around the "blade" that is next to the tip and started pulling the string back and forth. I broke 2 pieces of twine before the blade sawed off. I cut off about 1/2" of the blade to expose the tip. I could then saw off the tip. I broke one more piece of twine but the next one cut it off. Just be sure to not cut the tip completely off. You can kneel down on the passenger side of the engine and use a light to see what you are cutting.

I was surprised the intake manifold wasn't that much tougher than PVC.

 

I'd like to understand your process a little better, because I've been studying how to do this. Please clarify what nylon twine is. And then when you say you wrapped it around the "blade", I assume you mean the tip of the vacuum port, and not the saw blade you were trying to use? Sorry if I seem dense, but I just want to understand how to best to do this.

Also, which controller kit did you buy? One of the kits has an "EZ Tap" thing to tap into a different location to avoid messing with that vacuum port at the rear of the manifold. Don't know if that's the way to go or not.

Thanks for your help and advice.

 

I just got mine from topflight link below, theirs comes with a free EZTAP, took 3 min to get the vacuum done and never had to bust my knuckles trying to get to the back of the intake. NPP on my car was the best investment yet

http://forums.corvetteforum.com/c6-c...-in-a-box.html

 

PVC PIPE CABLE SAW

http://www.generaltools.com/858--PVC...SAW_p_121.html

 

At the back of the intake manifold there are three protrusions. Looking down they are, from the left, a Blade that is 3/8" tall, 1/16" wide, and 1" long (I have no idea what this is for other than to protect the tip from being accidentally knocked off), the NPP vacuum port that is capped off with a tip that has wings off of it, and the elbow providing vacuum to the power brakes. The NPP port is between the other two and is difficult to get to. The instructions say to twist the wings cast into the NPP vacuum port tip and twist off the tip. When the tip is twisted off you have an opening into the intake manifold to provide the vacuum to close the NPP valves.

The blade makes it difficult to get your hand in to twist the tip off and also blocks getting a knife or saw blade in there. Mine may have just been a tough one to twist off. I used nylon twine, sometimes used as kite twine or fishing twine, as my saw. Looping it around the blade I cut off 1/2" to expose the NPP vacuum port. I used a 30" piece of twine and pulled it back and forth across the blade building up heat and melting the plastic. Once the blade was cut I could loop it around the vacuum port, just inside the wings used to twist off the tip, and cut the tip off. Once I started I was done in less than 5 minutes. The nylon twine was twisted from three smaller threads. You can buy it at Walmart or a fishing supply store in 500' or 1000' spools for $5-$8. I had a spool left from tying weights onto duck decoys. I posted to find out what others had done. I would still like to hear from them because there may be a much easier way to do this and others need to know.

 

Okay, thanks for the clarification. Now I see what you mean by the "blade". I may try that procedure. Thanks again,

Chuck

 

This is what he was trying to get off.





It can be a pain to get off, but at least you're connecting the system correctly like the factory.

I like your method, sounds like another tip to add into the revised instructions.

 

I used a socket (I think 7mm) and that worked--I put the socket on the "wings" that you are trying to twist off, rotated the socket, and the socket fell away with the wings in it.

Having said all that, you can still see a little mark on my left forearm from forcing my arm through too-small a hole, touching a hot engine right as I got "purchase" on my target, and deciding to feel the burn rather than let go.

 

In the picture above, have you succeeded when you get that little wing thing off (as in picture)? Or do you need to get that next section off, that looks like a , yea, head off? Thnaks again.

 

You have succeeded when you get the wing thing off.

 

HALLELUIAH!!! And thank you SWGLENN for the suggestion! I used your suggestion of kite string (nylon). I skipped trying to cut off a portion of the "protection" blade, I pushed the string directly unto the nipple with the wings on the end ( what will be our vacuum port). I made sure the string was in behind the wing and against the base where its molded to the vacuum port. Then I started sawing back and forth with the string. It didn't take a minute, and a little piece of something came flying out (which I couldn't find). But when I felt in there, the wings on the end of the vacuum port were gone.

My only question, is there actually a hole there now? It feels like there is, but, since you can't see in there, I'm going to get a mirror and see if I can see it.

But again, thanks for the suggestion.

Chuck

 

Believe it or not, the hole you create by removing that little "twist-off" cap is VERY tiny! I cut mine off and couldn't get a small finish nail into the end of it. I figured I didn't cut off enough. Even using an inspection mirror I couldn't tell. I finally just pushed a length of vacuum tubing over the end of the port and started the engine. Bingo! The line had vacuum. So even the tiny hole that is created is enough to operate the NPP valves.

What a nightmare experience it is for a first-timer to acccess that vacuum port. It took me 3+ HOURS to get mine done. This is no joke... if I had to do it again, I would just remove the intake. I think I could R&R the intake in under an hour with zero frustration.

EDIT - Not to rain on your parade...but it's possible you just broke off the 2 "wings" of the plastic wing-nut thingy on the intake and you may not have a hole. You can break those wings off without creating a hole. Many of us found that out the hard way!

 

Ben, you definitely need to add this suggestion to your instructions, it worked great! See my above reply to SWGLENN. I was going to try an exacto knife, but I couldn't see how to get it in there to the right position, and then hold enough pressure on it and saw it back and forth. The nylon kite string worked great. The only thing I didn't mention in my reply to SWGLENN is that I did dismount the bank of coils on the right bank and let the whole bracket slide down (I just dismounted the the mounting bolts, didn't disconnect any wire harnesses). This gave more room at the rear of that right side valve cover to get your hand in to the back of the intake manifold.

I hope to get the rest of your kit installed tomorrow or the next day.

Chuck

 

Here are a few related threads worth checking out if anyone is getting ready to do a complete NPP install...

Getting at the NPP vacuum port on an LS3

Spend the $10 on EZ-Tap when you buy NPP-in-a-Box

Alternate Vacuum Line Routing for NPP

Alternate Location for Mounting NPP-in-a-Box

 

TOP FUEL, thanks for the suggestion to just test it with a piece of vacuum hose, I can sure try that. I feel pretty confident that I didn't just break the wings off, because I was "sawing" kinda' against the "base" of where the wings are molded on the end of the port.

So we will see. Thanks again.

 

Sounds like you're in good shape!

Getting the vacuum hose over the port is also somewhat challenging...but I have big hands. I had to soak the end of the vacuum line in a cup of boiling water for a minute so it would slip over that port more easily.

 

where is the vaccum port on the LS2 engines? Anyone have a picture?