Seems as if Mr Gasket wasn't 'Mr. Right'. ???

It appears as if the water actually worked it's way between the sandwiched fibers of the gasket. When the intake came back off (it was stuck on there VERY well)...the gasket actually came apart - some on the intake - some on the heads.

I took some pics:

 

And this...

 

Another...

 

Oh, also... I marked the heads where the intake edge lines up. Once I had the intake off, I laid a straightedge across the marks. I have about 1/8" from the top of the water port to the edge of the intake manifold. You can also see in the pics above that the water fittings that were tapped into the intake line up perfectly with the water ports - I don't see how there could be any obstruction there...

I got the Fel-Pro 1204's last night. They are a MUCH better looking gasket. Confidence is high.

 

Oh, and another thing...

I had the fuel problem remember? I pulled the fuel rail and with rags under them I turned the ignition on... I could hear the fuel pump whine and then quit. NOT A DRIP from the injectors. Nada. So when the fuel pump cuts out and the pressure drops back to zero, where is all the pressure going?

Please don't tell me it's the pump, because it was fine before I did the new intake. I have no signs of any fuel leaks anywhere.

 

Only other place to go is back down the return line, which means an internal leak in the FPR.

Those Fel-Pros are nice looking gaskets, aren't they? I just got some 1205's for my HSR.

In that first pic, the inside edge of the gasket seems awful close to the edge of the intake there...

 

I have to pull mine off this weekend to change lifters.

I always run a bead of RTV around each water port, under the gasket and on top of the gasket. Looks like you did that already.

 

Internal leak in the FPR??? I have a Holley on there that I bought 'NIB' from CamaroZ28.com! Figures. Do they sell something like a rebuild kit for the Holley? Heck, when I got it it showed NO signs of any prior use.

As far as the gasket in the first pic, I see what you are saying. I think that's where some folks have welded on some 'ears' to the intake to provide a better seal. I'm gonna line up the fel-pro's on there and see how much closer they are (if at all). If not, I'm not sure what I should do.

 

Yeah, I did. The only thing I can blame this time is the crappy gaskets. The prior leak I think may have been caused by too little silicone around the front water ports.

Let's hope that the 3rd time's the charm, eh?

 

The silicone impregnated gaskets are NOT reccomended for the TPI engines, they are prone to leakng, the only gaskets that I have ever used or ever heard of being endorsed by GM are the stock paper/metal core ones.
You are going to want to clean up the intake around the water jackets and carefully inspect for casting imperfections and/or errosion damage to the metal on the sealing surfaces. If the sealing surfaces aren't smooth around the water jackets you can clean them up good with a wire brush and acetone, dry throughly and apply some JB weld to fill in the area. When it sets up (24 hrs) file and sand it smooth and you're done.

 

It could be the regulator or even the fuel pump. The pump has a check valve inside to maintain pressure after it stops running. It's normal to leak down after 1/2 hour or so though, not right away.

 

Yeah, but WTF??? It wasn't doing that before I tore down the motor!

 

What usually happens is the diaphram tears or gets a hole in it, if this is the case and you still have your old FPR you could see if the diaphrams are the same and reuse your old one.

 

I use those same type of intake gaskets. I've never had a problem with them. Mine did however have the rubber beads around the coolant openings too.

 

I mean no disrespect here, but did you let all that silicone cure before you dropped the intake? If so that's probably why the gasket seperated. You want to put the silicone around the water ports right before you drop the intake and you don't want it to cure like it has to for the end rails.

 

I have always used the GM or Rol brand intake gaskets on my TPI and put them on with Permatex Hi-tack. I've never had a gasket failure in the 17+ years I've owned the car.
There was a write up years ago in Car Craft and a few other car mags that all said to avoid the Permatorque gaskets with the silicon around the ports when using an aluminum intake manifold, they were known to fail, especially at the water jackets, due to the different expansion properties of the cast iron and aluminum along with the silicon used in the gaskets.

Oh, and forget the fancy colored silicons, use Permatex Ultra black. It used to be called "OEM black" because thats what GM was using on their engines and other things.

 

Since you know it's not the injectors, clamp off the return line, cycle the pump and watch the pressure. If it doesn't bleed down then it's the regulator. If it does, it's the fuel pump check valve OR most likely, the pulsator/rubber coupling between the pump and line.

 

Did you bleed the air from the fuel lines? Trapped air can give crazy readings.

I normally disconect the return line next to the fenderwell and place it into a container. Turn the key and watch for steady fuel coming out. e carefull, it comes out fast.

 

1) Dont use blue rtv...always use Ultra Black for intakes. You will get much better results. Follow their directions for curing time before you set the intake in place, and let it sit overnight (or longer if it is cold) so it can fully cure, before you ever fire the motor.

2) I dont know what everyone else is saying, but if you turn on your ignition like you described, you should NOT be seeing anything come out of the injectors (if you see dribbles, your injectors are leaking). The injectors will only start opening if you actually crank the motor. Only turning the key on allows the fuel pump bring the pressure up in the rails before startup.

NOTE: I dont recommend cranking the motor with the intake and distributor off...you will have a much harder time lining up the distributor if you disturb the crank position.

Your fuel pump should be able to pump out much more pressure than your engine requires, so when you DO reach full pressure, the regulator bleeds the excess off back into the tank, just like it is supposed to.

However, your fuel pressure should not drop immediately to zero. Sorry to say, that when that happens, more than likely the check valve on the pump has died, or there is a leak (like the "anti pulsating device" between your pump and the hard lines. Both of which require you to drop the tank, so you might as well replace the fuel pump if it has a lot of miles on it.

 

Air isn't gonna happen in a 40+psi fuel system that's been run for a tiny bit of time. It'll come out the injectors or back to the tank.

 

Mine used to do that, just before it failed totally. The rubber line from the fuel pump to the hardline had a hole in it. Did you have a regulator on the original TPI? It might have been doing it all along. It took mine two years to totally blow out, (ie no pressure).

 

Thanks everyone for your responses. Here's what I have checked/done so far....


Pulled the fuel rails up so the injectors sat up above their 'bores" and turned the ignition on. No drips. Nada. So it seems to me the next likely culprit will be the regulator. Everything else in the fuel system was fine before and should be fine now. Maybe there is another adjustment on it somewhere that I don't know about???? I think I was just sold a bum regulator.

I pulled the intake off and have cleaned up all the surfaces. I'm almost ready to reinstall. I checked the surface of the intake using a straight edge and it appears to be fine.

I'm not going to get into the debate about what type of silicone to use because it seems everyone has used something different that worked. The method I used the 2nd time was this:

- Apply silicone around the openings of the water ports on the heads.
- Lay the intake gaskets on the heads.
- Apply more silicone on the "intake side" of the gasket where the water port openings are.
- Apply silicone to the front and rear "china walls"
- Wait 20 min.
- Install intake manifold
- Then I waited about 24 hours (if not more) before doing anything else.

Even with a 20 min wait, the silicone around the water ports is not hard enough not to 'squish' with the installation of the intake. The purpose of the wait for the "china walls" is just so the silicone is not so 'liquid' to drip down into the lifter valley and eventually down into the oil pan, right?

The design of the LT1 intake is going to make sealing up the intake that much more difficult that a standard SBC since the LT1 intake doesn't have the "ears" that the SBC intakes do. I've heard that the "ears" can be welded on, but no one has given me any insight on how much it's going to cost. Plus I'm sure I'd have to find someone who can weld aluminum around here...

Fun stuff!

 

one of the problems why it leaked is cuz you used blue.....it wont hold up

You need to use the red or better, like some have said use the black

Also, you only want to put it on the cylinder head side, you dont need it on the intake side

hope it works

 

It cost me 60.00 to 90.00 to get extra ears welded on all 4 corners. That was earlier this year and i can't remember the exact figure.

 

UPDATE.

OK, looks like with the new gasket (I ovaled the bolt hold slightly so it has a little more 'bite' on that ouside edge.

Using the red - it now holds pressure. Pumped it to 15 lbs (rating on the radiator cap) and saw no indication of a blowout anywhere.

I also pulled off the holley and disassembed it. Looks like there might have been a little *tiny* debris inside. I cleaned it real well and it worked - until I adjusted the initial fuel pressure to match stock ~45-50 psi... then it started to bleed down again like before. I checked this while the fuel rail was off and saw that one of the injectors was leaking a little. The L98 injectors look a little longer so I'll have to have these cleaned sometime in the future. For now, I think it will be ok. When I put the stock LT1 regulator back on, it held pressure just fine - even with the tiny leak at the injector (VERY TINY).


SOOOO... I will let you know next week if the sucker started up!

 

Well, I don't know where you people get the idea that pumping silicone all over the gaskets is going to be a good thing. There is only so much gap between two machined surfaces and the paper gasket is more than enough for the two to seal if they are in good shape and are torqued down properly. Pumping silicone all over the place and letting it start to harden is a good way to create a problem with the seal. The silicone will just serve to add to the amount of material between the two surfaces, creating an uneven amount of torque being applied to the gaskets along the surface, and will often even fracture the paper gasket material (which looks like what happened to you).

The way to do it is to only use the silicone (as stated above, black or the light grey stuff ONLY, I use GM brand) on the China walls and up towards the coolant ports on the heads about a 1/4 inch. That is it. Apply the silicone to the block as a 1/2" thick bead that is also about 1/2" wide (maybe even larger if you know there are issues with the block or intake). Place the paper gaskets on the head surfaces by pushing the little tabs on each end into the 1/4 of bead that was extended up from the China walls. Then apply a thin bead to the sealing surfaces of the China wall areas of the intake manifold itself. This is a trick another tech taught me waaay back when. Since silicone adheres to silicone better than anything else, it will ensure a proper seal between the two parts even if you get contaminents or debris on the surfaces - the silicone will surround the offending particles and still seal. Then put the intake on right away.... None of this wating around BS.... That does nothing but allow the silicone to 'skin' over and not allow the acids in the silicone to etch the surfaces (or blend with the silicone bead that was put on the China wall surfaces of the intake in this case) of the components at hand and firmly adhere to them. Follow that procedure, and use a quality gasket (I usually use GM, which are made by ROL, but sometimes go with Felpros for ease of application purposes), and you won't have a problem with an intake gasket sealing.

HTH,
Matt

 

Matt,
Thanks for your response. I think with a standard SBC intake that was already *MADE* for the engine it's being mounted to, you'd have no problem.

As you can see it the first picture, the opening for the water port was just too close to the outside edge. It's because the LT1 intake doesn't have the "ears" that a traditional SBC intake does...therefore there is not enough pressure on that outside edge to create a good seal.

The silicone that was placed around the water ports on the gasket was minimal. Merely enough to create a good seal. As the intake is torqued down, it wouldn't cause any problem with the gasket. If it was a little too think, it would just squeeze itself thinner by spreading out.

The silicone around the water ports is not allowed to skin over - it is applied right before the intake is set down.

Nope. The only reason the crappy paper gasket came apart when I pulled the intake off was (a) it was wet; and (b) some of the silicone kept part of the gasket stuck to the underside of the intake. As you can see in the 1st pic, this was good beause it made the problem VERY evident.

Well, I've heard differing stories on what silicone to use and how much...to wait or not to wait, etc.

OK, so I guess the blue has a lower strength than the red or black - that lesson I've learned the hard way. I also learned that silicone "goes bad"...the hard way. To wait or not to wait... hmm, I understand your statement and reasoning. The reason I actually think it's better to wait is that if the silicone is still fresh, what's to stop a bit of it from plopping down into the lifter valley...then making it's way someplace inside your engine where you'd rather it not be. That's the logic behind letting the silicone skin over. Just my $.02, but I'm no mechanic of course.

 

Nope, you should wait 10-15 minutes to let the silicone cure some before applying weight on the silicone, from pressing the bead out from the intake/block. GM even suggests this when using their sealant. (Worked at a GM dealer for 7 years on their cars). I have done 25-30 intake gaskets on LT1 intakes alone, and you always want it to have some cure time. There was widespread problems with the infamous LT1 intake oil leaks. GM came out with a new silicone part # to use with these intakes at that time. Also, there was a problem withthe EGR "flexible" tube to the manifold heating up the area on the back of the intake, weakening the silicone, resulting in leaks. I always use GM grey sealant, due to the great quality.

I do not like to use sealant arpund the ports either, but some aftermarket companies like Edelbrock sugest doing exactly that when using their products and gaskets.

 

glad you have gotten things straightened out and fixed, good job!

 

I too was a dealer tech, and that is where I learned my lessons on how to seal a SBC intake (the hard way at first). Done hundreds of em the way I describe with no come-backs (on customer vehicles, or friends and my own) because of how the silicone was applied or which silicone was used. But what I mean by no waiting around, is that you don't put all of that silicone on and then stand around for X amount of time. The time it takes to get all of the silicone on and the parts ready to be put on will give it enough setup time and there is no need to wait any longer. But I am not saying rush through it and hurry getting it set in place because you don't want the silicone to firm up at all.... You just don't want it to skin over (see above reasons).

Yes, from what I have been told/read, the LT1 leaks have been directly connected to the improper silicone type usage and the excessive heat from the EGR tube. Has nothing to do with waiting around for silicone or not.

I use GM p/n 12346240 grey RTV Silicone. I think it previously had a different p/n though.... Like back when the bottles were black and grey and said Goodwrench on them. That is the newer p/n for the blue and black GM styled tubes. I also used the darker grey GM stuff without a problem (I forget the p/n), but there was a shop-wide ban on the stuff where I was working for some reason (read: some retards were inept at wrenchin resulting in even more inept management making hasty decisions).... I have also been caught out of stock of the GM stuff a few times and had to run up to the local parts store and pick up some of the Permatex black stuff and have had good results with it as well. Still go with the GM stuff when given the choice though....

Tell ya anything?

Matt