Lower Intake Manifold Gasket Question

[redsn95gt]

I am replacing my lower intake manifold gaskets. Got the fel-pro set, comes with the 2 blue rubber end pieces. I have a systemax intake- I've read normally to not use the rubber end gaskets and just use a bead of RTV, but this intake fits a little funny on the back, pretty big gap to fill. Last time I tried this, I ended up with a vac leak. Should I give the rubber pieces a try? It says to install them dry, but I can see the need for some RTV in some spots, is that fine? Any other areas I want to seal? Want to be sure I can fix my vac problems.

Thanks!

 

[4Jenna]

Sounds like the lower intake needs to be milled to sit down flat/flush.

Have the heads been milled in the past?

I always use RTV, and recc to NOT use rubber/cork on the front and back of the block.

 

[redsn95gt]

Hi-

Heads are brand new AFRs, block was decked but very very minor. Intake has never been shopped either, it looks brand new but i got it second hand.

When i pulled off the intake, my big gob of RTV was stuck to it, I don't think it did the job.

EDIT - Here, to give you an idea of my gap I got, I molded it with some clay

View attachment 186615

 

[4Jenna]

How much was the block milled?
.010"?

I would have the intake milled down so it sits in their right. When you mill the deck, or the cylinder head this will change the way the intake sits in their. Prolly a couple thou of each side and it will make all the difference!

I usually do a nice thick bead of RTV front and rear, but have no gap to start with.

 

[redsn95gt]

I went ahead and did a giant fat bead of RTV, i hope it closes that gap. If not, I guess I'm going to be pulling this off again and having it milled. I would have to find my paperwork to find out how much the block was cut.

Thanks

 

[Adam95GT]

I went ahead and did a giant fat bead of RTV, i hope it closes that gap. If not, I guess I'm going to be pulling this off again and having it milled. I would have to find my paperwork to find out how much the block was cut.

Thanks

Mine looked about the same. I also used a ton of RTV.

 

[blksn955.o]

I had always used the rubber pieces in the past with 0 issues with just a few places with RTV.

My block is milled and the heads are milled a lot. I had a huge gap at the front and back of the intake. I simply did not like the fitment and had it milled. The runners also ended up matching better.

I could not and can not use the rubber end pieces anymore. due to the head and block milling the rubber pieces are simply too long.

Just lay a nice thick line of RTV and let it setup a bit. Then lay that intake down.

 

[revhead347]

I always use the rubber pieces. Everytime I didn't bother to get a set of the rubber pieces (they don't come with Felpro performance gasket kits), and just ran a line of RTV instead, it leaked.

Kurt

 

[Last5.0]

The factory uses the rubber pieces.

When I first swapped intakes years ago I used no rubber pieces and used a bead of Right Stuff. It worked good but was a pain to clean off when I removed intake. I then used the rubber pieces with some tack n seal on the bottoms to help hold them on and I still use them with no problems. Still need a bead of RTV in each corner where the rubber meets the gaskets though.

...one thing to remember if you are only using RTV....let it setup for about 5-10 minutes and skin over before laying the intake down.

 

[redsn95gt]

Thanks for the input guys. Yea, i let this sit a good 5-10 mins before putting the intake on. Seal seems to be OK, vac pressure went up about 5psi on idle, startup rev is a bit more solid, still not where I want to be but its better than it was.

 

[Last5.0]

Thanks for the input guys. Yea, i let this sit a good 5-10 mins before putting the intake on. Seal seems to be OK, vac pressure went up about 5psi on idle, startup rev is a bit more solid, still not where I want to be but its better than it was.

The what?

 

[4Jenna]

With boosted app's it's def smart to run rtv as the cork/rubber will get pushed out.

Just my exp.