For those who have installed lower intakes - Silicone or block end gaskets?

[5spd GT]

Well after some looking around it appears that my lower intake is leaking at the block ends (worse on the backside) and is leaking onto my transmission (which caused premature clutch failure) and will likely do the same to this one.

So has anybody used both methods or which did you use and say if you had an oil leak or not? Which did you prefer if you used both?

I have had the car like this for about 9 months and it just got very slowly worse (oil leak).

Also I got smoke from underneath the hood/interior thru the shift boot because oil got on the transmission. This was after a real hard run thru 3 gears...would the oil expel faster at the block ends when going WOT...I'm pretty sure it isn't the clutch "yet"...

I need to get new valve cover gaskets as well...hopefully this leak deal will last a while til I get some money/time together...but I wanted to get ideas now on what you thought was the best method...using the block ends with silicone in the corners or pure high-temp silicone?

Thanks

 

[93FIVEOH]

I've seen in the magazines say they like to run a thick silicone bead on the front and rear rails, not just corners. I am curious to which method people think are best also.

 

[DMAN302]

I ran a thick bead of black RTV, and heavier in the corners. After placing the bead I let it set for 5min, then droped the intake on. I don't truset the end seals and just toss them...no leaks yet using this method. Also try to let the car sit for 24HRs to allow the sealant to cure. Should also note I did use dowels to keep alignment on the intake while placing it into position.

 

[87mustang347]

yah i also like to use a very thick bead of silicon. i used it the last time my motor was together and i didnt have any problems. this might sound stupid but the guys on horsepower tv use the silicone stuff all the time too.

 

[stang22]

Derek,

I am getting ready to put my lower intake back on also. Do you put any silicone in between the heads and the lower part of the intake, or just use the gaskets? Thanks!

Tim

 

[DMAN302]

I put a small amount of sealer around the water ports on the head/gasket/intake sides. Also run blob in the corners ( corner where the head meets the block and intake) and a 1/4 bead across the back and front of the block from head corner to head corner (ends of block only). I give the end seals supplied to the dogs to chew on..may not be good for them, but those little bastards steal everything in sight.

 

[Wi Stang]

When I put my intake on, I just ran a bead of silicone, and dabbed a bit more in the corners. Set it on, bolted er up, let it cure overnight, and no leaks.

 

[stang1986GT]

I went ahead and used the end gaskets on mine WITH black silicone. No leaks yet. Hope I don't live to regret it. I almost didn't use them, but they seemed to be pretty high quality and fit really well, so I thought I'd give it a shot.

 

[Boss 351]

I use the end gaskets and put some RTV on the ends... never leaked.

 

[5spd GT]

I ran a thick bead of black RTV, and heavier in the corners. After placing the bead I let it set for 5min, then droped the intake on. I don't truset the end seals and just toss them...no leaks yet using this method. Also try to let the car sit for 24HRs to allow the sealant to cure. Should also note I did use dowels to keep alignment on the intake while placing it into position.

That is exactly what I did...I did everything by the book except I did use red high-temp silicone...

I know that Michael Yount uses the end gaskets

 

[Curse]

I used black RTV, at first no leaks at all, but after a few months it looks like I may have a tiny leak at the back of the intake. Maybe I didn't use enough?

 

[jrichker]

My favorite trick that saves time and effort is the stay in place gasket. Be sure that you scrape (don't use a wire brush) all the old gasket material off, then clean all the surfaces with acetone or MEK.

When the surfaces are clean, use weather strip adhesive on the head to manifold surface, and on the side of the gasket that mates to the head. Follow the instructions on the tube or can and when it gets tacky, press the gasket down on the head.

Clean the area where the rubber rails mount to the block in front and in the rear with more acetone or MEK and do the same trick with the weather strip adhesive that you did to the heads.

Coat the rubber seals and the gasket area around the water passages with lots of Blue Silicone gasket sealer and put it together. Wala! no leaks, and no gaskets that shifted out of place.

If you reuse the injectors from your old setup, a repair kit is available from most auto parts stores if needed. Coat the injector body "O" rings with oil before you use them and everything will slide back together.

 

[gregpro50]

I used the RTV on my ends and no leaks. I guess if it is the stock intake and you want to use the end seals, the rubber ones are best. Dont use the crappy cork ones. Also, if you have an aftermarket intake then you have to use RTV.

 

[Daggar]

I've use the cork and the rubber and have not had problems with either of them. I use the gaskets as nothing more than filler. I coat both sides with the black RTV and put beads above and blow the gaskets and let it sit for a while before installing. Even with boost, I've not blown any end gaskets. I would never consider installing those gaskets without sealant above and below. The sealant is the meat. The gasket is just a shim. hehe

 

[vristang]

I have not used the cork gasket for a while and have had little trouble. With the new motor though I have had alot of trouble getting the rings to seat, in other words Blowby. Then to make matters worse the PCV valve was bad. Long story short the crankcase pressure was blowing out the rear lower manifold seal.
Ask yourself if there might be a reason why the gasket keeps blowing.
Does any one know where to get the rubber U-shaped gaskets? It sits down on the rails, and the upside down U-shape keeps it from sliding out of place. Found them before, can't find them now.

 

[90LX306]

Thick bead of silicone, has worked flawlessly on the past 5 motors ive done...Later

 

[Stang8URMPRT]

I also like to use weatherstrip adhesive to keep the gasket in place. But I use RTV on the ends... Thick bead and more on the very ends... I also use RTV around all the water jackets on the lower/head gasket... But I don't run a "Bead" around them.. I put some on my finger, and just a very thin layer on both sides of the gasket. this will take up for any imperfections in the head or intake.

 

[5spd GT]

I don't have any leaks anywhere else. I just have it at the ends and was curious to what is truely the best method (like if someone had did both methods)? So it appears the ultra gray or ultra black is the best?

So the "raised" side of the gasket goes against the head and the flat side goes against the intake right?

Curse - Same thing happened to me...

 

[bluevenom867]

I used cork end gaskets with blue RTV on bother sides (small bead on both side of the cork) and more in the corners, also put RTV around the water jackets.Havent used the weather springing adheasive,but I use Edelbrock gasketinic.

 

[bluevenom867]

So the "raised" side of the gasket goes against the head and the flat side goes against the intake right?

No,other way.
The blue (Fel-Pro gaskets, Mr.Gasket is red) stripe around the ports goes on the intake side.