I always use the graphite/steel matrix gaskets (factory type) that don't require ANY type of 'goop' to seal.

If mating surfaces are clean, flat and aligned then paper or matrix gaskets should seal without any rtv. A gasket 'dressing' (for easy disassembly) is all that should be used with a paper gasket. Graphite gaskets go on dry. Rubber seals/gaskets (neoprene, viton, buna, etc) should be lubed with a bit of grease or oil so they slide and don't bind when tightened. RTV should only be used where machined metal surfaces have to mate and seal (tranny tailshaft housing to main housing, some diff covers, etc) or a dab where you have surfaces coming together in 3 different planes such as the head/block/lower intake or front cover/block/oil pan.

If rtv is required to get your intake gaskets to seal then it is likely that the mating surfaces aren't clean, flat or properly aligned.

 

Never used the Loctite rtv. Permatex, yes. Always use brake clean on surfaces for prep.

 

X2 some degreasers leave a residue behind and when you use some RTV it doesnt dry correctly.
Always use brake clean on both surfaces even if you cant get it all it will evaporate

 

Did you use that stuff to make the end seal gaskets?

I used the blue silicone rubber fel-pro end gaskets in my last intake gasket set and they don't leak.

Whatever you do make sure to use guide pins when installing the lower intake especially when using silicone for the end seals.

No way will the lower intake will line up perfectly the first time without them.
Buy 4, 5/16 inch bolts, 3-4 inches long and cut the heads off.

 

No way will the lower intake will line up perfectly the first time without them.
Buy 4, 5/16 inch bolts, 3-4 inches long and cut the heads off.

Kinda wishing I did this. I didn't and am now hoping everything lines up as it should and there aren't any leaks.

 

use "the right stuff" and dont look back.

 

x2 on this "the right stuff" !!!! Ya the black is Junk........

 

I always hear peo[ple saying to buy or use such and such bolts and cut em and use them. Well I have always had good luck using carb studs threaded into the corners to align the intake. Just a thought.

 

In this particular case, it was the wrong application for the loctite brand. It does not specify on the package (like the Permatex does) that it is "Maximum Oil Resistant Silicone".

The end seals I made with the loctite silicon appeared to just give way to the oil, leaking right into my bell housing causing my clutch to slip. When I pulled the upper I could see coolant had been leaking through also.

I just checked the surfaces of my lower intake, and they are all true.

As far as running a graphite gasket and installing it dry, I have yet to see one with the same intake port dimensions as a 1262, but I would give it a try.

I always install the lower with 4 alignment studs, then use a flash light and screw drive to line the intake runners up.

 

Loctite 598

Always frustrating when things don't seal. Permatex Ultra Black was developed when owned by Loctite, prior to a corporate split around 2000. At the time Permatex was sold the formulations were identical, but unclear who makes it for Permatex now, as they no longer source from Loctite.

The fact that the Loctite 598 was oily and easily rubbed off often indicates the material was past shelf life. When silicones get old they no longer cure to a hard rubbery material, and just stay as a paste. Best test to verify is to just squeeze out a 2" long bead, let set 3 days and if not cured to a hard rubber like appearance then it is old.

The shinny appearance is a metallic filler used to provide a high tech appearance to the material. Loctite 598 was the key gasketing silicone for may years at Ford in production applications.

The person who commented on using Brake Clean is accurate, as these materials leave no residue. Some cleaners use an oil to cut the grease to clean parts, but the oil remains as a residue which can affect adhesion.

2003 Mach 1

 

Always frustrating when things don't seal. Permatex Ultra Black was developed when owned by Loctite, prior to a corporate split around 2000. At the time Permatex was sold the formulations were identical, but unclear who makes it for Permatex now, as they no longer source from Loctite.

The fact that the Loctite 598 was oily and easily rubbed off often indicates the material was past shelf life. When silicones get old they no longer cure to a hard rubbery material, and just stay as a paste. Best test to verify is to just squeeze out a 2" long bead, let set 3 days and if not cured to a hard rubber like appearance then it is old.

The shinny appearance is a metallic filler used to provide a high tech appearance to the material. Loctite 598 was the key gasketing silicone for may years at Ford in production applications.

The person who commented on using Brake Clean is accurate, as these materials leave no residue. Some cleaners use an oil to cut the grease to clean parts, but the oil remains as a residue which can affect adhesion.

2003 Mach 1

Thank you for that information. It seems it could have been the degreaser cleaner I used that didn't allow the silicon to setup, but I find that odd since I have always used this same degreaser to prep the head/valley/intake surfaces. Then again, I have always used permatex ultra black.

To satisfy my own curiosity, I've performed a little home science project. I grabbed a couple of spare surfboard fins and a plastic cover, cleaned both surfaces with brake clean, and applied loctite 598 to the left fin and permatex ultra black to the right. I'll see how they setup in 24 hours, since thats what the directions call for. It is still possible that Summitracing sold me an expired product though.

One small difference I've noticed while comparing these two items recently, is that the permatex states on the package that its "Maximum Oil Resistance RTV Silicone Gasket Maker". The loctite brand doesnt mention oil resistance.

 

I prefer Motorcraft or Permatex Grey RTV for intake gasket work. I just put a daub on the ends, where the end gaskets meet the intake-to-head gaskets. Haven't had any issues, have done probably over a dozen intake gasket jobs on various engines.

The black RTV stuff is popular with some folks, but I don't like to use it, just from the smell of the stuff. Just personal preference.

 

About 24 hrs later...

The fin with loctite 598 popped right off with little persuasion. It was completely dry. Since it did dry, it seems it is not old.

I had to use both hands and a lot of force to rip the plastic cover off of the fin with the permatex. It still had some drying left to do, but it was a larger bead.

I dont know if you could draw any solid conclusion from this, but seeing the difference in the amount of force it took to separate them was enough for me to prefer the permatex.

In my personally opinion, Permatex must have changed the forumula since 2000. These two tubes of silicone in front of me appear very different.