Looking for input on hot tips for getting that PERFECT seal on the rear of the intake. Had a leak on my stroker when I bought the car, at the rear, previous owner used the rubber seals, the leak was at both corners where the heads, block and manif. meet. Worked a deal with a local mechanic trading a carb for work, he swears and has never had a problem with using NO gasket, rubber or cork, at the front or rear, just a monster bead of black RTV sealant. Now, leaking worse than before! Seems right near the dist. All the talk and previous experience of problems with the rubber 'walking out' under pressure has me wondering if cork isn't better, with gaskacinch or whatever? Opinions or input please, Thanks,

Randy

 

I think everyone here is going to tell you that not using the rubber gaskets and using teh RTV sealant is the way to go. Are you sure it's not something else leaking like right around the distributor?

 

I suggest using the gray sealer, using a gasket on front / rear of intake is not suggested. Also check gasket on distr and oil pressure line connection.

One additional way to check is to use the oil dye sold at NAPA, cleaning area and then use the special light (black light) to see source.

Good luck

 

It seems many are just using sealant, but for me it makes a mess. I am satisified using the old method of gluing the rubber seals down with weatherstrip adhesive first, then using silicone in the corners with a skim coat of silicone on top. After the weatherstrip adhesive dries in place, the rubber seal isn't going anywhere.

 

No gasket or rubber at front and back of manifold - sealant only.

 

Take a chisel, make crosshatched chisel marks like a XXXX on the block rail where the RTV goes. Place a big bead of RTV, let it sit for about 5-10 minutes before installing intake. Allow 24 hours to dry after installation. Uless your motor has massive blow-by problems that method should work also clean every mating surface with brake parts cleaner before applying RTV.

 

99.9% sure it's the seal and not the dist. gasket. Cleaned the back of the block REAL good, then fired it up and watched with plenty of light, oil soon bagan running out right behind the dist between the manif. and block. I was there when this mech. did the reseal and he used, I believe, brake klean on the fr. and rr. of block, don't recall if he shot down the manif. ends after the bath in the solvent tank. Perhaps, if he didn't, some residual solvent on the manif. prevented a good seal??? Blow-by not a problem, have crankcase breathers on both valve covers. Curious as to why I'm seeing more cork gaskets with aftermarket intake sets than rubber! By the way, mech. said no prob. to taking care of it, again, when he can squeeze me in.
Thanks to all of you for your input.

Randy

 

Gotta be extemely careful when using *cleaners*(carb/brake/et.al) before putting the RTV on the metal.
1. makes metal cold..very...they will will crystalize contanimates.
2. the metal is porous(sp?) and some cleaners stay in the pores and will NOT allow sealant to adhere properly because of this.
3. they drain into the cracks and stays there...spray pressure forces these cleaners further into the cracks.
4. is NOT compatible with sealants and will eat away the sealing properties.

Yes, these types of cleaners have been used for years with no problems...but when you DO have a problem, its time to go to plan B and start eliminating the causes of sealants not adhering properly.

You can try using a paint de-glosser (Parks makes one, found at s-Lowes, or Home Repo) to clean the surfaces.
1 its very inexpensive(a buck or two a pint), it dries very fast, it will evaporate from pores.
2. it will evaporate any other solvents from pores along with it,
3. doesnt make the metal cold,
4. applies with a rag, can also be applied with a small brush into cracks and other gaskets safely.
5. can be rubbed on vigorously.
6. has no oil whatsoever in it...where as tank solvent cleaners do.

Its also great for cleaning tons of other stuff too...road tar, oily or greasy parts, ect...
And then there is always the use of what its intended for...cleaning something to be prepped for painting. Prepping for a good sealing is the same...but you dont use carb, solvent tank cleaner or brake cleaners to prep before painting right?


The only time I have seen somebody have this much trouble, this many times has been due to:
1. too much pressure in the intake valley and blowing the gaskets/sealant out....the intake valley is seperate from the pressure from underneath the valve covers(though; it shouldnt be)...could be a problem with head gasket not allowing intake valley pressure to be equal throughout engine(wrong head gasket, upside down, or incorrect holes stamped/defective).
2. not allowing the *cleaners* to be completely dry or removed from the surfaces.
3. (oh, this is a doozy) not cleaning the CRACKS where the block and head match...solvents and oils get in the cracks and are absobed into some gaskets...this prevents adhering of sealants (this is where the de-glosser shines, it can be applied with a brush in the cracks and wipes out anything that will prevent adhering...can be blown with a light pressure air tip and applied again and again until thought clean.)

FWIW--I have never had this problem when using rubber or cork gaskets....just put light amount of sealant on on the gaskets and a bead in the corners...always worked for me.

As always---YMMV


Good luck and I hope this helps,
Jim

 

dont ever do any of this. if you use the gaskets apply a super thin bead of rtv to hol it down a nd a skim coat with ample beads on the ends/corners, on the top. if you use the rtv only, run a nice fat bead with an overlap onto the intale gasket in the corners. and you can install you manifold immedialtly after applying the rtv. and dont clean with brake or parts cleaner unless you plan on changing the oil before startup. only use a scraper or rotary disc and block off all passages and remove all debris. most quality gaskets will come with a sticky bottom to hold it down. i have had luck with both the gaskets and the rtv only. its never been that big of a deal.

 

I just put on a performer intake from Edelbrock and they tell you not to use the gaskets front and rear but use 1/4" bead of high temp RTV

 

I dimple the front & rear sealing surface of the block & intake with a small center punch and use RTV. Gives the RTV something to grip. Seals up tight.
Eddie