How do I fix my persistent leaky intake?

Venom351R · Apr 18, 2010

I have a 351W and ever since the TFSR Intake has been on it has leaked. I thought I figured out and fixed last summer but it still leaks. I have heard of issues with the lower intake and the block before and just want to know what you guys have done to fix the issue or have heard what others have done. Its leaking where the very back of the intake meets the block. A friend and I took it off before and scuffed up the block and the intake so the RVT would have a better surface to grip to (b/c we figured the CNC machine work on the lower intake was so smooth that the oil was being pushed right through) But now I can put my hand at the back of the intake and feel where the RVT bead line is and this is what it looks like and on the floor. Any advise would be appreciated. Id really like to get it so it does not leak anymore.

final5-0 · Apr 18, 2010

Allow me to share a different method with you

I know is not used by the masses

never the less

I've used it since the late 60's and I've never had a leak such as you
are dealing with at this time

Shock of all Shocks

I DO use the end cork gaskets

I use 3M weather stripping adhesive to glue the cork gaskets to the block

After they are nice and dry, I screw a section of all thread on each corner
of the heads

That ensures the intake will be lowered straight and not allow the
gaskets to shift or be knocked out of place

When I cinch down the intake I wanna do it in about three steps
and I want each step to be done evenly so you follow the torque
sequence you find in the books which means the clamping force
is done very precisely

I do not use a torque wrench
but
I'm such an old fart

I have a pretty good feel for how tight things are

I start the first sequence and shoot for about 5 or 6 lbs

To get even tightness on all bolts you are gonna have to run all the
bolts about 3 or 4 times :Word:

Next I run em down to about 10 lbs or so using the same method

Now this last step is where you gotta use a bit of common sense

You read in the books about the amount of torque you should use

however

This is for an OEM application

If you got Aluminum heads which have softer material than OEM iron
heads ... then ... I back off that value a bit

I usually use a final value that I would say is in the range of 16-18 lbs
when running Aluminum heads

I can not stress two things that I believe to be a must do kinda thing

1 Run the bolts as many times needed until you get an even amount
of tightness on all bolts

2 After two heat cycles ...........
Run A L L the bolts again until they all have the same tightness

YOU WILL FIND SEVERAL LOOSE BOLTS AFTER THOSE HEAT CYCLES :Word:

Hey ... It has ALWAYS worked for me with no issues what so ever

Grady

Tanus · Apr 18, 2010

I do mine exactly like he said, but with red rtv, which i let setup for @ 15min before dropping on the intake

Im with you on the torque wrench thing, I know some people who are torque wrench nazi's, haha

revhead347 · Apr 18, 2010

I'm with Grady on this one, kind of. Do not use a torque wrench. Even the factory torque specs can cause the intake to push the heads out, and blow the head gaskets. I always find the original style rubber gaskets that go in the front and back. I've never had one leak yet if I used the original rubber pieces.

Kurt

Venom351R · Apr 18, 2010

thanks I'll take that stuff into consideration when I get it back to my friends shop to try and fix this yet again.

toyman · Apr 18, 2010

As a added precaution add extra RTV in all four corners.

Black95GTS · Apr 19, 2010

I recommend that you do you use a torque wrench, and use the factory specs and sequence, but I'll agree with Grady in that you need to check the bolts after a few heat cycles.

This questions is similar to asking how to adjust valves, you ask 20 car guys, you'll get 20 different answers.

Adam

95Vert383AOD · Apr 19, 2010

Yeap get a set ARP intake studs. (i think $75 and reusable)

I also Use Black gasket maker on both sides of the front and rear cork gaskets and plenty in the corners. Although I know alot of instructions even from Trickflow tell you not to use the gaskets and instead a thick bead of Sealant.

When i test fit mine the gap was way too large for me to feel comfortable just using sealant and no gasket. Never an issue for me this way!!!

And yeah always use a Torque wrench!!! An extra 15 min. could cost you a few hours or ripping apart and reassembly. The sequence wedges the intake perfectly between the heads. I don't trust hand accuracy for this.

Chris

Bosko5.0 · Apr 19, 2010

Cork gasket

Ive done two intakes with no leaks.
I rtv'd the end gaskets on both sides used 4 bolts with no head to line everything up like grady suggested. But I torqued the intake the bolts in sequence. make sure to rtv the bolts that go throught the water jacket.

revhead347 · Apr 19, 2010

Basically everyone does it differently, so you're not going to get a good answer. Just to clarify, all intake bolts are reusable. Only Torque to Yield head bolts are not reusable. There are no intake bolts that go into the water jacket.

As far as the gaskets go, it's all hit or miss, all kinds of different methods work. The one thing I can guarantee you is that torquing your intake down to the factory torque specs can lead to head gasket failure. It take a lot less time and money to replace an intake gasket, then it does a head gasket.

Kurt

RIO5.0 · Apr 19, 2010

Like Kurt mentioned...everyones got a method...now let me tell you mine...
I only use the Blue end seals in the Fel-Pro MS 93334 set. I use acetone or the like to clean both surfaces for teh win as you say !!!! and 4 studs for alignment... I wouldn't feel comfortable with an 1/8" gap and just RTV....just my preference.

You get the dizzy o-ring and the IAC gasket in this kit to boot....

revhead347 · Apr 19, 2010

I do it the exact same way as RIO5.0.

Kurt

Venom351R · Apr 19, 2010

Thanks Andy, Kurt, Grady, chris and everyone else. Seems like there are lots of methods of doing it but one thing I am going to have to do is use gaskets as andy mentioned b/c its just to big of a gap for the RVT to seal it all on its own. Im going to get that gasket set and have the intake bolts tightened properly and I'll have them rechecked after the intake has gone through a few heat cycles. Hopefully this fix's the issues. Between my intake and my radiator my poor cobra is just leaking everywhere lol

Zero Signal · Apr 20, 2010

Just for the hell of it I'll be redundant. I also scuff the surface a bit and just install mine with studs. I do torque it though. When I torque it, I do it in 4 or 5 passes a bit at a time. But one trick some old engine builder showed me was to just finger tighten the bolts only a little, give the RTV a day or so to set, then torque it all the way. That way you are actually compressing the RTV. The only time I've had leaks was when I was impatient and didn't bother.

How do I fix my persistent leaky intake?

Venom351R

final5-0

Mustang Master

Tanus

New Member

revhead347

Apparently my ex-husband made that mistake.

Venom351R

toyman

Black95GTS

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95Vert383AOD

Bosko5.0

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revhead347

Apparently my ex-husband made that mistake.

RIO5.0

revhead347

Apparently my ex-husband made that mistake.

Venom351R

Zero Signal

Active Member

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