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intake manifold gaskets take three

K

Kooter

Member
I am on try number three with installing my intake. The first time I had small leak in the front right corner. It would drip about 10 drops a minute at idle. So I pulled the intake back off and put new gaskets and resealed everything. This time I have no leaks but have a few vacuum leaks around the back of the manifold making the car a bear to start. This is how I am installing the manifold. http://www.mustangsteve.com/intake.html All mating surfaces are cleaned with red scotch brite and alcohol prior to sealing. Am I just having crappy luck or am I doing something wrong?
 
It's not about luck...

Try Installing a couple long threaded studs on either side to help you line it up as you lay it down. I'd bet you are pushing it forward or back as you try to align things causing your problems.
 
That, combined with improper torque sequence and incorrect gasket type can cause lots of problems.

Do you have an aluminum intake manifold? If so, you need to use the Fel Pro Performance # 1250 gasket, as the standard steel shim gasket is designed for cast iron manifolds with 65 ft-lbs of torque. Aluminum manifolds only get 18-25 ft-lbs and respond better to softer gaskets. There's also a steel-core version of the 1250 gasket, although I don't recall the number at the moment.

Do NOT coat the intake ports on the gasket with RTV. Put a thin smear of ultra black around the coolant ports, and a good size bead on the front and rear of the block, but that's it. The intake ports will seal themselves just fine.
 
I was using felpro gaskets not sure of the part number. Last night I ordered a set of trick flow gaskets (http://www.summitracing.com/parts/TFS-51400921/). I do have a edelbrock intake and trick flow heads. I torqued the bolts to 20' lbs. I am using guide studs. That's why I'm frustrated with this dam thing. I am hoping it is only the gaskets and not something bigger. If the ones I bought last night dont work then I will go with the ones Starfury recommended.
 
The Fel Pro Performance versions are nice because the ports all have a silicone bead around them to improve sealing in low-torque situations. They can be ordered from just about any chain parts store. I make sure they're always stocked at mine...
 
"Starfury" said:
. . .the standard steel shim gasket is designed for cast iron manifolds with 65 ft-lbs of torque.
Click to expand...

That much torque on an intake bolt will surely pull those 5/16" threads right out of the heads. Stock spec is 26 ft-lbs, IIRC.

Robert
 
Hmm, could've swore my factory manual said something much higher than that, although it's been a while since I've had a cast iron intake. I'll have to go check again.

Regardless, the 1250 gasket seals much better with aluminum intakes.
 
Are you sure its a 1250 and not the 1262? My memory is a little foggy, but i thought the ports were a little larger on the 1262 and better suited for aluminum pieces.
 
The 1262 may be the steel-core version. The ports on the 1250's match the ports on my Twisted Wedge heads pretty well.
 
The 1250's are the correct sized gasket for Trick Flow 170's. The 1262's are better suited for a TFS 185 or AFR 205. Felpro 1250-s3 is the steel cored version; I used these with my Canfield heads as the water ports matched up much better then the standard 1250's.

I would first check the cylinder head and intake manifold mating surfaces with a straight edge to see if they are true and flat. If everything checks out then you can install the intake manifold. When I install head gaskets I like to start with long studs installed on all four corners. This helps with gasket alignment as well as helping guide the intake manifold down in the proper orientation. When installing the gaskets themselves I like to spray the cylinder head side of the gasket with gasket adhesive. This keeps it from moving around during the install and makes a good seal between the gasket and the head. With the gaskets on, install the intake manifold dry to see how much RTV you are going to need on the rails for 100% contact and minimal excess seeping from the gap. Take the intake off. Put the required sized bead of black RTV on the rails and slightly up onto the intake gasket. Since your Trickflow gaskets do not have a "Printoseal" around the water jackets I would put a thin bead of black RTV around the water ports. Install the intake manifold. Install the intake manifold bolts or studs. Slightly snug the bolts in the correct pattern, then begin torquing the intake down in the correct pattern in 2 or 3 different ft/lbs intervals.
 
Installed the new 1250 gaskets on Sunday. I have not tried to fire the car up yet. I will do it this coming weekend. Of course Murphy's law took over and my torque wrench rolled off the car and onto the floor. I reset it and started torqing again. Of course it was messed up and I stripped a bolt. So the next time I pull the manifold I will be installing a helicoil. I hate that about aluminum heads.
 
Third time was a charm. No more vac. leaks. But unfortunately I have to pull the dam thing back off again. I took the car to a mechanic since I couldn't get the dang thing to run right. He discovered I had two lobes on my cam that were toast. I swear this car hates me.
 
Ouch, been there, done that. Learned a lot about zinc-rich oil before firing up the motor with the new cam.
 
"Kooter" said:
Third time was a charm. No more vac. leaks. But unfortunately I have to pull the dam thing back off again. I took the car to a mechanic since I couldn't get the dang thing to run right. He discovered I had two lobes on my cam that were toast. I swear this car hates me.
Click to expand...

Is this a new cam or something thats been in the car for a while?
 
I'd call it newish. I installed it in 2010 but have driven the car less then 100 miles since install. I wanted to convert to a roller cam at that time but couldn't afford the upgrade. Now I will be doing the upgrade.
 
Sorry to hear about the cam.. bummer. I just went through the intake manifold nightmare too. I ended up using the Felpro 1250-s3 instead of the 1250. I put a dab of black sealant on the coolant ports based on the droves of feedback that I read on the various boards.

It seemed to work, I have no leak.

Good luck,
-Shannon
 
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