Correct way to install lower intake manifold -> head gaskets

Discussion in 'Fox 5.0 Mustang Tech' started by JasinC19, Feb 19, 2012.

  1. I've read a few different opinions.

    I have brand new heads/intake manifold. The gaskets between the head and intake manifold (intake ports): do I need any RTV on them? They are Fel-Pro gaskets.

    I was going to just put some high tack gasket sealer on each side to hold them in place, put a bead of black permatex on the block rails and put the intake manifold down on top of everything.

  2. i put that orange permtex on the block rails and thats it
  3. You need to put some permatex around the front and rear water passages on the head BEFORE you put the intake gaskets on. Use a nice bead across the front and rear rails...tq to 20ftlbs in the proper sequence.

  4. +1...

    Im sure you guys have had varied experiences, but I always wind up running the sequence about 4 times before they're all torqued to spec

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  5. Buy some threaded rod, or cut the heads off some bolts and put them in the corner bolt holes for the lower intake, so you can guide it down evenly. Otherwise, you may end up shifting the intake gaskets around and not even realize it.
    Doomstein likes this.
  6. Hmmmm ... I'm going to have to think about that one
  7. I've done the long 1/2" threaded rod trick before. The lower intake comes right down and doesn't move forward or back at all. For first timers its a pretty good trick to ensure it doesn't shift. Like Rick said torque with the proper sequence.
  8. :scratch:
  9. ive never had the gaskets shift on me. my head gaskets stuck out and the intake gaskets hung on them
  10. Don't forget to use a steel core gasket. All paper gaskets are K-rap.
  11. Hmm.. yeah I read that, but didn't know how true it was. I used what came with the top end kit. Fel-Pro 1250 I believe. Someone recommended 1250s (steel core).

    If the paper only ones are that bad, I guess it would be worth it to take it back off and redo it. Does this go for the upper->lower intake manifold gasket as well?

    I wonder if Advance/Autozone/NAPA sells the steel core ones.
    EDIT: Actually I am having a hard time finding anyone that sells the steel core ones. Can someone point me in the direction of the "best" set to use?

  12. While some members here have had good results with the Fel Pro 1250, I like a few others have not. The first set installed by a professional mechanic who builds his own race motors, and the second set by myself. And both sets litteraly melted causing a huge vaccume and coolant leak. Now I am on a third set of Fel Pros but this time I went with their MS93334 steel core intake gasket for 5.0 and have had no problem. 007 (3).JPG
  13. Geez.. yeah you just convinced me. Not a big deal to take the intake back off while it's on the stand. I can recheck my rails to see if I had a good RTV seal.

    Another thing: I torqued the manifold properly in 4 steps. A few minutes later I rechecked the torque and had to retorque the sequence two more times before the wrench stopped moving before clicking. Is this because of the gasket setting in and compressing? Will the steel core gaskets help with this or is this normal?

    Will I have to recheck the torque after the engine goes through some heat cycles?
  14. Yes

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  15. ^^
  16. sounds like a neat trick, will be doing the same in a couple weeks.
  17. I got the MS93334 intake manifold gaskets. Fel-Pro says they must be installed without any sealer. Trick flow says to outline water jackets with RTV black.

    What should I do?
  18. you can leave the RTV off but if the intake has any corrossion or pitting you might wanna do as Rick 91gt described above

    I have always used RTV even on new intakes and I have never had one leak or fail on me (stock, 1250, 1262 etc etc)
  19. Thanks... I'm sure this stuff been asked before, I just get a little gunshy sometimes
  20. By the way, I put sealer around the water jackets on the 1250's and did not let it sit overnight.

    I just took the manifold off a day later and the black had fused the gaskets to the block completely and utterly. I spent like 45 minutes cleaning everything up. The fat beads on the rails were still a tiny bit gooey in the center though.

    Pics to follow...