351 2v Weiand 7516 Intake Blowing Front And Rear Gaskets

Discussion in 'Classic Mustang Specific Tech' started by Walter Sparks, Jun 24, 2013.

  1. I purchased this car with a rear blown intake gasket. I replaced the gaskets and now my front and rear gaskets are blown out. Any idea why or how to stop it? I do not think that I am getting engine blow by.
  2. In what manner is your PCV system setup/laid out? PCV=Positive Crankcase Ventilation
  3. I never use those gaskets.they move and get squeezed out. Use thick bead of RTV instead.
  4. I was kinda thinking to use a thick bead of black RVT gasket maker. I kinda thought that seal looked like a bad idea.
  5. I will check the PCV set up today.
  6. Ok my pcv valve has a hose going to my carb. I took some pics. The other valve cover has a oil cap that just snaps in place, it comes out pretty easy and I would assume if there were excessive crank case pressure it would just pop off. I blew through the pcv valve to make sure it is not clogged. I noticed that the hose going to the carb is slightly flattened where it bends. 351 cleveland pcv 003.jpg 351 cleveland pcv 004.jpg 351 cleveland pcv 005.jpg
  7. The pics beg the question: Did the front and rear manifold gaskets blow outwards or did they move/get sucked inwards? The crankcase is, for purposes of this discussion, a sealed system and includes not only the crankcase, per se, but all areas where oil flows and returns to the pan, IE, oil pan, valve covers, galley under the intake, timing cover, etc. The job of the PCV valve and hose that is plumbed to your carb is to provide suction/vacuum to the crankcase system to relieve and evacuate pressure in the crankcase from blow by (even the freshest, tightest engine will have at least a little blow by) evaporating oil, etc. The filler cap on your driver side valve cover needs to be a filtered vent to allow clean fresh air into the crankcase to replace the air sucked out by the PCV. Picture what happens when you suck on a straw and then put your finger over the open end. If you suck hard enough the straw will collapse. The unvented cap is basically your finger over the end of the straw. All that said, I agree that properly applied beads of black RTV are a vast improvement over those damned end gaskets, however, your PCV system needs to be addressed also.
  8. they were blown outwards. I will try to find a vented oil cap.
  9. Right Stuff Gasket maker, in a tube not the can deal. Will not blow those out. My intake gasket let go at 20psi boost and I had about that in the crankcase and didnt blow the end seals out. Hell, I could hardly get the intake off. lol

    My intake was not flat btw is why the gasket didnt survive. However the ends held up fine.
  10. i never use the end gaskets , you can not keep them in or from leaking.a silicone bead will not blow out. the driver side oil cap is origonaly vented also by a hose going into the bottom of the air cleaner. the carb. also vents the crank case ,as the butterflys open creating vacume it relieves the crank pressure. rember the pistons are not only building pressure /compression
    on the way up but also to an extent on the way down as well, so atleast a vented oil cap would help. a pcv valve pulses so it is not as great a crank evacuation system on its own as it would be with a vented oil cap.
  11. OK I have been shopping new intake gaskets and I have noticed that many do not have the hole in the center for the water port, and others have some differences on the ends also. Also some do not come with the metal valley pan. Can anyone give me some guidance here with all of these differences but the gaskets say they are for the same engine.

    part numbers are

    Mr. Gasket Standard Intake Gasket Sets 214

    MS96012 Fel pro

    Fel-Pro Performance Intake Manifold Gasket Sets 1240

    in order

    gasket.jpg vally pan.JPG FEL-1240_xl.jpg
  12. if you aren't running breathers or the pcv is plugged that can blow out gaskets.
  13. PCV valve is not clogged. I will be getting a vented oil cap.
  14. Not sure about the issue for or against the valley pan. I think you will find that the center hole is not for coolant, but rather an exhaust crossover to help cold start drivability and warm up. Some engines benefit from this more than others, for example, FE engines are known to be cold blooded pigs until fully warmed up when this passage is plugged or non-existent! In warmer climates it usually is not a necessity. Many/most after market intakes do not have this crossover and even if they cast the hole, it often just goes to a short, blind, dead end. I'm not well experienced with Clevelands, but I am certainly aware that for the Windsor engines, not all intake gaskets are created equal. I'll leave it to some of the Cleveland "experts" here to recommend the best gasket set for you.
  15. Well I am in Savannah GA area so it is never really cold and mostly HOT HOT HOT. I dont think it will be a biggie to plug those holes then.
  16. The valley pan prevents oil from coking on the underside of the intake. Some people run them, some don't. They can be more of a pain to seal than not having a valley pan, from what I've heard. Some people even cut the areas that seal onto the heads off the valley pan and run a partial pan just with the ends that rest on the block. I did this. I drilled a hole to allow oil to drain if some gets around the edges and into the pan.

    The last 400 I put together I left the whole valley pan in and it sealed up fine. If you follow the directions you shouldn't have too much trouble.
  17. Thanks...I will see what happens....
  18. i usualy leave that pan out. if your intake doesn not have the heat cross over passage the bottom of the intake should not get as hot as one that goes through . if it does you can plug it off.
  19. The new gasket does not have the exhaust crossover hole. So I will just leave the pan out or cut the ends off where the seals keep blowing out.
  20. is it blowing any oil at the timing cover seal or rear main? just wondering.