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View Full Version : Intake Manifold Gasket - What Gives??



propless
05-27-2002, 02:33 PM
Out boating this afternoon and started hearing what appeared to be an exhaust gasket giving way (no major deal, but a pain none the less). Upon looking further, it is the exhaust manifold gasket?
I'm no rocket scientist, but in all my years of boating, never have I lost an exhaust manifold gasket and I'm at a lost at what causes the intake manifold gasket to fail.
Three questions:
1. Is this a major issue and should I have a pro replace this and look deeper into the failure?
2. Or is this not that uncommon, and should I be able to replace this? Any torque requirements or what outs that I should avoid?
3. If I mark the distributor before pulling it out, should I not be able to drop it back in without having to reset everything?
Boat was running great, no issues to report. It is an Indmar 454, Edelbrock aluminum manifold w/850 Holley - nothing very fancy.
As always - thanks for the help and comments.

cncer691
05-27-2002, 02:49 PM
I'm lost, did you lose your intake, or exhaust gasket. I've never had an exhaust seal, so I wouldn't worry about that. The intake is also a piece of cake. Just mark your dist. setting before you take it off. I believe the torque setting for an aluminum intake is 25 foot pounds. Don't take my word for that, though.

propless
05-27-2002, 03:27 PM
Sorry about that, I tried to indicate that it is my intake manifold gasket that has blown.

Banshee
05-27-2002, 05:17 PM
Hey Propless, to elaborate a little on what cncer691 said, mark the location of the distributor housing to the intake manifold. But also make sure that you mark the location of the distributor rotor relative to the distributor housing. Note that the rotor will rotate a little due to the helix on the gear as you lift the distributor out of the manifold (it will want to rotate the opposite direction when you put it back in). Then be sure to check your timing when your all done. If you’re careful marking it, timing will be very close but best to check it anyway.

propless
05-27-2002, 05:24 PM
Banshee -
Thanks. Blown intake manifold gasket is not common (not to me at least), should I be looking for something deeper or is it really no big deal? And is the torque rating of 25lbs for aluminum manifolds correct?
Thanks Again.

propless
05-27-2002, 07:07 PM
I know it's late, but there must be few of you still on line with a thought on my intake manifold problem.
By the way. And most importantly, Happy Memorial Day folks - I'm a Vietnam Vet and very proud to be an American. Think about it for a simple minute. Boating as an example, we wouldn't have this discussion thread, nor Hot Boat Forum's link - Thank you Hot Boat! And may each of you remember and enjoy, a price was paid for our joy of "jet boating", and our life as American's. Crank it Up!!

WetNwild
05-27-2002, 08:19 PM
As far as the manifold gasket goes, I've seen severial blown intake gaskets on cars. Remember it was made and put togeather by humans and we are not perfect. The bolts could have loosened up, or the gasket could have a flaw in it. Has the engine back fired, this might have caused to much pressure in the manifold causing the gasket to give. Is the engine running at a norm. temp. When you take the old one off examin it for clues. Any way I would replace the gasket and keep an eye on it, 9 out of 10 chances its nouthing serious.

Banshee
05-28-2002, 05:43 PM
As far a torque goes, I dug out my directions for my Weiand intake. Don't ask me why I save this stuff. And it says to torque to 30 ft. lbs. But the instructions also say to torque all bolts to 15 first before going up to 30. I don't think 5 ft lbs one way or the other will make much difference. Also use the correct torque sequence. That I believe is important. You can find that from a big block Chevy book. Or, if your really stuck, email me directly and I'll reply back with a scan of my Weiand instructions. Also it's a good practice to retorque the bolts after your first outing. Good luck!!