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fuel injection intake gaskets

Posted: Sun Jun 10, 2012 1:26 am
by mentalQtip
Confusion here. '77 two liter engine. Replacing the intake gaskets to the cylinders and the gaskets I was given at the parts store are close to a quarter inch in thickness as compared to what came off being not much more than paper thick. Was I given the wrong parts? I noticed that with the new ones the air intake manifold tubes are held further from the intake manifold distributor. I'm a little worried about the increased risk of air leaks. Thoughts?

Thanks

Joseph

Re: fuel injection intake gaskets

Posted: Sun Jun 10, 2012 3:02 am
by Bleyseng
They should be the phenolic 1/4" gaskets to insulate the FI intake manifold (and injectors) from the heads heat. I use a slight bit of sealant when installing them to prevent leaks.

Re: fuel injection intake gaskets

Posted: Sun Jun 10, 2012 6:49 am
by Amskeptic
mentalQtip wrote:Confusion here. '77 two liter engine. Replacing the intake gaskets to the cylinders and the gaskets I was given at the parts store are close to a quarter inch in thickness as compared to what came off being not much more than paper thick. Was I given the wrong parts? I noticed that with the new ones the air intake manifold tubes are held further from the intake manifold distributor. I'm a little worried about the increased risk of air leaks. Thoughts?

Thanks

Joseph
Are your old phenolic spacers stuck to the intake tubes or the heads? Clean everything shiny smooth. The new spacers should have the paper gaskets already bonded to it. I use light coating of grease as sealant.
You should have:
head/ paper gasket/ phenolic spacer/ paper gasket/ intake flange (torque to 14 ft/lbs)

Re: fuel injection intake gaskets

Posted: Sun Jun 10, 2012 8:05 am
by mentalQtip
My engine only had the paper gaskets and they were partly stuck to the heads. What is a better way to clean the sealing surface? I've been very carefully scraping with a screwdriver. Bet thats not the best way to go about it. I'd be kinda worried about sanding the surfaces and somehow getting grit in the head intake.

Thanks

Joseph

Re: fuel injection intake gaskets

Posted: Sun Jun 10, 2012 1:24 pm
by vdubyah73
razor blade. either type works. i prefer the thin scraper type over the thicker box cutter type. the thinner scraper type is less likely to gouge your soft aluminum, it has a bit of flexiblity. don't freak out if you scratch or even gouge the sealing surface a little. once it is clean you use the razor to litterally shave any any high spots alongside of scratch. stick a bit of paper towel, rag or, my favorite, a vinyl food service glove in the port/s to keep gasket bits and shtuff out of your engine.
i won't hesitate to use a flat mill bastard file on intake and exhaust manifold flanges. get ahold of a file that is long and wide enough to remain in contact with both ports on a type one manifold, when drawing back and forth.
in case you didn't know, you draw a mill file at an angle, you adjust the bite by adjusting the angle. you must keep it flat, best not to grip it but use your flat palms to manipulate it.
definetly use wheel bearing or chassis grease, never any sealant. i like anti-seize on both intake and exaust studs. good to re check torque after some miles.

Re: fuel injection intake gaskets

Posted: Sun Jun 10, 2012 2:01 pm
by Bleyseng
The sealant I like is Gasketcinch which is very thin but seals well. Grease? its a nice lube but will leak once its heated.

Re: fuel injection intake gaskets

Posted: Mon Jun 11, 2012 2:03 am
by vdubyah73
maybe with metal gasket but not with paper. plus, upon future dis-assembly, clean surfaces with paper towel and reuse gasket.

Re: fuel injection intake gaskets

Posted: Mon Jun 11, 2012 9:23 am
by Amskeptic
vdubyah73 wrote:maybe with metal gasket but not with paper. plus, upon future dis-assembly, clean surfaces with paper towel and reuse gasket.
I'm with Bill on this one. Paper gaskets do fine with grease. I use Permatex Aviation with the metal ones.
I like how grease lets you re-use/reassemble, and it helps keep the aluminum surfaces clean so you don't have to scrape so much next time.

Re: fuel injection intake gaskets

Posted: Mon Jun 11, 2012 7:36 pm
by SlowLane
I'm Hooked on Hylomar, myself. I use it pretty much everywhere. Total overkill for intake manifold gaskets, but it never hardens and fills up unfortunate screwdriver-blade-induced gouges just dandy. :geek:

Re: fuel injection intake gaskets

Posted: Wed Jun 13, 2012 7:14 am
by Amskeptic
SlowLane wrote:I'm Hooked on Hylomar, myself. I use it pretty much everywhere. Total overkill for intake manifold gaskets, but it never hardens and fills up unfortunate screwdriver-blade-induced gouges just dandy. :geek:
Many discussions about intake manifold gaskets and leaks and solutions . . . the most common cause for intake leaks here at the FI runners is, just like the exhaust flanges, overtightening!! No special sealants required after flatness is restored. 14 ft/lbs, that's it. Center nuts first, then outers.
BobD is at 86,380 miles with original leak-free intake gaskets, not yet disturbed.

Over-tightening promotes flange bending as the engine heats up, then the centers lose clamping.
ColinSeenItAThousandTimes

Re: fuel injection intake gaskets

Posted: Wed Jun 13, 2012 2:58 pm
by vdubyah73
in my experience, more often than not driveabilty problems turn out to be vacuum leaks. there are so many places for them to hide. a combination of hard to pin point minor leaks can amount to one major one.