1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Intake manifold gasket and "O" rings

Old Mar 10, 2006 | 05:59 PM
  #1  
jfachner72's Avatar
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"1ST GENS" THE REAL RX-7!
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From: long island
Intake manifold gasket and "O" rings

Well after a few weeks of my shop being too full to get me a lift for the day I finally got to do my gaskets and "O" rings on wed.

Firstly i must say that everything I have ever read about the nuts on the carb are true (what a bitch).

To all of you that have mentioned little pools of coolant under your carb on the manifold this fixed it.

My old "O" rings came out like jelly all soft and bloated.

While i had the manifold off I decided to play with the shutter valve. I disconnected it when i removed the nest but it was still there.

I took off the diaphram and drilled out the screws for the butterfly. With the butterfly removed the shaft slid right out.

Great but it did leave a hole in my intake. I uesd a vaccum plug of the approprate size and put it in backwards with a little black sealant.Then i took a short screw and a washer and screwed into the plug from the outside, securing that it could never get sucked into the manifold.

Now to the Diaphram.

There are 3 holes in the side of the manifold when you remove the valve. Two of them are just screw holes and the one in the middle is the vac hole.

I took the valve and cut off the end so i had just the part that attaches to the manifold. Fill the passage way with some black sealant and reinstall the piece upside down (just looks better cause the sealant faces down ).

The "O" rings didnt seam to fit right (a hair too big) getting them to stay on while i installed the gasket was a little tricky.

Once it was all put back together I must say that I think the car runs better. The Idle is still sloppy but decel is smoother and I dont have any more green puddles....

Spend the extra money and invest in the Mazda Parts....

"O" ring part number 8527-13-113, dealer net $2.96 (you need 2 of them)
Gasket part number 1881-13-111B, dealer net $4.20

Next..........

Jay
1984 FB
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Old Mar 10, 2006 | 09:05 PM
  #2  
inuissus_cendi's Avatar
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From: Minneapolis, MN
EXACTLY what I'm in the process of doing right now. I JB-welded those holes left from the shutter valve though. It's setting right now.

Now for my question... is it just mine or is the old gasket a bitch to get off? I'm sprayin gasket remover and scraping with a razor blade like mad, and I still got a ton left. Any advice or special tools?

Oh yeah and the nuts on the carb problem is made easier with a flex-head ratcheting wrench. I bought one just for that purpose. Its not perfect but it sure as hell helps alot.
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Old Mar 11, 2006 | 01:38 AM
  #3  
flight_of_pain's Avatar
its supposed to do that
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From: PNW
in all of my motors i have replaced the o rings by inserting 12x20mm freeze plugs in the rotor housing to mani coolant ports, unless you live in an area wher the temp is around 0-32 degrees all the time they really dont do anything anyway.


isaac
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Old Mar 11, 2006 | 01:54 AM
  #4  
blwfly's Avatar
kiwi from downunder..
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From: springfield,oregon
use a chissel to get it off may be eayser than a razor blade
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Old Mar 11, 2006 | 04:41 AM
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inuissus_cendi's Avatar
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From: Minneapolis, MN
I already got it off, it took me over two hours and enough gasket remover to make sure I get cancer later in life. So basically the idea is that coolant heats the intake manifold to make it the same temperature as the rest of the engine? What'd you do about the coolant line coming off the manifold then?
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Old Mar 11, 2006 | 05:41 AM
  #6  
jfachner72's Avatar
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I am not sure about pluging the lines.

Coolant goes in one way and out another which means If you prevent that you might prevent coolant from getting to the rear rptor housing....

Jay
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Old Mar 11, 2006 | 06:44 AM
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IanS's Avatar
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Coolant flows through the housings whether the intake has a passage or not. I am pretty sure that all aftermarket intake manifolds do not have the coolant passage (RB holley for example).
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Old Mar 11, 2006 | 07:14 AM
  #8  
jay-faircloith's Avatar
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From: omaha ne
watch out for this

I just did the intake gasket on my 1979 rx7 yeah those carb nuts are a bitch I droped one thought it hit the ground. no it went down the intake after getting every thing off i used a diegrinder to removed the gasket it took like 10 secs but alot of good it did me because with everything back together i fired her off to discover were my other carb nut went though my motor and out the ehaust that made one hell of a noise im waiting on my new rotor and housing to come in the mail got the motor torn down now.man that turned out to be a expesive intake gasket
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Old Mar 11, 2006 | 07:54 PM
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nick1's Avatar
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From: Kitchener, Ont. Canada
just ordered the gasket and o rings.

today i added some 2 stroke to the gas and ran the fuel pump for a few minutes to circulate the mix before attempting to start the car, and fuel started dripping on the ground. i looked closer and noticed one of the primary jets was dripping oil into the carb, and the fuel was leaking past my intake gasket, onto the engine block, and then onto the floor. now i know my intake gasket is fucked, since i used the old one when i installed this intake/carb, and i didn't even put any o rings on it cuz i didn't know there was supposed to be any there. i figured that out right away, when i filled up the rad with water and it leaked out past the gasket and onto the block, just like hwat's happening with the fuel

but anyways on tuesday i'll have the new gasket/o rings, and i'll finally be able to run the motor for more than 10 seconds and see how well she goes (unknown condition motor i just threw in cuz it was local). i should mention it has ran a few times, but onlyfor 10 seconds, i had to shut down due to oil leakage, and the fumes smoking my neighbours out of their places. lol
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