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-   -   O Rings and intake manifold (https://www.rx7club.com/1st-generation-specific-1979-1985-18/o-rings-intake-manifold-191168/)

TheMoonDog 05-29-03 06:26 AM

O Rings and intake manifold
 
Hi all,

I am starting to rebuild an engine I have here and when I removed the intake manifold there were no O rings on this manifold.

Is this normal?

I just went through installing an intake manifold on my 82 and had a bitch of a time with the O rings causing tears in my intake gasket because of the O rings. It seemed strange not to see any on this engine.

Rx7carl 05-29-03 04:41 PM

No they are supposed to have orings.

REVHED 05-29-03 04:54 PM

Unless the coolant passages on the engine have been blocked off you will need the o-rings or it will piss coolant out.

TheMoonDog 05-29-03 09:49 PM

That's what I always thought! :) May explain the green crud all over the engine huh? :p:

I figured that whoever had the engine before must have been playing with it or had no idea at all. It is obvious that they ran it like this and I have no idea how it still has compression but it does. One would figure that it would have blown the engine.

Thanks for the replies, I thought I was missing something there! :D

Suparslinc 05-29-03 10:32 PM

They could have disintegrated. I need to replace mine too, at the same time I plan to block off the ACV and shutter valve.

1st to 3rd 05-29-03 10:47 PM


They could have disintegrated.
Ah, no.
The previous dipshit must have omitted them for some upgodly reason. O-rings causing tears in the intake gasket? You mean they slipping out of place during install? If so, then just put a dab of RVT on them to hold them in place while intalling. BTW, rubber and RVT shouldn't be used together as they have different coefficients of thermal expansion, so don't glob it on there.


One would figure that it would have blown the engine.
Not exactly, unless it was overheating due to a lack of coolent. I bet internally your engine is clean enough to eat off of. Ever see a bonger after it blew a head gasket? Think of it as steam cleaning in insides of your engine.

Personally, I just block off the coolant lines to the intake. Cooler incomming air = more power. That and it makes future intake swaps a breeze.

Rx7carl 05-29-03 10:52 PM

Use 20mm freeze plugs in the rotor housings. ;) Oh and you owe me a 6pk now. :D

Suparslinc 05-29-03 10:55 PM

Exaclty why do you want to block off the coolant lines to the intake?

Rx7carl 05-29-03 11:12 PM

Less chance of a leak. Simplify,Simplify,Simplify,Simplify, Also it keeps the intake charge cooler.

Suparslinc 05-29-03 11:14 PM

That part I get. I'm confused about the intake; would blocking off the passages make the car run hotter?

Rx7carl 05-29-03 11:16 PM

No. That has nothing to do with the engine temps.

rxtasy3 05-29-03 11:27 PM


Originally posted by Suparslinc
Exaclty why do you want to block off the coolant lines to the intake?
If ur running an after market intake, the coolant doesn't run thru it anyway. So it makes it alot simpler when removing the intake at a later time without having to drain the coolant. I will be blocking mine off.

TheMoonDog 05-30-03 07:07 AM

Hmmm, after all those posts it seems like maybe buddy was on to something. 20mm freeze plugs? I am fairly green when it somes to all this so what exactly are freeze plugs. another 6 pk coming up! :p:

It sounds like not using orings may actually be possible if you put in the right stuff. If I am understanding all this correctly, it can actually help. Go figure! I'll tell you one thing for sure, it would be a hell of a lot easier to put the intake on! :D

fatboy7 05-30-03 12:22 PM

Hmmm, how do describe a feeze plug....... its basically a metal plug that you pound into the hole, its shape/pressure seals the hole, but if enough pressure on the inside is built up (ie, coolant freezing in the engine) it pops out, hopefully saving your block from cracking.

All engines have a few, ours are located in the rear housing, facing the flywheel and clutch.

fatboy7 05-30-03 12:23 PM

Basically 20mm freeze plugs are a good way to seal the coolant passages to the intake.

nipper 05-30-03 08:14 PM

frost plugs is what we call them 'way up here in Canada.

claytonjh1223 05-31-03 12:38 PM

so if i buy me the rb intake i should block the coolant lines where the o-rings are?

Pedestrian X 05-31-03 08:21 PM

yup, might aswell..

hanman 05-31-03 08:29 PM

Moondog,
Not to be rude, but are you sure that you are up to rebuiilding a rotary engine? Are you doing it by yourself or do you have help?

vipernicus42 05-31-03 11:24 PM

Hmmm... These o-rings are between the intake manifold and the engine block right?

Anyone know if there's supposed to be anything other than the plastic gasket between the intake manifold and the carb? I don't have anything other than the plastic there, and I've got a "mysterious" vacuum leak... I'm thinking of using something to gasketize between the manifold, the plastic, and the carb.

Jon


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