On my '80 race car ('85 12A engine) I open up the oil filler cap after the sucker has been running for a few minutes, and pressure lets out after I loosen it. I look on the cap and there's a slight amount of white foam-like stuff on it. I'm GUESSING this is coolant boiling? Or water maybe?

If so, what could be the problem?

 

You need to vent that cranckcase pressure. The foam is the moisture in the air condensing then mixing with the slight residue of oil on the oil filer neck/cap.

 

sounds like you need some new seals...

 

I agree with nimrod - do you have a line going from the base of the oil filler neck to the air cleaner? if not, run one. If you've removed your rat's nest (which I'm assuming so), then you'll have removed the line that vents the crankcase vapours, and you'll need to add one to get rid of the condensation. I had the same problem you described, so I tried just running a line to the side of the air filter canister, and it fixed the problem right away.


Jeff

 

Nearly impossible to get coolant in the oil... it's condensation, not coolant.

 

Hey is that a Model Rotary on your Altavar used for model RC airplanes?

 

yes it is

 

Yeah, that would be a good trick. If you seen a rotary apart you'd see how hard it would be to get oil in the coolant. Maybe coolant in the combustion chamber but definaely not oil in the coolant

 

Dumb question on this tpoic - does a Mazda type rotary use a PCV? I know there's no crank case per se, but what do they do to allow ventalation and combustion of oil fumes, other than that allowed into the combustion chamber to lube the seals?

 

They have a setup that incorporates the PCV with the carburetor bowl vents and the charcoal canister. It typically doesn't not work worth a damn.

 

and on EGI models?

 

Dunno. Something similar.

 

hehehe candid answer

 

In my experience, putting a small breather filter on the oil filler works better than running it to the air filter.

 

well, yeah However if your car no longer has emissions equipment then it's trivial to rig up something that not only works, but works better than factory.

find a big vacuum nipple on the intake manifold that sees vacuum all the time. on '81-85 manifolds there is a perfect one that is above the #2 rotor. run a hose from that to the threaded end (it's a tight squeeze but it will go over) of a Mitsubishi PCV valve (for a random vehicle, get one for, say, a '92 Dodge Caravan with the 3.0l V6), then run a hose from the other end of the PCV valve to the nipple on the OIL FILLER TUBE. Then, run a hose from the nipple on the CENTER HOUSING to the filtered side of the air cleaner assembly. It is important that it's the oil filler tube that sees the vacuum from the PCV valve because it's the one that doesn't have oil splashing up against it.

That's how i did it to my '83 12A. I'm sure that a GSL-SE would be similar, the only difference being, of course, finding an approprate nipple to hook to the PCV valve, and then routing the breather side to the throttle body duct.

 

I must be lazy. I usually just run a few inches of vacuum line off of the oil filler tube pointing downwards

 

So, to summarize,

An Oil Breather on the filler neck would be the best and simplest solution?

 

Yeah.

They sell breathers pretty cheap at Autozone with the APC ****. Just wear some sunglasses when you go, so no one recognizes you

 

Well actually its almost the same thing, its got a ventitatlion valve, its a black circular valve by the oil filter/cooler(?) etc.. When under vacuum (engine running) it allows the intake manifold to suck the crap outta the motor and then burn it via this valve. When the engine is off (no vacuum) it allows the charcoal canister to store this crap and when it starts it pulls the stuff outta the canister and burns it...

 

thanks

 

nice

 

What is this "crap" its burning? Is it help the engine to burn it, or did mazda just make the engine burn it for fun?

If it dosent help to burn the crap, then why not just use a breather thing? (other than saving yourself the embarassment of buying the rice...)

 

just to let you guys know. its not good to read a thread from the bottom up. i dont know why i did but it didnt make any sense.

 

haha, I just noticed this thread is really old...

and of course it didnt make any sence to read the thread from bottom to top, do you read books backwards?