Hi everyone, a bad news for me.
I recently noticed oil in the raditor, and the overflow tank. It doesn't seem to be much, but it is obvious enough to identifiy those floating objects are motor oil. I am not losing any large amount of coolant, maybe less than or about a quart per tankful of fuel. I also noticed an external coolant leak around the end of the header area. It is only a couple of drops per night sitting. Does that mean I have a water jacket blown externally?

The car doesn't overheat and runs extremely smooth for its condition and age. It is a 79 RX7 with the original 12A w/120k on the clock.

It smokes only when I first start it after it sits for 1 week or so. And no smoke on start up if I drive it daily, but also it always smokes (light blue) when I drive it hard at normal operating temp. Will the light blue smoke caused by the MMO as pre mix that I put in fuel?

I am going to plan on rebuild or replace the engine in the near future. I am looking for the easiest and most cost effective method. And have no intension to convert to electric fuel injection. What do you guys suggest? Approximately how much longer the engine is going to last?

Sorry for the long post. Any input will be greatly appreciated.
Nelson

 

When the engines cold, pull the rad cap then start it. See if you have bubbles in the rad, indicating bad water seals. If so, you could use some of that copper block seal they sell for boingers to get you by for now.

 

Yeah, I will check on that. But it depends on where the leak on the water seal is blown too right? If it is not blown thru the housing then probably there will not be any bubble coming out of the radiator.

 

I'm right there with you. The $100 SE engine that I installed has been overheated before... it has symptoms like oil in the coolant, I turn on the heater and hear bubbles gurgling behind the dash, gas pressure buildup in the cooling system (I have the Stant L-ver vent radiator cap now to relieve this after a day of driving) and having to add water to the radiator weekly. The engine idles great and runs well, nice and cool...but it's simply a timebomb now and who knows how long it will last.
Carl, wouldnt that copper block seal also plug up the radiator as well?

 

Radiators the same as a boinger right? Scientifically I dunno, but it works to keep a motor alive thats bleeding coolant.

 

Well, your car doesn't sound that bad off. I would just keep driving it till it gets worse. I've never heard of an external coolant leak on a rotary (anyone? Unless maybe the engine froze) I would check your coolant hoses before you right off your engine.

You said you see oil in your coolant, but is there coolant in your oil? The stuff you said looks like oil, could just be goo in your coolant. If the car's coolant system is not maintained (Flush and new coolant every 2 years at least) all sorts of nasty looking things can turn up in your coolant.

I would do a bubble check with the cap off like rx7carl said. Ive never heard of a bad coolant seal that didn't blow bubbles.

If it is the coolant seals, Blok weld can buy you some time, but, in my experience it doesn't work at all unless you do this:

https://www.rx7club.com/forum/showth...light=yaw+weld

I used this method on an old beater of mine and the car's been going strong for 2 years+ now (knock on wood)

Only draw back is it tends to blow out your water pump a few weeks later. (heard this from others as well as myself)

 

The funny thing is that, the appearance of oil on the dipstick seems to be extremely normal. I am going to change the oil in the next couple of day. I will keep you guys posted on how it looks.

Nelson

 

Oh, and I heard from my friend who have built many rotary engines before that oil usually don't get in the radiator.

Is there a way that I can confirm my engine is still at a good condition?

It fires right up, no matter warm or cold.

Nelson

 

Bring to a shop that specializes in Rotaries in your area. If your are near Racing Beats in Anaheim, got talk to them!

 

I will probably take it to a Rotary Specialist around here.
Oh, I just change the oil. It looks normal, nothing unusual.

Someone pls convince me that my motor is still fine.

 

pressurize the cooling system? if the pressure drops off, it means either you have a leaking hose somewhere, or you have an internal coolant leak. also, if you pressurize it, it'll force the coolant out of where it's leaking, so you can see it, without running the engine and getting burned. Just use a normal radiator pressure tester.

it almost sounds like the o-rings in your intake manifold are shot, which would explain the coolant dripping down around your exhaust...

 

Thanks, Good point on the pressure test on the cooling system. I totally forgot about that.

O-ring in the intake manifold? So coolant will be traveling thru the intake manifold to help warm up the carb and reduce emission?

I do noticed some "WetSpot" or a puddle of fluid like object sitting underneath the carb. on the top of engine.

If the o-rings are shot, is this a serious problem? How difficult is it to fix that? Cost?

Thanks

 

O rings arent a bad job. Inatke needs to come off (first the coolant must be drained). Replace and bolt it back on. You dont even need to remove the carb.

 

So I will need the intake manifold gasket, and the oil rings right? Anything else? Where can I get those o-rings at? Any online Mazda parts website you guys recommend?

Thanks

 

Sorry to stray from the train of thought, but I would recommend getting a chemical test done. Any mechanic shop can do it, doesn't need to be a rotary shop. That will detect the presence of exhaust gases in the coolant.
We now return you to your regularly scheduled o-ring discussion. Good luck! -WG

 

Another very good point. But that'll cost money. Might as well try a pressure test first.. that is, if you have a pressure tester...

 

All availible from Mazdatrix (www.mazdartix.com) or Victoria british. Nope nothing else I can think of.

 

So I just drove it few minutes ago. It fires right up w/some normal looking smoke. I let it warm up, and smoke is cleared. I drove it and took it easy for the first 5 -10 minutes or so. Then I took her to higher rpm in 2nd and 3rd gear ~4.5K to 6k. She was freaking smoking like crazy. It smoked only when I use partial throttle or completely let go of the throttle where the engine generate higher vacuum.

I am presuming my oil rings are shot. Leaky oil ring will only get worse when the vacuum is high. Because the suction that created by the vacuum.

However, she is still running strong. Pls convince me this can just be my Oil Meter Pump is stuck. Or the carb is running too rich, or causes by MMO that I use as premix.

Nelson

 

the MMO will cause it to puke white smoke like your burning ATF.Maybe your using too much as you permix. What ratio are you using? What color is the smoke?

 

You got it. White smoke..... I don't even measure exactly how much I put in the tank. I put no more than 4 oz per fill up. I usually fill about 8 to 9 gallion of fuel. Maybe I am using too much MMO.

If it is caused by MMO then it should only smoke when I step on it not when I let go of the throttle at high rpm right?

 

I think thats wayyyyy too much. I forget what the ratio is, but someone here should know.

It should smoke worse when you get on it. But itll prolly smoke a little all the time.

 

Does any know what is the proper MMO as premix to fuel ratio?

I still have a functioning OMP.
Thanks.

 

If your OMP is working, then dont premix.