Hey guys, I did a search on blown apex seals and found quite a bit of information. I am going to take a regular compression tester and take the schrader valve out of it and check the compression. However, I am unsure that the apex seal is blown due to the following symptoms:

The car will only do 40 MPH, floored, and a rough idle, both symptoms. However, the car starts very easily, like one spin of the starter. It will not stay running without the choke (idling). When revved up it vibrates less but is still not smooth. It takes a long time to rev it up if you floor the accelerator.

I am going to go ahead and check compression but is there anything else I should look for? Car is a well maintaned 84 from California, 148k miles. Thanks all

EDIT: I forgot to add, that if I do conclude that it is an apex seal, can I pull the engine apart and just replace the apex seals and other misc seals? I am not so concerned about having a long lasting new/rebuilt motor because I have a good 13B to put in later.. Thanks

Brian

 

I had engine probs once. I was about to order a new engine from Mazda when I located a rotary specialist. I took it to him and he fixed it. Underneath the carb is another "butterfly" valve. The pin had broken and the valve closed off the hole. Just a suggestion but my car had the same symptoms and I'm still driving it after getting it fixed 30,000kms later and it runs as well as it did before.

 

You know what, that could be the answer. An engine is going to show low compression if no air can get to the cylinder or rotor..

Thanks a ton. I'll check it out tonight.

 

NP man. Good luck. Let me know how you made out.

 

that "other" butterfly valve is the infamous "Shutter Valve" if it closes, the car won't idle right, and there will be a lack in power.... but I dunno if it would cause the car to only go 40mph floored.... I suppose if it was closed right off, the car would only be running on one rotor...

 

Hmm. Is it infamous because it often breaks?

I guess I should ask, do I take the carb off to take a look at it? I am not very familiar with these even though this is my third 7.

 

I should also say I didn't notice any unusual smoking or popping when it was running. Just an extreme lack of power.

 

What about a clogged cat? Mine did most of what you discribed when my cat disintegrated. I could floor it and only go about 35. But it was hard to start, not one of your symptoms.

 

ok now im replying to something that im just guessing at here....

but if you remove the air filter, you can feel suction from the air pump hole if its functioning properly. i THINK one of the smaller holes further back goes to the shutter valve, right?. if so, is there a way to check to see if its operating by that hole?

 

I'd definitely say the shutter valve is the culprit, but there' could be a vacuum leak somewhere too. and the Cat is a possiblilty, so check all of these, and replace your fuel filter too, while you're at it.

 

Try shifting out of 1st gear.

 

sounds just like my car when i only had 1 rotor

i think you lost a seal

 

kinda sounds like my car right now too...i think i lost a seal but im gonna check the shutter valve just to be sure before i buy a new motor

 

So whats goin on, if one of your seals is bad, is it really simpler to replace the whole motor than take it apart and fix it?

 

Simpler? Yeah, its simpler. Not much though. I just took apart my engine for the first time and I'd have to say that other then getting the flywheel nut off (had to use a friends impact gun after I BROKE my 1/2 ratchet), its been pretty straightforward. Stupid apex seal took out my rotor though.

Forcus: Does your engine sound the same as it did before these symptoms occured (assuming you know)? Mine sounded much different and worse after I blew a seal. Go figure, right? I still had a good bit of power after it went, but most of my seal stayed in the rotor.

Conway

 

I bought it this way. I figured since I have a very rusty 85 GSL-SE with a supposedly good engine, and a very nice 83 with a bad engine.. well you can do the math

Probably what I will do though is confirm that the GSL-SE motor is good, then take the 12A out and tear it down to see if the housing is chewed up. If so, and a replacement is not resonably priced, I'll convert the works over to a fuel injected 13B

 

needs a tune, friend had the same prob, was detonating becaseu the dizzy had moved very slightly, and was toooo far advanced

 

I would believe that but a tuneup wouldn't fix the zero compression showing on each face of the rotor

I'm physically checking out the apex seals through the exhaust ports today. I'll let every one know what I find.

 

yeah, check the compression first, that way you know wheather to keep looking, or not.

mike

 

Well I took the exhaust manifold off today and looked at a couple of the apex seals on the forward rotor. I found a tiny notch in one of them. It was about 1/3 inch long and maybe 1/16 or 1/32 deep. I would guess that would be enough to affect compression.