bones007

My car has a miss and will not idle...rev it up and it will backfire out the exhaust did it blow a apex seal?

diabolical1

iTrader: (3)

It's an '87, right?

Have you checked:
- vacuum leaks
- timing
- ignition wires (any of them out of place)

Aside from an actual compression test, the quickest way to check for six chambers is pull the lead plugs (one at a time) and turn the engine by hand.

bones007

So pulling the plugs and turning by hand... what should I look for? will I hear the compression? or will I hear a puff of air? and how often should it occur? ... every turn of the crank? or a quarter turn? or half turn? Sorry never messed with a rotor engine before I got this one...if a apex seal is gone .... will running the car potentially do more damage to the engine?

diabolical1

iTrader: (3)

Well, you're listening for three distinct bursts of air (a whoosing sound) from each chamber. If everything is okay, they should be pretty evenly spaced, and pretty evenly powerful. Also, keep in mind, if it is an apex seal, it means you've lost at least 2 chambers - so that chamber will only have 1 pulse with a lot of space in between. Me, personally, I like listening through the exhaust ports (with all plugs in place) because the engine gets to go through the whole cycle. However, it's sometimes a pain in the *** to remove the exhaust manifold, which is why I said remove the plugs. Besides, you can get most, if not all, of the same effect from the spark plug holes. If you ever have the pleasure of de-flooding your car someday, you will see what I'm talking about. When you turn the engine by hand, you want to go through at least a three revolutions because the rotors turn at one-third the speed of the eccentric shaft. However, one trick you can do is put a finger over the hole (NOT IN THE HOLE!!!) while you turn the shaft and you will feel the pulses.

Check this out:
Technically, you can lose an apex seal and no damage will occur. However, my guess (conjecture) is that there will likely be some damage in most of the cases. At any rate, don't put the horse before the cart. If you lost a seal catastrophically, you're not likely do any more damage than what's already done. Also, the car will not drive right, if at all. Think of a 6 cylinder engine only running on 4.

bones007

Thanks for the reply... I have driven the car around the block... And it is severely underpowered... basically you have to floor it to get any acceleration out of it. But I will try as you suggested... thanks

diabolical1

iTrader: (3)

I remembered something else that I forgot to mention in all of this "apex seal"-talk, but this would require you to take the manifold off and view the apexes through the ports. Sometimes, the seals can get stuck with carbon. In cases like that you can sometimes get them free by soaking them with Seafoam or using steam with the engine running.

That said, your situation sounds grim as you describe it.

Have you had any reason, recently, to remove the CAS or mess with the timing or any of the ignition system at all?

bones007

No I did not mess with the cas I did loosen and moved it once trying to start the car, but put it back in it's original posistion, which manifold are you talking about? Intake or exhaust?

diabolical1

iTrader: (3)

you can see the apexes through the exhaust ports.

Rotary Alkymist

Buy a compression tester. They're cheap and there's no guess work.