No Compression Questions
 

Hi, I need some help.
We have this car here at our shop, It's a 89 RX7 convert. I got two different stories from the customer about what happened with it. First he said the car has been sitting for a while and now it wont start. Second he said he drove the car and it wouldn't start the next day, So who knows what the real story is. Anyway the car has the 1.3L 13B engine. From the looks of it, it has been sitting for a while. When I first looked at it, it cranked real fast and sounded like it lost compression. I had one of these cars years ago with the same problem so I had an idea where to go with it. I first checked the little antifreeze bottle near the firewall that is used for cold starting and found that the pump was unhooked. I hooked the wires back up and filled the tank. Now the pump runs while cranking. Next I ordered two sets of plugs and put one set in. I still couldn't build up compression. Next I removed all the plugs and shot a lil oil in each plug hole. When I cranked it then I had a little compression. I pulled the plugs again and dried them off. I put them back in, pinched off the fuel line and cranked it over again. I did this several times. When I first hit the starter I got a few fires out of it for the first 5-10 seconds than nothing again, (I did this with the fuel line pinched and un pinched) I would pull the plugs again and reinstall dry ones. After a while I decided to crank the engine over without the plugs in. When I did this I had compression coming out of the rear two plug holes but nothing coming out of the front two. I verified this with a compression tester.

Is there anything else I can try to get the compression back? How do I know if the front rotor is shot? Do any of you guys have any other ideas? I don't really get too many of these cars in the shop so I don't have that much experience with them. The owner has a used car lot and he brings ALL his cars to us so I don't want to sell him anything he doesn't need or chase him away. I have both Mitchell ON Demand and Alldata shop manuals on out computer but there is no information on this problem in either program.

Thanks for any help,
MIKE

If you are not hearing any pops/chugs out of the leading housing (front) it sounds like the Apex seals on the rotor are blown. I would run a compression test on the front housing/rotor. I belive 120 psi or better is good (dont quote me) If this is truly the case, then its time for a rebuild or reman

FYI - rotor is 3 sided, 3 apex seals per rotor. If you loose one seal, you loose two sides of the rotor.

hope this helps.

Also - the plugs that were in the engine originally, how carbon fouled/fuel soaked were they?

the apex seals are not on the tips of the rotor, those are "tip seals", the apex seals go around the rotor to the housing, you will lose comp with a burnt or blown apex and same if you have a blown coolant seal, if you have a partial blown coolant seal the car might start ubt it will smell and smoke like crazy, the car you speak of has a blown motor no doubt about it... dont even try because it will not start, you said you did a comp test on the front rotors, what were the results ?

:confused:
I think you need to study your rotor anatomy. :)
or maybe i am just misunderstanding.

:confused:
Im with you ISUposs - not sure what he is talking about but the seals at all 3 corners of a rotor (that seal the rotor face to the housing) are apex seals.

WTF are you talking about? Tip seals? :bash:

I suggest you look here.....

http://www.rotaryengineillustrated.c...nat-rotor.html