Was driving home from work today, was accellerating at about 5000 RPM when the engine lost half it's power, there was no smoke, no bang, no grinding or rattling like it ate something. On further inspection when I got home, I figured out the rear rotor isn't doing anything. I've got good spark at all wires.

Oil pressure and water temp are fine. I read somewhere that this engine has a valve that shuts the rear rotor off when the engine is decelerating to save fuel, could this have caused my problem? If so, could someone tell me where this valve is located on the engine so I can check it.

Thanks.

 

No valve like that. Do a compression test to see if you lost compression. What year car and what type of engine, turbo or non turbo? This info would help.

 

85 GSL, non turbo.

What should the compression be?

 

I lost an apex seal like that too. What I did to verify this is remove a plug form the front rotor, disconnect the coils and spin the engine with the starter, then the same with the rear. I got pssht, pssht, pssht on the front and pssht,...,...,pssht,...,... on the rear. When u loose one apex seal, u loose compression on 2 sides of the rotor.

 

Sorry man it really sounds like you ate a rotor.

 

Checked around a bit today, there is a wrecking yard nearby that has a few 7s, the guy there said that 82 - 85 were the same engine, will a rotor and rotor housing from one of these work in my engine?

The guy there said he would sell me a motor out of one of them for $200, but he didn't know what kind of shape it is in.

This brings me to my second question, are the front and rear rotors and housings the same? (i.e., interchangeable)

Thanks again.

 

Yup

 

Yes there is... on 1st generations at least. Its called the Shutter Valve. It cuts off fuel to the rear rotor under deceleration to prevent backfiring. Its an emissions thing. This isnt your problem tho.

What year car is this?

 

The car is an 85 gsl.

While the car was running I pushed on what I think is the shutter valve (on the intake runner just under the carb between the carb and engine) and the car started to idle again by itself, and even ran smooth for a bit.

When the car was running, the plunger on what I think was the valve wasn't moving at all. The plunger is operated by the fourth solenoid from the front of the engine.

I'm still not sure if that was the shutter valve or not though. When I checked for compression on the rear rotor, I didn't feel anything at all. I either blew more than one apex seal on the rear rotor, or there is something else wrong.

I suppose I really oughta get a good service manual for this thing huh?

 

take the spark plugs out of the rear rotor and crank it
you should hear 3 strong wooshes

i hope you do, if so just wire the shutter vavle open

 

To make sure that the problem isn't the shutter valve, just make it non-working. It can't hurt. Many people do that anyway to prevent future problems.