Hey guys, Long time lurker first time poster
....With bad news of course!

I have a 1981 GS with what im told has its second motor in it.... the body has 94k on it. there appears to be a couple modifications to it... i noticed a vacuum line that was plugged with a bolt, and im told the carb was "repaired" or something along that line be the previous owner.

I had a leaking front mount oil cooler and upon removal i found cracks around the neck of the bottom inlet.

I removed it from the car, used JB weld and after it solidified put it back on the car. I then filled it with synthetic oil for the first time (which now after reading here isn't a good idea and am wondering if this may have contributed to the issue)

I took the car for a spin, to see if it would leak again, and after about 4-5 miles of driving i felt a sudden power loss and the engine began sounding like a diesel tractor. I pulled over and had the car towed home.

my first thought was possible oil starvation, so I took the cooler back off and made sure that the jb weld wasn't covering any of the holes. I also thought maybe i installed the oil director/thermostat incorrectly, so i took it out completely for the time being just to see if that helps. one thing that has made things harder to diagnose is that i can NOT get the damn oil gauge to work under any circumstances, as it was not functional when i purchased the car, and after reading a few things here im still at a loss.

I checked all of the vacuum lines, ignition system, disconnected the cat (to see if it was blocking flow) and have gotten nowhere, At this point i am concerned that there is an internal failure. I have read the repair manual as well as spent hours online browsing the forum for possible solutions...

I have below a video of the car after it has warmed up for about 5 min.

the motor shakes at 1000 rpm, and at 2-3k it makes a clank or ping type sound. at 4k+ it smooths out to almost normal id say. It has trouble idling even after warm up and usually will die after a minute. it revs slowly and drives very poorly.


Anyways... watch the vid and let me know if i should just light it on fire or if there is something that can be done i haven't thought of.

http://www.youtube.com/watch?v=ZtDa-20qlyM

 

does it sound normal when cranking? I would check the compression on the engine you may have a blown apex seal. also check the ignition to see if both leading and trailing are firing I worked on one of me cars it would start and run very poorly but held a real rough idle at about 400 rpm but the leading ignition was not working after fixing that it seems to run good.

 

from what ive read and hearty the sound of a lawn mower as the engine is a blow apex.. ide check compression man..

 

Yeah, thats what im afraid of...

The ignition system is fine.

my damn compression tester is broken., so ill have to find another one...

 

Try the three puff method.

 

If you had a broken apex the car would run bad throughout the whole rev range.

 

Sound almost sounds like severe detonation, which would be indicating a severely lean mix which might signal a major vacuum leak, or severely whacked timing/vacuum advance issues. Natually, from a video, it's hard to tell where on the motor the noise is coming from.

Have you popped the distributor cap and checked the rotor? Make sure the rotor's not whacking the inside of the cap?

Definitely first, do the hand-crank "air puff" compression test, that will confirm or eliminate apex seal issues.

One possibility is a broken apex seal spring (inertial forces would cause it to seal better as RPM increases), but being internal it's one of the last things you get to.

 

Ok guys, since my compression tester was broke, i removed the bottom spark plugs one at a time to try the "puff" test.

I heard distinct and even puffs from the front and the back, however the back side was significantly louder. am i to assume they should be even or is that normal?

 

They should be even.

 

So time to give up, huh?

 

No, it's never time to give up. You just need to quantify your problem better.

You should probably start thinking about how much time and effort you have to spare for this, though.

& keep in mind that a standard compression gauge isn't really good with rotaries. There are threads around about how to interpret results from em.

 

Well ive got PLENTY of time just no money.... im a full time student

 

Hmm I'm a full time student with no money NOR time.

 

either way... you have to have money AND time, so i think we're both sol.

 

Ok, so now that ive concluded that the engine is toast, i have another rx7 that has the same motor, that i bought originally to use for body/interior parts.... the guy let it sit in his back yard for about 3 years he told me, and that the motor ran when it was last parked.

Should i swap motors? if so, is there anything i should do to the motor before i put it in? (keeping in mind money is very tight at the moment) i have plenty of time, and a "decent" knowledge of traditional engines...

Someone give me some guidelines or ideas here.

 

Do the reading in the FAQ section and try Raised from the dead in the archives

I'd invest in a can of Seafoam, fuel filter, and fresh gas

then start trading things on the two cars
Carb, Spark plugs, Dizy, etc

 

Buy my car the engine has only 54k on it and put my engine in yours.

 

Ha, you must have missed the part where i said i had no money!

 

I was half kidding... it's too far anyway really.

I like that name "Barfdogg" coolness. Good luck. Suggest you rent or borrow a tester so you can confirm compression lost by instrument just to double check.

Otherwise you'll have to save up for a rebuild etc.

 

If I were in your shoes, questioning the motor in the parts car, this is what I would do:

1. Purchase/borrow/steal a can of Seafoam (just kidding about the stealing, and about the fact that this will run you about 7 bucks).

2. Pour about an ounce down the small barrels of the carb, then hold the throttle open so it can drain down.

3. Rotate engine enough to bring another face of the rotor around.

4. Repeat all steps until every apex seal is coated.

5. Let sit overnight.

6. Next morning pull the upper spark plugs out.

7. Rotate the motor using the starter if you can, or by hand if you can't.

8. Listen to the sound escaping of air escaping from the spark plug holes.

You're going to be listening for an even rythm of puffs, but also listen to the rate of the puffs. The only time that I've encountered a bad apex seal, it was not obvious what was going on by listening to the puffs. Everyone makes it sound simple, but it can be tricky. What tipped us off was not a miss in the rythm, but the fact that the front rotor seemed to be "puffing" at a faster rate than the rear. So pay close attention.

If it passes this test, then I'd put it in the car. Almost any other issue can be dealt with one way or another. This last motor I put in (replaced the original at 213k miles) had great compression, but when I started it up for the first time it turned out a coolant seal was shot. Nothing but clouds of smoke. Found a 4 dollar fix for that and it's worked out great all spring and summer, with no sign of failure in the future.

And after watching the video, I found myself not even considering the possibility that the motor was still good. That pretty much sums that up, I think. Didn't sound good at all. But then, you never know till you tear it apart, eh?

Best of luck to you...


.

 

thanks for the tips....

I was going to start pulling apart the second motor to check everything, and just do a basic rebuild with a 300 dollar seal kit, but your idea sounds much easier!

since i know everything (with the exception of the engine itself) is working well on my car, am i thinking right to pull everything of the current engine and put it on the second one? are there some things i should just leave on the second motor,like maybe the carb?

Anything else i should do while i have the motors out?