Ok, the results of my leak down test on my 82 5 speed shows all cylinders except #2 at 0 to 3% leakage. #2 is 35% leakage, no wonder I had a miss. BTW, I have new cap, rotor, plugs, wires, green wire, new injectors, intake refresh and timing is correct. The miss was there before the intake /ignition work. I am thinking that all the MMO and Techron in the world is not going to help that problem. I am afraid to continue to drive that we might cause more damage. Recommendations? I am probably going to pull that head to inspect. I've pulled the entire motor before on a 78 for a rebuild, but can the left head be pulled in the car or is it to much of a PITA? Thanks

 

where was the air leaking from? exhaust or intake or oil fill tube

 

Looks like it is coming from the exhaust. The car does not burn oil or lose coolant. There is no black or white smoke coming from the exhaust, just 100-110 compression on #2 cylinder and 35% leak loss. All other cylinders 155-160 compression and 0-3% leak loss. Funny thing, the roughness goes away at high rpm and cars pulls well. I guess a stuck open exhaust valve is more prominent at idle and low rpms than high rpms. The valve is still stuck but the engine has less time between firing cycles to manifest the miss. Thanks for any advise, but I'm pretty sure the #2 exhaust valve needs some work. I can't wait, yeah!

 

before you pull the head I would try the cleaner suggested mixed with the fuel at this point you dont have much to lose if the valve is burned then it will need to be replaced,
otherwise if its dirt then it may come free and thus the valve will restore its seal. the faster engine speed is masked du to the reduced time of each firing event so its harder to feel the miss

 

You could also try the "steam clean" technique if you are up to it or the SWEPCO 502[?] flush should some carbon deposit be causing this anomaly.

Doubtless some kind soul will explain the steam clean procedure- Roger said recently he has the SWEPCO in stock now.

I would have a go at one or both of the above before ripping the motor apart. No idea which one works best though.

Interesting that you saw a clear correlation between compression pressure and leakdown test results. Whereas the leakdown is a superior test I still believe a good compression test is a valid starting point and gives meaningful clues. With the leakdown test you can possibly trace back to specific problems with either the rings or the inlet/exhaust valves.

Hope you get a result

Fred

Regards

Fred

 

Thanks for all the inputs. I did add Swepco from Roger with no results on a oil change 400 miles ago The compression check was done weeks ago and the miss remains after all the injector and ignition work. I guess I will try the Techron and MMO before tearing the engine out. What have I got to lose? Hope something doesn't break in there and cause more damage.