Cylinder 2, 50psi... let the party start.

[joshuagore]

After replacing a bad fuel pump and driving the car for about a week my problems came back. Naturally I assumed it was fueling related as it felt eerily similar to my fuel pump problem.

Rough under acceleration except now its also rough during no load as well. Ruh roh.

I spent the day at the junk yard getting myself a pleasant stock of 'test' parts which would act as substitutes of questionable quality to help diagnose my problem(s). I couldn't justify buying a new cap/rotor, fpr, cps, injectors on a hunch, so $30 in junkyard parts might help (that included a glove box latch, door lock actuator, and body computer).

My first step was to remove any crap plugs I was using and replace them with NGK's. While I was doing that I decided to test the compression. I ended up finding cylinder 2 down to 45-50 psi. I immediately thought rings, but then I pressurized the cylinder with the valves closed only to find all the air I was pumping in the cylinder coming out my exhaust not my dip stick, or timing cover like I expected with rings.

So the project will begin. I will post pics in this thread. This car doesn't have to be my daily driver, but with my Subaru up for sale it would be nice not to put anymore miles on it. Who knows if the Suby sells I might be more tempted to do more than just valve/ring...... maybe positive crankcase pressure is in my future.



Josh

[632 Regal]

if lash is too tight could hold the valve open.

[joshuagore]

First thing I checked. That would have been great Its not the case.

Josh

[Tiger]

Spin the engine again and recheck. What about other cylinder pressure?

[joshuagore]

I rechecked several times. Other cylinders are within 5% of each other. 15X

Josh

[Tiger]

Looks like you need a valve job. Any chance you can borrow a lighted borescope? If yes, you can look at the valves from spark plug hole.

[joshuagore]

No, but I want one
HF has one for $200, but thats near what I am going to pay to tear the head off (gaskets, Wetc), and it has to come off either way. We will see where the costs go after the head comes off.... rings or valve(s).

Josh

[Mordan]

No, but I want one
HF has one for $200, but thats near what I am going to pay to tear the head off (gaskets, Wetc), and it has to come off either way. We will see where the costs go after the head comes off.... rings or valve(s).

Josh

rings? you mean seats? how can you check the piston rings once the head is off.

anyway good luck. what's your engine?

[whiskychaser]

Spin the engine again and recheck.

x1 but with a tsp of oil down the plug hole

[joshuagore]

I checked the rings with a compression test. The pressurized cylinder with no significant blow by but massive exhaust leak give me what I need.

If I do have a bad ring not caught by the above tests it should be obvious as the car was driven and the cylinder will likely be torched.
I still find it unlikely as 50 psi and bad rings normally results in massive blowby when the cylinder is pressurized at tdc. But you never know.

When the heads off I will have a better picture. That should be in a matter of hours assuming the wintery chicago traffic let's up and allows me to be at the shop sometime soon.

Josh.