lart951

Sold my head to minho for $ 200.00 shipped I bet you can't beat that.

minho78

Yes. I got a great deal with Lart. Also he was willing to negotiate. Thanks Lart.

minho78

Hey Ted, Yes the engine was at TDC in Cilinder 1 and 4. I could hear the air escaping on the intake manifold.

Tedro951

Bummer... Let us know what you find. I would think the compression #s would be lower if there was bent valves. Also, if the marks line up, those #s wouldn't stop an engine from running. It wouldn't be healthy, but it should run.

minho78

Cylinder 4 probably would still run, but cyl 1 definately doesn't have enough compression. I was praying that it was either spark or fuel related, but unfortunately the compression test showed otherwise.

Oddjob

The motor will start and run no problem on 3 cylinders (w/ zero compression on the 4th). It will also run on 2 cylinders firing, not sure it will start - some of the factory diagnostic tests have you pull two injector connectors for WOT signal testing.

I would still look for a fuel or spark problem w/ a no-start condition.

Lemming

There a guy in B'ham that does a fantastic job of reseating valves and decking for $200 (and that's on a 16 valve head).

minho78

Uhmm Interesting. So you are saying that this car should run OK, and I might have other problems.
Thanks Jim.

Oddjob

Couple thoughts:

If the car was running fine, then shut off and would not start - that is most likely not a compression problem, unless the t-belt failed and it bent valves. If it was over rev'd to 10k on a missed shift, it might also have had some valve contact.

I have done the WOT testing with the car running on 2 cylinders. And I have burned an exhaust valve on track and ran a couple laps trying to figure out what was causing the drop in power. It would still pull 120mph down the straight w/ zero compression on #4.

I was also in the passenger seat of a 89T that broke a #1 rod on track, and blew the engine apart. It also had burned a #4 exhaust valve during the incident. The driver/owner had to turn the motor off with the key, because it was still running.

I would recommend checking all the common fuel and ignition failure points (DME relay, ign coil, cap and rotor, spd ref sensors, fuel pump, etc) before pulling the head.

Van

Remember, there are two TDCs... one on the power stroke (at combustion) and one after the exhaust stroke. For this second one, the intake valve will be partially open (remember, the intake opens a little before TDC to maximize the air flowing into the cylinder).

I think it's much more likely that you just have a blown head gasket.

Chris White

Hmmmm …..strange coincidence….cylinders 1 and 4 are at TDC at the same time….

The difficult part is using the TDC at exhaust to intake phase – both valves are closed for only 4 degrees! (3 degrees Before TDC to 1 degree after TDC). Its much easier to rotate the engine 360 degrees and test on the TDC after compression.


>>>Looks like Van already caught that!<<<

Oddjob

When you crank it over - is it firing at all? Any popping or smoking? Or just cranking?

Chris White

It could be burnt valves – typically that would had a ‘chuffing’ sound at cranking since the area of the valve that is missing is fairly small you can hear the air escaping past it as you crank the engine.

Hearing the air in the intake during a leak down test would not be typical of a burnt valve – It’s the exhaust valves that get burnt.

I would also expect an engine with the compression numbers you listed to still start and run – maybe not very smooth but it should run and idle.

Sounds like you have something else going on….

Tedro951

Van clarified the reason I asked about TDC in each cyl. For a leak down check, think 8 TDC's....only 4 will work for the test.

Manny, this is where I was heading. Low compression in a few cyls wont stop an engine.

Van

Also remember that you'll get a little leak-down past the rings, which will go into the crankcase, which will go to the AOS, which will go to the breather/PCV, which vents into the intake (j-boot) for emissions... This will cause air to be in the intake, although it's not getting their via an intake valve.