Pictures of a 180k mile Z

[Ccmano]

Pulled the spark plugs to see what they looked like and gauge engine condition. Also ran a compression test.

Compression was very consistent across all cylinders at 150 plus or minus 5 psi. This first compression stroke of each cylinder was 85 psi. Corrected for alititute (I'm at almost 5000ft here near Reno) put them in the 90/180 range. While somewhat disappointing, but not surprising for a 180k engine.

The plugs (AC 41-800's) were shockingly consistent across all cylinders. If anything the engine might be running a bit rich. They look like they have been in there for a while.

Over all I'm pleased, she runs and idles very smooth and pulls strongly here at altitude.

I'm still planning to run her to over 200k. In the mean time I'll save my lunch money for a rebuild.

Here are the plugs.
H

[LGAFF]

Hans you can gain a lot of compression by cleaning the valves.....they carbon up and don't seal.

[Ccmano]

Originally Posted by LGAFF

Hans you can gain a lot of compression by cleaning the valves.....they carbon up and don't seal.

I wasn't aware the situation could be that dramatic. Looks like I'll be doing a plenum pull sooner than later.
H