Compression Numbers High

[Snk-Byet01]

First, I want to thank this group for their knowledge. From the recommendations, I installed the NGK TR-55 plugs with ~.48 gap. The factory gap was almost .60 so it took a little tapping on a wood block to get them down to ~.48. New COP boots and springs. It really woke up the engine.

While I was there, I decided to take a compression test. I had previously purchased a Craftsman compression test kit, when a local Sears was closing their doors (me, being a cheap SOB). I had never used it before.
Here are the readings and it surprised me how high they were:
1 - 225
2 - 215
3 - 213
4 - 207
5 - 205
6 - 210
7 - 200
8 - 225

Tests were done with all plugs out, fuel pump fuse removed, WOT, pressure removed from fuel rail and about 6-7 revolutions. I ran the test twice and came up with similar numbers.

I was expecting something like a 170 - 150 range. Is my compression gauge off, or do I have some major carbon build up in the cylinders? Is there a good way I can check to see if the gauge is working properly? The numbers are pretty close to each other, so I'm not too worried about burnt valves or blown head gaskets. BTW, 180K on the original engine.

I don't know if this kit can be re calibrated or not. I doubt it.

TIA

 

[decipha]

was this a cold engine ?

 

[Snk-Byet01]

was this a cold engine ?

Yep. It hadn't been started in about a month.

 

[01yellercobra]

With this type of stuff I've always worried more about the balance cylinder to cylinder. As gauges don't always read the same. One of my buddies had a gauge that never read over 100psi. He thought it was normal until he used another gauge that read higher.

Chances are the gauge can be calibrated. But it's probably not worth the cost.