Engine Compression - Generation 1

[FFFFAST]

Hello all,

I am new to the forum and have been/am searching for a Gen 1 NSX. Just learning about your (now our) forum as well as the intricate details about these fantastic automobiles --- by the way (slight segway), my wife has a 2006 Acura RL with 232,000 miles and I have a 2007 Acura MDX with 162,000 miles..... which attest to the reliability and durability of Acuras. Anyway, one of the tests I want to perform on any Acura I potentially acquire will be a cylinder compression test. I searched the FAQ section and didn't find the answer, thus I am asking for your help. What is the range of cylinder compressions on a healthy engine? Thanks for all your assistance ---- Doug

 

[Jinks]

I believe it is 175-210 psi. My Oem engine was around 210 each, my new built and boosted motor around 175-190.

 

[FFFFAST]

Thanks "JINKS" for the quick response -- you are my first NSX Forum friend (LOL). If someone else could confirm as this range seems to be quite wide.......

Also, please forgive me if this topic has already been discussed, as I am attempting to figure out how to navigate the forum. Oops! I now see there is a section below which lists similar threads. I will take a look at this a bit later when I have a few minutes as I am sure the answer is there as well.

Have a great weekend!

 

[goldNSX]

205-210 psi in my case on all 6 pots (120k miles).

Depending on the quality of the gauge you're using I'd expect some variation regarding the absolute measured level. If the gauge is consistent enough it's more important to have all 6 cylinders +-equal.

Why don't you do an engine oil analysis instead or in combination? It tells you more about the engine than a simple compression test and is easier to perform.

 

[Old Guy]

In the NSX Wiki, under the section Repairing Your NSX / Reference Sources you will find links to the service manuals. Always the best source.

For the 1991 NSX, the service manual specifies a nominal compression test value of 199 psi, a minimum acceptable value of 142 psi and a maximum acceptable cylinder to cylinder variance of 28 psi. I expect that these are sea level values and you need to correct for the test elevation. If the compression test is carried out at your location in CT, the sea level values should be just fine. Not so fine if you are having a PPI done in Boulder Colorado!