JDM compression test

[accordguy]

Does anyone know what the compression should be for a 92-96 JDM H22a with 10.6 compression. I’m in the process of buying another engine from an importer the engine they have for sale tested 180 across in all cylinders. Is this good or just average engine has 46,000 thousand miles on it.

 

[jdmh22hatch]

I was never able to find actual JDM specs for compression, all I was able to do was find out what everyone else was running. My freshly rebuilt JDM h22a with 11:1 cr showed 260 psi across the board. There is a math equation that you can find that will give you exactly what your compression should be, but unfortunately I can't find it again. It is out there however, perhaps someone else can post up a link.
Those numbers are average for a USDM h22a, so if anything I'd say they're a little bit low for your engine, especially with only 50k on it. Not below service limits mind you, but somewhat low.

 

[accordguy]

As far as I know the JDM H22A has a compression of 10.6. You said your rebuilt motor is 11.1. But at 10.6 I don’t think compression would be that high 260 PSI. I heard around 220 is real good almost new like for the JDM H22a at 10.6. How much did your rebuild cost you and what parts did you change.

 

[jdmh22hatch]

LOL - I think I answered this in my post on the other thread. I put in OEM type S pistons, which have an 11:1 cr, which is why my numbers are higher. The stock JDM h22a has a cr of 10.6:1, so naturally your numbers will be slightly lower. IMO 220 on four cylinders are good numbers for the stock JDM h22a.
My entire rebuild was roughly $700 Can. dollars. This was for the type s pistons, set of rings and a head gasket. No labor, as I did the work myself. I was quoted labor at $1000 by a local shop.

 

[tab]

the number itself is usually less important than the whole. All four cylinders should be within 5 psi of eachother. Large differences in the readings mean bad cylinders.

 

[HatchSpeeD]

Quoted post[/post]]
the number itself is usually less important than the whole. All four cylinders should be within 5 psi of eachother. Large differences in the readings mean bad cylinders.

True, in a sense & it would show the engine on all cyl. is wearing evenly. But my understanding, there should be roughly a number that would show what the compression should be at, given a compression ratio if lets say the engine was in perfect shape like right out the factory. In that case, does anyone know? I too, do not know the equation. My guess was around 220 for a h22a & judging by cylinder # 1 & 4 (the ones that tested good) being around 220, that seems about right. Anyone know?

 

[tab]

220 sounds about right to me.

 

[daily interlude]

My H22 with USDM pistons (10:1) tested to 210. I'd think JDM would be 220+ (more like 225-240ish).

180 is low...that's like 8.5:1 to 9:1 I believe.

Now, if they didn't do the compression test the same, these numbers will be different. The first time I did my compression test, I didn't remove the fuse for the fuel pump NOR did I have the throttle all the way open. When I did it this way, I got 180psi...