compression test results

[lovemysan2]

I checked the compression today and here are the results

#1 191psi#2 199psi#3 192psi#4 196psi

Does any one know roughly what the compression ratio is?

I'm still trying to find the miss. It comes and goes.

[lovemysan2]

Well my gage is not that exact. Those are just approximations of what it looked like.

[Checkered-Member]

-standard: 178psi-minimum: 149psi

you are probably running rich, if so you have carbon build up in the combustion chamber that will show these high compressions

[lovemysan2]

See pistons in my sig.

[DAEDALUS]

I'm still trying to find the miss. It comes and goes.

Have you looked at your plugs yet? Do they all look identical?

[ultimatuc]

a misfire can be caused by just about anything. Have you scanned for codes? this will probably narrow down where youre having problems. If you search around here, you can find the instructions on pulling codes manually.

when you did your compression test, did you remove all plugs, and hold the throttle wide open?

[lovemysan2]

I removed the plugs one at a time. I misread my FSM and didn't have it with me.

the plugs looked fine. No carbon or oil on them. Just amber coloring on the insulator. The distributer cap and button looked good. There less than 15k old. Plug wires checked good(ohms check). I'm getting some tapping so probly another lifter checking out.

I'll get the codes out in a few days. The lifter is getting worse so I'm gonna park it and drive the Danger Ranger, until I decide which cam to run.

[deviousKA]

Its pretty much impossible to decipher the compression ratio of an engine from the actual compression pressure (to do it accurately). With my kaE at 10.5:1 CR, i get same compression results as you. Cam, and cam timing have a lot to do with what you will get for pressure.

Looks pretty good tho, didnt you just rebuild it? Are you unsure as to which pistons you have?

[Calesta]

He's running 9.5:1 forged (I think) pistons.

You might want to check your plugs, wires, rotor/cap for problems.

[lovemysan2]

I wish they were forged pistons but there not. They are the cast 9.5 to 1 pistons from nissan motorsports. There are identical to the 9.1 to 1 pistons exept they are 1mm over bore verses .5mm. I'm running a stock 240 cam.

I believe the machine shop shaved the head. They must have taken a pretty good chunk in that case.

Thanks for the input people.