Well thats basically the question in askin ha.
I am going to pull the engine out of my Acura and replace it. I'm going to test compression on another b18. But it'll be out of the car because I don't wanna install it and it not work. So what's the right number to have with a cold engine?
Thanks

 

I looked it up on google and all I found was stuff for boats haha
It's a 95 integra. Will be using a b18.

 

As long as it is not real low, [not below 140psi] it is more important that all four are about the same, [no more then 28psi diff.], a wet test should be done also.

A leak down test will tell you more. 94

 

So even during a cold test they psi should not be before 140?
And by wet you mean dropping oil into the cylinder right?
Last time I did this. My tester got full of oil.

 

variance will be higher cold and numbers are lower. one of my type r's that had 260psi hot read about 220psi cold. i got in the habit of rigging up starters to jdm engines before i installed them to double check compression and make sure it was the same as the importer stated.

 

link on how to do this ? i'm swapping engines currently.

 

I usually just slap the transmission on, put 2. Bolts to mate it and put the starter on to turn the engine over.
I think with the right amount of washers on the starter/block surface, you can rig the starter to the flywheel with no trans.

But back to your type r. So basically about 40 psi lower while cold than when hot?

 

Okay.
I started up my engine that was knocking. Let it warm up. And did a compression test.
I had the same 90-95 psi of compression through all 4 cylinders.
This engine has new piston rings which I installed and I also rehoned the walls myself(700 miles on everything)
Should I just change the bearings And leave the pistons alone?
It is the compression so low that I should just ditch the engine?

 

I am backs other results!
I believe they are good. Just want some re assurance.

Tested engine compression.
Cyl 1-3 got 130 psi
Cyl 4 got 100
Did valve lash adjustment

Cyl 1-3 got 150 psi
Cup 4 got 120 psi.

Such a difference. But the car will run right?

I put the compression tester and cyl4 and removed the Gauge and plugged an air compressor hose and I held cyl 4 at tdc
And couldn't hear much air escaping?!?

But insight on those psi numbers please. And thanks n

 

I would pull the pan off and check the bearing on that rod.

You could have a spun bearing, bent valve, or bad rings in that cylinder.

 

Ditch it ! lol 130 is below the "service limit".

 

I'll remove the pan today.
And these numbers are on a cold engine. They go up once installed and warmed up right?

If I put cyl 4(low comp cup) at TDc with the valves closed and I put compressed air in it. I should be able to hear that leak right

 

If you spin it by hand, can you hear any slop/clunk in that cylinder?
A spun/worn bearing will change your comp on that cylinder even if the rings are good.

 

When I turn the engine over. It turns over easily! No clunks or noises
Haven't pulled the pan off, been burried in hw!

I can check for leaks by having the piston at tdc and valves closed and blow I blowing compressed air into the engine with the compression tester hose right?

 

Test #4 again then add a little oil into the cylinder and test again. If the number goes up, your rings are bad.