is this possible? if so can someone run it by me. i have a deal for this ls swap, i just wanna make sure everything is good before i go threw with it. thanks in advance guys.

 

Although it should be technically possible, in practice it's pretty freaking difficult. Ask me how I know. -facepalm-

If you are going to do it, make sure the block is on a stand, get a breaker bar and turn the crank bolt as fast as you can. Usually what happens is that you won't be able to spin it fast enough to build pressure in the cylinders.

I would recommend a leak down test, which involves using an air compressor to pump air into the cylinders while they are at TDC and a pressure gauge tells you whether or not they are holding.

Good luck bro.

 

its possible and easy infact when you go to a shop that sells jdm motors they do it for you. you need the have a tranny and a starter bolted to the motor. just jump the tranny with a battery or battery charger. ive done it several times no problems. i think it would be impossible to try and spin it by hand. leakdown test is good too if you have the tools.

 

This is the way I have done it. Its not that hard. Remember to hold the throttle body open when cranking the motor or remove it.

 

One thing to be considered,
"A compression test should be done with the engine
at operating temperature,all four spark plugs removed.."

Results from a cold engine will usually be inflated
and inaccurate to say the least.

 

The rings expand so you'll se a lower result

 

cold one will be fine, you are mainly looking for any oddball readings, or any one cylinder that is way out

 

That's my take on it as well.
If you are buying the engine and have the opportunity to do a cold compression test then go for it.
If the numbers are all over the place, just walk away from the purchase with no regrets.

 

Exactly.

 

you can do a wet compression test too, if any of the readings are low, squirt a little oil in the cylinder and do it again, if it goes up, it's a ring or worn bore, if it doesn't make any difference, it's in the head, low readings on two adjacent cylinders means a head gasket

 

I did a compression test on my 88 crx, and got the same results you speak of in your post. #1 175, #2 120, #3 120, #4 175, What would be the correct readings for a compression test on warm d16? The previous owner of the car says, the engine needs to be rebuilt, I say it needs a head gasket. TIA.

 

well it's an educated guess, but usually the two low ones right next to each other means a head gasket , thats not a guarantee,, but it gives you a better idea of what it might be, compression from one cylinder is leaking through the bad gasket into the other,

 

Gotta pull the head either way to find out. If there's a problem with the piston or rings you'll probably see it on the bores.