Stupid Question.. I know. But how many times are you supposed to crank the car when checking compression?

 

About 3.

 

What are d16 normal compression?

 

180-190

 

crank it until the gauge stops going up :P

 

Which is about 5-6 times, also hold the Throttle plate Wide open when doing this.

 

According to all my chevy manuals for working on v8s, they recommend that you run the motor till normal operating temp, shut it down, remove all spark plugs, then start testing. Yes it does make a difference on my v8 versus pulling one plug out -> test -> replace plug -> move to number 2. I've ran all my 4 cylinders that way as well, get it warm, remove all 4.. test one at a time. Replace. Oh yeah, battery should be fully charged to ensure proper stroking.

I think I read compression whenever I tune that 350 motor up, seems like I "tune" that motor every other month... stupid edelbrock performer carb

Before you begin testing, be sure to disconnect the live wire on the distributor (or take out the coil), don't want to get shocked by one of the plug wire leads.


There are several signs you need to yield to when testing, normal compression builds smoothly and evenly.

Low compression on the first stroke with a very small climb in compression the following strokes means worn piston rings. If that is the case, squirt some oil in the cylinder and see if it peaks right up. If it does, bad rings.

Low compression on the first stroke then it stays down low means you have a valve train problem, cracked head, blown headgasket. There are other tests to run if that's the case, like if you are burning oil on startup = valve leaking, water out the tailpipe = head crack/head gasket bad. Bad compression between two cylinders usually is bad head gasket.

I doubt you will have built up carbon deposits, so it's not likely you're gonna see compression spikes.

Let me know if you need to know anything else.

oh yeah, don't forget to WEAR SAFETY GLASSES nothing like having a fine mist of 93 octane sprayed in your eyes from the cylinders that don't have spark plugs in them.

-ryan

 

this is why you remove the ecu fuse.

 

bring car to opp. temp. remove wires and spark plugs then crank the car untill the gauge will not go any highrer. And do keep the throthle wide open. 98ctr