Compression Test - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

LinkBack Thread Tools Display Modes
post #1 of 3 (permalink) Old Jun 16th, 00, 10:18 AM Thread Starter
Join Date: Dec 1999
Location: New York
Posts: 15

I did a compression test dry/wet yesterday after hearing a slight ticking noise #1 cyl. All cyl were good 165 lbs ( 400 sm blk) except that #1... around 105 lbs. Any ideas on what to expect /look for when I start tearing the heads off ??? Oil pressure is down also.

I get about 38lbs at initial startup, but drops after engine is warm...about 25 -30 lbs
at 2500rpm...I should see at least 40lbs
correct ?

I get some oil smoke on guess it's time for new heads.
John69ss is offline  
Sponsored Links
post #2 of 3 (permalink) Old Jun 16th, 00, 07:14 PM
David Pozzi
davidpozzi's Avatar
Join Date: Nov 1999
Location: Central California, USA
Posts: 10,083

If you had a rod bearing problem the piston might hit the head. Or a cracked piston or broken ring land. That would produce blowby under acceleration.
Possibly the head gasket leaking?
Go around it with a piece of hose up to your ear like a stethescope and see if you can pinpoint it.
Also check the fuel pump, it can do it. And it's in that area. There is a rubber bushing under a fork that lifts the diaphram. If it splits and falls off it can tick.

The older I get, the faster I was!
davidpozzi is offline  
post #3 of 3 (permalink) Old Jun 17th, 00, 03:20 AM
Join Date: May 2000
Posts: 15

You might want to buy,barrow or rent a cylinder leakage tester.With the piston at TDC on compression with both valves closed you introduce compressed air into the cylinder.The gauge will give a percentage of leak down,0-10%is good,15-20%is iffy and 20 or worse is time to do a tear down.You can do the the test with just compressed air but you won't have leakage figure.Remove the oil filler cap,pvc valve,dipstik and radiator cap.Listen to where you hear air leaking from.Oil filler,dipstik = rings or piston.Carburetor or fuel injection intake = intake valve leaking.Exhaust pipe = exhaust valve leaking.Bubbles in radiator = blown head gasket or a crack in head or block.ONE WORD OF CAUTION!IF YOU USE A SOCKET TO TURN THE ENGINE OVER REMOVE IT AND KEEP ALL BODY PARTS AWAY FROM FAN,BELTS AND PULLEYS.WHEN YOU PUT AIR PRESSURE INTO THE CYLINDER,IF THE PISTON IS NOT AT ABSOLUTE TDC PRESSURE WILL SPIN THE ENGINE OVER.
usa z28 is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome