Compression Tester?

[FlaVert]

What compression tester do you all recommend for the LT5? I assume it's a little different than a standard V8 since the plugs are so deep down in the cam cover. Never had one, or used one for that matter, so I want to get some advice before I go purchase one.

Thanks,
Rick L.

[jonszr1]

just get one that has a hose and a quick disconnect for the gauge . another option would be a leak down gauge .

[flyin ryan]

I have a couple, but a not super expensive Lisle tester I use sometimes is one (1) piece. Hose is fairly long, works good, have used it on Zee's many times.

[Paul Workman]

Compression tester available at AutoZone, as well as the leak-down gauge.

The AZ compression tester requires that you actually apply torque to the rubber hose to tighten the adapter into the plug socket. Use some anti-seize grease on the threads and it will seal just fine. Be sure to put a battery charger on the battery to assure uniform cranking speed between tests. And, pull the "inj-1" fuse (open passenger door & find fuse near the center of the fuse panel). This will shut off the fuel and prevent it from flooding the engine, and or getting into that expensive oil!

The leak-down gauge uses compressed air to charge the cylinder and then by monitoring the rate at which the air pressure diminishes, it is possible to get a relative understanding of the sealing ability of the valves and rings among the cylinders tested. (I don't have one/ never used one, so someone else should chime in here!)

BTW, if you just want to test compression, AZ will lend you the tester, with a deposit. Return the tool and get your money back. Or, keep the tool and they keep the deposit - a very smart program, methinks!

P.

[flyin ryan]

Originally Posted by Paul Workman

Be sure to put a battery charger on the battery to assure uniform cranking speed between tests. And, pull the "inj-1" fuse (open passenger door & find fuse near the center of the fuse panel). This will shut off the fuel and prevent it from flooding the engine, and or getting into that expensive oil!

The leak-down gauge uses compressed air to charge the cylinder and then by monitoring the rate at which the air pressure diminishes, it is possible to get a relative understanding of the sealing ability of the valves and rings among the cylinders tested. (I don't have one/ never used one, so someone else should chime in here!)

Good info you passed on Re: Comp. Test. I always take this stuff for granted that just because i know, everyone else does too, right .

Leakdown testers are good, I use them often, can be very helpful before tearing down an engine, & you don't need the starter hooked up to use it which is nice when engine is on a stand. Only thing is...The cylinder that is being tested 'Must' be at TDC, otherwise the air will push the piston down the hole. You want the piston & rod 'Locked' in at TDC anyways to get a more accurate reading. Ssooo that means the Dampr (balancer) must be degree'd,... timing marks, at least at 0º-90º-180º-270º. I rotate the engine by hand every 90º & run through the firing order, so will end up turning the engine over two full revolution's, only.

Need to mention, me assuming again...,Need to be at TDC on the cylinder your testing, 'On the compression stroke', other wise the valves won't be closed. Remember the crank spins twice for every one camshaft revolution. So you can be on TDC in 'Two' places through out the 720º crankshaft rotation, easy to find, pull spark plug & put your finger over the hole normally, but not possible on LT-5's so a snug hose will do. Can feel the pressure with your thumb over the hole at end of hose turning engines over by hand, but in car is easier to have somebody spin the starter. Sorry I didn't mention this yesterday...

[jonszr1]

ryan thanx for the info on the leakdown tester .i never knew how much to turn it over after finding t d con the first cylinder

[tomtom72]

Thanks Paul & Ryan. I just learned the correct way to use those tools! I never did either test and I always wondered what is the proper procedure!

You guys rock!