Squeeze check; static? Dynamic?? Best way? - ZR-1 Net Registry Forums

Schrade · 07-20-2013

And how long for leakdown time is acceptable, for a static check?

edit:
Yes - talking about compression check; and what the best method is...

VetteVet · 07-21-2013

????

Schrade, when you say squeeze check, are you talking about compression? Unless you've got specialized equipment, it's impossible to perform a dynamic compression check. I do have that equipment. As far as a leakdown, there is no time period involved. You roll a cylinder to TDC firing, hold the piston at TDC with a breaker bar and apply the air pressure with the leakdown rig. The gauge displays the % leakdown. You can hold the pressure for 5 seconds or 5 hours, the reading will not change.

If none of this is what your post was referring to, please ignore.

Jep

mike100 · 07-21-2013

Leak down reading can be tricky on older engines. Warm or cold makes a difference...are you looking for massively failed ring or valve seal, or trying to assess wear on an older engine?

Another quick trick to sort of act as a cheap leak down test is to look at the rate at which your compression gauge needle jumps up. Healthy cylinders get over 100-120 psi in about 2-3 cranks where worn ones come up slower. This is somewhat approximate and varies from one engine type to another, but simply compare to the best cylinder in any given engine.

The one thing I never bought was a cylinder sealer that would leak down a block with the heads removed (checks for cracked rings after a dropped valve etc.)

07-20-2013	#1
Schrade Join Date: Dec 2012 Location: NC Posts: 1,786	Squeeze check; static? Dynamic?? Best way? And how long for leakdown time is acceptable, for a static check? edit: Yes - talking about compression check; and what the best method is... __________________ I'm getting my snappics / threads removed blindly as fast as I can, to get in compliance with copyright / license TOS on the boards here (lots of FSM pages and other copyright / license violations on my part; sorry guys). And thanks to all the guys who didn't whine when I posted those FSM copyrighted / licensed stuff in my threads... ( :thumbsup: [b]and to think I complied with a mod's request to delete a pic of him in a Challenge Car in NCM Museum, so he wouldn't get in hot water)[/b] Thanks to several guys here for sending parts FREE; BearlyFlying, WeGone, Geezer, GoldCylon, and more there, TonyD, mike100, fletchusmc... 1990 #2794; 4L60e Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless, Power Effects 3" [IMG]https://lh5.googleusercontent.com/-GHpfzty7DVU/UQn-0Ru2xAI/AAAAAAAAA14/08mz1p4QLD4/s445/Screenshot-5.png[/IMG] Last edited by Schrade; 07-21-2013 at 01:00 PM.

07-21-2013	#2
VetteVet Join Date: Jan 2009 Location: Mandeville, LA Posts: 340	Re: Squeeze check; static? Dynamic?? Best way? ???? Schrade, when you say squeeze check, are you talking about compression? Unless you've got specialized equipment, it's impossible to perform a dynamic compression check. I do have that equipment. As far as a leakdown, there is no time period involved. You roll a cylinder to TDC firing, hold the piston at TDC with a breaker bar and apply the air pressure with the leakdown rig. The gauge displays the % leakdown. You can hold the pressure for 5 seconds or 5 hours, the reading will not change. If none of this is what your post was referring to, please ignore. Jep

07-21-2013	#3
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,802	Re: Squeeze check; static? Dynamic?? Best way? Leak down reading can be tricky on older engines. Warm or cold makes a difference...are you looking for massively failed ring or valve seal, or trying to assess wear on an older engine? Another quick trick to sort of act as a cheap leak down test is to look at the rate at which your compression gauge needle jumps up. Healthy cylinders get over 100-120 psi in about 2-3 cranks where worn ones come up slower. This is somewhat approximate and varies from one engine type to another, but simply compare to the best cylinder in any given engine. The one thing I never bought was a cylinder sealer that would leak down a block with the heads removed (checks for cracked rings after a dropped valve etc.)