Small Piston Ring end gap symptoms
Burning Brakes
Joined: Nov 2001
Posts: 1,189
Likes: 2
From: Austin TX
Re: Small Piston Ring end gap symptoms (GRX)
Loss of power when the engine gets hot. As the ring expands under heat
the gap closes up. If there's not enough gap, the ring ends butt, and then
you wind up with alot of radial tension against the cylinder wall. In
some cases this will cause the ring to break, and then you'll have lots of
blow by.
the gap closes up. If there's not enough gap, the ring ends butt, and then
you wind up with alot of radial tension against the cylinder wall. In
some cases this will cause the ring to break, and then you'll have lots of
blow by.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Small Piston Ring end gap symptoms (danno85)
Also, if the ends butt together tightly enough, the ring will stick in the bore and pull the top ring land off of the piston. Better to suffer a little extra blow by the risk losing an engine? What is the perfect gap? Engines and operating conditions differ. You would have to be in there to observe to be sure. Go with the "experts" reccommendations for your engine and usage. Good luck, and...
RACE ON!!!
RACE ON!!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Re: Small Piston Ring end gap symptoms (GRX)
Nothing during the expansion process, that you would hear. You will likely hear the chunks of piston rattling around in the cylinder/combustion chamber after a ring land lets go. Good luck, and...
RACE ON!!!
RACE ON!!!
Pro
Joined: Dec 2001
Posts: 708
Likes: 0
From: Renton Wa
Re: Small Piston Ring end gap symptoms (CFI-EFI)
Yeah, the rings kinda make this Ewaahhhhh.. sound similar to the sound yo make when stretching :). oh wait thats just in my head. nevermind.
In all honesty there isn't anyway to tell if it's too small till they bust. If they bust you may even still have decent power. Things to look for would be excessive smoke out of the valve breathers to begine with, then some overheating. Do you have a magnetic drainplug? If not, GET ONE!!. If you see an excessive amount of "fuzz" on it, you busted something up. Like said earlier, it's better to just go larger gap rather than try to squeeze every ounce of HP out of it.
Every Expert seems to have a different view on the topic of rings, some say that every thousanths is critical, while others say that it really does not make any noticable difference, "nothing that you would feel anyways". So just overgap it. I ran into this worry for about a month till I finally felt satisfied. I ended up with 35 thousanths on top and 25 on the second. Now I just hope to god that won't butt under all the heat. Besides I have stainless steel tiop rings, so if they butt, they will most definitly take out the ring land rather than bust it's self up.
What are you gaps at currently? what kind of conditions is this engine seeing? whats the specs on this engine?
In all honesty there isn't anyway to tell if it's too small till they bust. If they bust you may even still have decent power. Things to look for would be excessive smoke out of the valve breathers to begine with, then some overheating. Do you have a magnetic drainplug? If not, GET ONE!!. If you see an excessive amount of "fuzz" on it, you busted something up. Like said earlier, it's better to just go larger gap rather than try to squeeze every ounce of HP out of it.
Every Expert seems to have a different view on the topic of rings, some say that every thousanths is critical, while others say that it really does not make any noticable difference, "nothing that you would feel anyways". So just overgap it. I ran into this worry for about a month till I finally felt satisfied. I ended up with 35 thousanths on top and 25 on the second. Now I just hope to god that won't butt under all the heat. Besides I have stainless steel tiop rings, so if they butt, they will most definitly take out the ring land rather than bust it's self up.
What are you gaps at currently? what kind of conditions is this engine seeing? whats the specs on this engine?
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Re: Small Piston Ring end gap symptoms (WashingtonRacer)
Well, hypothetically speaking, its my toyota I just rebuilt. I asked here at the forum because this place is the very best to get opinions on automotive issues. :bb My vette has gapless rings so that won't be an issue. The toyota is my main transportation. I rebuit it meticulously. Started it; runs great for about 15 minutes, then all heck breaks loose! Happens right after about 15 minutes of operation...I shut the motor off...turn it on and it shakes violently.....and the starter struggles to start it. I hope the rings are ok...I need to test more. It misses at idle and troughout the RPM range. Any way, I posted on the corvette forum because you guys have offered opinions before on my vette. Luvf this place. :chevy
[Modified by GRX, 7:43 PM 9/27/2003]
[Modified by GRX, 7:43 PM 9/27/2003]
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
Re: Small Piston Ring end gap symptoms (GRX)
a chevy with that would have a slipped timing chain. i don't know about a toy. sounds a tooth off
[Modified by Matt Gruber, 5:36 PM 9/27/2003]
[Modified by Matt Gruber, 5:36 PM 9/27/2003]
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Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Re: Small Piston Ring end gap symptoms (Matt Gruber)
Timing is right on. Valves are perfectly adjusted. I will check the fuel filter....feels like fuel starvation...I installed new aftermarket injectors and think they may be the culprit. Checked O2 sensor -its OK. No codes are being set. Maybe the ECM is shot? :banghead:
Pro
Joined: Dec 2001
Posts: 708
Likes: 0
From: Renton Wa
Re: Small Piston Ring end gap symptoms (GRX)
I bet you it's related to the ecu, Are you monitering the engine temp, Does it occure when the temp gets to operating temp? I bet the fuel ratio is leaning way out when the ecu reads the Coolent temp. Just to make sure, it works just fine and dandy up till 15 minutes. I would defnintly be looking at the ecu. Are you positive the O-2 is operating corrently? they are very tempermental.
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Re: Small Piston Ring end gap symptoms (WashingtonRacer)
I had a spare O2 sensor and swapped it already, but to no avail. Interesting though; During engine teardown, I damaged the water temp sensor for the ECM....the plastic connector housing separated from the brass casing....separated about 1/16". So I epoxy glued it together, carefully. I measure the resistance but it looked fine. MAYBE, that is the problem....bummer though, the stupid sensor is 70.00$ at the dealer. I have yet to check the fuel filter; and verify that the fuel injectors that I bought are indeed the correct units. Engine idles fine for about 15 minutes then misses bad if I re-start it. Weird. Also, even cold it will miss slightly at higher RPMs. :banghead:
