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How to check for piston ring breakage?
by
ffgb
on 23 May, 2011 23:08
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I have 5000 miles on my rebuilt 1.6N/A IDI motor. I have .50mm oversize pistons and Grant rings on this motor. I am going to replace the headgasket because it will not stop weeping. I am still burning some oil, not a lot, my car doesn't smoke on idle, only on hard acceleration, the smoke is barely visible. The engine mainly smokes when I start the engine, but it is only an initial puff. I did notice a lot of oil in the intake manifold from the breather hose! I also have the cam cover. I burn approximately 1/2qt every 1500-2000 miles. I am going to take the head off and replace the valve stem seals because I don't know if the person who replaced them used that special cap to install them, possible tear in some of the stems? HOW DO YOU CHECK TO SEE YOU HAVE A BROKEN PISTON RING WITH THE HEAD OFF? Do I count the lines on the cylinder walls? I do not want to take out every piston just to check for broken rings. Do I do a cylinder leak down test? Will this test show a broken ring? I know the valves are good because the head was rebuilt with new guides and new valves.
Thank You
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#1
by
Mark(The Miser)UK
on 24 May, 2011 02:01
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You have the head off.
I don't advocate extra work very often, but I would drop sump and pull the pistons. 
There is no realistic alternative.
Broken rings can conveniently hide in the ring groove and not reveal any scoring. Inspecting the pistons will show up broken or worn rings.
You would need pistons out if you had either in any event. 
Use 1/4" drive socket set to remove the million sump bolts and that's the hardest part solved. 
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#2
by
theman53
on 24 May, 2011 05:16
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What oil are you running?
It doens't seem that off with what you say you see in the pipe and intake, usage is a bit much though.
If you have it that far get some Goetze rings and a hone. Do the complete job and be satisfied. Stay away from the synthetic oil for a long while and run it slowly hard. Meaning use the full RPM range, but make it work and not floor it ease into it. That should make your problems go away.
That is all if you pull the pan and inspect pistons. If you just look into the head first you might not need to do that project.
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#3
by
zukgod1
on 24 May, 2011 07:36
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A cyl leak down will only tell you how things are in a specific hole.
A high rate of flow in a hole may or may not mean there is a broke ring, it may merely mean there is a ring that hasn't seated yet or is on upside down.
I agree with Mark.
Pull the pistons if your taking the head off and as theman53 posted you just as well get a new set of rings and do a quick hone as well. Either way there is a problem and a new set of rings is what $40.00? Your already there so just bite the bullet and know its good when you put it together.
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#4
by
Dakotakid
on 24 May, 2011 09:58
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Great, you have new pistons and rings. But, what was done with the head? Guides? Properly honed (there was a post about that recently here somewhere)? New valves or went back in with the old ones? Lots of "unknowns" going on here.
The oil smoke on start-up is giving hints....(which you are already thinking about when mentioning stem seals). But, stem seals may be like putting a new bow tie on an old suit of clothes.
As long as that head is coming off, I would spend some quality time examing the guide/valve stem clearance. Please tell me you aren't one of these guys who subscribe to the "break it in like you stole it" philosophy!
Edit: I just reread the original and see the new valves. I would still inspect for valve wobble.
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#5
by
ffgb
on 24 May, 2011 10:20
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All new valve guides were installed, the head was totally rebuilt! I just have been noticing a lot of oil leaking out the front part of the HG. Also, when I checked the oil one day, It was down about a 1/2 qt...its weird, the oil level will be at the full line after a trip from Norcal to Socal driving in the 5hwy, then after a couple of days of driving, stop and go, I'll notice a small drop on the dipstick. I am using Delo 10w-30, I don't know if that has to do with oil loss?
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#6
by
R.O.R-2.0
on 24 May, 2011 10:28
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i would look to the valve seals as being suspect. my seals are bad, and my car smokes like hell when i fire it up, and the first time i bring up the boost every time i drive it.. oil smoke, blue, stinks too.
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#7
by
Quantum TD
on 24 May, 2011 11:15
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If you're gonna have the head off anyways, I would pop the pistons and go with Goetze rings as noted above. A full set of Goetze rings should run about $80-100, and they're worth every penny. Grant have a suspect reputation. Goetze is about the best.
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#8
by
R.O.R-2.0
on 24 May, 2011 11:23
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If you're gonna have the head off anyways, I would pop the pistons and go with Goetze rings as noted above. A full set of Goetze rings should run about $80-100, and they're worth every penny. Grant have a suspect reputation. Goetze is about the best.
theres some people running total seal gapless rings too i believe, with great results. i will be running a set in the next engine i build..
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#9
by
ffgb
on 24 May, 2011 11:46
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Thats the first time i have heard of grant being suspect. I have always heard that goetz and grant were grat along with total seal. I have heard not so great things with mahle, topline, and prothe rings... Hummm
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#10
by
R.O.R-2.0
on 24 May, 2011 12:20
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i think prothe supplies grant rings doesnt he?
i havent heard much good about grant rings. everyone ive heard of running them, people have told them to beware..
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#11
by
Quantum TD
on 24 May, 2011 13:15
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Maybe "suspect" was a bad word choice.I would say, they probably have the life expectancy of Mahle.