Is this piston ring flutter? Correct answer wins money
Is this piston ring flutter? Correct answer wins money Symptoms:
Manual transmisson car, at high rpms letting off the gas in gear there is lots of oil out the exhaust, you can see a bus size cloud behind, and then again when I get back on the gas the is another cloud. Only happens during these conditions, no oil burning at start up, idle, WOT. No nitrous, no boost
Solutions I've tried:
I'm at the end of my rope, is it the oil control rings or could it somehow be the heads sucking oil past the valves because of the crazy vacumme at high rpm in gear?
How would I diagnoise anything beyond this. I have been working at solving this problem for almost 3 years now and am really frustrated.
Manual transmisson car, at high rpms letting off the gas in gear there is lots of oil out the exhaust, you can see a bus size cloud behind, and then again when I get back on the gas the is another cloud. Only happens during these conditions, no oil burning at start up, idle, WOT. No nitrous, no boost
Solutions I've tried:
- No PCV system, with breather
- LS6 PCV valley and updated PCV valve with AMW catch can
- Full long block rebuild, new rings, bearings, etc. stock pistons, rods, crank. (done by a local shop)
- Rebuilt Stock Unported heads, valves reground, new valve seals etc (also done by same local shop)
- Leakdown test came back perfect
- Compression test came back perfect
- Dyno'd 382wrhp with just a 224 cam (pretty strong)
I'm at the end of my rope, is it the oil control rings or could it somehow be the heads sucking oil past the valves because of the crazy vacumme at high rpm in gear?
How would I diagnoise anything beyond this. I have been working at solving this problem for almost 3 years now and am really frustrated.
Last edited by nytoy; Jun 29, 2006 at 11:00 PM.
When they did the rebuild, did they hone the cylinders or did they use a new block? Was the block being used ever over-heated? If you did a compression test and leakdown and they came back fine...within 10%...then I think it's your oil seals in the heads.
Are you spraying the car with nitrous? If so and the rings weren't grooved properly, then that might be an issue. Also, if the car is boosted (not enough info. given) then you may have issues there to address as well.
Are you spraying the car with nitrous? If so and the rings weren't grooved properly, then that might be an issue. Also, if the car is boosted (not enough info. given) then you may have issues there to address as well.
How is the oil getting in? Do you have oil in the intake? I'm gonna assume no. Let me also ask this question. Do you have oil in the intake runners in the heads? Maybe oil is getting sucked in through there if you have ported heads. Because an engine is a large air pump once you slam the TB shut thus putting the entire engine into a vaccum state being the motor can't draw in air from anyplace. Thus why it is sucking in oil. I suspect it's in the heads. Ring flutter might be a possibility with a older motor without the updated rings but being you've redone the motor that seems far fetched. Like I said I would check your rocker arm bolts and seal them up real good. Next I would guess valve seals, but those would tend to smoke more at startup than anything. Give the rocker bolts a look and see. What I would do is pull the intake rocker off and spray some carb cleaner down in there to wash the oil out and reassemble using thread sealer. DON'T DO THE EXHAUST ROCKERS. On stock heads both the intakes and exhaust rockers are blind holes and you can hydralic the bolt in there if you try to torque it and there is a bottom to it. If you have stock non ported heads then you can't do the intakes eithor. I'd take a look and see. Might be worth your time to pull the intake and everything get a real good look at it.
Originally Posted by NOSjohn
When they did the rebuild, did they hone the cylinders or did they use a new block? Was the block being used ever over-heated? If you did a compression test and leakdown and they came back fine...within 10%...then I think it's your oil seals in the heads.
Are you spraying the car with nitrous? If so and the rings weren't grooved properly, then that might be an issue. Also, if the car is boosted (not enough info. given) then you may have issues there to address as well.
Are you spraying the car with nitrous? If so and the rings weren't grooved properly, then that might be an issue. Also, if the car is boosted (not enough info. given) then you may have issues there to address as well.
The valveseals were changed twice in the heads.
No nitrous, no boost.
Originally Posted by kossuth
How is the oil getting in? Do you have oil in the intake? I'm gonna assume no. Let me also ask this question. Do you have oil in the intake runners in the heads? Maybe oil is getting sucked in through there if you have ported heads. Because an engine is a large air pump once you slam the TB shut thus putting the entire engine into a vaccum state being the motor can't draw in air from anyplace. Thus why it is sucking in oil. I suspect it's in the heads. Ring flutter might be a possibility with a older motor without the updated rings but being you've redone the motor that seems far fetched. Like I said I would check your rocker arm bolts and seal them up real good. Next I would guess valve seals, but those would tend to smoke more at startup than anything. Give the rocker bolts a look and see. What I would do is pull the intake rocker off and spray some carb cleaner down in there to wash the oil out and reassemble using thread sealer. DON'T DO THE EXHAUST ROCKERS. On stock heads both the intakes and exhaust rockers are blind holes and you can hydralic the bolt in there if you try to torque it and there is a bottom to it. If you have stock non ported heads then you can't do the intakes eithor. I'd take a look and see. Might be worth your time to pull the intake and everything get a real good look at it.
I've pulled and cleaned the intake about 20 times in the last few months, after each change in the setup. I can do it in my sleep, I have pics of it if that would help.
Stock unported heads. I haven't sealed the rocker bolts, because with a stock head the bolt shouldn't go into the intake or exhaust port correct?
Would it hurt to use thread sealant on the stock unported heads?
Is it possible it's the oil control rings on the piston?
thanks for the responses!
Last edited by nytoy; May 1, 2006 at 11:17 AM.
Originally Posted by nytoy
There is oil in the intake and on the runner of the heads, I haven't looked again with the PCV totally blocked off, but I'm guessing it will be there again.
I've pulled and cleaned the intake about 20 times in the last few months, after each change in the setup. I can do it in my sleep, I have pics of it if that would help.
Stock unported heads. I haven't sealed the rocker bolts, because with a stock head the bolt shouldn't go into the intake or exhaust port correct?
Would it hurt to use thread sealant on the stock unported heads?
Is it possible it's the oil control rings on the piston?
thanks for the responses!
I've pulled and cleaned the intake about 20 times in the last few months, after each change in the setup. I can do it in my sleep, I have pics of it if that would help.
Stock unported heads. I haven't sealed the rocker bolts, because with a stock head the bolt shouldn't go into the intake or exhaust port correct?
Would it hurt to use thread sealant on the stock unported heads?
Is it possible it's the oil control rings on the piston?
thanks for the responses!
The oil control rings are a possibility for the oil burning but that wouldn't account for the oil in the top end. If you have a ton of oil in the top end it's getting there somehow. If you pull the intake and you still have what appears to be oil in there then I would rule out the rings. If it is reasonably dry then the rings are the source.
I'll pull the intake again, but yes this was oil for sure, as I cleaned it and smelled it. Good thought with the brake booster, I'll cap that off and see if there's any change.
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Have you looked at all the vacuum lines going to the intake? I'd take them off and see which ones have oil in them. I'm with the previous poster, if you've got oil in the intake it's getting sucked in there, not blown up from the rings.
Now here's a thought, what if the oil in the intake isn't the issue? Follow this line of thinking. On decel you are creating a high vacuum condition in the top end. Without a PCV, you probably have high crank case pressure. What if the combination of vacuum (in the top end) and pressure in the crankcase is forcing oil into the combustion chambers??
Try this out. Pull your crankcase breather and see if there's pressure or vacuum at idle. Then have someone rev up the motor and see if the condition gets worse (more pressure, more vacuum) or changes.
Now here's a thought, what if the oil in the intake isn't the issue? Follow this line of thinking. On decel you are creating a high vacuum condition in the top end. Without a PCV, you probably have high crank case pressure. What if the combination of vacuum (in the top end) and pressure in the crankcase is forcing oil into the combustion chambers??
Try this out. Pull your crankcase breather and see if there's pressure or vacuum at idle. Then have someone rev up the motor and see if the condition gets worse (more pressure, more vacuum) or changes.
Mine does the same thing. Just instantly a huge cloud of white smoke. Makes you think the car is on fire. I have nitrous rings though. It is just a large amount of blow by that is causing it. It freaked me out on the dyno the other day.
Engine:
347cid Nitrous Built
3.905 Aluminum LS1 block
6.0L balanced crank
Eagle ESP Forged H-beam rods (6.2")
Custom Diamond pistons with tool steel wrist pins
ARP Main studs
ARP Head studs
317 casting (6.0L truck heads) with a Stage 1 port/polish for nitrous, decked .030 with polished combustion chambers
Multi-layer Steel head gaskets
Comp XER 224/230 camshaft
Comp R Hydraulic lifters
Chromoly hardened pushrods (7.40")
Comp 918 springs with titanium retainers
Ported LS6 oil-pump
Adjustable timing chain
LS6 Intake
BPR ported Throttle Body
SLP 85mm MAF
Aftermarket airlid
160 Degree thermostat
LS6 PCV system
Engine:
347cid Nitrous Built
3.905 Aluminum LS1 block
6.0L balanced crank
Eagle ESP Forged H-beam rods (6.2")
Custom Diamond pistons with tool steel wrist pins
ARP Main studs
ARP Head studs
317 casting (6.0L truck heads) with a Stage 1 port/polish for nitrous, decked .030 with polished combustion chambers
Multi-layer Steel head gaskets
Comp XER 224/230 camshaft
Comp R Hydraulic lifters
Chromoly hardened pushrods (7.40")
Comp 918 springs with titanium retainers
Ported LS6 oil-pump
Adjustable timing chain
LS6 Intake
BPR ported Throttle Body
SLP 85mm MAF
Aftermarket airlid
160 Degree thermostat
LS6 PCV system
Originally Posted by orangeapeel
Mine does the same thing. Just instantly a huge cloud of white smoke.
Grayish/blue is oil
Black-rich
Originally Posted by muncie21
Huge cloud of white sounds like water...most likely a leaking head gasket.
Grayish/blue is oil
Black-rich
Grayish/blue is oil
Black-rich
All this leads me to thinking it isn't a motor issue itself. He had the motor redone and I'm assuming it was stock before he had it redone. Something is amiss. Is your evap system still hooked up?
Originally Posted by muncie21
Have you looked at all the vacuum lines going to the intake? I'd take them off and see which ones have oil in them. I'm with the previous poster, if you've got oil in the intake it's getting sucked in there, not blown up from the rings.
Now here's a thought, what if the oil in the intake isn't the issue? Follow this line of thinking. On decel you are creating a high vacuum condition in the top end. Without a PCV, you probably have high crank case pressure. What if the combination of vacuum (in the top end) and pressure in the crankcase is forcing oil into the combustion chambers??
Try this out. Pull your crankcase breather and see if there's pressure or vacuum at idle. Then have someone rev up the motor and see if the condition gets worse (more pressure, more vacuum) or changes.
Now here's a thought, what if the oil in the intake isn't the issue? Follow this line of thinking. On decel you are creating a high vacuum condition in the top end. Without a PCV, you probably have high crank case pressure. What if the combination of vacuum (in the top end) and pressure in the crankcase is forcing oil into the combustion chambers??
Try this out. Pull your crankcase breather and see if there's pressure or vacuum at idle. Then have someone rev up the motor and see if the condition gets worse (more pressure, more vacuum) or changes.
There's no pressure at idle, with the breather off, or rev'ing, pretty much neutral.
Originally Posted by NemeSS
ur rings might have been installed incorrectly, upside down or gapped
wrong or
oil pump shimmed too much
wrong or
oil pump shimmed too much
The motor did it the exact same way before the rebuild. After the rebuild I used a new stock ls6 oil pump with no shim. Rings where done by an experienced builder, I asked specifically if they were upside down and he claims there is a dot so you can't install them wrong or something.
I do appreciate the suggestion though.
Originally Posted by kossuth
All this leads me to thinking it isn't a motor issue itself. He had the motor redone and I'm assuming it was stock before he had it redone. Something is amiss. Is your evap system still hooked up?
Me too, motor was bone stock before the rebuild. EVAP and EGR system is gone, hmmm think that's messing things up?
