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Old 03-03-2009, 03:02 AM   #1
methaddict
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Full Race TS, BW 8374 EFR

Default Blue white smoke out of exhaust on newly built motor

Initial reason for build was due to the infamous cracked oil pickup which lead to a spun bearing and rod knock.

short build list:
-sti shortblock stock liner bored and honed with p/w clearance of .003" to the drylubricant coating on the 100mm CP pistons
-CP ring gaps: top ring .26, 2nd ring .28 and oiling rings .15
-Manley turbo tuff I beam rods
-oem sti crank with .001" polished off the rod journals
-Cosworth main and rod bearings coated with drylubricant teflon coating
-ATI harmonic balancer
-jdm 12mm oil pump not shimmed
-Cosworth 1mm head gaskets PR7269 old style Cometic?
-Portflow in Harbor city, CA did minor hand porting to smooth out an overhang of the intake valve seats into the bowl area due to core shift in the original head castings, installed Supertech std size black nitrided intake valves and inconel exhaust valves, 80lb dual valve springs, ti retainers, and alloy seats, along with Brian Crower avcs 272 cams

I had about 500 miles into the break in period, no smoke until now. I have a base map on my Hydra 2.6 sent to me by Phil. It would stumble around 5200 rpm and tried adding fuel in those areas but stumbing still occurred. Hind sight , I should have lowered the rev limits below that stumbling until I got it protuned on a dyno. I started to try and self tune. After a freeway run one night after adjusting the fuel in that area and test driving it for several sessions, the next day started noticing blue white smoke out the exhaust. At first it didn't smoke at idle but if I held the throttle at above 3k it would start smoking faintly not heavily. I also noticed when driving the smoke would follow the trunk of my car when I let off boost. I did three oil changes, one after 20 miles, one at 200 miles, and one right at 500 miles right after the smoke started. Oil level was lower on this last change. Coolant level was fine.

I suspected broken ring or ringland, then thought it was the turbo seal. I drove it to my mechanic who assembled the motor after letting him know a day before what was happening. He asked if the engine was missing, which it wasn't. He asked if coolant temps were rising, and it wasn't. He was leaning towards a possible valve seal. He lent me his leak down tester for a couple days but never got anyone to help me do this since I became occupied with family events.
At home I inspected the ic piping from my Turboxs fmic at the compressor outlet side. There was some oil but not alot. I did see a small puddle near the silicone coupler. It seemed to run fine as long as I stayed under 5k rpm. I pulled the spark plugs and cylinder #3 had oil on the threads and was white on the prong above the tip. All the other plugs had normal carbon.

My mechanic scheduled to pull my motor out at my house on Sunday. I did all the pre work to disconnect everything to remove the motor: bolts on bell housing, power steering pump, remove nuts on engine mounts, remove radiator, disconnect fuel lines, harnesses, water lines, vacum hoses, turbo, downpipe, etc. He meant to bring his leak down tester but forgot it. We pulled the motor anyways and he took off the passenger side head to access #3 cylinder to remove the piston.

Upon inspection there was a little more oil on that piston compared to the others. No signs of scoring on the cylinder walls, cross hatch from hone is still very visible. Pistons had no detonation marks on the crowns. Ringlands were all intact. Rings were all intact. Top and 2nd rings could freely move within their respective ringlands. I did notice the 2nd ring seemed to have a flat spot towards both ends at the gap. But even with the flat spot it could freely slide in and out of the ringland without sticking in there. I called Mike, tech support from CP Pistons in Irvine today and described the condition 2nd ring to him. The cast iron 2nd ring showed wear on the bottom half of the ring (wear being the grey finish was worn and was shiny), which he said was normal. The ring was installed correctly with the lip facing downward. Now after telling him the wear started to gradually widen about a 1/8"before both ends at the gap, he said that is a sign of the ends butting. He said when they meet that could create a positive vacum and start pulling oil into the combustion chamber, I believe if I get his explanation right.

Now should I just take the head over to Tom @ Portflow so that he can inspect the valve seals or anything else that would cause this oil leak?

We're going to pull the other head off and remove the rest of the pistons this week to inspect the rest. I could tell he's reluctant to split the case halves but I kind of want to see the condition of the bearings. The motor seemed to manually turn fine. What do you guys think?

Anything else we should be checking? Stuck pcv valve? Keeping in mind with 500 miles into the break in and cross hatch still visible I may take the block down to the machinist for his inspection in case I need to rehone. They were honed to CP's recommended rough hone specification due to the hard chromoly top ring which Mike directly corresponded to with my machinist, John G Edwards of Costa Mesa R & D.

I'll post some pics of the piston, rings, and cylinder walls within a day or so.
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Last edited by methaddict; 04-11-2009 at 06:04 PM.
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Old 03-03-2009, 04:57 AM   #2
ronzogonzo
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so, oil smoke when your accelerating and decel or just decel? if your smoking on accel i would think there's some vacuum pulling the oil through the rings to get combusted.


have you checked your routing on your crankcase/pcv hoses? if routed in- correctly could be sucking vacuum through the crankcase causing to much positve pressure and there for sending oil into the intake.

i had in-correctly routed those hoses when running a dual catch can setup and had a s*** load of oil in one of the cans.

just a thought
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Old 03-03-2009, 01:14 PM   #3
methaddict
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Quote:
Originally Posted by ronzogonzo View Post
so, oil smoke when your accelerating and decel or just decel? if your smoking on accel i would think there's some vacuum pulling the oil through the rings to get combusted.


have you checked your routing on your crankcase/pcv hoses? if routed in- correctly could be sucking vacuum through the crankcase causing to much positve pressure and there for sending oil into the intake.

i had in-correctly routed those hoses when running a dual catch can setup and had a s*** load of oil in one of the cans.

just a thought
It was routed the same way before it started smoking and before the engine build. Both crankcases and pvc t'd together then routed to the nipple on the inlet. When I had the catch can I'd block off the pvc, t the crank case breather hoses together then to the oil separator then out to the nipple on the inlet pipe.

Last edited by methaddict; 03-03-2009 at 02:04 PM.
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Old 03-03-2009, 02:28 PM   #4
Fongers
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Since you upgraded to the 12mm pump, you will have some higher oil pressures. What kinda turbo you running? You might need a restrictor in the oil line to prevent the turbo from eating up the oil since its getting hit with more now on the 12mm? Maybe your problem as you mention its happening under higher rpm with less load (less air flow through the exhaust to mix out the). Good luck man.
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Old 03-03-2009, 02:44 PM   #5
methaddict
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Quote:
Originally Posted by Fongers View Post
Since you upgraded to the 12mm pump, you will have some higher oil pressures. What kinda turbo you running? You might need a restrictor in the oil line to prevent the turbo from eating up the oil since its getting hit with more now on the 12mm? Maybe your problem as you mention its happening under higher rpm with less load (less air flow through the exhaust to mix out the). Good luck man.
Right now I'm running the VF36. My mechanic said the same about the higher oil pressures. I thought the same thing about adding a restrictor in the turbo oil inlet line. Doesn't the IHI vf turbos have a restrictor built in? Well also CP saying the second ring ends butting together could also cause to push oil into the combustion chamber?
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Old 03-03-2009, 04:22 PM   #6
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From your statement about the condition of your second ring, I would personally install and square it in the bore and check the end-gap myself. Rings just don't flat spot without there being either something caught in the land area or the gap is too tight. Also if they were file fitted, make sure the gap is parallel.
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Old 03-03-2009, 04:57 PM   #7
methaddict
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Full Race TS, BW 8374 EFR

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I used a manual piston wheel grinder which keeps the ring squared and grinded one end and left the other. I placed the ring in the bore and used the piston to square the ring against the wall and at the depth where the 2nd ring would sit when the piston is at the top of the cylinder. How much of a drag should I feel with the feeler gauge? As I can remember it was a tight feeling drag.
CP recommended the initial clearances to 1st .26, 2nd ring at .28, oiling rings .15. After talking to them again and explaining the flat spot he recommended to use new rings and gap them accordingly 1st .25, 2nd .30, oiling rings .15

Last edited by methaddict; 03-03-2009 at 07:00 PM.
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Old 03-03-2009, 05:55 PM   #8
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Quote:
Originally Posted by methaddict View Post
I used a manual piston wheel grinder which keeps the ring squared and grinded one end and left the other. I placed the ring in the bore and used the piston to square the ring against the wall and at the depth where the 2nd ring would sit when the piston is at the top of the cylinder. How much of a drag should I feel with the feeler gauge? As I can remember it was a tight feeling drag.
CP recommended the initial clearances to 1st .26, 2nd ring at .28, oiling rings .25. After talking to them again and explaining the flat spot he recommended to use new rings and gap them accordingly 1st .25, 2nd .30, oiling rings .15
.025 is too much for the oil control ring gap, but still not enough to cause the issue. Try to look into a rod bearing going south causing too much oil splash for the rings to control. This would mean splitting the case I know, but better safe than sorry.
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Old 03-03-2009, 07:01 PM   #9
methaddict
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.25 for the oiling rings was a typo, it's .15. I will have the block split to inspect the bearings.
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Old 03-03-2009, 07:42 PM   #10
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That sucks man

Good Luck
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Old 03-03-2009, 09:20 PM   #11
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man i bet you have a ton invested in all that mess. please let us know the root of the problem
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Old 03-04-2009, 10:43 AM   #12
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Man, I hope you find a clear cut smoking gun - seriously, better that than a real "head-scratcher." Nonetheless, I sure wish you had put a leakdown gauge on it before you yanked the motor and tore it down. I'm not suggesting that you made any mistakes, but we tore down a perfectly good motor that exhibited the same symptoms as yours, only to find out later on that I had a simple, though bizarre, undiagnosed CCV issue. Just a word of caution to anyone out there...
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Old 03-04-2009, 10:55 AM   #13
mick_the_ginge
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Quote:
-CP ring gaps: top ring .26, 2nd ring .28 and oiling rings .15
Your rings are not butting. My last couple of builds used 24, 26 and we all know I built the living hell out of that engine and the rings showed no signs of butting. Latest build uses 22, 18 with CP rings on 100mm CP Pistons.. I say it's nothing to do with the rings.

Inspect the heads in detail, especially the head that showed the piston with the extra oil on it. Sounds to me like a bad valve seal or bad guide allowing oil to be sucked in. Was their carbon build up on the valves? Another sign of an issue with the valves.

FYI - Break in period IMO is the first 5 miles.
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Old 03-04-2009, 01:39 PM   #14
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Mick, I totally agree with you on the ring butting with that gap, the engine would have to get very hot to cause such an incident. It is possible that the pcv valve is bad, causing excessive crank-case pressure under boost, but there would be oil everywhere. The valve stem seals going out is questionable because then the oil issue would be worse under deceleration rather than boosting. This leads to the piston/rod area and the flat section on the ring
What caused this if the gap is correct and the ring moves freely in the groove? This flat section would surely cause improper ring seal and amplify oil consumption.... But why suddenly after so many miles?
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Old 03-04-2009, 02:43 PM   #15
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Quote:
Originally Posted by andya View Post
...but there would be oil everywhere...
I think he said there was. When it happened to me there wasn't a ton of oil in the I/C or pipes either - it all pretty much misted straight on thru to the intake and thru the motor. No argument here: I'm just trying to help the poor guy out like you, and I really hope he finds an uncomplicated "ah ha" in his search thru the motor internals. Frankly, I wouldn't wish my dumb mistake on any one else.
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Old 03-04-2009, 03:21 PM   #16
methaddict
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Last edited by methaddict; 03-04-2009 at 04:42 PM.
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Old 03-04-2009, 03:52 PM   #17
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Do all the second rings have the same wear? I am looking at one out of a 46k engine with less end wear than the one pictured. What was your hone finish?
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Old 03-04-2009, 04:42 PM   #18
methaddict
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Originally Posted by andya View Post
Do all the second rings have the same wear? I am looking at one out of a 46k engine with less end wear than the one pictured. What was your hone finish?
We haven't pulled the other slugs yet. I don't know the exact specs of the hone finish but CP told me that it would need a rough hone. I'll try to get the exact specifications of the finish from CP. The shiny area on the bottom half of the ring was said by CP to be normal but see how it tapers wider to the ring ends. That's what CP says to be an indication of the ends butting. I posted a 2nd pic showing the wear on the ring.
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Old 03-04-2009, 04:51 PM   #19
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I would tend to agree with the end butting, but ring groove depth or a high tension ring can also cause the same thing with a coarse finish.
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Old 03-04-2009, 06:06 PM   #20
mick_the_ginge
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Holy...... I would question what the *actual* ring gap was when that puppy was installed. Is does look like it's been touching.

Is the internal bevel on the top or the bottom of that second ring, it's hard to tell in the picture.

On the Top ring it should be on the top at the back and second ring it should be at the bottom at the back.
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Old 03-04-2009, 06:13 PM   #21
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CP rings just have a scraper groove facing down on their second ring.
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Old 03-04-2009, 06:31 PM   #22
methaddict
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The bevel on the 2nd ring was facing downward from the crown of the piston. I'll set the 2nd ring into the cylinder and measure the gap with my feeler gauges.
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Old 03-04-2009, 08:31 PM   #23
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I was just trying to work out if the rings were in backwards, ie #1 in #2. #1 has a bevel on the backside off the ring whereas #2 on CP rings does not.

The second ring has a napier cut out on the front side which should point down.

I just looked at my CP rings that I pulled out of my last build. They look in great shape.
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Old 03-04-2009, 08:52 PM   #24
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Quote:
Originally Posted by methaddict View Post
We haven't pulled the other slugs yet. I don't know the exact specs of the hone finish but CP told me that it would need a rough hone. I'll try to get the exact specifications of the finish from CP.
When I brought my CP pistons and rings to my machinist and he found out that CP called for a 280 stone, he said "hell no". Something along the lines of it being too coarse, and recommended a finer finish. I haven't taken mine into super high boost yet, but I see 8-10 psi often, and no smoke or consumption to speak of. 875 miles to date.
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Old 03-04-2009, 11:34 PM   #25
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Seems that you are not the only one having problems with smoking!

Quote:
Originally Posted by calisti
Mike, CP tech support gave me ring gap numbers: top ring .025, 2nd .028, oiling ring .15, and also recommended due to the hardness of the 1st ring the cylinders must have a rough hone. I had my machinist call Mike to get the proper ra (roughness average) numbers and what grit honing stones are required.

That's what I gapped mine to (I was worried that it was too large of a gap) and after removing one head (I installed a comp ring upside down and it was smoking, had to fix that) and re-installing a new ring set on the piston, I noticed the walls with my rough hone were nice and smooth (the rings seated pretty quickly) and the car no longer burned oil. I have ~250 miles on the motor (plus a bunch of idling and revving) and it has a tad bit of slap when cold, but goes away once warmed up. Seems like it is going to be fine. These are ceramic coated CP dropins.
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