Detonation due to Oil Consumption?

[jckrieger]

All,

I've been getting some considerable spark knock on my CSX and am wondering if oil consumption is the root cause of my pre-ignition. Ever since I installed the forged pistons, the car has used a little oil, but last fall I hurt one of the pistons (lost a fuel injector) and now a cylinder is down to 140psi on the compression test. The car now uses about a quart of oil every 200 miles and is spark knocking as low as 18psi at 11:1-12:1 A/F ratio running premium gas with methanol/water injection or straight E85 injection. I'm planning to blow the car up at the track this weekend, but am curious if anyone else has had issues with detonation and oil use. I've never had a damaged piston that still held 140psi before...

If my problem is oil consumption, I will be buying a new set of pistons and will build my 16V motor. What are you guys running for piston to wall clearance on your high power motors? I've always been dropping std pistons in std bores and don't want to fly by what the manufacturer lists and find out the piston is getting tight while under boost.

[Speedeuphoria]

What kind of PCV setup do you have? Are you using a catchcan?

[johnl]

Ditto on PCV, catch can will tell you whether you have a lot of oil - blow by.

140 lbs is pretty good.

A leak down test might tell you whether the oil is coming from valve guide(s) vs piston rings.

[turbovanman²]

Yep, oil will cause detonation.

I am running .005 with the Venolia's, ran .004 with the JE's. Was told I could easily run .004 with Venolia's too.

[Turbo3Iroc]

What were the compression numbers for the other cylinders? I would suspect your turbo is leaking the oil. SDAC 17 going down the track I was getting very audible knock at times with a heavy 110 mix in the tank. Turned out to be the turbo leaking oil into the intake stream.

[zin]

Oil is like anti-octane, it will cause big issues with detonation. Sounds like you need to keep the boost to a min until you can fix it.

[Turbodave]

Oil can certainly cause it to knock as others have said.

The 5.2/ 5.9 Magnum engines had problems with plenum gaskets on the intakes that would let them suck oil from the oil valley into the intake causing knock, seen that on a few Rams over the years. While your setup is much different the symptoms are the same.

That 140 Psi sounds pretty good for compression, never seen a damaged piston read that high.

[moparzrule]

Did you have the cylinder's honed when you installed the pistons?

I would suspect the reason for the lower compression was that there was no fuel to lube that cylinder and the bore ''glazed over'' so to speak but only slightly since it's still 140.

But yeah I've had oil make detonation come. I tried to run Royal purple twice, both times cracked a piston with it. The only thing I could figure was the oil is so slick it was getting past the rings causing detonation. Stopped using royal purple, no more issues. Wierd.

[jckrieger]

What kind of PCV setup do you have? Are you using a catchcan?

Right now the car has the stock PCV setup under vacuum, and under boost it just vents... to the top of the transmission. The PCV is dumping more oil than normal, but I'm also boosting a lot more than normal. I plan on a complete teardown to determine the condition of the bottom end after a couple passes at the strip.

When it comes to compression, all 4 cylinders were 150psi after I assembled the engine. I honed all the cylinders, and have never had oil consumption issues with any of my previous builds. I'm not sure exactly when one cylinder dropped from 150psi to 140psi, but it was around the time I had my S60 turbo die.

The turbo shouldn't be leaking oil, as it was a new Turbonetics Stage 3 "F1"/S50 trim hybrid and only has about 2,000 miles on it. I checked for shaft play last night and it's still as tight as it was the day I installed it.

Go figure the one engine where I installed NEW pistons, rings and valve seals is the one that has the oil consumption problem. None of the plugs are getting fouled with oil, but I've had 3 turbos on this motor and they've all smoked equally (except when the S60 blew up).

I've never had a motor that had 140-150psi compression, 20" of vacuum at idle, and have it burn so much damn oil. I'm completely baffled. Could not having vacuum on the PCV from the airbox cause massive oil consumption? I've never had this problem before with the same setup. I'll check my hoses tomorrow and see if this turbo is spewing oil.

[MiniMopar]

I've never had a motor that had 140-150psi compression, 20" of vacuum at idle, and have it burn so much damn oil. I'm completely baffled. Could not having vacuum on the PCV from the airbox cause massive oil consumption? I've never had this problem before with the same setup. I'll check my hoses tomorrow and see if this turbo is spewing oil.

No, but I have had stuck PCV valves snort lots of oil into the intake. If this motor has burned oil since the beginning, perhaps there is an issue with the oil control rings or perhaps the bores are egg-shaped at the bottom.

EDIT: to answer your question, I too have had detonation caused by burning oil. A quart in 200 miles is a lot of oil. My CSX has oil control issues in the bores as well, but it has never used more than a quart in 1000 miles and that is with the worn out original turbo.

[jckrieger]

No, but I have had stuck PCV valves snort lots of oil into the intake. If this motor has burned oil since the beginning, perhaps there is an issue with the oil control rings or perhaps the bores are egg-shaped at the bottom.

EDIT: to answer your question, I too have had detonation caused by burning oil. A quart in 200 miles is a lot of oil. My CSX has oil control issues in the bores as well, but it has never used more than a quart in 1000 miles and that is with the worn out original turbo.

I'll check the PCV valve and see what it's doing. I've never replaced a PCV valve, and sometimes when I'm moving heads and vacuum harnesses around, good parts get switched for bad parts. This block... well, I don't remember where this block came from, but it was in pretty good shape and the ring end gap was on the tight side of the service limits. Of course, that doesn't mean the bores are round, but before the piston swap the motor didn't use this much oil. I guess the only way to know for sure is to take the poor motor apart.

I checked the PCV and it seems to be holding, but it might be a little sticky. I also did a cold compression test and the results were 145-150-145-140 with the engine at around 60 degrees F. Some variation could be due to the hand-carving of the combustion chambers in the head, but I'm a little concerned about the 140 cylinder. Also, all 4 BR9ES plugs were relatively carbon fouled, but not oily.

[turbovanman²]

You can still have good compression and have bad oil control rings. Looking at the plugs or piston tops thru the spark plug hole can help determine where the oil is coming from.

[moparzrule]

What were the gaps of the piston rings? Specifically the oil rings.....and also did you stagger the ring gaps?
Oh and one other thing, the center part of the oil ring groove, did you make sure that piece did NOT overlap? It's very easy to overlap that thing, but it's just suppose to come together and touch.

[WickedShelby88]

I've been told to run a different bore size for forged as well.. If your car came with cast like ours then the thermal expansion of the pistons is different I believe a forged piston requires tighter tolerances. This is just off the top of my head without any specs either. Oil will really lean out your mixture and especially throw your O2 off. My 3.0 mini while it runs okay spark knocks if I don't run at least premium. If its using oil though.. Do you have any issues with your dipstick popping out? Matt's right on that oil ring groove. Thats an easy one to goof.

[jckrieger]

I'm pretty sure I installed the rings correctly, as the Wiseco set actually had some pretty darn good directions with the piston set. The gaps were definitely staggered, but I can't remember if I even measured the oil control ring end gap since it was all .std bore stuff. I measured the compression rings to make sure they were in spec, but the oil rings I figured were in spec since the bores and compression rings all checked out.

I actually took the car to the track today and discovered my clutch is junk. I made a pass with a passenger and clicked off a 13.63@105.68 with some clutch slippage and "low" (20-22psi) boost. I then cranked up the boost and ran a 14.00 @ 100mph... with the car at 7,000rpm all the way down the track in all gears.. no clutch. Luckily the car had plenty of clutch to drive home, but those ceramic clutches are garbage. I'm tearing the car down to install a new clutch (if I find something that's 400hp capable) and will inspect the pistons/rings/head closeley at that time. It's now time to go back on those clutch threads...

[Putter]

Good to see you made it home.

I remembered another clutch brand that the vendors don't carry. SPEC has a full lineup of clutches for our cars. Give them a call see if you can't get an engineer on the phone.

[MiniMopar]

It's now time to go back on those clutch threads...

Which clutch are you running now?

[jckrieger]

Which clutch are you running now?

I'm running a Relentless Performance 6 puck ceramic clutch setup that was supposed to be good to 350-400hp. The clutch can't have 10K miles on it, but it definitely can't hold more than 22psi at the track. On the street at higher boost levels, the tires would just start spinning, but with traction the clutch starts "spinning"

[MiniMopar]

It's probably not worn out. It's just at its limit. The marginal clutch in the CSX didn't show up until I hit the track either. After that it was glazed and I could make it slip on the street too.

[jckrieger]

It's probably not worn out. It's just at its limit. The marginal clutch in the CSX didn't show up until I hit the track either. After that it was glazed and I could make it slip on the street too.

I had the same problem when I took the CSX to the track stock. It had an aftermarket T2 oganic clutch and used to chatter on release. At the track I glazed it pretty bad and it started slipping above 10psi. That's when I put in the 6 puck clutch... and first time at the track it failed me. I guess my setup must be making at least a little torque...

[jckrieger]

It's time to revive the thread from the dead. I got the CSX together with the new block and fresh cylinder hone, along with the new clutch. I've put a few miles on the motor to seat the rings and idle vacuum is about 21" on the autometer gage. Now, for the bad. The car smokes like a mosquito fogger when at idle or decel, but does not smoke at all under cruise or boost. The intercooler hoses are bone dry, the turbo bearings are like new, and there is almost no blowby. I am going to do a compression check, but I don't think there is any way the bottom end is the culprit.

The only times I've had a massive blue mosquito fogger is when I had a failed turbo. I don't think this engine could possibly run if all this oil was going into the cylinder. I guess I'll swap this new Turbonetics turbo out for a stocker and see what happens :(.

[moparzrule]

Yeah sounds like the oil is coming out of the turbine side of the turbo. But check the spark plugs just to make sure.
How fresh is the head? When I had the valve guides go it smoked pretty bad.

[turbovanman²]

+2 on the turbo and what do the plugs look like?

[Russ Jerome]

You can still have good compression and have bad oil control rings.

I'll second that!

It used to be common practice for vendors to give you
over/undersize oil rings with the pistons (.020+ slugs
and .030" oil control rings). You cant size those rings.

This does not work period.
All your left with is broken oil control rings even after
the most anal install, will take you two evenings of
diag time before you finaly pull the shortblock and
see the broken oil control rings....grrrrrrr ;(

[Russ Jerome]

The car smokes like a mosquito fogger when at idle or decel, but does not smoke at all under cruise or boost.

Turbo smoker, can be fun messing with tailgaters!
On decel at high vac, just brake stand it all the time!

[jckrieger]

These last few days I ran the car with the "new" block to try and seat the rings a bit better. I put about 100 miles on the engine at 20psi, unknowingly with Bosch platinum plugs! The car was smoking like crazy at cold startup, but would clear up after about 30 seconds of idling. I checked the plugs and cylinders 2 and 3 have oil fouled plugs, 1 and 4 are perfectly white. The oil is also black and smells like crap. I'm guessing I have ring issues on the middle cylinders, so I pulled the head tonight and noticed no unusual scratches or wear on the cylinders. I guess it's time to buy some rings and hope for the best! The turbo was clean and is still tight like new, so I'm guessing I still have a ring issue even after the block swap.

[BadAssPerformance]

What is the bore clearance on the inner 2 vs. outer two? Forged slugs swell a bunch, got two tight ones?

[jckrieger]

What is the bore clearance on the inner 2 vs. outer two? Forged slugs swell a bunch, got two tight ones?

I'll go out there with a feeler gage and see what the clearances are. When I pulled the pistons from the first block, the skirts looked pretty darn nice. The pistons are actually pretty loose in the bore, but never measured the clearance in this block. I'll go check and let you know what I find.

[BadAssPerformance]

No scuffs on the skirts? Got a bore gage to check to see if the bores are egg shaped too? Check compression on each cylinder? Was it the same two on the last block?

[jckrieger]

I measured the bore-piston clearance with a feeler gage, and all 4 cylinders are about the same... .024" between the upper ring land of the piston and the cylinder bore with the piston rocked to one side. This seems huge, so I'm wondering if the .std bore Wisecos I got were machined wrong, as the ring end gaps I measured on my more heavily worn block were well within the service limits.

Compression check was 145-150-145-150. Go figure.

[jckrieger]

No scuffs on the skirts? Got a bore gage to check to see if the bores are egg shaped too? Check compression on each cylinder? Was it the same two on the last block?

I don't think it was the same 2 cylinders on the last block, I'm thinking with the old block cylinders 1 and 3 were darker than the rest.

I don't have a bore gage, but this block with old factory mahle pistons had no oil control issues whatsoever. Same with the other block I ran. I'm guessing there's a problem with the .std sized Wiseco pistons.

I guess with .024" of clearance, I should be able to order some .020 oversized Wisecos and drop them right in my .std bore block, heh.

[jckrieger]

I measured the bores on the block and they're all about 87.4mm... and I measured a random 2.5L piston I had laying around and it was about 86.7mm. That's about .027"... imagine that, right about what my Wiseco's measured. So WTF is wrong? Does anyone even sell JE pistons that use standard rings anymore?

I'm guessing the top of the piston has a smaller diameter than the skirt, so the typical wall to piston clearance is not the clearance I am measuring. According to the service manual, I should be measuring a few thousandths between the skirt's OD and the bore diameter. Since both pistons are giving me about the same geometry, I still say my bores are ok. I'm tempted to throw in a good set of stock Mahle pistons and iron rings and see what happens. For $50 it'd be worth the effort to know for sure. Problem is I'll be beyond the limit of the poor cast pistons.

[jckrieger]

Alright, I give up... this engine is going back together with some good cast Mahle std. pistons. If the oil consumption issue is fixed, I'll order a set of Venolias or have some custom Ross racing pistons made since JE's seem to be unavailable. Will run the crap out of the car until the cast pistons fail before installing new forged pistons.

[bris09]

I maybe way off here but, what you are describing sounds like worn valve seals. How old is the head?

[jckrieger]

I maybe way off here but, what you are describing sounds like worn valve seals. How old is the head?

The head is old, but I believe I've used it before without issues. It has been long enough that I can't remember anymore. I'm going to throw the original head back on the car since it won't take long and see what it does. If it still smokes after that, the pistons are coming out.

[turbovanman²]

Got pics of the piston tops.

You measure clearance at the skirt, aprox half way and 90 deg from the wrist pin. Measuring at the ring area will be so far off, you'd have thank they were the wrong size.

Remeasure and post up. I hope you honed it with a ball hone before you put new rings in.

[jckrieger]

By popular demand, I installed a known good head on the CSX today and started it up. I honestly can't tell if it fixed the problem at this point, as my nose stopped working a couple days ago. I will say I ran the car in my pole barn for about 10 minutes and I didn't smell like burning oil. Due to the rain, I probably won't be able to drive the car until tomorrow evening at the latest, as I'm picking up a CBR600 in the morning.

[johnl]

CBR 600!!!!! Way cool.

Since you'r going to swapping heads, why not swap the guide seals out? Get some of the viton or teflon ones with the little springs that choke the seak against the stem.

[turboshad]

I maybe way off here but, what you are describing sounds like worn valve seals. How old is the head?

A big +1 to valve seals. Even if the head was fine before they can crack and split. I had the exact same problem which I found by going from regular oil to synthetic after a break in. I went from wicked top end to nothing with instant knock making me raise the FP. If kind of confused me how an oil change could cause knock. The end result was I learned Mobile1 will cause knock much more than regular oil and that I had a cracked valve seal. My only warning is that you make sure you get the keepers seated when the job is done or you may get to learn things the hard way like me. :(

http://i54.photobucket.com/albums/g103/turboshad/DSC00797.jpg

The only good thing is that souvenir began the 2.4 project which I don't regret in the least.

[jckrieger]

Well, today I ran the car with the new head the the results look exactly the same. If you look at the exhaust valves on the old head, cylinders 2 and 3 are oily black, and 1 and 4 are a nice clean tan color. Today I'm going to order a new set of rings and finally do what I should have done over a year ago.

If all goes well, hopefully I'll be reporting some good findings in a week. I think Chris had a .std set of piston rings in his shop, so we'll see how it goes. Since I'm doing the rings/hone again, would you guys use a ball hone or a 3 stone hone for getting these rings to seat? I'm guessing my issue lies in the oil control ring assembly... guessing I put them together wrong the first time however many years ago. If I remember correctly, it's impossible to put the oil rings in upside down, so I'm not sure what could have happened.

[turbovanman²]

Well, today I ran the car with the new head the the results look exactly the same. If you look at the exhaust valves on the old head, cylinders 2 and 3 are oily black, and 1 and 4 are a nice clean tan color. Today I'm going to order a new set of rings and finally do what I should have done over a year ago.

If all goes well, hopefully I'll be reporting some good findings in a week. I think Chris had a .std set of piston rings in his shop, so we'll see how it goes. Since I'm doing the rings/hone again, would you guys use a ball hone or a 3 stone hone for getting these rings to seat? I'm guessing my issue lies in the oil control ring assembly... guessing I put them together wrong the first time however many years ago. If I remember correctly, it's impossible to put the oil rings in upside down, so I'm not sure what could have happened.

Use a ball hone.

You could have simply not honed the bores enough last time, broke it in incorrectly or used/switched to synthetic too early, or put the engine together and had issues getting it running, which ruins them-that cost me an engine, :(

[moparzrule]

180 grit ball hone for standard iron rings. Use a drill with a slow speed, less than 500 RPM. Lube the stones and bore with oil or heavy with WD-40, go up and done the bore with a speed that seems relative to the RPM of the hone to try to get a nice 60 degree crosshatch. Doesn't have to be perfect, but try to get close. About 10-20 seconds in each bore is all it should take.

[jckrieger]

These are Wiseco Forged pistons, so they are the "low tension" moly rings. Last time I honed the cylinders I used a 1/2" drill since it has serious gear reduction. I'm guessing I botched up the oil control ring expander on 2 cylinders or something.. going to pay close attention when I take the motor apart so I don't repeat the mistake. Compression was great, so I don't think the top rings were the issue.

[moparzrule]

Well, I also used the 180 grit ball hone for my Wiseco's and had no issues. Most people would recommend the 240 grit for moly rings, but whatever. IMO the 180 is the pretty universal.

[jckrieger]

Alright guys, I found the problem after 2+ years. Wiseco evidentally f'ed up and sent me a bad set of rings with the 2.5L std bore pistons. The oil ring expander was so far out of spec that the oil control rings had no tension at all. In fact, I could drop the piston in the bore without a ring compressor and it'd just fall to the bottom of the bore. I never checked the oil rings as an assembly since that's not exactly standard procedure. The directions even say no fitting is necessary for the oil rings. I guess from now on I'll install each piston without the top rings and make sure the oil rings have some tension. You guys have no f'n idea how much this pisses me off! No more Wiseco products for me... they just don't know what they're doing in our market.

I forgot to mention, the new rings I got from Chris W had a different coating and have good tension in the bore. The original oil expander ring was a gold color and the new expander rings are a gray color.

[BadAssPerformance]

Glad you figured it out Clark! :thumb:

[turbovanman²]

That sucks, :(

Too bad you didn't post pics of the piston tops at the beginning, we could have told you rings or ? right away.

[Ondonti]

Just wanted you to know that when your motor sucks oil really bad, it will give higher compression numbers. Remember that trick where you put oil into your cylinder to see if compression goes up. Well some of our motors already do that for themselves :(

My motor runs clean until it warms up then it pumps out smog.
My highest compression piston is also the one that burns the most oil and has the biggest piston clearances.

Probably feels good to have your issue worked out. :bump2:

[jckrieger]

That sucks, :(

Too bad you didn't post pics of the piston tops at the beginning, we could have told you rings or ? right away.

The piston tops were clean, but were slightly wet with oil each time I removed the head. All 4 pistons appeared the same. No excessive carbon buildup, but also no hot spots. I have a tad bit of experience with these engines, but not so much experience with ring sets that contain the wrong oil expander rings.

[jckrieger]

Just wanted you to know that when your motor sucks oil really bad, it will give higher compression numbers. Remember that trick where you put oil into your cylinder to see if compression goes up. Well some of our motors already do that for themselves :(

My motor runs clean until it warms up then it pumps out smog.
My highest compression piston is also the one that burns the most oil and has the biggest piston clearances.

Probably feels good to have your issue worked out. :bump2:

Hell yeah it feels good to get this figured out. I've been promising big #'s from this car, but since I installed the pistons the car has always run sad numbers.

The compression issue is interesting, as this engine definitely had slightly higher compression than I expected. My numbers were close to 150psi cold, even with considerable material removed from the combustion chamber. Never really thought anything of it.

[Ondonti]

My compression is like 7.15:1 and I once got 130 out of my worst burner and only 111 out of my cleanest cylinder. My one clean burning cylinder runs like 10psi below all the others. I love that cylinder cause I never gotta worry about that plug fouling.

[jckrieger]

This last time I pulled the head each of the pistons had some oil pooled on top of them. Turns out I had the car idling for about 20 minutes before shutting it off, and that allowed a TON of oil to accumulate on the piston tops. Funny it didn't burn out. Never noticed this the last times I pulled the head.

[jckrieger]

Today I finished putting the CSX back together and took it for a run to break in the rings. I started with horribly wet, fouled, black spark plugs and returned home with 4 nice, tan colored plugs. This is the first time the car has had clean plugs since the Wisecos were installed. Now I just need to figure out what's up with my calibration.

[Turbo3Iroc]

Awesome :thumb:

[WickedShelby88]

This is probably one of the best threads I've read so far. I learn more and more every time I actually dig to find a solution to potential problems. I gotta give you some serious credit for persisting like you did when many have given up. It is "ALWAYS" better to never give up and find the problem than it is to walk away. Good man Clark!