jaxcam02

iTrader: (1)

So my 02 SS has been experiencing low mpgs for the past few years as well as oil consumption problems. Well I replaced the LS1 valley cover with the LS6 one and got rid of the pcv system. When I did this my intake was covered with oil so I assumed this was the final fix. Well the problem still persists (not as bad) but the intake and hose from the new valley cover is bone dry.

I'm starting to think the issue lies with the piston rings and cylinder walls. Am I thinking right here or is there anything cheaper and easier I could try before tearing the engine apart and get it bored and new rings and pistons.

1 FMF

iTrader: (1)

i would first question your method of calculating fuel economy and how you drive the car to know if you are really getting bad mileage. my suggestion would be drive for 10..15 minutes to warm up car, fill tank, do as consistent as possible highway drive for 60 or more miles with no stoppage. exit and refill tank and use those numbers, if less than 25 mpg then yeah you might actually have a problem.

removing the pcv system is a bad idea, its purpose is to keep the oil and crankcase clean, it will also help reduce oil consumption by keeping less than a 1 psi vacuum on the crankcase. if you were getting liquid oil past the pcv valve into the intake and burning oil that way then i would fix that problem not remove the entire pcv system.
with pcv removed do you have the crankcase properly vented? if not and you are building any positive pressure that will hurt oil consumption past piston rings and past valve guides.
best thing to do is get a pressure/vacuum gauge that will reliably show +/- half psi and hook it up to a hose clamped onto tube with oil dpistick removed to measure crankcase pressure, and run the hose out the engine bay into cabin where you can watch the gauge as you drive under various engine rpm and load conditions. if you see any positive pressure over 0.5 psi then that is bad.

1 FMF

iTrader: (1)

http://m.harborfreight.com/fuel-pump...not%20provided

these are the cheapest i know of, you dont need high tech accurate just enough to know if you are more than 1 or 2 psi positive or negative. pcv hose and fittings and clamps can be scrounged at home depot, pcv hose or equivalent will work for sliding over dipstick tube and electrical tape wrapped around it to seal it for neg. pressure, it should not be more than 2 psi and its a temporary setup.

jaxcam02

iTrader: (1)

I've been measuring fuel economy for the length I've owned the car recording every single drop of fuel I've ever put in the car using A mobile app called acar. Definitely noticed over the past few years it's slowly gotten worse. Also as far as the crankcase pressure is concerned, from research I've done the LS6 valley cover performs the pcv function and still vents positive crankcase pressure into the intake manifold minus the oil consumption which it definitely does. Where the oem pcv hoses connected at the heads I plugged with caps. I don't think there's any reason the pressure doesn't escape through the new valley cover into the intake.
I guess I could still measure the pressure to be sure but I think the 115k miles have taken it's toll and has a minimal amount of blow by via the piston rings because I don't have symptoms of a blown head gasket and there is no oil pan or rear seal leaks.
However there's no smoke either oil or coolant. Either way thanks for your input and I'll check out the link.

LS6427

iTrader: (2)

When you are cruising next time at say 55mph.....go WOT and stay on it for about 5 seconds. If you get an initial cloud of smoke and then it goes away in 2-3 seconds you have bad valve seal(s) in your heads.
If the trail of smoke continues you have bad rings, broken ring(s) or just very worn rings.

And its best to do this at night with a friend behind you about 6-7 car lengths back from you. His headlights will allow you to see the smoke easier than in the day time...if its a slight amount of smoke.

That test will typically tell the tale.....

.

CamaroWhoopAss

iTrader: (1)

General concenses would be to do a compression test first... bad compression, engine restorer is your cheapest option until you can fix the mechanical issues causing the loss in compression and oil consumption.

Unertl42

iTrader: (63)

REALLY???? Engine Restorer?

CamaroWhoopAss

iTrader: (1)

Did you even think about what you read before you replied to me? I said it was the CHEAPEST option, until he could FIX THE MECHANICAL ISSUES CAUSING IT. As in, hey, this is a band-aid fix, you still need to fix the real problem. Jesus Christ...

RPM WS6

iTrader: (3)

How bad is the oil consumption at this point? And how much MPG has been lost for you to conclude that the two items are both related to an internal condition? Gradual loss of some MPG over time, as you have indicated in your post above, is pretty normal over 115k miles - especially if O2 sensors (and other sensors relating to A/F adjustment) are original and/or if the MAF isn't in squeaky clean condition.

The problem with this test is that the smoke may simply indicate an overly rich mixture, even more likely if MPG is lately poor. It's hard to be certain about the source and exact color of the smoke if it's just a quick 2-3 second puff at WOT.

jaxcam02

iTrader: (1)

Im putting about a quart of oil in it every 2-3000 miles. As for the mpgs, I haven't lost much in the way of city mileage but I do notice a dip in highway mpgs of about 28 down to 24 over the last four years.

As for the O2's the upstreams are less than 3 years old. The MAF I clean once a year give or take and more recently have completely cleaned the intake system and runners and replaced with new gaskets as well when I changed the valley cover to the LS6 PCV style (6 months ago). It runs much healthier since doing that but the oil consumption is really confusing me.

I have put cardboard under the car to check for leaks and nothing. Completely cleaned the oil pan from road grime and don't see leaks from the pan, rear seal, head gaskets. I just checked the intake for oil through the new valley cover extraction hoses, etc. The only thing I can possibly think of is through the piston rings but I have never seen smoke or had difficult start ups, never had friends behind me notice any smoke. lol

I think I'm just going to wait to get heads and a cam then get the block bored and new bearings, pistons etc.

Darth_V8r

iTrader: (4)

I felt the LS6 valley cover greatly improved my oil consumption, but it does still let some through, I later found out. I have since installed a catch can. In the months since I installed it, I have pulled the throttle twice and behind it is still perfectly clean.

A catch can might be in the cards for you. If you install a catch can and still lose oil, at that point it is likely ring wear unless you have ported heads.

Side comment but I e change my oil every 3K, and I'm almost always minus a quart. I honestly wouldn't worry about it unless it gets to 1500 miles per quart.

dailydriver

+1 and ^^^THIS, except that a catch can/air-oil separator will do nothing for his MPG drop, unless he was dumping MASSIVE amounts of oil into the intake.

RPM WS6

iTrader: (3)

So a loss of 4mpg on average, gradually, over the last ~4 years? Are the front O2s OE brand? Do you have LT headers that have located them further downstream? Any additional mods performed sporadically over that time? Is the car tuned for any changes beyond simple catback/air lid?

What about conditions not specific to the car, such as changes to the traffic content on your average highway drives? Perhaps your schedule has put you in more of a peak traffic commute? What about changes to local fuel? Are you using E10, and has that always been the case over these four years? What about driving style, have you become more aggressive with the throttle over time?

The fact that city mileage hasn't really changed would indicate less of an issue with the engine and more of an issue with either A) ambient travel conditions, or B) A/F issues specific to fuel trim cells at your typical highway cruising speeds (likely having more to do with aging sensors/components than with an overriding mechanical condition.)

That level of oil consumption is probably a bit higher than it should be for an LS1 with the LS6 conversion and no evidence of a leak, but it's not so high as to be immediately alarming or force a premature rebuild IMO. If it's consistent at this point, I would just keep an eye on it and not worry until/unless you plan bigger internal mods.

LS6427

iTrader: (2)

Take two of the spark plugs out of each side..or all 8 would be better but we all know its a hard job..........see if you have oil on the threads. If you do.....bad valve seals.

When I was at cruise speed and then went WOT I would get a cloud of smoke for just 2 seconds. Then it was clear as I kept accelerating. The reason for the 2 seconds of smoke only....and not a continual trail....was because that initial hit of the throttle drops the pressure in the heads and sucks oil from the valve covers through the leaky valve seals. But as you keep accelerating that pressure equalizes and no longer pulls oil from the valve covers......

I was also losing 1 qrt every 2,000 miles. Pulled my heads and got a valve job....problem solved. Never used any more oil at all.

.

RPM WS6

iTrader: (3)

I've had valve seals go bad on one of my SBCs before, and there was no oil on the plug threads at all. Just a puff of smoke on a cold start that lasted a few seconds. No noticeable puff at WOT either.

On the other hand, I've had plugs with oil on the threads when the valve seals weren't bad at all. This was due to a weeping valve cover gasket, but wasn't noticeable as a leak until it got much worse.

I was not using 1qt. in 2k miles in either case, but they weren't Gen III engines.

LS6427

iTrader: (2)

My valve seals were so bad that they would fall out of the head from gravity........lol...

.

kingtal0n

iTrader: (1)

I love economy threads. Let me share some easy tips for adjusting and improving your fuel economy, and diagnosing the engine problems.

first, the engine itself.
1. compression test, make sure the cylinders are consistent, write down your results!
2. What kind of oil have you been using? Thicker oils reduce economy.
3. Figure out where the oil is coming from, and where it is going. The most important part about a "race car type engine" besides it's internals is it's pcv system and oil control facility. Oil making its way past the baffle due to blow-by is a major concern, but you need to make sure it really is blow-by related with thorough diagnostics. The engine should not have significant blow-by at 150k unless there was a manufacturing problem, or it was ill-maintained, or tuned improperly. A lean condition and high EGT is typically what "fries" piston rings (they lose tension) and then you have blow-by as a result.

to continue with #3:
check every plug for oil, figure out where the oil is coming from and going. You say it burns a quart; if this is due to blow-by there is nothing short of a rebuild waiting for you. But it could be coming through, say, the PCV system instead, and fooling you into spending thousands. That is why I emphasis on tracing the exact nature of your problem, which starts with a compression test. If you have a chance to inspect your exhaust near the engine, look for traces of oil exiting the engine. Another test you can perform is a leak-down, but these require more experience so I generally leave that for absolute last.

#4 if you are fairly certain your engine has blow-by issues and needs a rebuild, there is more you can do to check. ex. Install a high resolution (0-60" of water) pressure gauge on the crank case and diagnose the crankcase pressure directly. The pcv system could be blocked, filled with sludge, have you ever changed your PCV valve and PCV related hoses? The crankcase pressure (blow-by generated) from an OEM engine with 1 miles (brand new engine) is supposed to be evacuated into the intake plumbing by the PCV system, perhaps yours has become clogged and is no longer working properly. Inspect and replace all pcv related hoses/hardware before jumping to the conclusion your rings or cylinder walls are the problem.

#5 Catch can is a band-aid. If you are 99.8% sure the cylinder wall/ring is the problem, its not the pcv system, its not the valve seals, it isnt any gasket, it isn't the oil baffle and your raised rpm capability, then you can either rebuild the engine or band-aid it with a catch can temporarily (just to get around until you rebuild the motor)

Now, on to the actual economy, once you have the oil situation figured out and corrected, you can focus on the real economy problem.

#1 weight. It takes just as much fuel to push a vehicle with a 4cylinder or 10cylinder engine, plus or minus rotating losses of course. In other words, having a V8 does not automatically entail you to poor economy, it is the vehicle weight which ultimately has the most effect on your fuel mileage. So reduce weight as much as possible, take out the spare, take out the passenger seat, whatever you can get away with or live without. The same goes double for anything that turns, use lightweight wheel, lightweight driveshaft, lightweight lug nuts, grease anything that takes grease, etc.. I found about 10lbs of pennies in a car I bought once in the corners of the trunk; look everywhere and clean your car up really nice.

#2 rolling resistance is just as bad as weight. Is your vehicle hard to push? Maybe a pad is sticking. It should push by hand easily, and when coming to stop by itself there should be no "brake" feelings, i.e. the vehicle should gently roll to a stop and not rock backwards as if you had the brake applied. Check your tire pressure, make adjustments and log fuel economy if possible, there is an optimal pressure for highway travel. Make sure the alignment is good and it doesn't pull. How are the wheel bearings? driveshaft balance? Lightweight wheels/ tires? accessories? Does your engine have any unnecessary spinning pulleys like a smog pump for instance?

#3 exhaust system (gas velocity) will affect economy. Too big and the piston is working hard to push out exhaust gas (if we try running the engine with an open header, economy will drop even worse if the engine is mostly original). Same thing goes for any exhaust restriction like a clogged cat, it is bad for economy. something to be aware of, you cannot take a stock engine of any displacement and ruin the exhaust system from it and expect good economy. The engineers which designed the OEM exhaust have taken into account the "best tradeoff between performance, sound, and economy" to give you a system which, while may not give the best power output, will produce nearly the best economy (since they need to meet certain guidelines for selling vehicles) to truly lockdown your exhaust system's economical benefits, you will want it coated, wrapped, blanketed, etc... anything you can do to keep the temperature IN the exhaust system where it will help push the molecules farther apart which will increase their energy/velocity.

#4 Tuning. This can go on for miles, but let me make it short without technical detail; there is a cruise timing number, say 36 to 38* BTDC of timing you need to hit on most modern V8 engines. Sometimes it is 34* even. My point is that the ignition timing needs to be in this region for a highway cruise to give any measure of economy. If you are running only 24 or 28* this is a major setback to the engine's economy. The line is thin so make sure you are on it. As to fuel- you should be using a closed loop narrowband sensor (ANY narrowband O2 sensor will work) but you need to make sure it is working. Either directly punch the O2 signal wire with a multi meter and verify that it is indeed flipping back and forth from 0.002volts to 1.002 volts while driving, or install one of those cheapy flashy lights air/fuel gauges (the ones that go from red to green and back) or use a real wideband; Do whatever it takes to make sure you have a good working O2 sensor and that the ECU is actually holding your fuel duty where it needs to be for good economy. You'll also wish/hope that the injectors are not clogged or giving issues; maybe have them cleaned after 150k is not such a bad idea either.

We covered rolling resistance, weight, tuning, exhaust gas velocity from the economy side of things,
and we covered the issues facing you about the pcv system and blow-by diagnosis. Let me know if you have any questions

Darth_V8r

iTrader: (4)

Talon, that was a truly excellent post. I will disagree with you on one point, but after that I won't get into anything so as not to hijack the thread.

On the LS1 and LS6, if you have truly diagnosed the issue as a PCV issue, sometimes the can is simply necessary. Example:

I had a brand new LS6 valley cover continue to allow oil mist through - though far less than the LS1 factory system I burned in a barrel in anger. And I know for a fact it wasn't any other source for where the oil was in the intake - I had vented everything elsewhere. The oil was right under the PCV port puddled in the intake. Couldn't possibly have got there from any other source.

The catch can was simply necessary to stop the oil mist. And here's the kicker. Oil mist was contributing to KR, which robbed me of both power and efficiency.

So, to my mind, not a bandaid, but a properly diagnosed and addressed issue with the factory PCV on the early LS's.

RockinWs6

Bet you have 2 simple problems, the cylinders are carboned badly the rest was edited by this web site eff it....good luck


My last post helping anyone bite me

kingtal0n

iTrader: (1)

This is not a disagreement, you are simply calling a band-aid something else. Several engines are known to have oil containment problems from the factory; the S2000 engine from certain years is a great example. You take an OEM engine and run it around a track a few times and it will fill the engine bay with oil. The owners are doing radical things to their valve covers- drilling holes for example- to correct this factory oversight. Such attempts to correct the factory's initial error can be considered custom mods, or band-aids, depending how you look at it, its just terminology. The NEED to use a catch can due to a poorly designed part or incorrect machining is never a real answer, i.e. the bandaid is temporary, you still have a major wound to heal up (the factory part causing the problem). So regardless of how the factory error got there (manufacturing mistake or intended consequence of the design) the catch can is not a true solution, as it is simply additional volume attached to the crank case masking (band aiding) the real problem, thus I call it such. Any additional crankcase volume due to poorly designed parts is not a solution. A real solution stops the troubling oil flow, fixes the problem, instead of masking it. In the case of the S2000, if the holes they put in the valvecover assist the oil return flow and put a stop to the issue- then I suppose I would not consider that a band-aid, since it fixed the problem. But you are welcome to call it anything you want, I am not right or wrong.