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And has he actually pulled the TB/etc to see if he has similar oil build up? Even stock cars will look like that after a bit. Each time a catch can is emptied, every 3k-4k miles most LS owners are dumping out 3-4oz. Even bone stock, and with stock valve covers. Higher performance, and non-baffled just makes it worse.
And has he actually pulled the TB/etc to see if he has similar oil build up? Even stock cars will look like that after a bit. Each time a catch can is emptied, every 3k-4k miles most LS owners are dumping out 3-4oz. Even bone stock, and with stock valve covers. Higher performance, and non-baffled just makes it worse.
Just to be clear, Katech valve covers do have integrated baffles.
(snip) but on #2, I think a better solution is to just pull the manifold and drain it.(snip)
Ok.
I got lazy. Rather than pulling the coils, PCV and evap plumbing, fuel rail and the manifold. I decided to jack the back of the car up and high as I could get it... ...then let it sit half-a-day while oil drains from the back of the manifold forward to the TB mount where I'l do as Steve and Jason suggested: soak up whatever oil I can find. After that, I'm going to continue with another thousand miles of oil use testing.
Last edited by Hib Halverson; 01-14-2019 at 02:48 PM.
(snip) The bad news is that when I pulled the throttle body, I found a lot of oil behind the throttle plate and inside the intake manifold. I had that problem with the original build and, apparently, I'm having it with the rebuilt engine. I shot a bunch of pictures and sent three of them to Katech. They're also posted here.
(snip)
Well...the above listed "problem" turns out to be not that big a deal. I jacked the back of the car way up in the air and let the oil drain overnight from the back of the manifold to the front. Next day, I soaked up the oil with a couple of paper towels, then wiped up the last part with a lintless rag. In fact, beyond what is shown in the images, there was way less oil inside that manifold than what I expected. No doubt a good catch can installation would easily "catch" that volume of oil.
The next step is to schedule another road trip of about a thousand miles to once again check the engine's oil consumption using the new oil level requested by the folks at Katech.
Originally Posted by Hib Halverson
Originally Posted by C6Z06Silverbullet
So with there disappointment with you changing the tune are they voiding your warranty?
Unknown, but if they did void it, they'd be within their rights.
On voiding the warranty due to my changing the PCM calibration...
The original build smoked at wide open throttle and had high oil consumption even before I started changing the cal. Back then, I was reminded by Jason that changing the calibration would void the warranty. Later, once the car was back at Katech and the engine was torn down, its assessment was that my later changes in the WOT fueling caused the cylinder walls to wear excessively.
I cited the oil use problems prior to changing the cal then asked if Katech was willing split the cost of rebuilding the engine. They refused and...(sigh)...while some might see that decision as a bit harsh, Katech was within its rights to do so. Later, during the rebuilding process, Katech softened its position a bit. Originally, the plan was to bore the block .005-in. over then install Mahle .005-over pistons. When obtaining the pistons became impractical, Katech supplied a fresh LS7 cylinder case at no charge. While that wasn't splitting the difference, it did lessen the "damage" of the near $20,000.00 spent on the rebuild and installation.
I appreciated that gesture.
I'll post another report once I do one more thousand-mile oil use test.
Last edited by Hib Halverson; 01-17-2019 at 09:41 PM.
Reason: Oops. forgot sig line
What was the lambda (or AFR) at full throttle in your cal that Katech claims wiped out the cylinder walls? Please PM me if you don't want to post publically.
Last edited by Dan_the_C5_Man; 01-18-2019 at 01:27 AM.
What was the lambda (or AFR) at full throttle in your cal that Katech claims wiped out the cylinder walls? Please PM me if you don't want to post publically.
Yes, however, once I got to changing WOT fueling, I was calibrating for .85 to .87 Lambda at WOT. It is possible that my WB was faulty. I have not used it since then. Before the next time I do use it, I'm either going to have it tested by its mfg or get another.
Originally Posted by Apocolipse
How rich were you running it? Enough to throw black smoke the whole time at wot?
It wasn't rich. It was too lean. Smoke was blue-white, not black.
Last edited by Hib Halverson; 01-18-2019 at 08:57 AM.
I don't think I am speaking out of turn here - that Lambda ratio is totally reasonable, not lean, and if the motor was running so lean to cause an issue with the cylinder walls you'd have major timing pulls in the logs from detonation. I am assuming you were logging with a WB installed during tuning, not solely relying on a calculated PE table.
I don't buy it - I think the problems existed before you picked up the car, nothing you did caused the excessive oil consumption..
Note - I went back through my previous posts, it's clear I am a broken record on this topic - I hope it all works out to your satisfaction.
Last edited by Dan_the_C5_Man; 01-19-2019 at 08:14 PM.
I don't think I am speaking out of turn here - that Lambda ratio is totally reasonable, not lean, and if the motor was running so lean to cause an issue with the cylinder walls you'd have major timing pulls in the logs from predetonation. I am assuming you were logging with a WB installed during tuning, not solely relying on a calculated PE table.
I don't buy it - I think the problems existed before you picked up the car, nothing you did caused the excessive oil consumption..
Note - I went back through my previous posts, it's clear I am a broken record on this topic - I hope it all works out to your satisfaction.
Actually, I shoot for 0.86-lambda and, I agree, that's reasonable.
Not sure what you mean by "predetonation" as there is no such thing as that, but my logs showed the engine was detonating, but not bad enough that it was in preignition. Evidence of that was KR even after I took a lot of spark out of the main spark tables, but no evidence of preignition, ie: burned pistons, spark plug side electrodes burned off and etc.
As I've said before, it's possible my WBO2S was faulty. I'm going to address that before the next time I use it.
Actually, I shoot for 0.86-lambda and, I agree, that's reasonable.
Not sure what you mean by "predetonation" as there is no such thing as that, but my logs showed the engine was detonating, but not bad enough that it was in preignition. Evidence of that was KR even after I took a lot of spark out of the main spark tables, but no evidence of preignition, ie: burned pistons, spark plug side electrodes burned off and etc.
As I've said before, it's possible my WBO2S was faulty. I'm going to address that before the next time I use it.
Hib, What pistons did Katech end up putting in your motor? I am running their new Mahle pistons with the thin ring package. Granted they didn't build my motor but a very reputable company did. I burn about 1 qt per 500 miles of mostly highway and spirited driving. Original motor used next to no oil. I'm certainly less than happy with these very expensive pistons from them.
Hib, What pistons did Katech end up putting in your motor? I am running their new Mahle pistons with the thin ring package. Granted they didn't build my motor but a very reputable company did. I burn about 1 qt per 500 miles of mostly highway and spirited driving. Original motor used next to no oil. I'm certainly less than happy with these very expensive pistons from them.
My pistons are forged Mahles, but they were ordered with stock CR because I burn 91-oct fuel. Not sure of the ring package dimensions but the rebuild has higher tension oil rings.
Nothing report at this point. I'm still running an oil use test. I have not driven the car much since December because of distractions at work and wet weather. Since I put the Cup tires back on it, I won't run a long distance trip if bad weather is predicted. I need to make a run to Northern California in the next week or two and that trip will finish my oil use testing. Once I'm finished with that, I'll have a lot more to say.
About the only other stuff I've done is continued to work on calibration when the engine is idling and I found a used set of carbon fiber rocker covers which I put on...kind of expensive but they look really cool.
Last edited by Hib Halverson; 02-23-2019 at 12:40 PM.
I finally completed what I think is an oil use test of reasonable length. It took me longer than I'd like to finish it because, once I drove the car back to California after the Katech rebuild in November of last year, I elected to put my Cup tires back on and save what was left of my Pilot Super Sports for the National Corvette Caravan this coming August. As a result of that and because the West Coast has been drenched this winter, part of the long time in finishing this test was used up waiting for good weather for longer road trips. Cup tires are ok in light rain, but more than that and they can be treacherous on the highway.
The final test sequence was a 764-mile drive from Goleta in Southern California to Rio Vista in Northern California and back, a trip I made two days ago. Exact oil use for that last test drive was 2-qt 4-oz or 2 ⅛ qt in 764 miles which maths-out to 359.5 miles per qt. In total, since the rebuild, the engine has used 7.4995-qts in 6358 miles for an average of 847-miles per quart. Looking back over various oil use checks since early November, the trend seems to be towards increasing oil consumption. In the first 4046 miles after the rebuild, 4.0-qts were used. In the last 2312 miles 3.5125-qts were used.
The oil in the engine is what Katech suggested: Mobil 1 5W30. The oil checking method was to run the engine until oil temperature reached at least 150°F. After engine shutdown, I waited exactly five-minutes then checked the oil. This procedure was used consistently.
The duty cycle has been, primarily, normal street driving with a lot of highway use in sixth gear with speeds varying from 55-100-mph. Once the engine had 3000 miles on it, I began to run it hard. I have not yet run on the chassis dyno I use, Westech in Mira Loma CA, but I have run maybe a dozen 1500 rpm to rev limiter "pulls" in third gear with my wideband in the exhaust. There is no question the engine makes a ****-lot of power. First gear is almost useless unless you feather the throttle a lot. In second spinning the tires is easy. I've even had the back end loose in third if it's cold outside.
It just uses a lot of oil. If I was primarily a track rat, I would not be so uncomfortable about the engine's oil use, however, its oil consumption is more than I'd expect from "Street-Attack LS7" used primarily for high-performance street driving.
What I don't get is why.
I wish I owned a decent bore scope so I could look at the cylinder walls. So far, in the last 12-months I've tested two different "low-cost" bore scopes and neither of them worked for ****. I guess I need to cough-up about a grand for something that provides a decent view of chamber walls, valve faces and cylinder walls.
I believe building high-performance engines with forged pistons which, also, have reasonable oil consumption is not rocket science. Corvette Racing's 5.5L engines ran LeMans in 2017 and used only half a quart of oil per engine for the whole 24-hr race which is about 3000 miles. That information comes directly from the guys at GM PRC who build those engines. The ZR-1's new LT5 has forged pistons and, so far, I have not heard reports of high oil consumption by those engines in normal street driving.
As for calibration...the only changes I have made are to tables relating to curb idle. Any cal items related to high-rpm/high-load are just as Katech tuned them last November.
Katech told me vial email a couple of days ago that they have a plan they'd like to implement. I don't have the time this week to do a conference call with them and find out what this plan might be. That will happen early next week.
Hib can you tell my which pistons they installed in your engine? I have a set of their Mahle with the 1mm rings and my engine burns oil excessively as well. Very expensive pistons; certainly not worth it.
Hib can you tell my which pistons they installed in your engine? I have a set of their Mahle with the 1mm rings and my engine burns oil excessively as well. Very expensive pistons; certainly not worth it.
I know they are Mahle forged pistons, but I specified a stock CR because all we get in the West is 91-oct fuel. I do not know the specifics of the ring package other than what Katech told me which was that the oil ring tension on my rebuild was higher than it was for the original build.
I know they are Mahle forged pistons, but I specified a stock CR because all we get in the West is 91-oct fuel. I do not know the specifics of the ring package other than what Katech told me which was that the oil ring tension on my rebuild was higher than it was for the original build.
Well Sir I believe if your pistons have the 1mm ring set which I bet they do is your smoking gun. You and I are in nearly the same boat. I burn about 1-2 qts per 1000 miles pending driving style. My engine builder warned me my engine would burn oil due to these pistons after he saw them. But I thought it would not be this bad and figured KATECH and MAHLE would have tested these piston ring packages to ensure a superior product. I was obviously mistaken..
I don't think it is the rings either, and it would be a stretch.
If its not the pistons or rings then please explain your thoughts! Hib and I have similar builds and are using the same pistons and have similar problems. I have brand new Advanced Induction heads and he is likely running WCCH or KATECH heads. I've been around "Real" racing engines for 20+ years and have never had this issue but again I have never ran the 1mm rings either. I would certainly not call it a "stretch" but a "possibility".
Plenty of people run those rings and 1mm rings without huge oil consumption issues though. Maybe it is easier to mess them up, or not get them to seal.
01-14-2019, 08:07 AM
