Eurospec2

iTrader: (2)

hello!

I just did a head/cam swap on my vette, and in 300-400 miles i have consumed 1.5 quarts of oil.

From observing conditions while driving i only seem to smoke some when decelerating, now i take this as meaning it could either be my PCV system (which was modified during the swap) or valve seals, any advice yall could give me to figure this out would be much appreciated, thanks!

magius231

iTrader: (8)

i ran into the same thing after my cam swap, everything was good until I fixed my PCV valve, then suddenly I started using oil. Personally I think its being drawn into the intake. Try putting a catch can on it and see how much shows up in it.

98C5LS2

It sounds more like seals. Did you assemble or did someone else. Maybe they aren't seated correctly.

GOaT Cheese

Doesn't it feal good when we answer our own questions?

zo6vetteman2003

iTrader: (1)

What you need to do is install an oil catch can. Your pulling oil from the valley tube, through your PCV valve and it is going straight into your intake manifold. This is coating your I/E ports, valves and combustion chambers with sludge. The can will trap 98% of the oil and a treatment of Seafoam should be used every 2 oil changes to keep it nice and clean.
http://cgi.ebay.com/ebaymotors/Unive...49922739QQrdZ1
A universal can works just fine on the Vette.

cam

iTrader: (9)

Did you change your push rods? What valve seals are you running?

I ask because mine does the exact same thing it only blows oil smoke on decel. The funny thing is I am on my second set of push rods and seals but the first didnt do it at all. I'll explain if you bear with me.

I built the engine myself with used stage 2 heads purchased off a board member. I bought all the parts aside from the oil pump and rod bolts off board members actually. So there is a nasty gouge on the head surface when they arrive so I have them milled but the assembly looked great and fresh. I had already bought Manley 7.4 PR's and I doubled checked with my adjustable PR the preload and it was just over .100 ( cant recall exact number now ) which is high but still within limits. After reading that the TR224 was a very valve train noisy cam and the cure was to run more pre load I figured I was good. I get the car running ( this is a conversion ) and drive around for a week or so making WOT passes on the stock limiter ( 6200 RPM ) and everything seems great. No smoke, ZERO valve train noise, running strong, no tune though.

So I book a tune with my local LS1 shop and we head to the dyno. We ran into two problems one the TPS sensor wasn't working so we ordered one which left us plenty of talk time while we await the TPS delivery. We discuss my build and the issue we are having with the power curve going completely flat at 5200 RPM. After I tell them how much pre load I'm running and that the 918 springs were used they both urged that I had WAAAAAY too much pre load for max power and safe high RPM running. We also suspected valve float as my main issue for going flat. These guys have tons of real world experience so I followed their advice and took the top end apart again and ordered a set of 7.35 PR's and new patriot gold springs.

Now I had Manley 7.4's in there and replaced them with Comp Cams chromo's and immediately noticed how HUGE the oil hole was in the Comp Cams vs the manley ones. The Manley ones were about the same size hole as stock but the Comp Cams were double the size. It stirred a lot of curiosity for me at the time but I carry on and assemble everything, New seals ( although the ones on there were new I changed them with the new ones patriot sent me ) Only difference was the seals patriot sent were all brown high temp and the ones on the heads previous were only high temp browns on the exh side the intake side were black ( tighter fit around the valve )

Now she runs strong... much stronger up top it is VERY noticeable but the valve train noise is soooooooo loud I thought I had broken something but the engine builder and tuner said it was normal. I have been ringing the **** out of it and it seems fine nothing has changed aside from this oil usage on decel.

It pours out of the exhaust after I wind it up and for you other PCV guys... I deleted my PCV with the filter oil cap deal. I ran this same set up identical before with no oil smoke at all and now the only thing different that could make a difference is either the seals which are new.. Or the push rods with the huge hole in them.

Got me to thinking that perhaps the oil flow is too high to the top end causing the oil to pool up in the heads. On decel when the vacuum becomes high it draws the oil easily passed the seals as they are soaked in it. Its either that or the brown seals need to be changed on my intake side. Anyways thats my thinking so I am curious as to what PR's and seals you have.

zo6vetteman2003

iTrader: (1)

Yeah, good point regarding the valve seals. The diameter of the push rods should be approx. the same. I would think that valve seals is more of a mileage issue based on seal wear. Another point might be made regarding the oil pump. If the pump bleed off spring wasn't touched, this can result in flooding the top of the motor with oil, or go with a new ported oil pump. Another problem is not using gasket sealer in the corners of the timing cover where it meets the oil pan. This will cause oil to leak out where smoke can be seen during deacceleration. Success is in the details with any swap to avoid having to take it apart again to a point where you could easily install another cam lol!

shoemike

iTrader: (25)

more power = more oil consuption

5ltrBetr

iTrader: (3)

One other thing to consider is valve guides. I ported a set of 241's and had the machine shop deck the heads and do a valve job. These heads consume about a quart of oil every two or three weeks. The seals are new and I have pulled the intake to see little puddles of oil on the backside of the intake valves. IOW - bad valve guides.

zo6vetteman2003

iTrader: (1)

I installed the oil catch can. Here is a pic. of where I put it. The C5 Corvette PCV system has been modified more than any other component on the car over the years. I would say the main reason is the 01' Zo6 oil consumption issues are the main reason for the mods. They still haven't figured it out other than to eliminate the PCV valve all together in the late 03's and 04's.

GMTECH4

i'm having the same problem mine started after the header/ory install. my car never smoked or burned oil until header/ory install. it's like "CAM" said at high rpms and on decel we sucking oil into intake via the pcv. i just changed my plugs and all of them look the same "ashy". if you guys are having the same problem i guess the ls6 pcv would be a waste of money for me. my catch can helps but did not fix the problem. i'm lost

zo6vetteman2003

iTrader: (1)

I'm going down to Pennsylvania for the Vettes @ Carlisle at the end of August. There is going to be a discussion on the oil consumption issue that I'm attending with GM. I'll let you all know what happens with the discussion and post what was said here for all to see. Anyone else going down is welcome to attend.

zo6vetteman2003

iTrader: (1)

Not only during decelleration is this a problem, but also at idle where vacuum is also it's highest. Here is what I've seen. At start up before the oil and coolant temperature both reach above 140 degrees, there is oil and moisture that is drawn up through the oil valley tube. Basically there is alot of condensing going on inside the engine. Without an oil catch can, this would be drawn through the PCV valve directly into the intake. I empty my catch can at least once a week or every 600 miles or so. Every two oil changes, I implement my Seafoam through the PCV valve and through the power brake booster vacuum hose. This provides great coverage to the front and rear of the intake manifold. I first noticed I had a problem during a head swap. My stock 243 heads had a sludge coating to the intake/exhaust ports, combustion chambers and valves. I discovered the catch can from a Nissan website. These guys have been dealing with this issue forever on their turbo motors. I saw what these guys were doing and have followed suit ever since. For me, it has eliminated 95% of the problem along with a strict Seafoam regiment. Installing carbon filters to trap the oil vapors would get me closer to solving the problem fully. Just to let you know, when the motor is condensing, the PH level of the moisture is #4 out of 10. (4) is acidic, and is comparable to the acidity of orange juice. Oil and water mixed with your fuel for combustion lowers your overall octane content. If you are running alot higher compression like me, detonation is a concern along with higher temperatures.
While I had my heads off I replaced all my lifters with Comp pro-magnums and also drilled two 1/2" holes at the base of my lifter retainers. This keeps oil from pooling in the retainers and returns it to the main oil galley alot sooner. Just a little tid bit of information to keep more oil in the pan for sufficient engine oiling.
Oil consumption on the early 01' Zo6's was a piston ring problem. Oil blow-by would cause the same issues on the other end. The LS6 with it's windows cast in to the base of the cylider liners was to promote better cylider to cylinder crankcase ventilation, but may have opened a can of worms with the PCV system. This is where I think some of these issues originated. They have continued to modify the PCV valve on the C5 after 1997 all the way to 2004 where they got rid of it. They never nailed it down all the way, but the catch cans do help keep the problem under some sort of control, but cause an additional maintenence issue.

cam

iTrader: (9)

What I'm puzzled about is mine did not do it until I changed the push rods. To clarify the outside diameter of the first and second set of push rods is identical. Its the oil hole down the center of the push rods thats much larger on the comp cams ones I'm running now. I know sometimes oil restrictions are placed on engines to limit oil flow to the top end so I'm wondering if this is what i need? I have NO PCV so thats not my issue.

zo6vetteman2003

iTrader: (1)

The pressure drop through a larger diameter hole in the push rod should be less than before. Have you changed the oil pump, or did you use the SLP shim at the pump bleed off spring during the cam swap? One other issue is if you are getting more oil up top, this is not consumption as long as the oil is finding it's way back to the main oil galley and not leaking anywhere. It would be consumption if it was getting into your intake, or blowing by your rings. This would cause smoke too during accelleration, or decelleration. Check around your oil pan and underneath the car for oil. The only time I've ever seen smoke just during decelleration was a leak in a timing cover at the bottom corners where the cover meets the pan. Alot of people miss this step during a cam swap of adding a dollup of gasket sealer at this location, because they think that the timing cover gasket and the oil pan gasket will seal it. It doesn't. This is a step shown in the manual and cannot be missed. The smoke can be seen heavily during decelleration in the rear view mirror. The thought of breaking it down again, removing the balancer isn't pleasent, but it is what I've seen in the past to solve this problem. The problem doesn't show up right away if it is a leak at these locations.

zo6vetteman2003

iTrader: (1)

Here is the result of a quick search. Scroll down and see comments from redheartbeat on the first link see the pics. on the second.
http://forum.ls1truck.com/lofiversio...php/t4240.html
http://www.chevyhiperformance.com/te.../photo_16.html

cam

iTrader: (9)

zo6vetteman thanks. I did put sealer there. I had the whole engine appart ( never ran it before I bought it this is a conversion ) I put in a new LS6 oil pump stock from dealer I dont like the shimming idea and I have great oil pressure 40@idle 65@WOT. I thought shimming the spring was to raise pressure? New rod bolts, all gaskets, timing chain, ported heads etc. Only thing i didnt freshen were the bearings and rings because the engine spun smooth as butter and the cylinders looked perfect.

I'm pretty demanding about quality if you saw my car you would see for yourself its very clean. No oil leaks anywhere. Every part underneath is painted in base clear etc. The entire exhause is custom purge welde stainless etc etc.

I hear you re the actual "consumption" issue but its getting into the cylinders somehow so lets call it "uneccessary oil usage" if its a more exact term regardless it shouldnt happen. Mine is not excessive and its only when I wind it out passed 5500 or so is it even evident. This is why I was wondering about the pooling effect with vacuum drawing passed the seals at closed throttle. It only happens when off the throttle. Unneccessary oil usage would equate to about a quart every 1000 miles or so but I'm on it alllll the time

zo6vetteman2003

iTrader: (1)

Cam,
It sounds like maybe it is the valve seals. When I did my head swap, I went to the dealer and bought all new valve seals. The factory LS6 seal sits below the spring and is all one piece, not a cap type seal like we usually see, the spring holds the seal in place. I had 40K on it at the time and figured why go back and have to do seals later on, plus I had sodium filled valves, so I wanted to reuse them. It sounds possible seeing it sounds like you have good oiling and valve seals could be the culprut. I reused my stock oil pump also, no problem getting oil up to the heads. I didn't use the shim either. My catch can has clear tubes, so I can see the oil and moisture travel at idle at start up. My problem was getting excessive oil in the intake through the PCV valve. I would empty about 4-6oz. of oil per week as the catch can would be 1/4 full. The can has a site glass on the side which makes it easy to monitor. The seals ran me around $60.00 if I recall. The bitch for you is having the heads on the car and getting to the springs under the firewall as you know.

cam

iTrader: (9)

Ya maybe. The seals are new but they are all the brown exh style I wish I put the black ones on the intake side. Ahh well maybe I'll change em next winter but I am still curious about the oil restriction issue. I'm going to see the local LS1 shop soon so I'll inquire there and see if I can turn up any good info

cam

iTrader: (9)

Well my mystery is over.... Found a valve seal spring stuck to my oil drain plug today so I guess one ( or more? eeks ) of my valve seals is doing bupkiss. Shitty thing is I am track bound this Saturday so I hope its okay. Its not using more oil than it was so I'm sure this thing has been toast since that first WOT pass. So much for my push rod theory lol.