aaronc7

Thanks for the reply. PCV system seems to be working properly. Even with my not-the-best idle vacuum there is suction on the pcv system/oil fill. I temp removed the pcv/dirty side line and popped off the oil fill cap- little bit of blowby fumes were coming out, hooked the main pvc line back in and it was suctioning it all out vs coming out the valve cover.

My next step of testing will be the high rpm low load stuff and see what's going on with regards to crankcase ventilation. Might try to jump on a dyno too so I can 'drive' the car while someone else can watch the engine bay.

It was a 'new' block, 5.3 I believe that was bored out/made specifically for this engine rebuild. My old block was trash--cracked a cylinder liner/wall. You'd think it was done right, I don't have the exact specs on hand but I can get them.

aaronc7

Talked to engine builder and he seemed pretty familiar with these issues and offered some tips.

He agreed it simple just sounds like more ventilation is needed.

Keep in mind I have a stock 2003 LS6 pcv setup, but he recommended blocking off the passenger side valvecover vent to the throttle body. In place of that, put a -12AN or similar size fitting/hose off the rear of the driver side valvecover and run that to a vented can. For the valley cover I could cap it off or run it to the same vented can.

This of course eliminates the stock pcv system and now you have some negatives such as less oil life, oil vapor (smell/oily residue). I need to think thru some alternative sealed system alternatives. Biggest issue with stock setup seems to be the small 3/8" fittings/hoses. The above linked oil cap breather im hoping will be a good stop gap for the time being.

racebum

if the 15" is stable and there is no wiggle in the needle you don't have a major compression problem. whenever you have a down hole an analog needle will flutter on a vacuum test

that particular piston is excellent for the street because it doesn't expand much more than cast. if the machine shop followed the directions and did not measure the coating to get your pwc you should be good. mahle had a really specific way they wanted those pistons measured for bore and i forgot what it was. all i remember is they said do not measure the coating or account for it as it rubs off.

you may just need more crankcase ventilation via a vented catchcan or VC breathers or more volume going to the air intake tract.

if you told the machine shop you were going FI and or racing they may have set the pistons a hair loose and if so that's more blow by. may not be much but it only takes a few psi of air to pop that dipstick up

3-4% sounds great but testing all 8 is required. if one cylinder is twice that you will have found your air leak

my best guess is you just need more ventilation or a vacuum pump. the stock pcv system is really sub par on a super tight cast piston. add in your larger cam with less vacuum and the higher blow by of forged vs cast and you have just created the need for more ventilation.

also note, just noticed you mentioned a new block. if it was new, like brand new. they can shift once they heat cycle. remember those 9000 rpm honda engines in the s2000 and integra R? honda had so many problem with ring seal and oil burning with those when they first came out that they actually started hot boring the blocks. the bore was done with the block at 200deg and torque plates used to simulate a built load. this is unrealistic for any small machine shop but it could be some of what you're running into. keep track of your oil consumption too. if you have very little that's an excellent sign. under 1qt every 2000 miles would be excellent. if you run it hard it would be natural to use more

Mr. Jones

What type of catch can did you have on there?
It needs to be a large can. The picture you posted looked like it was a air/compressor filter these are very restrictive.
The shops recommendation is old school and not the best for your motor as you know.
What rings are you running?

aaronc7

Vacuum maybe bounces around a few kPa but yes, very stable. So far 700 miles on the engine (no hard hard driving), I haven't seen the oil go down one bit, or not enough to detect on the dipstick. The builder is schwanke engines and I trust they know what they are doing, specializing in road race type engines. That piston is their go to so I would imagine they have that all sorted out. I did mention track use and how my previous one failed, so ring gap a hair loose is fine with me.

I may get around to doing a full leakdown if things don't add up, but going to press forward for now. Feeling pretty good about it since the comp test showed only minor variance from cylinder to cylinder-- there was no oddball one that was out of whack.

Will continue to dig into vent setups.... no crazy vacuum pump for me. One thing that has always intrigued me was running a sealed can, and running the outlet to an exhaust slashcut for some suction on the crankcase. May not even need the can, but might provide a nice barrier in between. My biggest concern with going custom and just adding vents to the valvecovers is making sure they are baffled and oil wont just splash all up into them.

aaronc7

It is but I removed the internal filter which is really the only restrictive part. Without that its just a basic can which I understand wont 'catch' as much as a proper one, but I also didn't want to restrict flow too much. Probably on par with a generic ebay catch can or something. It still collects a decent amount of stuff- my thought process was that it's maybe not the 'best', but certainly better than nothing.

I might be OK with a pure vent setup if it works out well. I already change my oil pretty often anyways from the track days.

Mr. Jones

those Mahle piston are good.
I am using Moroso PCV Air/Oil Separators 85472 on my C7 it is nice
looking and well made with metal mesh to collect oil on and a drain valve.
The can on my C5 is no longer available it is larger and has a PCV valve mounted right in the can.
Before you do the exhaust tie in I would use the breather/filter that replaces the oil cap. The one with the valve so you keep vacuum most of the time.

aaronc7

Not totally surprising and goes along with the direction this thread has gone-- but new pcv valve, taking catch can out of the loop did not solve the issue. At least things on the passenger side of the engine won't be rusting from a fresh coating of oil every now and then.

Now the waiting game begins with the valvecover/oil filler breather. I guess in the meantime I can think/plan out some backup plans. If anyone has any specifics relating to how they converted their LS6 pcv setup to include the driver side valve cover and such please post up-- pics or diagram if able.

Another random question, how snug is everyone else's dipstick when sitting in the tube? Mine has a little o-ring on it, but it doesn't even touch the side of the tube, so its loose and really just sits in there. All of my other cars you can feel the O-ring being compressed and takes a little more effort to pull it out. Obviously I get that strapping down the dipstick isn't a solution to excessive crankcase pressure...but still got me thinking/wanted to compare to the rest.

RonSSNova

Later engines actually had two O-rings on the dipstick and fit very snug.

Stock batwing pan on your engine?
You aren't overfilling it are you?

I don't run any sort of PVC setup on my turbocharged 5.3. It's forged and is an L33.
Even with the ring gaps set up for boost, I don't get any appreciable blow by. I don't use a catch can either. Just the stock valve cover nipples with a small filter on them.

FWIW, you can buy a fitting that fits where your oil fill cap goes and has a -12 or -10 aN fitting that you can run to an external catch can. Want two? Get a second drivers side valve cover for the pass side.

Good luck, keep us posted.

Ron

aaronc7

2003 Z06-- reused existing batwing on new engine, and same dipstick. It's about 5/6 the way up the hash marks right now. Shop did the last oil change, but I belive it took around 7 quarts, which is about right considering I have a (small) oil cooler built into the radiator.

When I first had the problem, oil level was a big thing I looked into, but couldn't really find anything that would make be believe something would be off/different than old setup. Looked into all of the older vs newer tube/dipsticks... mine is the 'newer' one where the tube bolts directly to the head. Dipstick only has one oring though and just justs in there, feels like the metal spiral is the only friction force when you pull it out. Pic below.

Also was browsing mightymouse's catch can website for some ventilation ideas. Apparently his cans have a one way check valve/ball in them similar to that breather filter posted above. I'm liking the idea of venting the oil filler tube or even 2x like you mentioned. If you got a can that can do 2x -10AN inputs, why not. Could just weld a -10AN bung on the rear port that has a plastic insert or something like that IIRC on the ls6 driver cover as well.

RonSSNova

Maybe just find a different O-ring for the dipstick.

My old worn out LS1 puffs a bit out the breather. I have a filter in the oil fill like you show. But it has no check valve. A little smelly, but it doesn't blow the dipstick out. I run it to 6800.
However, I disconnected the stock pvc because I got tired of oil in the intake manifold.

Good you have the stock pan. Was just wondering in case oil windage is pushing the stick out.

By all means do the full leakdown test. My old turd was 5-7% across the board. It's a piston slapper with 95k miles.

The exh thing won't work well at all with mufflers btw.

Mr. Jones

That mighty mouse setup is a good system.
You want to get this fixed, oil will burn. You don't want to lose the car
in a fire.
Does Mahle provide the rings with the pistons and are they moly coated. These would be setup at 500 mile.
Some of the real hard steel rings can take longer-usually used for NOS, turbo.
I had run gapless ring in a past motor. They were just OK.
Compression check and leak down looked good. HP was good but a
run on the track with sustained high rpm push oil out the dip stick.

aaronc7

I will probably hold off on the full leakdown until after I give the breather a go... if I still have issues with that, then it will definitely be worth digging deeper into leakdown and maybe even the oil/windage thing.

I was under the impression that as long as you don't have cats and the mufflers are not near where you bring in the line, the exhaust evac system would be pretty good? I have the GHL exhaust (not sure if theres multiple models.... small mufflers and it's loud, I'd imagine they are straight thru design), headers/x pipe, no cats.

Exhaust evac is low on priority list anyways... I like the idea, but probably way more complex solution than it needs to be.

It appears it is moly coated:

https://www.summitracing.com/parts/mle-ls1314898f04

aaronc7

Breather gets here Monday... took those jokers almost 48 hours to ship it. Amazon prime has spoiled me. Tuesday going to the dyno to create driving conditions while someone else can see what's going on with the crankcase ventilation/pcv stuff and hopefully nail this down and come up with a solution.

Until then it's playing the waiting game. I also do like the mighty mouse "wild" setup above and maybe start working towards that as a long term solution. Could run a -12 AN line from the oil fill and another -12 or -10 from a fitting welded onto the rear of the driver side for a pretty legit setup. I have an old basic breather can left over from my turbo Miata that would be a cheap/easy pure vent (no stock pcv system) setup as well...but I'd like to keep stock system/functionality in tact if I can within reason.

racebum

have you tried driving the engine around and keeping it in vacuum, then checking the stick? i would expect to see it stay. gradually increase the rpm level and see where it pops out. if it starts popping up more the higher you spin the engine it's likely just a pressure issue that your new venting will take care of

color of the oil and spark plugs also will tell you a lot about ring seal

aaronc7

Yeah when I kept it below 4000 rpm during the first 500 miles, never had a dipstick/oil spewing issue. Around 5000 rpm seems to be the threshold but I haven't got too specific into it. Not a big deal for street driving but on track that will definitely be an issue and I get up to about 145 on the main straight... in 4th gear its a lot of time up at high rpm before I hit the braking zone.

Oil looked great/new at 500 mile change, spark plugs looked great when pulled for comp test. Jury is still out I guess, but feeling pretty optimistic with regards to big picture engine condition/ring seal etc.

If things don't pan out Tuesday, looks like I will be taking my daily driver Focus ST to the track, woohoo.

racebum

really sounds like a venting pressure issue and nothing else. beings the c5 uses aluminum VC's you could even weld 3/8" or 1/2" bungs on and plumb to a vented catch can and or a sealed one to the intake tract. lot of good designs online. i think once you start and plumb it up your problems will vanish

btw do you like the ST? the RS has been on my short list for another car

aaronc7

ST is a great little car, I have ridden in, but never driven an RS. ST has a lot of features/qualities that a 'driver' will enjoy. Overall steering feel and response is great, in part due to the quick steering ratio. I took it autocrossing and never had to move my hands from the then 3 and 9 oclock position. For me it's a great DD, fun, reliable, good mpg, comfy, lots of tech features with the ST3 package, plenty of power.

I'm sure the RS is an improvement in about every category, I would love one, but it was hard to stomach the price difference/value. AWD would be nice.... FWD definitely has its limitations, but I can live with it. On the track/autocross the rear brake trickery makes it fun and helps you get the nose pointed where you want at least.

ssrallyred

OP which Dyno are you going to on Tuesday ? Pensacola or around Ft. Walton ?

aaronc7

Fort walton, emerald coast motorsports. They did the motor swap on the car, and as far as I know, have the only true load bearing dyno in the area (if and when I want to do tuning).