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Discussion Starter · #1 · (Edited)
Have had an issue with my turbo 4cyl for a while now. On each 1/4 mile pass it will puke about a 1/2 qt of oil into my catch can. I have checked everything I know to and am stumped.

Combo is a 2.9L with a BW 69/75 turbo. JE pistons, Crower rods, etc. Running 35psi it runs 9.60-9.70 at 140 in my 3250lb T-bird
I bought this as an unassembled setup and the parts were new with an unknown ring set. I set the ring gap at .026 on top and .028 on second with a standard tension oil ring.
It had the oil puking issue with it so after a few months I pulled the engine and replaced the rings with new TS AP stainless rings, set them at the same gap with a fresh hone and it didn't change a thing. Still pukes the same amount of oil as before.
The car runs good and doing short but high boost street blasts puts nothing in my catch can but a full 1/4 mile run does it every time.
I run a -12 hose from the block and another -12 hose from the VC to a large vented catch tank. Block and VC fittings have a baffle plate below them so no direct path for the oil. No dips in the hoses to trap oil and make a blockage. No crank scraper or windage tray in the bottom end.
I have tried running it a quart low and made no difference.
I did a leakdown test and came up with the following:
#1 9%
#2 11%
#3 12%
#4 11%
Not spectacular but not bad enough to cause this, right?
I have looked at vacuum pump and dry sump setups but that seems like overkill. Any tips/tricks/ideas?
 

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Gas port your pistons. I run the regular TS top rings and they usually lose tension between rebuilds but the gas ports keep them sealed no matter what. No blowby issues even when the top rings lose tension.
You can also try running less oil. Does it stabilize after it pukes a quart? Will it keep puking a quart after every run? Do you have a larger oil pan on it?
 

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I have had this issue in the past... I run 2qt over full because I had issues uncovering the pickup. IMHO 1 baffle isn't enough. clearly you are pressurizing the crank case and theres not enough air/oil separation. Its tough to get something in there that flows air and deflects oil well. If its only oil, and not water... I wouldn't sweat it. Maybe run a larger catch tank and a larger diameter drain. fuel cell foam works well, but if you are puking 1/2 qt every run... it may get to saturated to flow air well. Might try some sort of homemade filter out of fuel cell foam that can gravity drain the oil back to the sump. line the baffle area in the valve cover or valley cover?

Ive done it in the past with some success. But I wasn't pushing a 1/2 quart each pass.
 

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Discussion Starter · #6 ·
Gas port your pistons. I run the regular TS top rings and they usually lose tension between rebuilds but the gas ports keep them sealed no matter what. No blowby issues even when the top rings lose tension.
You can also try running less oil. Does it stabilize after it pukes a quart? Will it keep puking a quart after every run? Do you have a larger oil pan on it?
Don't the gas ports in the piston eventually get blocked with carbon buildup?
As for the oil, I run it a qt low at the track already. When it pukes another 1/2 qt it is usually off the dipstick or close to it. Not brave enough to risk seeing if it will go lower.
 

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Discussion Starter · #7 ·
I have had this issue in the past... I run 2qt over full because I had issues uncovering the pickup. IMHO 1 baffle isn't enough. clearly you are pressurizing the crank case and theres not enough air/oil separation. Its tough to get something in there that flows air and deflects oil well. If its only oil, and not water... I wouldn't sweat it. Maybe run a larger catch tank and a larger diameter drain. fuel cell foam works well, but if you are puking 1/2 qt every run... it may get to saturated to flow air well. Might try some sort of homemade filter out of fuel cell foam that can gravity drain the oil back to the sump. line the baffle area in the valve cover or valley cover?

Ive done it in the past with some success. But I wasn't pushing a 1/2 quart each pass.
Here is the setup. Note the lines go into a 1/2 gal size catch tank on the driver side. The breathers on that tank were getting excessively oily so I put a second large catch tank on the passenger side and ran 3/4" tubing to connect them. A small amount of oil (couple of tablespoons) makes to this catch can.
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Can't see the pickup point (looks to be on the rear of vc) but try running the breather off the front of the VC. I have a car that I tune doing the same thing because there is no baffles and oil slings right to the vent lines just like yours does. Put a 2 bar map sensor on the pan or vc and log it during a pass.
 

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Discussion Starter · #11 ·
Can't see the pickup point (looks to be on the rear of vc) but try running the breather off the front of the VC. I have a car that I tune doing the same thing because there is no baffles and oil slings right to the vent lines just like yours does. Put a 2 bar map sensor on the pan or vc and log it during a pass.
Being a OHC engine there is a lot of oil slinging around in the VC. A front mounted vent may be better but looking at the insides of the hoses/fittings it looks like most of the oil is coming from the crankcase.
When I first built the engine I didn't notice there was no baffle plate under the crank vent. I thought that was the smoking gun and installed a baffle plate from a spare block when I swapped to the new rings but it made no difference.
I am running a stock oil pan with a stroker crank and the rods were actually hitting the pan during mockup so I had to build pockets on the pan. It would seep a little oil thru the welds on the pockets so had the pan powder coated which stopped the seepage. Pan came out real nice, almost too nice to hide under the car, lol. So basically a lot of crank stroke spinning at 7500rpm. Maybe a windage tray would help.
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High gas density due to high crankcase pressure causes large oil droplets to form. Lack of energy input to drive PCV action causes pressure scalar to provide kinetic energy to gas flow which flows from a region of high pressure to low pressure carrying oil with it. The piston becomes the pump which is pushing oil from the engine because pressure scalar has no direction associated with it, as in a tire, collisions occur in all directions equally.

The solution is generally a vacuum pump. Vacuum pump supplies gas with kinetic energy vector component which relieves the piston as a pumping effort scalar and reduces gas density which helps oil return to oil pan quickly in a gravitational field as opposed to forming large oil droplets due to collisions with dense gas state driven all directions at once in pressure scalar.

Luckily the turbocharger can be used as a vacuum pump. All OEM turbocharged vehicles in the world use the intake filter pressure gradient to drive WOT PCV which performs this function providing kinetic energy to the crankcase evacuation system. I recommend copy the OEM pcv system from a Toyota Supra or Nissan Skyline, e.g. Route one crankcase valve cover vent to the intake filter tube between the filter and turbocharger inlet. Route the other valve cover through a Supra PCV valve to the intake manifold. This is OEM pcv for turbo cars, it will maintain low gas density and high kinetic energy PCV flow provided the correct intake filter is used. You can measure the PCV crankcase pressure using a 1-bar or 2-bar map sensor in order to see the system is working properly. You can adjust as needed at the intake filter once you are monitoring the crankcase pressure. If you need a video I have one to show how this is done.
You must also pressure test the entire plumbing system to ensure there are no leaks, especially pcv valve leaking. Use a Supra 95-98 PCV valve for best results, chevrolet will usually leak too much.

If you need pictures of the setup and video of how to measure I have all
 

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Discussion Starter · #13 ·
On the OEM setup for my car it was VC breather to intake between filter and turbo and crank case vent to PCV valve plumbed to intake manifold. On that setup, under boost, the PCV valve would close to prevent intake pressure from making it to the crankcase thus relying on the low pressure in front of the turbo to act on the VC breather.
This setup worked well until you tried running 25+psi of boost. At that point the PCV system could not keep up and would start blowing the oil dipstick out and causing leaks at the oil pan and VC gaskets. It also caused oil buildup in the turbo inlet and intake manifold even at lower boost pressures.
I would think a dedicated vacuum pump would be better to make sure absolutely no oil is being drawn in thru the turbo?
 

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I would never run any PCV system on a high boost Engine.

Breather hoses have to be large and any catch can very, very well vented.

Especially a SOHC 4 cyl, any oily vapors just help reduce the fuel octane.
 

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This setup worked well until you tried running 25+psi of boost. At that point the PCV system could not keep up and would start blowing the oil dipstick out and causing leaks at the oil pan and VC gaskets. It also caused oil buildup in the turbo inlet and intake manifold even at lower boost pressures.
I would think a dedicated vacuum pump would be better to make sure absolutely no oil is being drawn in thru the turbo?
Well firstly, a bit of oil lube is good for the turbo, I encourage all my builds and tuned hundreds of turbo vehicles to coat their compressor with oil film for reliability as is done in OEM applications

Here is quote from borg warner engineer on this subject, encouraging the oil film lube manually Spray or due to PCV
he oil could benefit the exposed threads of the shaft and wheel and the comp nut which are both made of ferrous materials and will rust. As you point out crankcase ventilation is often directed into the comp inlet so oil vapor is present in this area. There is no harm in a small amount of oil or lubricant like WD-40 being on anything in the compressor stage.

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Next, as we increase boost pressure and blow-by mass, the crankcase pressure will require more suction to be dealt with otherwise it will rise and the engine will begin to blow oil again as you have noted.

The fix here is at the air filter, the tube which scavenging the crankcase is driven by a pressure difference, as noted here in fluid mechanics book

Note the equation p/y + alphaV^2/2 +z and the difference between the kinetic energy and hydraulic grade lines.
In the intake filter system we have some p/y which is pressure/specific weight of the moving fluid. The height and kinetic energy component can be considered negligible for this example because we are not using a venturi or kinetic energy capture tube, it is simply pressure driven.

The pressure drop is associated with the air filter restriction and that is the key to this whole thing. That and a full pressure test! It sounds like you neglected the pressure test and the PCV valve you used was leaking boost into the crankcase causing the oil mess to form, honestly I see that too often. If you perform a pressure test properly (Ask me for video pls) and If you monitor the crankcase pressure (also have a video) and adjust the filter to provide the necessary scavenging to the crankcase the blow-by issues and oil aspiration issue will be under control and the low gas density will prevent large droplets of oil from forming and being ejected- the compressor wheel will stay so clear from oil you will need to manually lubricate it periodically in my experience.

THis is what you are looking for, data you will capture to control the crankcase oil flow,



here is an example engine recently the last 2.5L I setup and was tuned recently
Notice directly connection crankcase to turbo inlet


This engine has large piston ring gaps, running E85 and 30psi of boost


No issues with oil blowing from the engine. However if we removed the air filter it would begin smoking and blowing oil at wide open throttle just like you experienced. The intake Tube then becomes a 'catch can' as atmospheric pressure scalar inside the tube forces the piston to act as the PCV pump creating higher gas density than atmospheric and the resulting pressure scalar above atmospheric has no unit direction- no vector associated with it, no kinetic energy component is enacted (as opposed to a vacuum which supplies the energy necessary to rapidly organize crankcase gas flow and direction) exactly as inside a tire. This allows molecular collisions time to form large oil droplets and remain suspended, and the energy supplied to drive PCV is a function of the piston pumping action 'pumping loss' which costs energy and time to organize the molecules and force them out of the crankcase along with significant oil mess into the catch can.
The key is the filter pressure drop, and a pressure test to ensure fully sealed crankcase and effective scavenging.
Of course a vacuum pump is ideal. However they are notoriously fickle, require maintenance, add complexity, it is unwanted in a street setup. Nevertheless they are king of PCV and oil control and piston function.

After 5k miles or so I will remove the intake tube and expect to find a slight oily residue there along with some trapped debris that bypassed the filter. This is another really good sign as the slight oil coating helps trap debris which would have worn the turbo compressor and embedded to the intercooler. We can simply wash out with some water and soap. While the light oil coat preserves and protects the delicate features of the compressor wheel. I will also apply some light WD40 because I'm in there anyways.
These are keys to longevity, reliability.
 

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Discussion Starter · #16 ·
You lost me at oil on the compressor wheel having benefits. I have never seen any rust on the shaft threads or nut on a modern turbo. Oil getting into the intact tract is a bad thing..no other way around that. Manually lubricate a compressor wheel? You must be the only person on the planet that does that.
The whole point of this is reducing crankcase pressure without the introduction of oil in any part of the compressor or intake manifold.
 

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Agree on your points.

My Engine of choice is the ancient Turbocharged Chrysler 2.2.

Similar in some ways to your Ford 2.3 with its 8V, SOHC, cyl head.

I run a hose off each valve cover nipple to the atmosphere with no oil dripping.

High boost blow-by can't be harnessed so my experience is to let it breathe.

Any restriction promotes drawing oil along with any blow-by.

I feel any restriction acts like a venturi and draws oil out of the Engine.

Guys in my world with catch cans etc. never seem to vent them well enough.

They always end up with oil exiting from the Engine somewhere.

Presently I'm experimenting with a basic pan evac system just for fun.

Exhaust vacuum might be OK as long as its not connected to the Engine air intake.

Not scientific for sure, only sharing my anecdotal experience.
 

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If its on gasoline or E85 lateral gas ported pistons or gas ported rings from Total Seal will give best performance over time and not have issues with carbon build-up. A windage tray is always a good idea on any wet sump engine. Crank scrapers are a pain in the ass to make fit properly but can be extremely helpful in oil control on something running high RPM especially a long pull like 1/4mi racing. Running a vacuum pump is a good option that helps maximize ring seal and windage is minimized. If you put a vacuum pump on it obviously it has to be air tight, however since a vacuum pump is positive displacement if the blow-by or a piston failure exceeds the pumps capacity it has to be able to vent or it can pressurize the engine enough to push oil out a gasket surface such as the valve cover possibly causing a wreck. I use a very economical plastic spring check sold by McMaster that uses a chemical resistant viton seat. This relief line dumps to a vented catch can and once the pump meets or exceeds the blow-by rate again the spring check seals and returns the crankcase to vacuum. On my 402CID engine a Moroso Enhanced 4-Vane would keep it in vacuum the entire run at ~40psi boost pressure running 50% of crank speed. Hope this helps.
 

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I know it seems new, scary, difficult to believe, but I am sure what I say and have quotes from the manufacturer himself posted to supplement. And more to come.

It took me 25 years of building and tuning hundreds of turbo cars and 15 years of college, chemistry and engineering courses and an MS PhD and discussions with the engineers behind turbo manufacturing and GM engineers with experience in PCV systems to finally come to terms with this.

A little tiny bit of oil residue is found in all OEM turbo applications using with factory PCV, they are all routed the same way, as residue collecting inside the intake filter tube and coating the compressor wheel keeps it healthy for 200,000 or 300,000 miles by design. I realize many of you do not expect 200k miles and use the engine for racing- so will not care or desire this type of influence. Nevertheless it is helpful conceptually to understand the difference between helpful oil coating and oil contamination due to blow-by gas and also especially the nature of clean oil, what is clean oil and where is clean oil allowable inside an engine? And how to keep that oil clean, and what oil really is? Oil is alot like gasoline. Some oil is always burning with gasoline in the combustion chamber, it gets in via cylinder walls, valves, intake suction, whatever. The oil only really becomes an issue when it coats the spark plug noticably, that is when you have a problem. Otherwise we have what I call the carbon cycle, oil hydrocarbon chains are oxidized with gasoline alkanes together and the difference in stereochemistry is what lends the variability of fuel octane (ask me for an interesting picture for this). But I digress... The air filter particulate filtration is an essential component of oil cleanliness for OEM PCV but I won't go there right now.

I've examined around 1000 imported JDM turbo engines and the ones with catch cans and atmospheric PCV systems are generally ruined, the turbo is worn out by air particulate and aftermarket filters. The engine is ruined from lack of PCV. PCV protects the engine, protects the oil, prevents deposit formation over the course of high mileage.
Atmospheric venting allows blow-by gas to mix with engine oil which creates deposits- 'atherosclerosis' which leads to catastrophic failure. If you look closely the information is there, knowledgeable engineers will say it, for example

I didn't write the following!

The crankcase relies on the vacuum generated in the intake manifold for evacuation suction, and with most turbo builds, this is only present during idle and deceleration providing almost no evacuation to remove the contaminant laden vapors from the crankcase and this allows them time to settle and mix with the engine oil accelerating wear and eventual failure. So it is critical to use a system that provides full time evacuation suction.
So you would never want to use a can with a breather on it, as that is breaking the evacuation cycle leaving the contaminants in the crankcase, and also allows pressure to build and be pushed out which is never proper. That technology went out with the 1980's.
Somebody figured it out way before we did, before I did. I only just caught up finally. It was like the cherry on top of a lifetime of searching for the ultimate reliability. In racing, you would desire a vacuum pump of course. I am not suggesting we all need super clean OEM pcv systems and oiled compressor wheels given the lifespan of a setup may be much less than 200k miles. Nevertheless it is an important concept to gain, a tool in your belt. something to keep in mind. Please consider these and I have oh so much more to give on this subject.

For example on Supraforums I discuss the proper use and pressure test for OEM Pcv systems. We use these 1000rwhp for daily driver supra 3.0L engines and Skyline engines as I show above, successfully to achieve high mileage. I don't like working on the car, I want to drive it. I setup many vehicles over the years and have figured out how to deliver this effortless longevity and the #1 and #2 primary aspects of reliability and mileage is OEM pcv done properly and the right air filter filtration particulate rate.

Thank you for being open minded
 

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Discussion Starter · #20 ·
Bringing this back from the dead.

I pulled the engine for a winter go thru and noticed some damage in cyl #4. I had the block honed to see if if the scratches would get any better but I still can catch a fingernail in the bottom horizontal mark.
The top horizontal mark and the vertical scratches can't be felt. I am thinking this may be the cause (or part of it) of my excessive blowby causing it to puke out a 1/2 qt of oil into the catch can on every 1/4 mile pass.
A friend looked at it and said that cylinder is going to need a sleeve. He thinks it is trying to crack thru the bore wall. This a rare motorsport iron block so it is worth spending money on to a point.
Any opinions on what is going on here?
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