Oil in intake.

[dfarr67]

Wondering if this is hurting me- or just ignore it as I'm not about to pull the engine right now. Have a relatively fresh 385 sbc and have noticed oil in the plenum of the TPI (FIRST) and not a small amount some time ago. I suspect a poorly running efi/break in may have washed the cylinders, or perhaps the Moroso 20206 oil pan (I think- never saw the interior of the pan). I have a couple catch cans out there and with another DD collects a nasty mix of water/carbon/fuel, on this engine it is collecting clean oil which would be nice to drain back to the crank case...I'll just keep an eye on it and empty at each service. Engine does not smoke, I don't notice oil usage on the dipstick. I haven't tuned in awhile so it may have been an issue for octane tolerance which I thought at the time was leaning out, in a couple months will get it tuned by a pro and see what he thinks about knock- but that particular issue was before installing the catch can. Whats your opinion- sure hate pulling a fresh engine.

[dannobee]

Is this a street engine? What are you running for a PCV system?

[dfarr67]

Street, TPI ish stock PCV system pulling fresh air through TB to pass valve cover, PCV drivers valve cover to air/oil separator into back of plenum. Will be trying open breather on fresh air side. PCV valves I have on hand are a mix from TBI and TPI don't know whether they are important other than clean. Valve covers GM vette magnesium. Wonder if PCV baffle could be stuffed with mesh?

[dannobee]

Did the baffles that are built into the valve covers match? Did someone remove the ones from under the L98 valve covers?

[Belgian1979]

If you connect the PCV to the plenum and full vacuum you need to have some sort of valve in place that regulates the amount of air that is being pulled in that way. Otherwise it will pull a lot of oil out of the engine. The valve needs to be correct for the vacuum that the engine pulls. (maybe your new engine pulls more vacuum than the old one did).
And if you do have a valve in there, the bottom of the valve needs to be at least 3/8 from the baffles or else it will pull oil as well.
Preferably you'll have a catch can in there after the valve and before it goes to the engine. The Moroso type of cans are nice and allow for drainback (which I do no suggest in any way).
I used to have this type of issue and went with the Wagner adjustable PCV valve and Moroso catch can. The hose to the engine is completely dry now. Once in a while I just have to drain the can.

To test if it is the pcv, just disconnect it and leave it to ventilate to the atmosphere. If the oil goes away it is the pcv-system.

Just my .02$

[mag2555]

Just keep in mind that even low amounts of oil infusion into a gas fueled motor can greatly deminish a given fuels octane rating, and once ping and knock takes place especially above idle rattling the piston around loss of ring seal will compound the oil dilution / octane problem.

[dfarr67]

Good info thanks- I looked briefly at that adjustable pcv, I'll look again. Which do you think does the bulk of the job- catch can or pcv?
I use a catch can with my 15 Honda Accord DI, I still find it amazing the crap it catches in my bi annual oil change- especially when you think that this particular engine although not known for coking doesn't have regular injectors to wash the valves.
The liquid that the catch can so far has picked up in the 383 is more pure oil (to the eye). Other than being pinched for roller rocker clearance- the baffles are as GM placed them.
And yes- the oil/chamber issue is in mind for octane problems.

I like this product, looks oem and blends in.
http://www.saikoumichi.com/internal_baffle_design.html

BTW, since this is an aftermarket intake and vacuum ports are sparse, I run hydroboost so the pcv is tied to the brake booster vacuum port.

[Belgian1979]

Look at the wagner item for an adjustable unit. Not cheap though, but a quality item.

[dfarr67]

Working on getting six buyers through various forums= 24% off.

[bentvalves]

perhaps the engine is being slightly overfilled with oil?

try 1/2 quart less, and see if it still pukes oil into the catch can.

[dfarr67]

I have a couple tubes and dipsticks kicking around- I'll compare. Factory block and factory dipsticks.

What would happen if the fresh air supply was sealed off only using the pcv valve?

[dfarr67]

Looking at this Wagner valve:



http://mewagner.com/?page_id=1927



Expensive....but other than a catch can- may go a long way in dealing with oil in the plenum on a 383.



http://67-72chevytrucks.com/vboard/show ... p?t=787630



If I can get another five interested in a purchase- it would be a substantial savings.

[BobbyB]

Looking at this Wagner valve:



http://mewagner.com/?page_id=1927



Expensive....but other than a catch can- may go a long way in dealing with oil in the plenum on a 383.



http://67-72chevytrucks.com/vboard/show ... p?t=787630



If I can get another five interested in a purchase- it would be a substantial savings.

How many buyers do you currently have?

[dfarr67]

Me

[dfarr67]

Looking at this Wagner valve:



http://mewagner.com/?page_id=1927



Expensive....but other than a catch can- may go a long way in dealing with oil in the plenum on a 383.



http://67-72chevytrucks.com/vboard/show ... p?t=787630



If I can get another five interested in a purchase- it would be a substantial savings.

How many buyers do you currently have?

Dave,

Sorry, no group buys at the present time. You only need six so do some posting or ask around. We will let you know if any group buys take place in the near future.

Barbara Wagner