Where did this oil come from?

[GrabberBooGT]

When I recently removed my charge motion delete plugs, I noticed the general area of the intake runners where the delete plugs sat were a little "oily." During the original installation of the plugs a few months ago, I noticed no such oil in this area or on the intake butterflies -- though the butterflies had a "scorched" look that could have been oil on the butterflies.

I checked the throttle body, pcv line, and the cold air intake -- they are dry and clean as a whistle. So, where the heck did the oil come from? Note, it wasn't fuel.

If it is blow-by, is it normal for the delete plugs or plates to increase this?

 

[trill gear head]

oil blow by. Its those 2 tubes that connect from each valve cover and connects to the intake manifold & CAI.

 

[AJ]

maybe you would benefit from a catch can

 

[Five Oh Brian]

Increased power = increased blowby = increased oily crud in the intake stream. Get an oil catch can (like many of us have) and it'll be greatly reduced (or eliminated).

 

[GrabberBooGT]

Thanks for the input. A couple of follow-ups:

So, the small amount of additional power created from the plugs/tune would have caused this and should be considered normal?

How come no evidence of oil in the CAI (where the pcv hose connects) or in the throttle body? Is it possible that the blowby could be sucked in the intake and collect at the bottom of the runners without leaving a "trail" at the throttle body or CAI elbow?

 

[HG6283]

Thanks for the input. A couple of follow-ups:

So, the small amount of additional power created from the plugs/tune would have caused this and should be considered normal?

How come no evidence of oil in the CAI (where the pcv hose connects) or in the throttle body? Is it possible that the blowby could be sucked in the intake and collect at the bottom of the runners without leaving a "trail" at the throttle body or CAI elbow?

All engines have -some- blowby. Engines with power-adders have more.

There is also some intentional flow-through-Ventilation.

In the "Ventilation" circuit, air is pulled from the intake tube (after the CAI but before the throttle plates) and flows through a small hose to the passenger side valve cover.
The larger hose which runs from the other valve cover to the intake manifold is what -pulls- this air through the engine.
Any blow-by gas in the engine is also pulled out with this air.
The blow-by gas can contain oil mist and oil & gas vapors. These can condense inside the intake manifold and on the charge motion plates. Also causes crud buildup on the valves and in the combustion chambers.

In answer to your question, look at the direction of flow through these lines. The CAI and throttle would not be exposed to the blowby gas.

A catch can installed in the hose between the left valve cover and the intake manifold can trap a Lot of blowby contaminants. This helps keep the intake -and valves- much cleaner.


.

 

[Casey4s]

My car is low milage and I was amazed how much crud was on my TB. This blow by also adds to the carbon problem on the plugs in these motors. I added two oil separators to my system and don't vent bqck into the intake. I have the intake nipples blocked off. If i decide to vent back into the motor (for inspection) all I need to do is hook up two hoses, about 3 mins work.

 

[GrabberBooGT]

All engines have -some- blowby. Engines with power-adders have more.

There is also some intentional flow-through-Ventilation.

In the "Ventilation" circuit, air is pulled from the intake tube (after the CAI but before the throttle plates) and flows through a small hose to the passenger side valve cover.
The larger hose which runs from the other valve cover to the intake manifold is what -pulls- this air through the engine.
Any blow-by gas in the engine is also pulled out with this air.
The blow-by gas can contain oil mist and oil & gas vapors. These can condense inside the intake manifold and on the charge motion plates. Also causes crud buildup on the valves and in the combustion chambers.

In answer to your question, look at the direction of flow through these lines. The CAI and throttle would not be exposed to the blowby gas.

A catch can installed in the hose between the left valve cover and the intake manifold can trap a Lot of blowby contaminants. This helps keep the intake -and valves- much cleaner.


.

Very informative and on point to my questions. Thanks to you and to all who replied.