Rb25 Cam Cover Baffles, An Inside Look

[reaper1721]

Ladies and gents. I am not sure If something like this has been posted before, I googled and had little success.

Here is an inside look at r33 rb25det can cover baffles (likely also the same as r34 rb25det baffles)

We will be refering back to this picture a few times...

As can be seen on the baffle plate above, there is a nice smooth transition into the two drains back into the head. The bottom side is shown below.

I assume they have been positioned on that side to drain the oil into an area which would be under a slight relative vacuum created by the rotating camshafts. I may check this theory later.

Moving on, this bad boy here is to the best of my knowledge, there in an attempt to separate oil as a liquid from fumes. This is done by slowing the heavier, denser, liquid (as opposed to vapour) allowing it to fall back down onto the baffle plate and drain back down into the head.

It is made up of a sheet of 'fly mesh' concertinered, bound by wire and soldered. It is held in place by two cast ridges in the alloy of the rocker cover, and a small indentation on the baffle plate.

Here's that first pic again,

Just to the right of the separater, is an indent to allow clearance for the throttle body.

At the far left, the oil filler can be seen. And just to the right of the oil filler a 'wall' can be seen. This wall seals off the baffles so that oil/ oil fumes can only enter from the rear.

Queue ms paint...

Fun fact: These baffle plates are held in by mushroomed studs of alluminium that are part of the cam cover casting. If you choose to remove your plates for whatever reason (modification, make your own from scratch, cleaning etc.) it might pay off to use a dremel or similar to grind around the lip of the mushroom and leave as much of the stud intact as possible ready for the plates to be refit.

Keen eyes may have noticed that I drilled mine off. This is because I will be modifying my covers, and if this, or any baffle plate is refit, I will be drilling, tapping and locktiting bolts in place.

Now something that has one of my eyebrows raised, is the large cavity at the rear of the covers, and the odd shape of them that is not mirror from left cover to right or vice versa.

In that area, sits another baffle plate bolted to the camshaft bearing caps, however, I wouldn't have thought they would need so much room above them.

My only theory thus far, is that they are there to increase capacity as a bit of a bandaid fix for our beloved (or not) RBs problem of filling the head with oil. This theory being that under acceleration, much of the oil is pushed to the rear and is allowed to fill up the cavity instead of pushing up into the baffles through the rearward opening as well as the two drains. Would any knowledgeable person care to confirm this?

Now this may beg the question "if these baffles are designed to stop oil from making its way through the breathers, then why does my catch can keep filling up with oil?" well, here's a practical answer to that question that everyone can try at home. Fill a large container/bath tub with water. Place your cam covers in and allow the water to fill above them. Those that have their witts about them may have now realised that baffles don't work very well when submerged.

[hardsteppa]

I am thinking you are long gone? but #1 for a helpful post..i applaud the man that posts info for others future reference.

[7amooda.007]

This is why I love forums, although ppl are moving away from them.

A new r34 owner and digging around in this forum from posts around 2005, this amazes me and will contribute as i can.

Where did everyone go? Maybe got married and have kids now, probably sold their skylines to teen drifters haha.

[skylinecouple]

No logical way to fix this. Sealing off the baffles just stops oil vapor as well. Only thing to do, as a simple fix, is to get some course, heatproof foam as per HKS baffle filters. Tip, the internet has some interesting options. Clark Rubber also had some good products a couple of years ago.

If you were to completely fill the baffle area with similar material as per standard baffle this would also slow down the amount of oil going to the intake. The only way to go better than that is to have a catch can that drains back to the sump.

I've cured mine years ago by doing the above, extra material in the baffle. When I check the small pipe going to the intake it is usually dry now.

A catch can that collects oil mist but feeds back to the turbo intake is not really efficient. NO oil before the turbo intake is what we are after. Unfortunately with the average Skyline, regardless of model, once you have a bigger turbo or more boost or both there is far more suction from the valve covers. Standard baffling is easily over powered in this instance.