heres my cheap one so that everyone can ignore it again https://www.rx7club.com/showthread.p...hreadid=252344

 

Hmm...new idea.....even cheaper.......

Why not fit a large housing directly on top of the oil filler pipe?

As soon as any oil forms, it would simply pour straight back down the filler - and a bit of pipe a couple of inches long on one side linked to a breather would eliminate any oil managing to get out of there.

cost = $3 for filter, and a couple of dollars for a saucepan (lid welded on)

lol, even cheaper than yours rockshox

 

The solution, like all else that is Good and Pure, is and will always be witnessed by the modern Oracle that is <trumpet blaring> eBay"...

THE eBay catch can solution

 

 

Now thats what you call resourcefull (or is it just being cheap?)

 

...it would simply pour straight back down the filler just as it does now with the stock plain tube and oil cap

Your idea would still allow the engine to inhale the oil into the intake. You have to essentially route the oil slosh outside the oil filler tube. Remember, the whole reason of the catch can is to keep from sucking oil into the intake tract.

 

sorry, I forgot to say the bit about capping off those pointless bits at the bottom of the filler

Sowwwweeeeyyy!!!

lol

 

This may be a stupid question,

But why not just fabricate a new oil filler neck entirely? It's not like the stock one is anything high-tech - and I've seen this done before on other rotaries.

 

You could, but you might as well use what you've already got - loads simpler

 

No, because what we've already got obviously sucks.

A new design would rotate the filler neck 90 degrees clock-wise or as much as possible and use larger PCV outlets.

 

Back from the dead. Race season is coming and I had an idea'r.

The turkey baster mod on the cap seems to really limit the amount of oil ingested. My idea is to make it harder for the oil to climb the fill tube in the first place by putting a restrictor in the tube. I pictured unbolting my stock FD fill tube at its elbow and placing a metal plate in there that only has a 3/8" diameter hole in it for instance. Seems to me this would limit the amount of oil that is capable of sloshing up the filler neck and you could even add another turkey baster into the plate. It would be the Stage II turkey baster mod

Only downside I see to this is that when adding oil to the car you may not be able to just dump it in; you may have to pour more slowly to keep it from running over. Am I missing anything?

 

Damon,
I have something like this. It is an angled plate at the bottom of the upper portion of the filler neck. Basically a piece of cut AL that i have wedged down in the filler neck. I dunno how well it works if at all. Sure does making the filling of oil a VERY slow process though
Wouldn't hurt to try it though. My thought is though if you are going to do this why not just install a pan baffle plate and reduce the ampount of oil even entering the filler neck base?
[*sigh*]
Crispy

 

Because I don't wish to remove the oil pan. Your description is certainly more elegant.

 

Another question on this:

Adv/Dis of sealed catch cans vs unsealed.

I would think the one major adv. would be a lack of oil everywhere when the can does fill up. A dis. would be that the blowby gasses would be ingested by the engine due to no vent filter. Kind of a trade-off in that oil itself is left in the can, but the vapours are still combusted (which is how OEM is anyways, sans the oil that goes through the piping).

 

clayne, but when the oil catch can fils you are then going to be ingesting oil back intot he engine and not just gasses...kinda defeats the purpose of the catch can no? The solution is to stop oil from getting to the catch can in the first place.

Since this thread has been revivied I thought I'd share an observation I made last week while looking at the engine bay of a new RX-8. Seems like Mazda recognized this oil "slosh/pickup"problem too. If you look at the filler neck on the RENISIS engine the pickup tube is located in the same place it is on all 13B blocks however the upper portion of the neck now bends all the way over such that the filler cap is in the ***CENTER OF THE ENGINE!!!*** Well I'll be darned. I wonder if there is some internal changes to the filler neck that are not visible also? Take a look the neck time you get a chance and you will see what I mean.
Regards
Crispy

 

Could you tell if the oil filler tube was a two piece like the FD? Maybe those that have removed a lot of clutter in the engine bay (single or non-seq) could install just this part.

Rebuilding engine next week with a friend and he has an RX-8. I'll take a look and take pics.

R

 

My plan is two build a new oil fill tube to replace the stock plastic one. I'm going to cap the two lines from the stock filler and not use them, merely going to vent my new filler with a crankcase breather. Since there will be no path to the intake the engine can't ingest the oil and since there is also no catch can the engine can't loose the oil in filling the can. All oil will stay put If I get emissions worried I just put the old filler back on and plug the lines in.

 

rceron,
Yes the neck appeared to be a two piece design. And yes I also was looking at could just the upper portion be retrofitted. Doesn't look likely....at leats not without some extra work. The RX8 upper filler neck literally sits right over the top of the motor...rouighly where the frotn two intake runners of the FD UIM are
But please take pics and let us all know what you think
Regards,
Crispy

 

Hey Damon,

Can you post some pics and thoughts when you get done?

I'm curious to hear about how it works out as well as any extra nasty fumes you might get.

 

For now, I am going to stick with the stock Filler tube and add a baffle which will sit inside. I still think, like crispy and others had said. If you can stop the oil before it has a chance to rise far enough up the filler tube, then it won't have a chance to enter the Vac hoses/engine.

This is what I am going to make.
Make a cylinder which has 4 chambers. The 1st and 2nd chambers (starting from the bottom) should slow the oil. Those chamber will have holes on the left side only. Chambers 3 and 4 will have holes on the right side.
I think this should work. The question is, the size and location of the holes? I also have a 2 larger holes, one below the 4th chamber and one just under the filler cap. The larger holes are for the relocated vac hose (tapped into the filler cap) to the manifold.

Please..any suggestions are welcome, such as locations of the holes or maybe the number of chambers I have planned to use.

The idea is not to rely on a catch tank, but to just slow the oil or stop it completely. If this does not work then I hope others like Damons will work.

 

 

Of course. But I'm saying in case it *does* fill up would you rather burn off the excess or be dumping it down the side of the car and under the tires - as you've already experienced? I'll take the blue smoke - I've done the catch-can cleanup activity enough to not want to do it anymore.

That's what I was saying a couple pages back about fabricating a new neck.

 

Just came back from the NYC autoshow. You are right. There is no way the top half of the RX-8's oil filler tube would work with the FD. It basically goes over the front rotor so it would hit either the throttle mechanism, alternator or UIM.

Plan B required.

R

 

Another option is no neck whatsoever. Use a block off plate and integrate a seperate "crankcase" vent. When you need to fill the oil, pull a bolt off the plate, rotate it out of the way, and fill it up with a funnel. Or one could integrate some kind of baffling/valving into the plate and place the vent nipple there - leading to a catch can. This would be more difficult as the same issue would persist, however.

 

That's essentially what I am going to do. I'm going to build a new filler neck and remove the PCV and the line to the primary intake; just a simple neck that is topped with a crankcase breather. I'll attach the breather at the top of the filler with a quick release clamp so I can add oil easily.