OC94Rx7

Just wanted to add a photo I found in a back issue of SCC. They show a 2000 C-West RX7.

First they have a (green) hose running off the filler neck to a larger oil catch tank, then a second (green) hose running back to the fire wall with a breather filter (not 100% sure but it must be a breather) located at a higher level.

Sorry for the poor scan quality

//Oliver

OC94Rx7

Sorry, seems the forum will not accept my photo?...will try later

KevinK2

oil level is initially below the pan seal line. a steady 1 G right will reposition the top of the sump oil at a 45 deg angle, which is still well below the kink in the FD fill tube. also, the pan baffel and air in the fill tube will both resist inital slosh overshoot when going from a left directly into the hard right (turns 7 and 8 at old summit point). oil does rise high enough to block the air exit path into the filler tube.

the sump pressure will now build and start to push oil up the fill tube untill a) it is pushed into vent lines, or b) the sump level drops enough to allow air to bubble up through the partial oil column in the fill tube. both modes gets oil into the vents. If cap vent only and case a) mode, then the baster would make it worse by creating dead air space around it ... less fill capacity. I suspect a) mode is more likely, esp if one runs 1/2 on oil stick range.

for those with single turbos on FD's, a simple solution is to run a 2nd vent line from the unused oil return port. when the fill tube vent path is oil blocked, the new vent on the right side would prevent any sump pressure increase, and oil will not rise in fill tube like a manometer as it now does. The new vent must be angled up from the block, to allow quick drainage after a hard left.

Both vents could run to a simple jaz catch can, with low oil accumulation expected. a 3rd line could go back to the turbo inlet, vs the open filter.

for other models, more difficult shop job. 2nd vent could be a similar turbo drain type location, or off the front cover at a place where oil thrash off chain is not too bad.

concept is to prevent oil from rising too high in fill tube, so it doesn't make it into the vent there and has to be delt with.

P'cola FD

To bring up a long dead thread, I was at Walmart yesterday, and found what looks to be an aluminum turkey baster/flavor injector that fits perfect in the stant cap. It was $2.94 and the partnumber is 007328707700 it's called an "injection baster." I figured I'd throw that out there for anyone who might be looking to do the baster trick earlier discussed in this thread.

KevinK2

update ... a member has been pm'ing me about the single turbo option to use xtr drain as a 2nd vent, as noted in my recent post. He has hard core track car, and oil accumulation in overflow tank was dramatically reduced. but just one data point so far.

maximtaylor

Great minds must think alike Kevin, I had the same solution in my head in using the spare oil drain. Luckily enough I have a single turbo and have this option.

I have an extra baffle plate on the sump - looks great but doesn't cure the problem.

I'm hopefully going to be fitting the second pipe in a couple of weeks - I've got a couple of track days to do first, Brands Hatch (UK) next week and Nurburgring the week after.

I only seem to have the problem on long duration right turns, the short turns are no problem, but this leads to another concern thats gnawing at me.......

I may fix the 'filling the can' problem, but am I getting oil starvation in the pick up tube anyway?

Anyone gone the dry sump route on a 13b? I know a few of the 3 rotor guys have. Suggestions and price tag please!! As I've ripped out the air con - I thought I could use this point as a possible pump(s) mounting location and run off the main belt.

Max

DamonB

Never seen it on a street car but I have on several race cars. Mazda even makes a dry sump front cover with the pump built in; very trick:

Part # 0000-01-9312 Dry sump front cover $2423.40 (from page 1 of this thread)

I have yet to see someone use that cover though. The dry sumps I have seen seal the bottom of the motor with a plate and sit the pressure and scavenge pumps on the left side of the motor where it's easy to plumb. Custom brackets and adaptors were made to bolt up the pumps and plumb them.

maximtaylor

Thanks Damon - Think I'll check the bank balance and go that route.

Max

KevinK2

max,

as long as the pick-up is at the sump lateral center, oil pressure should be ok. if oil starved, gauge would show it. the "long duration right oil vent problem" is explained at my earlier post.

FUEL STARVATION on long right's is another problem, with an easy solution possible. many oem in tank pumps have a mini-tank surrounding the pump, that is pre-filled, usually by a small primary pump down there. Since the mini-tank is usually clamped directly to the pump, the concept of a retro fit of the can and primary pump, to the fd pump assembly, seems within easy reach. This is a saab pump design from the 80's:

http://www.thesaabsite.com/shop/catimages/9321621.jpg

on a longish hard right, the mini pump is starved, not the main pump as long as some fuel is still in the can.

DamonB

That essentially just a surge tank built into the fuel tank, right? I didn't realize there were stock systems around that already did this. By chance know of any other models that do this? Is it common among other cars?

Marcel Burkett

Dont know if this was mentioned before 'cause I didnt read all the posts in this thread , but you can try this , get one of the older metal filler necks , plug or remove the factory tube , and replace it with an appropriately sized metal (weldable ) angled 90 deg fitting . Drill out a hole to fit it , put the angled section into the the tube so that its facing upwards toward the filler cap and and located in the center of the tube (away from the filler tube internal walls) then weld or braze it in . If oil travels up the walls it wouldn't get into the opening at the end of the fitting , since its located away from the wall , you would have to have a **** load of oil move up the filler neck to totally fill the tube to get it escaping into the fitting, in that case you have too much pressure leaking down and should probably be looking at "freshening up" the side seal / corner seal clearance.

KevinK2

z28's have a version of this, with return fuel also added:

http://www.racetronix.com/Racetronix..._Pump_Kit.html

stock FD:

http://reganrotaryracing.tripod.com/denso.htm

The '86 saab 900 pre-pump with screen could deliver into a custom can, and run off the main pump power. Return fuel could also contribute to can.

the_glass_man

iTrader: (2)

Anyone else working on different solutions? I think I'm going to go the route of utilizing the currently unused rear oil return line. I'm surprised that nobody doesn't already make a nice oil filler tube that helps alleviate the problem.

M104-AMG

iTrader: (8)

So what's the consensus/best practice to solve this issue other than a dry-sump conversion ?

I was on street tires at Roebling Road raceway, and had oil all over the place. Freaked me out.

:-) neil

CrispyRX7

iTrader: (139)

UGH RR would be horrific for this problem. The toilet bowl being the big contributor. My sympathies.
Crispy