Carl Fausett

I'm with you there, buddy - studs and all.

But you do not have to pull the motor.
Suspend the motor and drop the crossmember - you can still drop the pan with the motor in the car.

Or, if you installed the studs with Loctite, warm them with a Butane Microtorch and turn them right out. Heat is the magic tool for breaking Loctite products loose.

BC

I don't think we should let this thread die. OIl issues are a major theme with 928s.

SwayBar

First of all, I'm not one of those/many who say, 'oh yeah, that's a great idea, I'm in, design and build it!!!!!!', and when it comes time to actually buy the finished product, all the vendor hears are crickets chirping, and looks on at the resultant shelf-load of parts gathering dust in the corner.

With that said, I would be the first in line to buy a dry-sump kit made specifically for the 928. If Mark Anderson had his race-proven dry-sump setup for sale, I would have bought it yesterday. Sure it's going to cost some money, but all it has to do is save one's engine one time to pay for itself.

Kevin, absolutely no disrespect to you, but it doesn't look like a crank scraper will work with the crappy 928 oiling system as their addition only seems to exacerbate the condition. Teaming the crank scraper with a dry-sump seems to be the only way around the super-shallow oil pan. Have you ever seen and worked with a pan as shallow as the 928's? If so, then there is hope!

I still contend that the <seinfeld voice>'big ball of oil'</seinfeld voice> that is scraped off the reciprocating mass and unceremoniously dumped/splashed onto the pan and into the sump, thus overfilling it from it's stock operating parameters, is the root-cause.

Next, when the crank comes around and pounds into the big over-flowing puddle of oil, it flings it up into the crankcase as mist/droplets, as well as displacing the oil up into dipstick, or any other orifice, pounding away on it. It's the same affect as the angry sea crashing up against the sheer rock faces along various coasts we've seen so many times; the displaced water has no where to go but up, and spectacularly so at that.

GlenL

Where does this new volume of oil come from? It'd take extra quarts for the level to reach the rotating parts. The scrapers should (and do) reduce the windage. Why more ejection? Does the scraper both reduce and create windage and foam? No. I think there's another actor in the play. (above!)

The trick is to get the oil into the sump. and keep it there. Dry sump? Sure. If the next step (new drain channels and sump top) doesn't clear things up that'll be my winter project.

drnick

if there was a tested drysump pan out there for a 928 id buy it tomorrow. any vendors with such an item pm me!

GlenL

Kevin,

Not following the application of this part. Use it to draw vapors out of the crankcase? What's the outer tube for?

GlenL

The tube from that fitting runs up between the belts and the block. It's about 1" across and takes a jog to clear a bracket. Looks like a tight fit with some need to crunch the tube to make it go.

Carl Fausett

Good Stuff, Kevin. Nice prototype. I understand the principals involved and that would definately work/help. The finished product could/should be one piece or at least braze welded, not soldered, but as this was just a mock-up, it doesn't matter.

Carl Fausett

Kevin started me on this line of thought.... a few pictures back in this thread he shows filling a 928 oil pan with water... and how at 6 quarts the fill tube entrance on our 928 is already "below the water line"

I removed a spark plug from my 928 and hooked up a cylinder leakdown tester with only 15 psi of shop air attached to it via regulator.

I inserted a dipstick with a good seal on it into the dipstick tube. I noted that I was at the "Fill" mark in my oil pan for this experiment.

Photo 1 : at zero seconds, air is coming out of the crankcase vent into the oil separator, as normal.

Photo 2: I take my finger and cover the breather vent. Oil is pushed up the pipe and half way up the separator chamber in 1 second.

Photo 3: Filled to the brim in 2 seconds - I had to let go. I took one for the team here, boys, when I removed my finger the oil splashed all over.

And this was only on 15 psi of shop air! Imagine how long it takes under combustion pressures....

DEVEK used to market a shut-off valve for the standpipe, don't know if they still do. You'd open it to add oil into your motor, otherwise you'd leave it closed all the time. I have a sense that would start to build up pressures and blow gaskets and seals if that standpipe could not assist with venting.

But - because of this experiment, I am mocking up a restrictor plate for this standpipe, I should be able to pass gasses yet slow the rise of the oil by at least 50% (long enough to stop braking and accelerate out of the corner, when oil goes to rear of pan and loading the front fill tube no longer happens).

Carl Fausett

I should also report my findings on the Mann-Hummel Oil Separator while I am at it.

I fitted one with the new motor and was really impressed with it during 500 miles of street driving at 4 to 8 psi of boost. No problems.

Went to Road America and had a 20 minute track practice session, and I blew the top off of it. I figured I had failed to completly click it shut and the fault was mine... but at the Milwaukee Mile the next weekend, It happened again.

The first problem is the safety valve in the lid (see arrow in the picture). It is designed to open at 50 Milibars of pressure.

The little plastic fingers that hold the spring in place on the safety valve failed (got soft and let go) in hot oil, and the safety valve opened, pouring oil all over my headers and making me real popular with the other racers.

I "fixed" that at the track by inserting a thick washer on top of the safety valve (the lid just snaps apart) - see secod photo. Then the damn safety valve stopped opening on downshifts before the lid blew off a gain after about 3 laps... just like at Road America. And this time I KNOW I had closed the thing correctly.

All I can figure is that, in the heat underhood and hot engine oil vapor, the plastic is becoming soft and the latches let go.

I am removing the Mann Oil Separator from our catalogs now until it gets fixed.
I'll go back to an aluminum catch can/separator with a breather on top.

Rick Carter

Carl,
I was hoping the oil seperator would work better. I'm currently using two catch can/separators with breathers on top. When I first start the car there is always the smell of oil in the cabin and in the garage when I shut it down, other than that works great.

SharkSkin

Carl, do you think it would make sense to come up with a float/check valve, something that would allow free flow normally but would float upward on the oil and plug off the tube? That J-shaped tube that Kevin showed in post #79 seems workable at first glance but seems like it will fill with oil sooner or later. I think it's better to assume that oil will get in that tube and just manage it.

GlenL

I'll be trial-fitting that vent pipe this weekend.

Putting a valve in the fill hose is an old idea. I've tried it and noticed no improvement. The pressure needed to pump the oil up the tube is low at around 0.05 bar. However, that kind of pressure will make air move quickly. For those of us using the filler cap as the exhaust point, the pressure inside the filler will adequately equalize to the crankcase pressure. Put in practical terms, I've never found the dip stick pushed out so the crankcase is not getting overly pressurized.

This does recall an experiment gone horribly wrong. A lister/friend/mechanic suggested re-routing some lines at the track. This involved blocking the exhaust line that Carl put his finger over. The result was the same: it pumped quarts of oil out of the pan, through may catch and onto the ground. Engine was rebuilt that winter due to broken rings and pistons. Compression tests now show high and even results.

BC

How many of these people recording problems have 16V and how many 32V?

I know Sterling was 32V.

Tom Cloutier

There is a dry sump pan design at a local machine shop waiting to be CNC milled from a solid billet of aluminum. I'm hoping chips will start flying this week. Obviously it has not been tested yet, but soon. The first 3 are spoken for.

Cheers,

Tom Cloutier