Operation IDIocracy: CDR Turnaround Bracket

ON THIS EPISODE OF BIG CHUCK’S DIESEL GARAGE

So after the turbos themselves were installed, I was staring down doing all the grunge work… the auxiliary systems that make the whole thing happen. Not going to lie, solving the geometric positioning problem was far more satisfying, because this is the “nickel and dime” stage of the project where I’ll have to buy this fitting and that hose and this fancy washer, and so on, over and over as I figure out more of what has to be installed.

The subsystems that had to become existent consist mostly of the crankcase ventilation system and the oil return system. Those are the critical ones; I was also planning on adding some gauges and other pointering-devices so I knew what was imminently going to explode

This post will be about the former, usually called positive crankcase ventilation. In dieselworld, this part is apparently called a “Crankcase Depression Regulator”, which presumably helps get the engine out of hiding in bed and takes it on a walk down the unusually scenic river promenade, having a ponderous conversation about what fulfillment means in life.

Seemingly called the “tuna can”, this big valve sits right behind the Intake Cave. My understanding of how it works is that because diesel engines do not pull meaningful vacuum (unlike gasoline engines which pull a strong vacuum), it just lets the crankcase pressure evacuate constantly unless the vacuum becomes too high, upon which it will start closing.

“High” vacuum is relative, as we’re talking inches-of-water territory (tenths of a PSI or less); apparently you don’t want the crankcase to be under atmospheric pressure by much, as it will start sucking in contaminants from outside through seals and gaskets.

The back of the canister is vented to atmospheric pressure to allow it to open and close, and the very weak vacuum pressure differential is why the can is so large compared to thumb-sized gasoline engine PCV valves.

Well, in any case, the problem here is that I’ll soon be shooting above-atmospheric pressure into the thing, and it has no backflow prevention (unlike a PCV valve) so I’ll be pressurizing the entire engine to 8-10 PSI! That sounds not fun.

First, let’s remove it to see what I have to deal with. It just unbolts from the two flange screws holding it on, and pulls upwards out of the (extremely stiff and dry-rotted) fitting. There’s a rubber washer that is the interface between it and the intake manifold.

So all the kits available for these engines have you move this canister somewhere else. Makes sense, since it has to be attached to a source of intake air at a slight vacuum relative to atmospheric pressure. The part I found troublesome is they all had you move it either deeper into the Engine Cave, or hanging awkwardly off a hose somewhere (like Spool Bus has).

I noticed that maybe I could just turn the can around and seal off the intake manifold hole with a plug. That will point the “outlet” backwards, allowing me to run a hose down over the transmission and into one of the air filters. Presumably in the final Vantruck integration I’ll tee off an intake hose in the same general location.

Well it turns out it’s not QUITE symmetric. I’ll have to space it outwards about 1/2″ or so, so I can’t use this OEM riser bushing. It’ll be an interesting little challenge to make an adapter for the thing.

Oh, in removing the CDR valve, I had to unbolt the OEM glow plug controller and that’s when I found the horrifying secret it was hiding this whole time.

Snekvan has always had this congealed goo that ran down the side of the engine block and transmission. It wasn’t oil; degreaser wouldn’t touch it. It wasn’t congealed coolant, as I couldn’t wash it off with water either. It seemed to be some kind of resin that had melted and flowed all over the place.

Well I found out where that resin came from: The entire underside of the glow plug module, seemingly made out of some kind of potting compound, had disintegrated and was EVERYWHERE. It seemed to be filled with some kind of particulate stuffing, too, which is the little yellow kernels.

Whatever it was, it had mixed with all the oil grunge and other …. substances and formed this cured cake of OH GOD. I had to take some terrifying solvents, a scraper, and a wire brush to it before I was willing to get any closer.

Much better. At least the problem is now hidden from view (The underside of the intake manifold will be cleaned in the future and is surely a horror show).

While I was in this area, I was also searching for places to deposit the oil that will be returning from the turbo bilge pumps. I noticed a little drain plug of sorts back here… what could it be?

Out it comes! I was hoping this was some other access to the crankcase, since right in front of it was the CDR exhaust port.

Imagine my surprise when I found that this plug is hollow, and it was just a “pan drain” to let liquid run down the side of the block from the central valley. Well, the more you know.

Check out this impressive difference between a generic automotive 7/8″ coolant hose and this 7/8″ McMaster-Carr sourced coolant hose!

Okay, it’s a bit of an unfair comparison. The automotive world sells these by the outer diameter, and McMaster seems to sell by the inner diameter. Still, the difference in wall thickness and reinforcement fiber count was staggering.

Here’s my battle plan. I’ll be using the thick-wall industrial coolant hose pressed over the CDR inlets and outlets as a hose “collet” of sorts. The CDR valve does not have an outlet nipple, so I hatched a plan to flare the hose over the port and capture it with a bracket.

Similar products do have a proper outlet hose nipple, like these for the 6.5L GM engines found in Humvees – I may get one to see if they can serve the same purpose.

This is what the “Hose Collet” looks like in the end, after I slit the hose segment with the bandsaw. It will be on both the inlet (pictured) and outlet.

The capture bracket for the outlet hose, which also doubles as the mounting bracket for the outlet side, is made from a regular ol’ chunk of 3/16″ thick steel barstock I had hanging around.

The native hose outer diameter is right around 1-3/8″, which made for a somewhat difficult slip fit using a regular 1-3/8″ step drill. Once flared over the outlet fitting, it’ll be trapped by this plate.

This is what the hose collet looks like once it’s been flared over the outlet and the capture bracket’s installed. It doesn’t stay on by itself too well, but that’s what the bracket is for!

The installation proceeds! I ordered a rubber plug of the right diameter from McMaster. It has a flange, which I generously rubbed with silicone (my friend for this project, the copper-filled silicone) and stuffed in.

This little pinhole on the CDR is how it access atmospheric pressure, so it shouldn’t be blocked. I made sure the plug top allowed it to breathe still – if it were blocked, I’d have had to space it out with a washer or something similar. Luckily, it was outside the flat part of the plug’s dome.

Foiled, part 1: The passenger side of the intake manifold sticks out a lot. I had to cut a corner off the capture bracket to clear it.

Here is everything in place. The new grommet going into the engine is made from a “poke it yourself” rubber grommet which I cut an offset 7/8″ hole into, such that it was able to connect with the new centerline of the turned-around CDR.

A short length of the 7/8″ Autozone coolant hose bridged this gap; the hose clamp on the bottom closes the “collet” hose, and the rubber grommet provides the sealing.

For the other end, I just drilled a hole into one of the air filter cans and just stuffed the 7/8″ OD hose in.

This hose runs up from the passenger side, following the transmission fluid dipstick.

And this is what it looks like on the bottom. The CDR’s outlet port now feeds directly into the right side turbo intake. Like I said, for the final Vantruck integration, I’ll probably try to tap an intake hose somewhere as it runs forward. I just wanted to prove the concept for now.

Next up and last before firing everything up, how I routed the oil return from the turbos!

Operation IDIocracy: So…. What Now?

What better way to light off 2022 than with another IDIocracy post? Really, getting the two turbos fitted up and mounted was the easy part. There’s a whole bunch of other things going on that I had to dynamically learn about, usually by pretending to be a complete idiot on forums to assess what the general sentiment was. This is one of my favorite tactics to weaponize; after all, the best way to receive information on the internet is to be publicly and nitpickingly wrong about it.

In terms of support systems and concurrent mods to the engine, I still had to “complete” the turbos themselves by adding fittings and gaskets, add the oil drain and purge system, and figure out a solution for the positive crankcase ventilation valve. The PCV can no longer point into the intake manifold (as it’ll be under pressure), so it has to get routed somewhere. That and figure out the billion hoses that need to connect these things.

First things first, I’ll fully dress out and prepare the turbos. Remember when I said it seems like there should be a gasket between the two halves of the turbine side? I decided to pick some up (again, on eBay, only the finest motorsports performance wares!) and install them. Maybe you can get away with cranking the bolts tighter, but it didn’t feel good.

The little circular cutout is to seat the wastegate washer. It’s fairly on-size, and I could see misalignment here causing problems with the wastegate being able to shut. For insurance purposes, I filed the circle outwards just a little more.

Also arriving the same time was some bottom-tier canister air filters. I figured for now, as long as it wasn’t inhaling rocks or small animals, it was good enough. I can avoid drive testing through standing water for the time being, if need be!

I got all-metal distorted thread locknuts and M10 screws from McMaster. I also did some rummaging for hoses that are flexible but can take the charge air pressure (around 10-15 PSI), and found this duct hose which I’ll nickname slinkyhose. McMaster sells it as “High temperature flexible duct hose for fumes”

I got the impression you’re supposed use these nice but expensive silicone elbows and aluminum couplers everywhere. The number of turns I needed to make, though, would have meant the Nice Silicone Elbows were the single largest cost center of the project, not to mention I’ll have to cut so many joints I wonder if it would be worse than just having a slightly rippled hose.

In lieu of that, and without it actually needing to perform, I was like “eh, why not… whatever hose can take some pressure and heat wins”. And hence, slinkyhose arrived as a sample length.

Imagine the Inverted Johnson Fitting moment I then had when my friends went “Ooh, you’re using brake duct hose for boost?”

BRAKE. DUCT. HOSE.

Well damn, guess I learned something. Again, the most troublesome part of anything van related has consistently been “What do car guys call this thing?”

This hose isn’t like one of those flexible expanding hoses I got for Spool Bus intake duty. It has a steel spring inside, so it bends but will try to straighten out. It’ll need to be restrained, but can otherwise take any curve. The outside is then wound with fiberglass thread to keep it together and prevent it from inflating. The hose itself is made of fiberglass cloth that seems to be infused or co-molded with silicone.

Overall, I’d definitely trust the 25psi rating that McMaster gives it, just from looking at its construction. The hell you people need such hardcore hosiery for brake cooling ducts?

I was also receiving other odds and ends from eBay Racing & Development during this time. The Chinesium turbo world seems to have settled on AN fittings for their plug and play solutions, so I went ahead and got some -4 AN oil inlet flanges and -10 AN outlet flanges.

On the very left is a small Facet “clicker” type solenoid pump, that I bought off eBay as well. It will suck on the oil outlets on the turbos as the lowest point in the system and send the oil back upwards into the crankcase. This is necessary since I have both turbos mounted well below the oil level.

I was confident in the flow rate it could push, but what I wasn’t sure on was if it could handle the temperature of the post-turbo oil. One way to find out!

One substantial source of disagreement on the Internets seems to be what oil orifice size you need for these things, or whether or not you need a restrictor (which typically seems to be a 1/32″ or 0.8-1.0mm orifice). They’re Garrett knockoffs, so I once again wandered over to Garrett technical documents which said a 1.5-2mm orifice is typically enough. Yet there were plenty of forum vape bros who swore these needed “full” oil pressure. What the hell is “full” pressure?!

I learned that it’s ball bearing turbos which need a restrictor, as they’re more or less drip-fed oil, whereas sleeve bearings need oil pressure supplied directly to them. The way I understand fluid bearings to work, it’s the viscosity of the fluid doing most of the work once things are up and running anyway, and the flow rate is a function of the “ring size” – the clearance between the shaft and the bearing surface.

I figured “more is probably better” in this case and knocked these fittings from 1mm to 4mm. The aluminum these are made of is so soft I wonder how they were even able to hold onto them in the CNC machines.

Next up is some welding monstrosities. Remember how I said i had to kink the right side downpipe a little to give the turbo and transmission some more breathing room?

Well, I decided that I didn’t have the patience to do pie cuts, and I was out to experiment anyhoo. I tried to see if there was a way I could pie cut without pie cutting, like leaving the… pies connected.

The answer is yes, but keeping the cuts all aligned is difficult, you get sub-degree bends per cut, and there are big gaps to close at the place they all connect.

I learned the more legitimate version of this quick experiment is called “tiger cuts” or other stripey-animal cuts. I’m going to name this careless version the Raccoon Cut.

Okay, maybe I should have left the welds unground. A grinder I paint is the welder I…. something.

Whatever, I got the ~0.5″ of distal movement I wanted out of these cuts.

Gee, in comparison, the left turbo is positively wonderful. The “downpipe” stub is now firmly bolted in place with a stainless steel gasket and using the distorted thread locknuts.

The right hand side has a Point of Unserviceability due to the way I made the 90 degree turn. Can’t get a ratchet in on either side, so just have to bear it 60 degrees at a time with a regular wrench and hex key.

If I’d gotten the commoditized fitting, it has threads so I won’t need nuts on the other side.

And the completed terrorism that is the right side turbo assembly.

The next day, I got (finally) these 1/8 NPT tube bung fittings and decided to go ahead and install them. I’ll plug them for the first tests, but these will be where exhaust gas temperature probes live in the final product.

The last challenge was the wastegate actuators. I’d mentioned before that the stock mounts that these come with (pictured next to them) have them in another county, and I needed to come up with a “close tuck” solution.

They just have a 2 -bolt interface and are diaphragm-based, so they can take a fair amount of misalignment. This makes my job easy, as all I really have to do is make a single plate with their bolt pattern and one bolt hole for the compressor side clamp screws. I had some 1″ wide 1/8″ thick steel strip laying amount that was proper for this, so this was a quick markout and drilling job.

Here it is! I slightly bend the steel strip mount to point the rod in the somewhat correct direction, and can adjust its orientation slightly by swinging it on the compressor housing clamp screw

The actuator rods had to be substantially shortened. I did this just by cranking a M6x1.0 die as far as I cared to go, then cutting off the excess.

Now we have two completely dressed and ready turbos. The “stock” wastegate setting is allegedly 8 PSI, which is when the rod is barely preloaded over the wastegate arm.

Oh, yeah, it turns out that’s how you “Adjust” these. I thought they had little springs inside you could change, but that’s for nicer and more expensive ones. These have a fixed spring and you have to play with the preload – how far you have to tug it to sling the rod end over the wastegate arm is a direct function of how many pounds of force is needed to overcome the spring, which is related to the boost pressure by means of the area of the diaphragm.

Okay. “Not how I’d do it, but….” seems to be the movie poster quote of this whole project.

Viewed from the back towards the front, the left turbo is now mounted. Notice the oil like going up to the right – there is a oil channel plug here on the engine block, so I used a tee fitting here which will also serve the other side.

And the right side with the Terror Pipe is in. This is pre-tightening, so the turbo is still resting on the transmission. The post-tightening gap is about 1/2″ – good enough.

And here we have it. Turbos are mounted, oil is fed, and filters are on. The last steps of integration will be to pipe in the PCV system to one of these air filters (giving it some atmospheric pressure to near-suction) and work on the oil return hosiery!