1HD-FT EGR delete with a 3D printed crossover adapter!

[John Young]

The 1HD-FT that is in my Omani 80 (the thread is badly out of date) series actually came from an HDJ81 mistake. I was so innocent then.... Sigh.

Anyways, the Omani 80 with the FT is just about ready to ship and frankly looks georgeous.

(Disregard the missing trim strip on the bumper. Clips are coming.)

And it has a very nice interior now, complete with heavy canvas and camel leather upholstery.

This project has taken so long that the registration and insurance have long expired and anyways I wanted to get blue export plates on it so I could drive it around for a week in Dubai and maybe not feel too insecure when the truck arrives in the US when I take a little chance and drive it to the local DMV for registration. I has been well over a year since I last drove it at all and when I did I re-learned that it had some bad habits.

The HDJ81 had been an automatic. The Omani is a manual. The driving experience was really terrible below 2000 RPM. I'm the kind of driver who likes driving on the lower end of the RPM range--and I've putt the taller 5th on most of my LCs; so this was doubly annoying. It was so bad that I was pretty uncomfortable trying to merge in traffic. We were in the middle of prepping for shipping but I asked the Ancient Swede at PowerTec UAE here in Dubai if anything could be done.

(Dramatization)

He's got quite a bit of experience with the HZ/HD lines and had a look and juiced up the pump and that helped a bit, and then in a separate effort we tore it down enough to adjust the timing which, it had turned out, was way off. That helped some more. But it is still not as nice as my 105 with a 1HD-T, which is no jackrabbit but it is fine to drive. Anyways, with these adjustments, the Omani was no longer traffic hazard. Spending all this time playing with the engine I got to thinking about the EGR.

Ages back I had taken the intake apart just a bit and had seen how incredibly dirty it was inside. I cleaned it up and I won't tell you whether blanking plates appeared anywhere, but it stayed in this form ever since:

I've been spending a lot more time around diesels the last few years and gotten a lot more comfortable with them. To the point I've started swapping diesels into most of what I have. And when I looked at this engine I got pretty offended by the clutter. I then started reading up on it and found the Mr. Toyoda had made both EGR and non-EGR versions of this engine.

This got me looking into a real EGR delete, given the fact that if the Omani, which started out with a 1HZ, had gotten a 1HD-FT from the factory, it would have had the non-EGR version. But here we were, days away from shipping. I did have a spare crossover that we were no longer going to be using because of an intercooler but it was of the 1HD-T rectangular variety, not the largely square cross section of the 1HD-FT. I asked the Ancient Swede about this and the reached over and handed me a block of aluminum.

I do enjoy machining and they do have a Bridgeport, but we did not have a lot of time and the Bridgeport has very limited tooling. I could see myself hacking something out but not being able to do something of high quality in the time available. So I did nothing but mull it over and keep busy with other things.

 

[John Young]

Skip forward a few days. I'm still mulling. And still test driving the Omani. The very last day I could legally drive on the blue export plates...

(Can't resist a beauty shot with the blue export plates.)

I dropped the Omani at the garage late on the last day when the blue plates were useable in Dubai and the garage was closed and I needed a bathroom before driving home in my daily driver. The garage is in a complex of small warehouses, some of which still had activity, but it was pretty late. I wandered first into a metal fab place that had just moved in but I did not see anyone and I did not feel comfortable just using their john, so I walked on to the end unit.

There I found two nice young men who happened to have a 3D printing startup called Innofab45. That is Louai on the left there.

They have a pretty impressive setup, with some large format printers and most importantly, printers that are capable of printing high temperature industrial materials such as PA6 carbon filled nylon, good up to 180C and pretty impervious to diesel and oil.

I figured that young people are energetic, so why not pose my problem to them, namely make an adapter from the 1HD-FT intake manifold to a 1HZ/1HD-T crossover.

(1HD-FT crossover)

(1HD-T crossover)

We spent some time discussing and they thought it was doable within the time constraints and at a cost that would make it viable. The next day Louai one came over to the garage and looked at everything in person and I gave him both the 1HD-FT and 1HD-T crossovers. A couple of hours later he came back with a little test print to check dimensions.

 

[John Young]

I'm going to pause here as it is getting late in Dubai but I will tease by saying that a lot of progress has been made and I'm optimistic.

 

[John Young]

Here was the fist stab at an adapter, printed using inexpensive non-heat resistant material:

 

[John Young]

Conceptually it was fine but it had some shrinkage, angular and fastener issues. That said, it looked doable with some refinements.

I grabbed an angle grinder and made some messy adjustments, primarily to change the angle so that the crossover would fit in a more parrallel fashion over the engine.

With this amended first draft my new young friend Louai went back and made a series of partials to refine the dimensions and angles without the waste of printing a full part.

 

[John Young]

More partials:

 

[John Young]

Getting closer to a final design:

But looking at the overall geometry I felt that it would be easier to connect up the turbo end if we could make the adapter substantially thinner. As it stood, the adapter was about 44mm at its thickest point. I challenged my young friend to see if he could shrink that by half to about 25mm. He went back to their very nice industrial-style office/warehouse and gave it a try. The next day I dropped by:

 

[John Young]

This is about as thin as the adapter can be made while still accommodate the threaded inserts we wanted to use:

Dusting off some materials engineering principles vaguely recalled from coursework 40 years ago, I asked him to make a few more refinements to remove stress concentrations, for example I suggested adding fillets where possible and especially a fillet at the bottom of the fastener wells:

And make the wells .25mm deeper so that the tops of the inserts would be absolutely flush:

Then it was time for hopefully the last test print:

 

[John Young]

Today I got a look at the shortened adapter, still in the inexpensive test print material.

And it fit very nicely.

 

[John Young]

There is a fair amount of offset from the turbo inlet. But less now with the thinner adapter.

I have to check if the low temperature side of the turbo can rotate. Can't really tell from the parts diagram:

The part number shows as a 17201-17030. When I do an image search for that it seems it is a CT26 turbo. I happen to have one of those taken apart--and a replacement arriving in a few days. AI says that rotating the compressor side is called 'clocking' and that the CT26 design allows this within reason, so I think we may be good subject to the Ancient Swede's approval.

 

[John Young]

There is one thing that occurred to me last evening and that is that the electric heater element has the same dimensions as the rectangular inlet on the intake manifold casting. I tried fitting it on there today and I think that it could work, which would preserve the cold start function. It would move the crossover pipe up and more to the left requiring more rotation of the turbo compressor side. On Monday the first thing I am going to check is if the heater function actually works. I'm also wondering if it could simply be triggered by the starter. I don't think it was hooked up because this truck did not come from the factory with the 1HD-FT.

 

[Dougal]

If you get that part working then get the 3D model and replicate it in aluminium. The 3D print guys might even know someone who can laser sinter.

 

[John Young]

If you get that part working then get the 3D model and replicate it in aluminium. The 3D print guys might even know someone who can laser sinter.

I thought about that. Perhaps Send Cut Send in the US. But I am planning to see how it goes. The graphite filled nylon should be good for operating temps up to 180C / 356F. The one uncertainty is how hot and how fast the grid heater heats up. I tried fitting it on the intake manual side and it seemed to work just fine. and that might change matters a bit.

 

[John Young]

Today I cleaned up the old heater block and confirmed that it would fit on the intake manifold. I needed to take the longer studs off of the exhaust side casting that we no longer are using:

And put them on the intake manifold.

With the longer studs the adapter fits just fine but I did discover that the lands on the lower edge of the adapter needed to accommodate a bracket that holds a bunch of air pressure lines. Not sure what they all do, but one of them is where we read the boost pressure.

 

[John Young]

I took a couple of photos showing the dimensions of the bracket lands:

They are about 18mm across with a 9mm radius on the curved portion.

I then went back to Louai and showed him the issue and he made some final changes, including the enlarged 20mm lands on the lower portion.

I'm now at the point of committing to the more expensive nylon/carbon filled material. I would have preferred the Ancient Swede have a look in person before I do that, but unfortunately he's got a nasty fall flu of some kind.

But we did exchange some messages and he gave the go-ahead if I felt the design was ready. I do think we are at that point so I asked Louai to go andad and print the final.

 

[John Young]

So today I worked on the other end of the crossover. The alignment of the outlet of the crossover and the end of the turbo was not the best, but I suspected that on a CT26 turbo that the inlet could be rotated. And it so happened that today I received a Chinese copy of a CT26 so I could check more easily than with the CT26 on the Omani. Frankly I was astounded.

There is an overwhelming number of Chinese turbo manufacturers/sellers on AliBaba. Very hard to tell one from another. I ended up selecting one simply by its name, PowerTec, which happens to be the same name as the garage here in Dubai where a lot of my stuff gets worked on.

Near as I can tell, aside from no casting numbers, they are virtually identical.

 

[John Young]

And the quality appears very high.

In the picture below I had moved the clip so I could use some shop air to check the wastegate function. Notice that it has a paint mark on it to show if it had moved. That is some reasonable attention to detail.

This was an experiment for me. I had been hunting in Dubai for ether a good used CT26 or a new Chinese CT26 but had not liked what I found in either category. On a lark, because of the name frankly, I shelled out about 225 USD for this unit, shipped. I then had to pay an additional 200 AED in customs duty which brought the total cost to about 280 USD.

 

[John Young]

Anyways I was very pleasantly surprised by what I received from China. It also let me verify that the inlet turbine housing was pretty freely rotating from the body of the turbo. Armed with this knowledge I got a soft mallet and wanged on the housing in the Omani to move it to a better position for the new crossover.

It is a little off but with a silicon hose I think this should work without any big issue.

The final part is being printed now. They had to wait to dry out the filament. Apparently this printing material is highly hygroscopic and without carful drying the print quality will be low. Looking forward to getting a look at the final product. Not sure if I am going to be able to keep the heater block--it makes the spacing a bit more challenging If I insert the 25 mm block below the adapter plate.

 

[Dougal]

I thought about that. Perhaps Send Cut Send in the US. But I am planning to see how it goes. The graphite filled nylon should be good for operating temps up to 180C / 356F. The one uncertainty is how hot and how fast the grid heater heats up. I tried fitting it on the intake manual side and it seemed to work just fine. and that might change matters a bit.

The claims the filament makers have are at odds with material science. Sure they'll hold shape at 180°C unstressed, but add in bolts and pressure with heat and it will creep and deform.
To hold shape under heat and stress plastics need reinforced with continuous fibres of high melting point. Auto makers use a lot of glass reinforced nylon for water pipes etc. The reinforced nylons used in 3D printing are all very short fibres that can't help as much.

 

[John Young]

The claims the filament makers have are at odds with material science. Sure they'll hold shape at 180°C unstressed, but add in bolts and pressure with heat and it will creep and deform.
To hold shape under heat and stress plastics need reinforced with continuous fibres of high melting point. Auto makers use a lot of glass reinforced nylon for water pipes etc. The reinforced nylons used in 3D printing are all very short fibres that can't help as much.

Well, this is something of an experiment. I appreciate the comments. I've been reading more about this stuff. This PA6-CF requires a heated chamber is something of a challenging material. I went to have a look at the first prints in PA6-CF today.

I've been thinking about getting a printer for myself primarily for my Land Cruiser and machine shop use. Getting a little first-hand exposure is quite helpful in getting up to speed.