Engine Swap: Cummins R2.8

[Digger556]

Getting back to the adapter...

I spoke with our manufacturing engineer at work in order to get a recommendation on a machine shop. (our shop is busy most of the time) He looked at my project and thought we could fit it into the schedule, so we had some back and forth discussing how to produce my bell housing adapter, what machine should run it, who would program it and what was critical. I went ahead and purchased the raw material, a 50lb slab of 6061-T651 aluminum plate that measured 18"x18"x1.5"

After about 4 weeks, it was time to run my part. The guys really did a great job. It was run in a horizontal mill with a pallet changer and a 35HP spindle. It made short work of my plate.

The final product is beautiful and dead accurate. The guys CMMd the part and the critical dowel pins holes were all within 0.0002" of their nominal positions. The dowel holes were reamed, so press fit will be very precise.

 

[Digger556]

With the bellhousing adapter finished, I needed turn the 10mm dowel pins down slightly. Given that the holes in the engine were reamed, I didn't have the right measuring tool to accurately measure the ID to 0.0001". So I ordered standard +tolerance dowel pins and test fit them. They almost wanted to go, but not quite. Because the dowels locate the engine to adapter to transmission, I couldn't just chuck them in the 3-jaw and turn them with cutting tools. I needed something more precise. Generally when you're working under 0.001", you need to grind, not cut, so I rigged up a makeshift tool post grinder with a Dremel tool. I also loaded the 4-jaw chuck and dialed the dowel pin to the lathe so there was less than 0.0001" runout.

I ended up taking off 0.0004" over 4 passes of the grinder.

You can barely tell anything was done, but the upper 14mm of the dowel is a smaller OD.

Now the pins slides in easy, but is still tight enough to seal the air behind it.

After grinding a lead-in chamfer, I pressed all 4 dowels into place.

 

[Digger556]

Now for the moment of truth...
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Perfect!

The fit on the engine side was so perfect and tight, I had to slide the adapter in very squarely or it could get stuck, but lined up right, it just slid right on.

I also checked the starter clearance. Just enough.

 

[Digger556]

While the guys at work were machining the bellhousing adapter, I was at home working on the crank adapter. I already had to redesign this once after sourcing material proved to be difficult. Now it's a little smaller. The crank adapter proved to be a challenge to manage all the tolerance stackup over all the features of two adapters plus flywheel etc. After giving some thought to the manufacturing approach, I got started.

Starting out with raw stock...

...I faced the part (after dialing it into the lathe), punched the center bore which located the 2nd crank adapter, and turned the counterbore that locates the adapter to the crank. Tolerances for the critical features were all sub-thousandth of an inch. I was aiming for 0.0003 or less deviation from print.

Turning the hub face for the starter ring

A-side completed.

And test fitted

 

[Digger556]

Now things starting getting frustrating. I spent the first 5 hours of the 2nd day trying to get the part dialed back into the lathe. After trying a few different configurations and switching measuring tools, I got it as close as possible. After reading the factory calibration report, I am at the limits of what this lathe can do.

After finishing the B-side and measuring runout, I moved the part to the mill to punch all the holes.

More holes

And counterbores

What a mess.

After tapping all the holes, the finished product

Checking bolt fitment vs the model

Finally, checking fit on the engine

 

[Broncobowsher]

Looks REALLY good.

 

[EB70]

I admire the accuracy. What I am really curious about is the outcome. I have a Bronco that the engine would work well in. If I could reliably pull 20 MPG with decent power and 35-37" tires I would be all in.

I am likely going to run the Jeep 5-speed though as I have it already.

Keep it up, we are watching.

 

[Digger556]

I am likely going to run the Jeep 5-speed though as I have it already.

Keep it up, we are watching.

That would be an easier route. Axis has adapters for that already.

Looks REALLY good.

Thanks!

 

[Btempy]

Looks good! Jealous! Im already dreaming up a R2.8 build

 

[EB70]

I highly doubt I will tow anything etc. Just drive it around. I highly doubt that fuel will go down in the next 4-5 years so the better the MPG the better the chance that I will actually drive the thing.

I am guessing the AX-15 will stick together. For whatever reason I am not a fast 4x4 kind of guy and I actually find my stock 302 to be plenty for how I use it.

Keep it up. What is your approximate ETA on finishing this? I know projects take too long but I am just curious.

 

[chickenman]

Nice build! This has been a great read. Thanks

 

[904Bronco]

Very Nice Work!

 

[toddz69]

Beautiful work! You know you'll have to add these parts to the catalog....

Todd Z.

 

[markw]

I'll pile on as well. Very nice work, impressive!

 

[B0neCrush3r]

wow! looks amazing.

 

[Digger556]

Thanks everyone!


The new boost and pyro gauges showed up tonight.

 

[Broncobowsher]

Really nice gauges. I have been running Isspro for years now. They are way overlooked when people go shopping for gauges. Full sweep electric gauges made in America. And priced comparable to the imported race brand stuff.

 

[ntsqd]

I wondered what Digger would buy. I tend to think of all other common gauge brands as farkles rather than useful tools.

 

[Digger556]

Well that is good feedback. I have a set of Autometer's in the F250 and they have been very disappointing.

The pyro quit working after 2 years, the trans temp gauge has moisture trapped inside. The boost gauge is okay but they are low tech. Incadencent bulbs with color covers, screws terminals instead of plugs and hardwired lights.

 

[Yeller]

Agreed on gauges, I like the autometer volt gauges that read different +/- 3 volts over the course of a day....... so much for knowing if your alternator is really working correctly or not. Guess that's why I don't put too much stock in them, big ass red light for the important stuff like over temp and no oil pressure. If I really want to know what is going on I use a blue tooth OBDII adapter and use a free diagnostic ap. but they don't read piro....

Looking great, I really enjoy your builds. Great detail and not the "average" cookie cutter build with good engineering.