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Intercooler arrived today! I don't think there could be a better size if I had it custom built.

And I don't care if it doesn't make the best sense, this thing is going in front of the AC condensor. I'm putting performance before comfort. Oh, and just a little bit, I want to see that CAC through the grille. :)

I spent some time on a Full Size Jeep forum and found out that the sweet ticket for Disc/drum hydroboost is a 94-95 Astro, and there just happened to be one on Ebay locally. The only trick is fabricating a mount for it. I should have just bought one online. This took me probably 4-5 hours, but it's sweet, and stainless.

I took some mis-cut 1/4 plate for the base, used some 3" tube, and cut up the stock mounting plate for the keyed hole in the ID.

Some welding and polishing and I have a mounted hydroboost system.  I had planned on using the vacuum booster, as the Isuzu engine has a vacuum pump for it, but I need more space and clearing for the turbo.  Hydroboost is a better system anyway.  It's more complicated, and will take some extra lines to the PS pump, but I don't really have a choice; and this turned out perfect.

I was getting some of these other things done because my turbo finally arrived damaged.  I pulled it apart to re-clock it for the motor.  You have to set the CHRA (center housing rotating assembly) so the oil inlet is on top, drain on bottom.  This also gives me a chance to align the compressor outlet for the best spot.  Well, while I had it apart, I noticed some rough edges on the turbine wheel.

I emailed the seller right away.  He apologized and said he'd make it right.  Within 2 hours he found a replacement, sent me a picture, and mailed it out the next day.  
Not sure if this damage is from overheat/overspeed or engine parts coming out the turbo.  My first guess was 50k RPM and white hot molten turbine tips melting the leading edge away, but I learned in the forums that the turbo parts can stand much higher temps than pistons.  Which makes sense high grade steel vs. Aluminum.  Probably a better thing too.  If this failed from heat, I'm sure all the bearings in the CHRA would be smoked too.

Got the replacement turbine, and the next task was to mount the turbo.  Exhaust manifold is a T25 flange and the Turbo is a T3.  The holes overlap, so it's not an easy adapter.  
First attempt:  I thought that I could plug the holes on the manifold and then drill/tap new holes and bolt right up.  So I threaded bolts in, cut them off flush, tacked them in place, then started drilling.  The problem is that cast welded with high nickel filler rod is like drilling into HSS tool steel.  Super hard.  I couldn't even drill into it, and the thought of tapping the holes made me stop trying to drill it.  FAIL.

Second attempt: I bought a cheap $25 adapter from eBay, but it's too big and puts the turbo into the master brake cylinder/reservoir.  Because I've nearly made the manifold scrap metal, I figured I had nothing to lose by trying to weld a flange from the adapter straight onto the manifold.  I had some practice with welding cast, and realized high nickel filler and red hot base metal was the key.  I got a torch out and heated the areas I was going to weld red hot.  I only welded one side at a time, taking my time to fully heat the area.  


After spending many hours looking at the turbo/intercooler/fresh air/filter routing, I realized that I wasn't going to think this project together.  So I moved to a different hurdle.  Building the transmission cross member seemed like an easier task.

Still need to drill some more holes and buy some more bolts, but I'm happy with the results.

Update October 9, 2017
I moved on to my next challenge with drivelines, driveshafts, propeller shafts, whatever you want to call them.  I've learned a lot.  I started trying to figure out why all my yokes, drivelines, and transfer case connections don't work together.  Turns out most of them are 1310 series, but one is 1306.  

Notice on the rear shaft that the yokes are out of phase.  Also notice that the front shaft has a double cardan constant velocity driven end yoke.

I knew I needed a shorter rear driveshaft so I just went ahead and cut the driveline apart and trimmed up the slip yoke end since it had a booger weld holding it to the axle tube.

Then I used our very expensive tube cutter to shorten the tube.  This device is great because it cuts perfectly square ends on tube.  Measure 4-5 times, cut once.

I tack welded the tube in place but decided to test fit it once just for giggles and to pat myself on the back for such great work.

I noticed that there was play in the D300 transfer case end yoke.  Great.  
The non-slip yoke end of the rear driveline has this odd sized U-Joint wich is screwing up all my plans.  On the right is a standard 1310 U-joint.

At this point I finally loaded up both driveshafts and drove down the street to the driveline shop to see what they thought I should do.  Brian the tech is a big 4x4 guy and started quizzing me about the whole project.  We finally got to the subject of the rear offset D44 and he handed me a copy of the "Spicer Driveshaft Installation Techniques".  

1. There is a limit to the drive line work angles.  1-3* is optimal, up to 7* will work, but 13.9* is way too much.
2. I have to raise my front mounts as much as possible (3/4"), and lower my tranny cross member mount as much as reasonable (3").
3. The offset D44 rear axle I have will give me 9.6* work angle alone, and even if my up/down work angle is 1*, the compound angle is too much.
4. Looks like I'm replacing the rear '77 Dana 44 with a center diff unit from a '96 D44 out of an Isuzu Rodeo.  59" wide, Center Diff, 4.30 ratio, 6 on 5.5 bolt pattern, disc brakes.
5. I'll have to relocate the spring perches 4" wider (2" on each side), re-tune my brakes for disc/disc, and hope the springs clear the rear calipers.

In an ironic twist, I have an Isuzu motor that's going to turn an Isuzu rear end... if it works.

Update: October 18, 2017

Got the new axle.  Had to make several modifications to make it work. 
1. Spring perches moved from the bottom to the top and 2" farther outboard.
2. Axle shaft wheel hubs turned down from 4" to 3.5" to fit my stock steel wheel centers.
3. By the book I found replacement wheel studs that should fit a metric hole, with a 7/16-20 thread.  But once they showed up there's no way they were going to fit in the holes.  I checked my measurements again and I'd either have to drill out the holes on the hubs and hope they'd fit, or just buy metric lug nuts and remember to never mix them up. They're different enough to not even start to thread on.  I went with metric lugs nuts.

Replacing the rear axle has kind of made me go backwards in the project.

In order to weld the spring perches in place, I need to know final angle of the output yoke on the transfer case.
I can't really measure that precisely until finish the motor mounts. Aim was 5-6 degrees tilt on the motor, but 7-8 might work better to get 2* work angle.
I can't do any measuring until I roll the chassis onto a flatter spot in my shop. Turns out my floor is .8-1.3* tilted where I'm working. It's not just a simple flat plane tilted, it's twisted in a compound angles and too complicated for me to account for in my measurements.

So in order to move the chassis, I'd rather push and use the steering than a forklift to move it around to find a flat spot. That means I need to finish coping in the motor mounts so the steering shaft will not interfere. 
That means I'm lifting the engine again and pulling the mount to work on it. 

It's like I'm going all the way back to the beginning and starting over again. This project is completely 2 steps forward, one back. Not really complaining because I love it. But it is taking forever.

Anyway, this is how I went about coping in the steering shaft so it would clear the motor mount.
First I rough cut where I thought it would go. Then found a piece of Sched. 40 1.5" pipe to use as a guide and slowly ground to fit.

Then I laid the pipe in place, marked cut lines with a sharpie and used a grinder with a chop wheel to cut the pipe on the floor.

Then tack in place, grind flat, deep hot tig weld top, mig weld the back solid, blend, then lay down a pretty tig weld.  Not perfect, but I like it.

I'm going to guess that other than on the internet, nobody will ever see this bit of work that took me so long to work on.
I also washed over some of the Mig welds that I didn't want to blend out. I could hit these welds with a "purple wheel" (it's like a scotch brite grinder wheel) or a passivator acid wash to take out the color, but I like it and I'm leaving it.