'55 Chevy 3800 Cummins

[nblehm]

1" to spare. Nice. I would have ****ed up one of the cuts and had to buy another stick

[6DoF]

**ignore this, just compiling for reference**

at some point:
https://www.garrettmotion.com/news/n...00-horsepower/

TURBOCHARGER(S)

Turbocharger: Garrett GTX5009R
Frame: GT50
Compressor Wheel Specs: 80mm Inducer, 108mm Exducer, 55 Trim, .69 A/R
Turbine Wheel Specs: 99mm Inducer, 91mm Exducer, 84 Trim
Turbine Housing: T6 .96 A/R

Turbocharger: Garrett GTX5533R Gen 2
Frame: GT55
Compressor Wheel Specs: 94mm Inducer, 133mm Exducer, 50 Trim, .96 A/R
Turbine Wheel Specs: 112mm Inducer, 102mm Exducer, 84 Trim
Turbine Housing: T6 1.24 A/R

Peak Boost: 106psi

***

2019 pikes peak:
https://www.dieselarmy.com/news/chuc...th-toyo-tires/

The compounds on board are a Garrett GTX 58MM secondary charger fed by a Garrett GTX 70-MM atmosphere turbo. That may not seem all that enormous, but its enough for what they’re setting out to do.

If you were to put a more traditional “big power” set of compounds on this truck, at this elevation, it wouldn’t have the excellent acceleration they’re after. In fact, prior to Pikes Peak, Smokey had a larger 80-MM / 106-MM combination.

***

2020 pikes peak:
https://www.enginebuildermag.com/202...turbo-cummins/

twin Garrett turbochargers on it – a G42-1450 for the big one and a GTW3884 for the small one – those are 80mm and 67mm.

Old Smokey’s 6.7L Cummins is what Freedom Racing Engines calls its Stage 2 build. It’s a 6.7L bored .020˝ over and was drilled and tapped for 14x2mm head studs and the mains were drilled and tapped for 9/16ths main bolts. The block was also line bored for cam bearings throughout the entire cam tunnel and features a Hamilton Cams 188/220 camshaft

[Cobound]

[6DoF]

smashed out some progress! i don't know why, but i love the frame "kit" picture.

i also managed to fixture the main rails and get the rear legs welded on before realizing they were backwards the miter at the front end went out vs in. lucky for me, i still need to cut the rear to length, so i just re-mitered the front and lost 1/2". redid the 3D and we're good.





and tonight it's a whole thing! tack welded and ready to start crossmembers. also need to get Colin to cut my plate soon!

[nblehm]

So why the little extension pieces in the middle of the bends instead of just making one steeper miter cut? Stronger to have 2 joints and less angle than 1 steep joint?

[6DoF]

Originally Posted by nblehm

So why the little extension pieces in the middle of the bends instead of just making one steeper miter cut? Stronger to have 2 joints and less angle than 1 steep joint?

Its a compound miter in multiple planes, the down leg wouldn't be "virtical" or seam well without. I tried for hours to fudge it close, but with fish plates this will just be cleaner, look better, and ultimately shouldn't be any weaker. Just another joint. Tue plates cover all 3 pc of each bend with one plate.

[Sir Sam]

I’ll say it again. You ought to get the chassis galvanized when you are done.

[6DoF]

been doing a lot of prep work on all kinds of parts from the trans crossmember to the fuel tank mounts. re-designed the mounting of the crossmember though. this new design doesn't require drilling into the frame, will hold weight with no nuts on the bolts still, and can be removed down or back with no binding. no it's not double shear, but the loading doesn't require it at all, and not having to slot the bushings will make everything easier.

i've also been doing a fait bit of welding on the frame, and even got the rear brakes set up. 2008 GMC 3500 rear rotors, standard 14B studs, GM 3/4 ton D52 calipers, and BTF weld on brackets that have been in my shelf for like 10 years. the studs are a tiny bit sloppy to the rotor holes, so i wrapped a little tap on 2 studs to center them before pinning them in place with all 8 studs. nothing should move, Pirate4x4 couldn't even argue it works great, but another one of those "i guess we'll find out". i didn't feel like having custom sleeves machined if i didn't need to. had shims between the rotor and the caliper, more shims caliper to bracket, new pads, then made an adapter to hook the caliper to my air compressor. held everything square n tight while i tacked em in. yes the bleeders will be on the right side when actually installed, and they are installed below the axle to make sure they don't have any chance to hit the frame on articulation. looks weird to me though since i'm normally trying to keep them high from hitting rocks. lots of wheel clearance, so game on.

[6DoF]

Got the rear links as far as I can until I get plate to keep going with bag mounts and the link mounts themselves. I even managed to not warp the thread insert!!! For reference I used a 1-1/4" threaded bushing.

[6DoF]

Seat choices ... thoughts?

so i came down to 2 final selections, but only 1 is really an option. the Iron Ace bomber seat is hands down the seat that best fits this build, but at over $2000 there's just no way. a PRP bench however, kustum designed with the black/grey and blue stitching/piping is only just over $500. should be more comfortable and still fit the build pretty good.

[6DoF]

more progress happening! got the transmission crossmember totally welded up. once the engine and trans are fit into the chassis/body i'll make the bushing mount then. got the gas tank mounts mostly built up n ready to weld to the frame when the time comes. i still need to figure out a strap set-up though.

my new air fittings finally arrived! i was able to mock up the front end for the first time complete and watch it travel. other than the wheel to LCA clearance turning that i already knew about, it's game on. of course, as soon as i did that, i tore it all completely apart. LCA mods, and without the crossmember was MUCH easier and cleaner to fixture on the front frame horns. i decided after i started building that i would use the stock style steering, but i NEVER would have guessed that the frame needed to hold it would be straight off the way it is. next frame i'd make the 6x2 longer and have the steering and cross member in the same layout. oh well, this does have space saving benefits at the core support body mount.

finally i started to prep the frame for the fish plates. i normally don't like to grind welds, but can't add plates without it flat. of course it's hard to just end the grind, so i carried it over the ends too. the top however i went back and tacked in to fill the weld under-cut witness lines and re-ground them.

i also started to modify the front LCAs with stiffening gussets before i chop out clearance for the wheels to turn more, but i'll post that when done.

[xj_man_646]

Originally Posted by 6DoF

Seat choices ... thoughts?

so i came down to 2 final selections, but only 1 is really an option. the Iron Ace bomber seat is hands down the seat that best fits this build, but at over $2000 there's just no way. a PRP bench however, kustum designed with the black/grey and blue stitching/piping is only just over $500. should be more comfortable and still fit the build pretty good.

The top seat looks like it might be tough to have happy fun times on the road with. Jussayin' .

[xj_man_646]

Progress is looking pretty good too!

[Cobound]

Ace Bomber looks killer, always loved seeing them in rods, but they don't look all too long ride comfy. You got skills, make them.

I'd go w/ a comfy seat, myself, if you plan on driving it more than down the street.

Sweet progress, damn you and Damon got some mad skills!

[nblehm]

Yeah that first seat looks terrible to sit in. No thanks

[6DoF]

first up was another mod to the LCAs for steering. the extreme back spacing coupled with the extended travel got the wheels into the outer lip of the CA that's turned up. so i went about adding some gussets inside and under the arm before cutting back that clearance. i chopped the lip back about 3".

at this point the LCAs should only need a bump stop added to be all set. i am also however having a clearance issue with the UCA and the Belltech brake caliper mount gusset on the knuckle. currently that's my next steering stop. and should be the last clearance issue to get the full range of steering out of this box/geometry. full range is just better than 35deg i think, and that's not bad. the sheet metal will still be a limit depending on height though, stay tuned with me to find out how much. haha

then got everything back together to re-test just as my steering box showed up finally. so the steering is all on there and making sure i got it in the right spot.

[6DoF]

soooooo ... seats ... Iron Ace is out for cost, but now PRP is out cuz they said 10-12wk lead time.

found myself a 2002 Yukon 2nd tow seat somewhat local for $75. should be super comfy, has a console with cup holders while still being a bench, and has a foldable back even. just ugly old light tan. i'm trying to find a custom designed reupholster kit for it vs just a cover.

[6DoF]

so i'm looking for a patina set of something like these




i guess worst case i can still get new ones for pretty cheap and just paint them off-white.

https://www.summitracing.com/parts/ksc-h3641#

[Cobound]

10-12 wait, how soon you gonna be ready to mount them?

[6DoF]

Originally Posted by Cobound

10-12 wait, how soon you gonna be ready to mount them?

my goal is still to have the cab on the chassis before the end of this month. once that happens i need to get the new pedal assembly in there. i have the steering column, but need a seat to place both at the same time for a cumfy driving position. then some overly complicated seat mount, and i need the column in place to be able to fab up the clutch pedal and where that will mount on the firewall, plus the rest of the steering shaft fab.

i won't run hoses n wires before i blow it all apart for final clean-up n paint, but that kinda stuff has to be done. my goal is still to drive this in the spring.