Re: K30 Downgrade to Cummins Project
 

Looks like this will be a sweet build! Would love to see some pictures of your engine stand.

Re: K30 Downgrade to Cummins Project
 

Its still a pile of steel laying on the shop floor right now :) Waiting on the steel place to get my DOM in.

Re: K30 Downgrade to Cummins Project
 

Since this truck will be a 9spd (with the gearvendors behind the G360), I'm trying to figure out the rear axle I want to run. The 14 BFF in it needs brakes at least, and has the dumb behind the hub drums and is 4/10 open :(

I have a 11.5 AAM 14 bolt sitting here in a dmax parts truck in 3.73 with a g80. I'm pretty sure i will be swapping it in, especially looking at the engine RPM calculators when towing. I shouldn't tow in double overdrive according to gearvendors. Here are the engine RPM's, let me know if you guys think the 4/10 is better for any reason. Again, loads could be up to 12,000 in tow, Intercooled with larger injectors, larger turbo, feul pin/gov mods.

First attachment is empty (double overdrive) with 3.73's.

Sedond is towing in regular overdrive (either gearvendors on in 4th , or gearvendors off in 5th.)

Re: K30 Downgrade to Cummins Project
 

Here are the same charts for 4.10 gears. Anything hard about swapping in the 11.5 rear? I'm not sure if the spring pad spacing is the same or not, its probably wider in the newer axle.

Re: K30 Downgrade to Cummins Project
 

My bone stock cummins tows just fine in overdrive with 3.55s. I think you'll want the 3.73s. We ran an '05 10.5 AAM on the 82 frame for my brothers crewcab. We had to relocate perches and shock mounts. I've also noticed the limited slip GM uses now (still has the RPO G80) is a different and more reliable design.

Re: K30 Downgrade to Cummins Project
 

Cool. Do you know when the g80s improved? Also has anyone been able to harvest the perches and reuse them without destroying them or the axle? In the past, I hhaven't been able to save both but maybe a clean torch tip would allow it but I'd be nervous operating that close to the axle tube. Got a good source for heavy duty perches that fit these sumo:sumo: axles?

Re: K30 Downgrade to Cummins Project
 

The 11.5 AAM has the different limited slip. As for the perches, ditch the stock crap. I know it's a more abusive environment, but the government trucks in our fleet needed the perches built up from wear. They are rounded on the edoes and allow for more movement. I wasn't happy with the aftermarket ones my brother bought either. I would have rather made my own. I'll be running a ladder bar setup on his for added strength

Re: K30 Downgrade to Cummins Project
 

I'd run the 3.73 14 bolt. You'll be over all more happy with it I think. I have reused cast spring perches that were in good shape. You can get new ones for a reasonabl;e price from Diy4x4.com.

Re: K30 Downgrade to Cummins Project
 

Got the forklift done, and tested it out for the last couple weeks. Lifted a 30' tower, a duramax and ally assembly, and 2500hd frame. Also Jmader (Jeremy) stopped by on Sat to pick up his 67 K10 I had and drop off a cab and a parts 305 V6. He was kind enough to have both on pallets so unloading was a snap with this forklift! I really like it, turned out like i wanted, no doubt CAD helped get it right the first time.

Getting used to this miller 252, I am liking it more now.

I decided to add a couple more hooks, chain ties, and a receiver mount and paint it. I have a receiver mount vise and it will be handy for moving trailers too.

Re: K30 Downgrade to Cummins Project
 

Cool!!

Re: K30 Downgrade to Cummins Project
 

That turned out really nice! Great work.

Re: K30 Downgrade to Cummins Project
 

Thanks guys, it feels good to actually finish something, wish I was better at that with my vehicles!

Re: K30 Downgrade to Cummins Project
 

Trans is out. Finished parting the dmax truck, now have a little extra cash, a 3.73 G80 disc rear and some new 285 rubber. Looking at this allison here, tempted to make it work but the thing is frickin huge, about the size of a sbc! Think i'll stick with the g360 since I don't want to lift the body or buy a $tandalone alli$on controller. Too bad eaton ho52's don't have 3.73 ratios, i guess i have to live with this 600 lb monster 11.5 ;)

Re: K30 Downgrade to Cummins Project
 

Do you guys know the service life of the 11.5's with G80's? Assume it has towed intermittently, not heavy loads all the time.

Re: K30 Downgrade to Cummins Project
 

Looking at upgrading the turbo and piping since you guys are telling me i should to meet my towing goals.

I got some quick prices from a guy I know here in MN, are these good items and prices?
Hx35 good used- 350 (btw, what years used these?)
downpipe exhaust- 20
cold elbow and IC plumbing from 96ish- 160

Re: K30 Downgrade to Cummins Project
 

I think my 2005 dodge has a 11.5 in it very similar to the gm one you now have. It got a gear set under warranty at 40'000 I'm. It just recently broke at 390,000 km. turns out was just a axle that broke tho. Gears were still great and re used. Truck tows 20,000 lbs weekly and 10,000 almost daily. I'd have to say the service life is quite acceptable.

Keep up the great work. Cummins powered Chevys are hard to beat !!

Re: K30 Downgrade to Cummins Project
 

$350 is a little high, unless it is really nice. No shaft play and not real rusty. HX35W's were used from 95-02. Some 24v non ho trucks had HY35's, and the 94's had a H1CW. You can get a he351cw for $350. The he turbo is from an 04.5-07 5.9cr and will make a little more power and will spool a little sooner because they have a tighter exhaust housing. 9cm on the he351cw compared to the 12cm on most hx35w's.

The down pipe seems cheap, the IC piping and elbow, I'd buy elbows and build it myself before I spent that much on the stock stuff. The upper horn is usually $50 used. A bead roller, some 45* and 90* 3" elbows, a welder, and you're in business.

Re: K30 Downgrade to Cummins Project
 

Good thing you said this Ryan. I was going to buy an HX35 for 360. The only thing that stopped me was this post!

Re: K30 Downgrade to Cummins Project
 

That's a badass crew Vintage Windmills. Keep up the sweet work!

I hear ya about how hard it is to pass up an old truck lol.

Re: K30 Downgrade to Cummins Project
 

Good to hear on the rear, although thats 240k, you work it more than many, certainly more than my application!

Good info Ryan. How are you coming on working up the cummins parts list for me? Almost done with the engine stand ;)

I really need to banned from craigslist, too much temptation for trucks that can be saved/converted!!

Re: K30 Downgrade to Cummins Project
 

Get an HE351CW. They can support more horse power than an HX35 and spool just as fast if not faster.

Re: K30 Downgrade to Cummins Project
 

Jud, I'll try to have it done before Friday. PM me your email addy please.

HE351's can run higher egt's than a HX35w too due to the smaller exhaust housing.

Re: K30 Downgrade to Cummins Project
 

Been real busy at work and restoring wood windmills lately. Finally getting back to this thing, I really want to get the head off and see if I should just fully rebuild it as long as its out.

I did get my engine stand all done! I like it. Doing the stress and deflection calculations and CAD paid off. I will still proof load it with another 750 lbs just to make sure the welds are strong since I am still new to my MIG welder. That will take a bit to rig up so if something gives it still chained to a structure for the testing.

Re: K30 Downgrade to Cummins Project
 

Been playing with the engine stand, it works really well and is solid. There's just the right amount of friction in the headstock so it never takes up the slack in the coupler as you go over center of gravity.

The chain coupler is a slick way to couple things and keep from overconstraining things and loading up shafts just as things are bolted together. Its a common machine drive trick. Makes service a snap too. I do need to tighten up the taper lock on the gearbox shaft since it isn't gripping the shaft tight enough to overcome the torque and the key is taking out the slack by itself.

Re: K30 Downgrade to Cummins Project
 

that is a sweet coupler. nice stand!