K30 Downgrade to Cummins Project

[ryanroo]

on a non i/c ve engine in a 7000# + truck towing 14000 lbs. i doubt you'll maintain 40 mph. not if the mountains you are going to tow in are like the ones locally.

you might be able to hold 40 with the big block and 21k gross, but i bet the gas gauge would move fast enough to actually see it. and if you are going to run a nice MPFI on the BBC you will blow 2k there alone. probably more.

i think in the long run you would be happier with a little more pep from the cummins.

[Dieselwrencher]

Stock H1C and stock injectors, no gsk, you will be able to tow, but not nearly as great if you spend some money now. I wouldn't tell you to do it if I didn't think it was worth it.

[burnin oil]

Stock you are looking at 400ftlbs of torque and low revs. Not a good recipe for power pulling a hill. At the bare min get the fuel pin and gov springs. These parts are pretty cheap and will do wonders to wake the motor up. Dieselwrenchers suggestion on getting a newer turbo is a good one. Most first gen motors had good size exhaust housings that are slow to spool up. I think they were all 16 or 21cm housings where the 2nd gens HX35 had a 12cm housing. Another good swap turbo is the early 3rd gen turbo from a 600 series CTD. That one will take a little more work to install but I do prefer it to a HX35. Keep an eye out and you can get a HX35 used pretty cheap. A rebuild kit is around $100 last time I checked. Most people say that they need balanced but I know of several people, including myself, who have replaced the bearings and ran it.

[Vintage Windmills]

So everything could be added once its in the truck, right? Except I should know the turbo arrangement to only do piping once. At what point would the stock head studs not be up to the tasK? I know iI don't want to mess with that.

Specs say truck only weighs 5300 lbs, can that be right? That must be with a 350 engine

[burnin oil]

Factory bolts are good to around 35lbs. Some more and some less. Alot of people retorque them before hitting it with increased boost. I would strongly suggest doing the pump mods right after the motor is up in running. Power difference is like swapping a 250 six for a big block. The other thing is the higher RPM gov springs let it fuel harder at a given RPM. In other words the pump wont start running out of fuel at 2200 RPMs. The tighter turbo housing also effects AFC fueling. I am not an expert on rotary pumps but that is the way the inlines function. Diesel wrencher is pointing you the right way and correct me if I am wrong on the rotary pumps function. Unless you decide to go twin turbos, which you said cheap and simple so that is out, keep the exhaust housing tight and the motor will be alot more responsive. Diesels run oxygen rich so you want to keep it inhaling as much clean air as possible. Diesels blow black because there is not enough oxygen, not because of fueling. Usually hopped up diesels dont have the air flow to keep up with the fuel mods and that is why you see them rolling coal. It is just stupid easy to add fuel beyond the available airflow.

[Dieselwrencher]

Jud, I would do a newer turbo before closing the hood on the truck for the first drive. As in mock up. The newer turbo burnin oil is speaking of is a HE351 and are on 04.5-07 5.9 CR's. They are a good turbo but can be alittle more pricey than a HX35W. The HX3W will almost be a direct bolt on. The exhaust configuration may be different depending on which year model HX35 you get. Plus, if you get a used one, maybe it will come with the 3" cast elbow you need for the intercooler piping. I probably have an extra elbow, and I might have a turbo I could rebuild for you. I'd have to check. My supply is getting down. For what you're doing, you won't need studs, but I would recommend replacing the oil cooler gaskets and head gasket with the engine out of the truck. If these gaskets look like they haven't been replaced recently, change them and save yourself a headache later. The early gasket material was not all that great and they changed it in 93 or 94 I believe.

[ryanroo]

Originally Posted by burnin oil

Unless you decide to go twin turbos, which you said cheap and simple so that is out

Truth! haha

[mx289]

Cool project Jud.

I will stay tuned in.

[Vintage Windmills]

this showed up saturday! I am very happy with the truck! no rust that i can find and even has factory black on the frame yet.

[Vintage Windmills]

pics

[Dieselwrencher]

It definitely looks nice Jud!

[Vintage Windmills]

Originally Posted by Dieselwrencher

It definitely looks nice Jud!

Thanks Ryan! Its a refreshing change from the condition of some of the 67-72's I save from the crusher.

I also feel good about the frame after measuring the thickness and looking at the size of the main rails. Its quite a bit more substantial than I thought, looks like the moment of inertia is higher than the dodge cummins trucks. This frame is about 10" tall under the cab!! Its probably 3x the moment of inertia of say a 67-72 K20! Remember the moment goes up to the 3rd power (exponentially) with section height. Double the height and the strength goes up by a factor of 8. The stresses from towing with 3000lbs of tongue weight are more to be concerned about than even 900 ft lbs from a diesel. If the frame rails are 3' apart, that amount of torque is only putting 300lbs force on each rail, not much at all really. More torque comes out of the trans but the frame is larger at that point.

[kevinr1970]

Do I understand right that you gave him his asking price, and you are going to replace the engine?

Mark is a good guy, glad you were able to find him to do the inspection for you, he knows his stuff!

[Vintage Windmills]

Lets just say its worth every penny I did. Definitely there is value in this motor. It will either be sold or used in another vehicle. Mark is a good guy for sure!

[brimc]

Congrats on the new truck. It looks really clean. Defiantly a perfect Cummins swap project vehicle

[Vintage Windmills]

Yep, I see you also have an 86 with a cummins, so glad to have your knowledge here. What did you do for a xmember?

These do seem to be perfect vehicles for Cummins. Its too bad GM didnt figure it out in about 86!!

[brimc]

[QUOTE=Vintage Windmills;6936391]What did you do for a xmember?

I bought the material at the metal superstore and did a lot of measuring and cutting and welding and came up with my own version. I would only do it this way. "Built not bought" approach. I have several posts and pictures in my build for you to reference.

[Vintage Windmills]

Picked up a core support on my way home from IA thanksgiving weekend with no damage. The one on the truck is bent, as reported before I bought it. Just too cheap to not replace, plus this came from a truck with AC if that helps me install a condenser. He also had a rust free 73-78ish gate for a decent price so i grabbed it.

[ryanroo]

good tailgates are on my list of parts that i always buy if i can afford them. if you cant find a use for them they are easy to sell. looks like a good score.

[Vintage Windmills]

Originally Posted by ryanroo

good tailgates are on my list of parts that i always buy if i can afford them. if you cant find a use for them they are easy to sell. .

agree 100%! I actually saw the gate advertised and then it turned out he had a core support. Now i can mock up the intercooler on the core support and leave the truck together. Probably have to cut 2 rows out of IC...

I also tripped over a set of 67-72 4x4 ram horns and picked them up for $20 when there.

[Vintage Windmills]

Just sold the 502 engine with forged internals. I hope I wont regret it, this torque and power isn't cheap to get, and when i get that old camaro.... Anyways, I think the sale price was fair and I've now recouped half of what I have in the truck. Now that I have cash in hand, she is going to come out and then I can start taking measurements for building an Xmember that will allow me to keep suspension lift to a minimum. Really want to keep it practical for cross country trips.

I'm wondering if I should pull the core support now or wait until i have the xmember designed. It may make it easier to yank the driveline now i suppose.

[ryanroo]

You are a stronger man than I. being a recovering BBC addict, i think it would have been REALLY hard for me to sell that.

i say pull the core support and front fenders first. actually pull the hood then the front fenders and core support. you may want to take some measurements first, but i would just strip the core support and leave it handy to sit back on the frame as you are figuring engine placement. it is terribly difficult to deal with the front clip one the truck as you are trying to swing the behemoth 6bt around and its not much better trying to pull the BBC. save the dings and scratches and pull it all right meow.

[Dieselwrencher]

Exactly what Ryan said. You nearly have to tip the engine on it's end to get it in there with the core support in place. Plus you'll get tired of leaning over it,

[Vintage Windmills]

Originally Posted by ryanroo

You are a stronger man than I. being a recovering BBC addict, i think it would have been REALLY hard for me to sell that.

During the grassy field test drive (for him to check out engine), believe me i was having second thoughts! The power was awesome and it sure sounded great too without being loud. But like you said earlier, the diesel is just way more practical for what I want.

Originally Posted by Dieselwrencher

Exactly what Ryan said. You nearly have to tip the engine on it's end to get it in there with the core support in place. Plus you'll get tired of leaning over it, :LOL:

Yeah, there really is no reason to try to leave the core support on since this one is bent anyways.

[Vintage Windmills]

I need new tires for my HD so I bought at least 2 new ones. They came with some other goodies too, like an disc brake AAM 11.5 and an unscathed a1000. Here are the parts

The guy just put new tires on about 1 week before the fire, per the date code on them. Its sad but a fuse (or improper fuse probably) is responsible for this truck being destroyed