1994 Diesel Suburban Build

[deejaaa]

have you researched the conversion from DS4 to DB2 yet? there are several write-ups on it if needed.
might rethink about adding front a grille block on the front. air flow suffers on the GMT400's already. # 8 & 7 cylinders are the most prone to overheat which leads to HG failure.
a fully loaded N/A suburban will have a hard time going up hills, esp when going to a higher gear.
interested in your project.
i finally got my 93 back on the road but still weeding out problems from sitting 4 years.
almost forgot: at 70 mph i'm running 2000 rpm with 4:10 gears. i have a GearVendors unit.

[aardvarcus]

Deejaa,

Yeah I have a printed off injector pump conversion guide I have read through a few times. I think I have most of the parts except the throttle cables of the correct length. Still have to check what all parts I am able to source from my parts truck, I think I can get the pedal assembly and cruise control unit.

Yeah, my old 1991 K2500LD taught me lots about GMT400 airflow or lack therof, any grill blocking will be done cautiously. I hope to eventually redesign the front end enough to create a greater pressure differential between the engine bay and the front to increase the airflow.

I don't mind downshifting if necessary, especially when loaded. I hope to reduce the weight and drag to the point it can hold overdrive up a moderate hill when empty with the steeper gears. I already have to downshift to climb certain hills in my Tacoma. If I do forcibly induct my 6.5L, I don't know that I would use a turbocharger, maybe would try a clutched supercharger setup.

Is your 1993 a single rear wheel or a dually?

[cRiPpLe_rOoStEr]

Originally Posted by aardvarcus

If I do forcibly induct my 6.5L, I don't know that I would use a turbocharger, maybe would try a clutched supercharger setup.

Though a turbocharger is more efficient in a Diesel, a supercharger looks cool. BTW have you ever considered to set a variable-ratio similar to those used in some ancient aircraft?

[deejaaa]

Originally Posted by aardvarcus

Deejaa,...Is your 1993 a single rear wheel or a dually?

mine is single. can't check mpg right now. have a 30 gallon tank mounted in the bed and no in cab gauge. it's mounted on the side of the tank. i got a best of 20 when i was running mostly freeway.
i will get a saddle tank and sending unit after i start working the new job. will get them from a junker. can get both for about 40.00. i will use the bed tank as a siphon tank. when it runs dry, i will then use the gauge from the saddle tank.
that's the plane at least.
mine is about to go under the knife again. need to remove the valve covers to trace down a noise. a lot has to come off to get to them.

[aardvarcus]

Cripple Rooster,
I had never really seen variable ratio superchargers before, just looked them up. Neat concept, I will keep it in mind.

Deejaa,
Sorry to hear you have to tear into yours, I would love to get a 92-93 CC SRW 6.5L one day as a tow vehicle. Just got to finish the Suburban first.

For those wondering, the prior Saturday (3rd) I did tear into the Suburban, and despite a few hiccups managed to pull the old engine, transmission, and transfer case. Sorry I once again forgot to load my pictures. I have been cleaning and degreasing the parts and pieces I will be reusing, as the old motor had some oil leakage that gave everything in the engine bay a nice coating.

Had some family stuff come up, basically consumed most all my time since, I am sure everyone can relate. When I do get a few minutes I have been weighing all the parts and pieces I have taken off, I want to get a good baseline for where the weight is on these GMT-400 vehicles. I have plenty of little projects do to get this thing ready for the next campaign of installing the new powertrain.

[aardvarcus]

I am going to document some of my progress a bit after the fact, as I did not have time while it was taking place.

I began the engine removal by pulling accessories and other items off of the engine, attempting to photo-document and label pieces as I went. Started with the skid plates, radiator hoses, engine fan, fan housing, etcetera. Pulled the alternator, power steering pump, and associated bracket so that I could use a bolt through one of the tapped block holes as a lift point. I drained all the fluids from the radiator, engine, and transmission. Got the transmission supported and pulled out of the way (with some difficulty due to an overlooked bracket for the rear HVAC heater hoses) and was then able to lift the engine out of the engine compartment. Sounds simple, but took a full day for just this. Got the Suburban rolled back outside, and called it a night.

[aardvarcus]

With the Suburban back outside, I turned my attention to cleaning up the engine bay a bit and continuing to disassemble parts as needed. I removed the firewall insulation, as I will be replacing it with new.

On the inside, I started to pull the interior out, thinking I would just remove the seats to be able to deep clean the carpet. Then I pulled the trim so that I could clean all the way to the edges. Then I remembered I need to peel the carpet up so that I can cut the hole in the floor for the stick shift. Before long I just kept pulling parts off so I am down to bare sheet metal for most of the interior. The pictures were in progress shots, so there is more pulled than shows. I still need to pull the dash and headliner.

[aardvarcus]

Made a bit more progress on getting the accessories switched over to the GEP engine. Using a mix of the GEP and Suburban parts requires a bit of modification on some items. I had to bend the GEP hard fuel return line to get a bit more clearance around the passenger side of the coolant crossover. The GEP single thermostat crossover unfortunately doesn't block off the bypass line when the thermostat is fully open, so I used the Suburban single thermostat version which does. I used the rubber hose and clamps from the GEP engine from the water pump to the crossover, had to trim the length down a bit.

I installed the existing Suburban alternator (which appeared recently replaced) and the existing power steering pump on the new engine. I used the existing suburban brackets for these items, had to modify the back alternator bracket to fit around the fuel line. I used my new to me vintage 80s mill-drill to eat out what was necessary, plus a bit more for a touch of extra weight savings.

I did get all the rest of the interior, dash and headliner, out of the Suburban as well. Have to have the dash out to put the clutch pedal bracket in. Good chance to weigh and clean everything, some of the panels I will probably swap out with the versions off my parts truck which are in better shape.

[aardvarcus]

Made a bit more progress. I previously posed how the aluminum threads on the water pump crossover galled up, cracking the crossover when I cranked down loosening the bolts so I had to weld the cracks back together. I drilled out the repaired aluminum and tapped it for a Helicoil. I put the helicoil in with red (permanent) locktite as I don't want it to back out as the thermostat bolts are put in and taken out. The stainless helicoil threads shouldn't gall up like the aluminum against the steel bolts.

I also picked up a nice set of tan leather middle row bench seats to go with my leather third row I found earlier. Now I just need a decent set of front seats to match. Won't directly help MPG, but should encourage others to ride with me versus the ratty and worn old seats to improve my Passenger-Miles per Gallon.

[aardvarcus]

So maybe I got a little carried away stripping the interior….

Interior is bare sheet metal at this point, other than the brake pedal (which I have marked and cut down from the automatic transmission size to the manual transmission size). I have been looking at interior insulation products for the inside of the firewall, already have something for the outside. I have been focusing on some Ensolite or similar products, basically PVC-NBR foam which is available peel and stick with acrylic adhesive. Common temperature ratings seem to be 200-220 degrees F, which should be sufficient for interior application when there is an exterior firewall mat present. The more insulation I can stuff into this thing, the less I will have to run the AC in the summer.

In powertrain news, last weekend I tore into my parts truck, 1991 Chevy K2500LD, removed the NV4500 and all associated parts I had swapped into it. GM was kind enough to pre-punch the hole I need for the manual throttle cable in the suburban, so I can use the parts truck throttle pedal and just ordered the (hopefully) correct throttle cable to reach the DB2 pump. I haven’t found any luck finding the appropriate cruise control cable, either will need to junkyard it, relocate the cruise box, or modify another cable to work. I have the GM parts numbers, but all are discontinued and don’t cross reference anywhere.

Anyway some pictures.