Played the 6.2L Lottery, did I win or lose?

[Mark Krieger]

I bought a retired 1988 USPS Parcel Delivery Van on eBay and I need some help figuring out if it's healthy or not. I paid $3,500 so there's not too much at stake, but any help would be appreciated!

It's a Chevrolet P-30 chassis with a Grumman aluminum van body. It's rated at 11,300 GVWR and included a beautiful lift-gate at the rear.

It had 78,000 Miles on it with no indication of any tampering. The motor is a 6.2L diesel with a TH400 automatic transmission.

On a 75 Degree summer morning, it starts right away without touching the accelerator pedal. It seems to run smooth with no smoke at startup and the exhaust begins to become visible only at full throttle. The transmission shifts firmly on both up-shifts and down-shifts.

I've looked for bubbles in the radiator with the engine running and found nothing. I've also run it with the oil filler cap off, and didn't notice any pressure or vacuum in the crank-case.

Is there anything else I should be looking at to figure out if it's in good shape? Should I try to figure out if it's heavy-duty or not? Any suggestions to help me figure out if its any good?

http://photos2.ebizautos.com/210/346489_1_400.jpg

[CleviteKid]

IF there is an EGR valve in the middle of the intake manifold, after you take off the air cleaner, then it is a light-duty engine. No EGR, heavy duty.

You are only a compression test away from having a winner in the 6.2L lottery - 350 psi minimum in each cylinder and you win.

Looks like you have the makings of a great work truck, or even a unique mini-RV for traveling the country.

Dr. Lee :cool:

[Mark Krieger]

I've got to figure out the rear axle ratio and do some math so I can calculate RPM's because there's no tachometer. I can boogie along comfortably at 60, 65 and even 70 MPH and still have room to go a little faster. I'm used to hearing a diesel at low RPM's, but at 65 MPH the engine in this one seems like it going too fast! (There's no overdrive.) It's doesn't sound bad, but I don't want to hurt it by overdoing the RPM's.

The question is this: what RPM is safe for this motor for extended periods of time?

[catmandoo]

to check the rear end gears,if it's not posi,just jack up one side til the wheels off the ground,mark the tire,and then turn it 2 turns while counting the turns of the driveshaft.

[Keith Richards]

I may be wrong ,but I've never seen a one ton GM with taller than 4.10 gears. Its probably that or 4.56 which can be taxing on the highway,but obviously great for hauling at slower speeds.Looks like a sweet work truck.Is thhat what Its gonna be used for?Good luck

[Mark Krieger]

Originally posted by Keith Richards:
I may be wrong ,but I've never seen a one ton GM with taller than 4.10 gears. Its probably that or 4.56 which can be taxing on the highway,but obviously great for hauling at slower speeds.Looks like a sweet work truck.Is that what Its gonna be used for?Good luck It's for fun, but hopefully it'll bring in a few bucks now and then and make work seem more like fun. It's actually a two-Ton truck with an 11,300 GVWR. I found the RPO decal and here's the breakdown...

B3J Diesel Equipment
DET PLANT CODE DETROIT, MI, USA
D1X Gear, Spedometer Driven
E33 Body Equipment, Foreward Control Var 4
E5Z Less Spedo Gear Adapter
E6C
E78
E92
FS3 Suspension System, I-BEAM Construction
GAM VEHICLE GOVERNMENT (G.S.A. SALES)
G60 SPRING REAR AUX
HC4 AXLE REAR 4.56 RATIO
JB8 BRAKE POWER, DISC/DRUM, 10,000 LBS
J55 BRAKE SYSTEM HEAVY DUTY
K81 GENERATOR 66 AMP
LL4 ENGINE DIESEL, 8 CYL, 6.2L, HEAVY DUTY VIN J
MX1 MERCHANDISED TRANS AUTO PROVISIONS
M40 TRANSMISSION AUTO 3 SPD, TORQUE CONV, VAR 1
NA5 EMISSION SYSTEM FEDERAL, TIER 0
NPG SHIELD NOISE ABATEMENT
NWJ EXHAUST DUAL OUTLET EXHAUST
R05 WHEEL DUAL RR
SLL SALES PROCESSING SOLD ORDERS
V73 VEHICLE STATEMENT USA/CANADA
YD8 SPRING FRONT BASE EQUIPMENT, SCHEDULING GVW PLATE
YJ1 EQUIPMENT REGULAR BODY OPTIONS
01L Exterior Color Secondary, Special
01U Exterior Color Primary, Special
2TX TIRE FRONT 8.00R19.5/F BL R/PE ST TL HWY (SEO)
3TW TIRE REAR 8.00R19.5/F BL R/PE ST TL OOR (GOODYEAR G133) (SEO)
5F6 Lever, Parking Brake, Orschelin
6W5
8B3 COOLANT ETHELENE GLYCOL (-34 DEGREES)
8D6 Reinforced Rear Frame Rail
8H5 Bumper, Front Delete
8K5 EMBLEM & NAMEPLATE DELETION
9E6 GVW RATING 9,600 LBS (SEO)
9H4 FUEL TANK 152L, 40 GAL, W/AUX FUEL FEED PORT

[Mark Krieger]

Here's the information I needed...

1:1 3rd Gear Ratio
4.56:1 Rear Axle Ratio

8R19.5 Tires, 626 Tire Rotations per Mile
2,854 Engine Rotations per Mile (3rd Gear)

185,546 Engine Rotations per Hour at 65 MPH
3,092 Engine Rotations per Minute at 65 MPH

199,819 Engine Rotations per Hour at 70 MPH
3,330 Engine Rotations per Minute at 70 MPH

So, these figures are accurate with a locking torque converter and I'll bet this one DOESN'T lock so I'll have to add another 500 RPM or so.

At 70 MPH, I should be operating around 3,800 or 3,900 RPM if there's torque-converter slippage involved. I think this is beyond the red-line for this engine and not healthy to operate like that for any length of time!

Even doing 65 at 3,500 RPM, I've got to believe it's close to red-line and still not healthy for extended periods of time.

Does anyone have any experience with operating a 6.2L diesel at these RPMs for extended periods of time?

[NH2112]

I don't think you'll see 15% slippage with a non-locking torque converter. 3% seems to stand out to me as the average amount of slip. You shouldn't have any problem maintaining 65MPH for as long as you need to, I've driven CUCV pickups (4.56 gears) and humvees (5.24 gearing - 2.73 R&P and 1.92:1 geared hubs) at 65-70mph on the autobahn for hours at a time without any adverse effects.

[arveetek]

You can't over-rev a 6.2L by driving down the highway. The injection pump has a built-in governor that will limit engine rpm, somewhere around 3600 rpm, though some are set a bit higher than that. You can run the 6.2L, or any diesel, at the governed rpm limit all day long with no damage...it's just hard on the ears and on the fuel mileage. So don't worry about running the engine too fast, it won't mind one bit.

The only way to over-rev the 6.2L is to hold it back in too low of a gear when going down a steep hill. I don't think the TH400 will allow that to happen, though.

Casey

[Mark Krieger]

Over the weekend I put in six or seven quarts of Mobil Delvac 1300 Super 15W-40 and a new AC-Delco PF-1218 filter and it sounds more comfortable at high RPMs.

Whatever was in it was sure black! I noticed that the new oil was turning black after only a minute or two running. I know that motor oil will darken with age, but this was BLACK. I'm kind of regretting the 500 Mile drive I made from Dallas to El Paso when I picked up the truck! I hope I didn't hurt anything...

Do you think I should change oil again soon to get it flushed out? How does used oil look in a diesel as compared to a gas engine?

Also: There's nothing in the air intake when I changed the filter so I guess it's a heavy-duty engine. Other than EGR, what does "Heavy Duty" mean in the 6.2L diesel?

[arveetek]

Originally posted by Mark Krieger:
Over the weekend I put in six or seven quarts of Mobil Delvac 1300 Super 15W-40 and a new AC-Delco PF-1218 filter and it sounds more comfortable at high RPMs.

Whatever was in it was sure black! I noticed that the new oil was turning black after only a minute or two running. I know that motor oil will darken with age, but this was BLACK. I'm kind of regretting the 500 Mile drive I made from Dallas to El Paso when I picked up the truck! I hope I didn't hurt anything...

Do you think I should change oil again soon to get it flushed out? How does used oil look in a diesel as compared to a gas engine?

Don't worry! The design of the 6.2L engine pretty much turns the oil black as soon as you pour it in. This is due to the black soot getting past the rings and into the crankcase oil. Very normal. That's why we recommend short oil change intervals, like 2500-3000 miles. That's also why using synthetic oils won't let you have longer drain intervals, because you're still getting soot in the oil.

My new oil looks sort of black when I pour it in, but even after running the engine for just a few moments, it's pretty much all black. That's due to the new oil mixing with the old black oil that you can't get out. You'll never be able to flush all the black oil out.

Casey

[jbell]

I did the unthinkable and swapped out the th400 for a 700r4 on my 3/4ton burb, the lockup makes a HUGE difference, as does the OD. Not only am I faster, but MUCH quieter as well with the 700r4. Fuel mileage jumped from 14-16 to 20-21.
I'm real uneasy running a diesel over 3K rpm's for very long -- just my 2c.

[moondoggie]

Good Day!

Doesn't seem unthinkable to me. A 700R4 rebuilt by a good tranny guy is an excellent choice. My rebuilder said that if I wasn't hunting or locking/unlocking the TC, I couldn't break the 700R4 he rebuilt for me. I only drove it 40K miles or so after he rebuilt it, but had no problems.

I think it would be unthinkable to listen to that 6.2 SCREAMING :eek: like it will with no OD gear & no locking TC, if you had the option to do what you did.

The TH400 is one of the best AT's around, but it's power handling ability isn't always necessary, & lower revs improve almost everything.

Blessings!

Brian Johnson, #5044

[laidback383]

my 88 has a 700r4 in it it was rebuilt 30,000 ago and it has take a licken and keeps ticken i drop the fluid about every 10,000 and its always pink and it has never let me down

[Mark Krieger]

I just went to an informational meeting with FedEx tonight to see if there's part-time work for me and possibly more.

They talked about the fact that FedEx Home Delivery is operated completely by contractors and the need to obtain your own vehicle was a requirement. People were asking about the cost of trucks ($35,000 to $45,000) and leasing cost versus qualifying for financing. One guy was concerned that the first to qualify for financing would be the first to get a route and leave everyone else out in the cold. You should have seen his look of panic when I said that I already had a truck and needed to know the cost of a set of FedEx decals. Fortunately for everyone, the selection process is a little more sophisticated. Having the truck already doesn't give me any real advantage.