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new to the 6.2L

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wk96

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long story short, after my brother had to sell his hunting truck, I went out and found a cheap fixerupper (or so I hope) that is more than comparable to his old 74 ford pickup we used to use.

it's an 85 K5 with a 6.2L on 15.5x38s.

I've had it for a few months, but he took it to try to fix any and all things he could to save me some money, but he's no professional mechanic, and I'm even further from it. here's where you guys come in...

the exhaust is not in a condition that can be saved, and I wouldn't even if I could. what do you guys recommend for this truck, to help it get through the ruff stuff? be kind to my MPGs, I've gotta get it from central florida to georgia a few times a year, about a 3.5 hour drive at 60 mph.

and just about everything I do to this truck will be done by a shop, unless I can find a book with pictures showing me how to do it myself with a drill and screwdrivers.

appreciate the help!
 
The nifty thing about a diesel engine is that the more air you can cram into the cylinders, the more power it makes, and the better fuel efficiency it offers.

It doesn't really matter if you run a single exhaust pipe, or run duals, just remember that bigger is better for a diesel. The less back pressure there is holding exhaust in the combustion cylinder, the better. I personally run a 3.5" straight pipe on my turbocharged 6.2L, and it seems to do very well. A single 3" pipe, or 2.25" duals would be more than adequate.

You will want to run a muffler on your truck however, as they are very loud straight piped without a turbocharger. When you buy mufflers, avoid purchasing any glasspacks as the diesel soot / exhaust temps will wreck them, and specifically look for a muffler that has a straight through design similar to a hooker Aerochamber. If you can't see right through it, you probably don't want to run it on your diesel engine.
 
Like Russell said, free flow is the key for exhaust on these. Since a shop is doing it, I'd recommend either dual 2.5" all the way back or a 2.5" Y-pipe into a 3" single. Use flow-through mufflers (best but loudest) or turbo mufflers, not glasspacks. Glasspacks tend to collect soot on a diesel.
 
thanks for the quick reply

I read a few posts about the banks turbo kit for the 6.2L, will I use that increased power on the highway and on some semi rough trails? I don't need the truck for towing or climbing walls, but I can drop $1800 if it'll help it to not sound like I'm squeezing the life out of it going faster than 55 and keep the truck running longer.

what are some numbers on how the turbo kit will affect power and fuel efficiency?
 
These trucks came with true dual 2.25" exhaust pipes from the factory. Probably the cheapest and easiest would be to just have a shop bend up a 2.5" duals. The 6.2 sounds pretty equivalent to a gas engine in regards to what mufflers you use (I've ran everything from glasspacks, turbo mufflers, and now Flowmaster 40's) and everybody comments on the sound and that they can't tell it's a diesel until they get close enough to hear the typcial diesel clatter.

If if decent shape you should get good fuel mileage out of this engine. Obviously the 38" tires don't help, but the MPG will be higher than a comparable gas engine version. The biggest key is the axle gearing. Speaking of which, if it still has the original 10-bolt rear axle and/or the stock gearing it will likely be a dog and get far from optimum mileage. The stock rear axle is definitely far from beef in regards to durability.

For routine maintenance these engines are very picky about having clean fuel and air filters. Mine would always run like crap if you let either of these items go.

The turbo is nice, but I'm not sure if it is $1,800 nice. From my experience you will get the most benefit from it on the highway. A lot of off-road conditions you won't get much if any benefit from it.
 
A turbo is the single best thing you can do for the 6.2 diesel in my opinion. Naturally aspirated diesels of any sort are dogs, and the 6.2 is no exception.

A 6.2 with a Banks performs roughly like a mildly built 350 gas engine. I had 3.08 gears, 33" tires, and overdrive in my shortbed and could cruise on flat ground at 60-65 (would have to downshift for hills). I am currently in the process of switching to 4.10 gears and 35" tires.

If you do go turbo, just run straight exhaust pipe. It's not obnoxious - rather, it sounds very good.

Banks chart says the following:

62L-turbo-graph.jpg
 
it's got a dana 44 in the front, and a 60 in the rear. I have absolutely no idea if the gearing can be figured out just knowing that, but if I need to climb under the truck and try to read something, I'd be more than happy to.

and this truck, even with 38"s, is destroying my 2004 dodge ram with a V6 on MPG. I'm thinking of making her a daily driver once all of this is taken care of and just ignoring the fact that it will probably be more expensive in the long run when I have to replace those tires...

edit: I saw that chart on the banks site, didn't know if I could trust it... you're telling me I'll actually see +60 HP with the kit?
 
Yup, pretty likely.

You can do the swap far cheaper if you buy used however. I turbocharged my 6.2L using a GM-3 turbo setup from a 93 6.5L mechanical diesel engine. Everything bolts right up. Only trouble was running an oil line to the turbo, and the return line. You can use your original injectors and injection pump, just need to turn the fuel rate up a hair.
 
I'll look into that, see if I can manage it with a few helping hands. are there any other realistic upgrades you suggest?

thanks again for all the help guys
 
I would suggest looking at your gearing in the diffs. With 38s your gearing should be lower than 4.56 imo to get some performace. But as stated, the diesel will do well on fuel if you maintain it well and its not worn out.

-Doc
 
as I'm lower than a rookie at things like this, how much effort will it require to get it set up for lower gears?

I have a feeling I should be moving this thread out of the diesel forums soon..
 
Setting up gears requires some specialized tools, and a lot of patience. I've always just had the gearing done for me.

On that note, you may want to consider upgrading your differentials at the same time. Bolting in bigger 3/4 ton or 1 ton diffs is easy. You are also more likely to find diffs with the gears that you need already in them.
 
I would have the gears in there checked, the differentials should have a tag on it with a number.

If the tag is gone, there are other ways to check your current ratio.

Changing gears in a rig can get rather tricky.
 
I'll climb under it with a flashlight tonight, see if I can get some numbers off the diffs. believe it has a posi, but I guess trying to read something off it would hold more weight than my limited knowledge of such things.
 
Cool Blazer!

Ideally, since you will be running on the highway, you want to gear it sao that you'll be running the engine at right around 1800 RPM. The 6.2 seems to be real happy and makes the best fuel economy there.

If you keep the 38's and have a 700R4 (or NV4500 manual) transmission, 4.56 gears would put you right there at 65 MPH.
 
What he said. If it's a non-OD transmission then you want to probably stick with a 4.10 gear at the most. Big Ugly has 4.56's and 38's and the TH400 always has me wishing for an OD gear past 55mph.
 
alright, here's what I know.

both the front and rear are d60s, corporate 14 bolt, trac loks. 4.10 gears. the front diff was shot not too long before I got the truck, what's in both of them is relatively new.

so, any tips on what I should know as far as failure, things to watch for, pros, cons, abilities, or any tips on the best way to learn how to handle them would be a great help.

on a side note, she's not starting, but she'll roll over and sounds fine doing so. means the fuel injector isn't providing enough fuel, I assume?
 
More likely a glow plug issue, unless it's out of fuel?

Rene
 
it's got more than 3/4 of a tank of gas, and I've not had an issue with the glow plugs not working. it's been pretty hot lately anyway (not sure if that'll actually help), and I'm hearing the click when the glow plug light goes off on the dash.
 
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