To 6.2, or not to 6.2

[82Diesel]

I’m a 6.2 noob but a square body veteran. I just picked up an 87 suburban 2wd with a 6.2 in it. It’s a 2 owner truck and was meticulously maintained. Motor runs great with 700r4 and 3.08:1 gears. I just got 23.5mpg’s on a highway trip last week averaging 70mph. It’s not flat land here in Maine either. Yes, it is underwhelming in the power department. I also have a 12valve Cummins in a dodge 1ton that I’ve done work to so I’ve been in a powerful diesel.

But, that being said, so far I’m liking the 6.2. I’ve already added a glow plug manual override solenoid in parallel with stock controller and manual advance/high idle switch because my temp sensor is bad and at over $100 for a new one. I’ll just do it manually. I put fresh Delco 60g’s in it and it starts great. We’ll see how it does in really cold weather but it had a block heater too.

Soooo.... if you want mileage, the 6.2 is the way to go. I wouldn’t bother putting a turbo on it, just embrace it for what it is. A fuel sipping motor that will get out of its own way but barely. But you do need the whole package. If you are planning on running the TH400 and your truck has lower gears in it, you’re just wasting your time.

Ben

Glad you are liking it, They really are great motors minus some Flaws... Turn the IP Pump up and you'll get a bit more power / maybe less MPG... Your Decision, As for Block heaters try and find a 1000 Watt or higher one... They work best & Last much longer than the 5-700 ones. Amazon has them.

 

[MrMarty51]

One thing that these engines fuel system needs is a constant fuel supply from the lift pump.
I got a kit from a supplier that convers the lift pump to a relay system and also has a switch that can be turned on to prime the system.
The system that I got supplies 10 psi fuel pressure under a pulling load.
Anytime the lift pump on the 6.2 or 6.5 system fails, the IP will pull fuel from the tank but it will not do it for very long, by the time the engine dies from lack of fuel, You are too late, a new IP will be required.
I also got a fuel tap fitting and installed a lift pump pressure gauge so that the system can be monitered, gives a first step in fuel system diagnostics too.
Another good thing to install is a piece of clear tubing from off the injection pump onto the return piping at the front of the engine, a little upside down U looking piece of hose. The clear hose replacement will allow You to see air bubbles in the fuel system if there is an air leak anywhere in the system.

 

[TPISly-C10]

What kind of mileage are you getting

i don't really know but feel like modern EFI truck

 

[Andreas Wickman]

I have a fresh 6.2 in my C20, and I have 19.5 mpg. With the camper on it si 13-14 mpg.

 

[84 M1008]

Okay I’ve been reading a lot, and I mean A LOT, on this topic and I am growing more conflicted and would like to weigh in on the opinions of others and get a general idea of any extras I will need to buy.

My truck is a 82 k10 with a SM465 and a weather seized 350.

I love the idea of the 6.2. It has the potential for awesome mpg and diesel consistently cheaper than gas here. The engine is a drop in with some minor wiring and other plumbing. Since My truck is a 1/2 ton I won’t be towing much with it therefore don’t need a ton of power. A local junk yard has a 86 Chevy g30 van that has a 6.2 and they will sell me the engine with all accessories for $300. The catch is the yard owner thinks it has a bad motor but it has been so long he can’t remember if it was that van or the cucv van he has. I can get a rebuild kit for the engine for around $400.

Unfortunately the junkyard van is an automatic so I would have to try and track down a diesel flywheel or some sort of balancer for the engine, if I’m not wrong in my reading. I could probably work out a deal to get the hydro boost setup and some other odds and ends I’ll need to do the truck such as a radiator and some batteries.

I have also located a turbo setup, minus the intake, off of a 6.5 for $100. Not sure if that is a good deal but I have read it is a direct bolt on and gives a power and mpg boost as long as I keep the EGTs under 1100f and the boost 10psi.

I am assuming the 350 in my truck will need to be bored and need a ground up rebuild to be reliable. The truck has been sitting outside for 6 years and I tried to rock it back and forth in gear with my buddy’s truck and couldn’t get it to budge at all. That was after the cylinders were filled of marvel mystery oil for a little over a week.

All I want out of this truck is to be a reliable daily driver and to get good mileage. If I had the money and time I would do a 4bt swap. But I need this truck running before winter hits.

What do you guys think. I need honest opinions. Thank you in advance.

Truthfully, I would look for a 6.5 and put a mechanical pump on it. The 6.2 is a gremlin waiting to pull the pin. I've had 2 of them, one with the Banks turbo, and the one in my present truck. By the way, the one with the Banks turbo would walk away from a 6.5 all day long. You need to determine the condition of a 6.2 before you turbo it. It could actually shorten the life of the engine if the engine is tired.

 

[Arkansas_V8]

But you can still pick up crate 6.2s from military surplus. I got 1 a while back when I got my tires. Sold quick. The J code is just a bit better motor.

 

[hunters628]

Truthfully, I would look for a 6.5 and put a mechanical pump on it. The 6.2 is a gremlin waiting to pull the pin. I've had 2 of them, one with the Banks turbo, and the one in my present truck. By the way, the one with the Banks turbo would walk away from a 6.5 all day long. You need to determine the condition of a 6.2 before you turbo it. It could actually shorten the life of the engine if the engine is tired.

I am considering buying the 6.2 and doing a re-ring and new bearings before it goes in the truck. It is a J code motor so it already has the emissions deleted. And I can get a 6.5 turbo setup for $100. There is a 6.5 in the yard but it has been pretty well picked over on top and I’m not sure what all I would need to finish it.


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[olred86]

having done the swap with my r3500 recently, (got it running and took it for a road trip last week) i can say that i am truly impressed with the j-code 6.2 that i got. colorado springs to san antonio hauling a car one way, and empty back, i got 20mpg with the 6.2/th400 with 4.11 gears, 245/75R16 tires and averaging 65mph. converted to the serpentine system, advanced the cam one tooth on the chain, and advanced the injection pump 2 degrees. will be replacing the timing cover and timing set with a 95 6.5 timing cover and timing set for the crank sensor to use for tach input for trans controller for 4l85e.

here is the rub, i wouldnt recommend doing this swap unless you have access to everything from the outset for less than it would cost to get a good replacement 350 ($500-$1000 average), and i fully endorse vortec4.8/5.3/6.0 and nv4500 swapping it if economy is a major concern... as mentioned, the 6.2 is a little heavier than a 454, so your front springs will need to be addressed. you will need to remove the electric fuel pump for gasoline, and ether modify or replace the fuel inlet as diesel pumps are a different size than gasoline pumps. i spent over a month redoing wiring and fuel lines. if you are set on this conversion, save yourself some headache, (not money unfortunately) and just get the diesel radiator and radiator hoses. "converting" even the 454 radiator to work with the 6.2 is a nightmare and leaks like a sieve. your truck is a manual so the transmission cooler isn't an issue for you, but the factory oil cooler is on the passenger side of the radiator where a typical trans cooler is. the factory 6.5 turbo and exhaust manifold interfere with the A/C box and if it doesn't break when you torque the turbo flange bolts, it will be broken the first time the engine twists under torque. the banks sidewinder manifold is best if you can find one. running the turbo at more than 10psi will damage the 6.2 pretty quickly, as far as diesels go they are among the highest compression ratio engines around, and too much cylinder pressure will cause the block to fail spectacularly.

again, i would not recommend this swap unless you have everything you'll need readily available for free or less than it would cost to get a good replacement 350 and an nv4500. if that is not the case, then going with a vortec/manual trans setup would potentially still be cheaper than converting to a 6.2.

 

[peats]

Sounds like a lot of work and money to me. i would find a used engine for around $800 and use the money saved for gas. Or buy a corolla like mentioned earlier.