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350 to 6.2L diesel

Discussion in '40- & 55-Series Tech' started by Ardent, Aug 18, 2006.

  1. Ardent

    Ardent

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    Anyone else swapped their 350 for a 6.2L diesel? I have an '80 FJ40 with a 350 conversion, really considering the swap as I do long distance trips here in Canada, and the 6.2's mileage is mighty attractive, plus I just like diesels.

    Now my stumbling point is the gearing, currently mine's running an SM420 transmission and 3.93 gears, with 35's on it's just right. Once I go to the diesel though, rev range is going down a lot, so I've been thinking the gear change will occur in the diffs, if I can find somebody who'll gear down my diffs, every one gears up. I don't want to lose the SM420 in the swap, that 7.05:1 first gear rocks.

    So any advice? thanks in advance. :) I've also heard the 91-92 6.5 turbos are a good engine, and are not electronic yet.
     
    Last edited: Aug 18, 2006
  2. my64fj40

    my64fj40

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    Wow

    That would be interesting







    3B diesels seem to be the best for 40s though
     
  3. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Welcome.


    Your post is kind of confusing....


    You talk about a 6.2 and then a 6.5....and then talk about a 3.93 rear end ratio...


    If you have Land Cruiser axles under the truck, and you meant to type 3.70 gears, you will not find a higher ratio than that...
     
  4. Ardent

    Ardent

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    Reason for the 6.2 talk is that the 350 and the 6.2 share the same mounts, and the 6.2 will bolt right up to my SM420. The 91-92 6.5 is an engine recommended to me by a GM mechanic if I wanted more power than the 6.2, as it is a non-electronic turbo, and I do believe it has the same compatibility for my application. I likely will choose the 6.2 however, given the greater simplicity, and less of a reputation for cracking cylinder heads.

    The 3.93:1 reference refers to the diff ratio the fellow I bought from quoted, I could well be wrong there.

    Cheers and again, any advice is appreciated, only ran into info on one 6.2 cruiser, I'm sure there's many more out there.
     
  5. Ardent

    Ardent

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    Ah, I see, on re-reading I note a brainfart, yes I jump around and mention 'once I go to the 6.5', all I mean is once I go diesel. I'll edit that.
     
  6. my64fj40

    my64fj40

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    I say go for it and let us know how it comes out.

    Post up some pics when ya get done too





    You can get 3.70 gears for the disff which wuold lower teh rpms more than these 3.93s


    Do you even have toyota axles cuz I havn't ever seen anywith 3.93s
     
  7. Gumby

    Gumby Supamod Staff Member s-Moderator

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    There are a couple of threads in the 60 section about the pros and cons of the 6.2.


    I did it and undid it
     
  8. Brian in Oregon

    Brian in Oregon

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    I've been wondering about this too. I notice with my 4.10 gears and 33" tires that I'm doing a bit over 3000 rpm at 65 mph. Is that a sustained rpm for a 6.2?

    As for the 350 to 6.2 swap, from what I can tell, it's a direct swap as far as physically dropping the motor in. I don't know if the 6.2 requires a unique flywheel though. (I'm not a Chevy expert by any means. My background is mainly with older Ford engines, primarily FE engines.)
     
  9. handcannon

    handcannon

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    Last fall, while working in his house, I met Ross Stuart. Some here on mud may know him for his shackle reversal kits. He showed me his 40 that he had put a 6.2 in. Looked neat and very interesting. He said that it was a very tight fit, I think it was because it is longer than a 350. If my memory is correct I saw an electric cooling fan between the radiater and the bib. I was on the clock so I didn't spend as much time looking at it as I wanted to. I don't remember what tranny or gearing he had.
     
  10. bandy rooster

    bandy rooster

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    i can only assume with the diesel and the sm420 your going to have some pretty extremely low gearing. A guy from st. petersburg in FLorida under the name of stevefl on Ih8mud runs a 6.2 gm to nv4500 mated to the splitcase... His setup has been working great as far as i've seen and i'm sure if you asked him any specific questions he'd answer them, hes a cool dude. (he's also running biodesiel)

    i think it sound pretty neat and but if i were you i'd go with some bigger meats on the 40.
     
  11. Ardent

    Ardent

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    Thanks to all great info and I might have to send some messaages, and as for the diff gears, I do now believe them to be 4.10's, my mistake.

    Here's the truck in question if anyone's interested, and yeah going a little higher on the lift, and bigger tires along with the diffs, would likely help. But then there goes some of the all important fuel economy I was trying to gain, laf.

    [​IMG]
     
  12. CruisinGA

    CruisinGA

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    the 6.2 is a heavy dog.

    the 6.5 is a heavy unreliable dog

    IMO toyota or cummins 4bt diesel.

    Or get your gearing/tires right so that you are turning about 2000 rpms at 70 instead of the 2500 you turn now. A healthy, properly tuned 350 shouldn't have a problem with this.
     
  13. Fast Eddy

    Fast Eddy

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    This overgeneraized statement is false.
     
  14. FL cruiser

    FL cruiser

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    The 6.2 is only 40lbs heavier than a 2F.
    Not all 6.5's are unreliable.
    Toyota has some issues with a couple of their diesels too. I know.
    Can't really generalize on diesels on what's good and what isn't. Lot's of research to be done.

    I would keep the gearing the same. The 6.2 doesn't have that much torque.
    Mine has 3:70's with 33's. I slapped some 35's on once, and it turned into a dog acceleration wise

    If you keep it the way it is, you've reduced your highway speed from that of the 350. Just because the 6.2 feels like it's screaming when kept above 2500 RPM.

    The only pactical thing you can do for a 6.2 conversion that will be driven on the highway is put is a 5spd overdrive.
     
  15. Gumby

    Gumby Supamod Staff Member s-Moderator

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    However, it has been my anectdotal experience that it is true.


    I guess reliable is a relative term

    as is heavy.


    It's about as heavy, gutless and unreliable as a 2F, but the parts that regularly go bad are very expensive.
     
  16. Tigerstripe40

    Tigerstripe40

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    When was the last time you could find a Cummins 4BT, or a Toyota Diesel in pretty much any junkyard in the United States or Canada for next to nothing?

    Parts abailability, I thought, was one of the main reasons for a GM powertrain swap?

    I suppose that if one lived in Australia, Europe, or any other place that the toyota diesels were imported, then it would make sense.

    And the 6.2/6,5 can make power.
    Just need to make a call to Gale Banks, Bully Dog, or any of the other Diesel Performance guys.
     
    Last edited: Aug 22, 2006
  17. dieselcruiserhead

    dieselcruiserhead

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    The 6.2 gets pretty lousy mileage and it pretty dog like, I don't think its worth it. Plus for any swap you will be in it some $$ for all the weird misc stuff, + adapters, exhaust etc.. Not worth the energy IMO.. I would hold out and save the $$ if putting the money into this 60 is worth it... Just my $.02...
     
  18. FL cruiser

    FL cruiser

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    If you are accustomed to V8 gas engines or later US truck diesels, a 6.2 will feel t like a dog. But if you are used to Toyota, Isuzu or Mitsubishi diesel trucks, the 6.2 feels noticeably quicker.
    I find fuel mileage comparable to Toyota diesels made in that era.
    As a previous owner of a 2H powered HJ60, and a 6.2 powered 60, I find that the mileage is about the same.
    At one time I owned an HJ45 pickup and my brother owned an 85 GMC one tone dually flatbed truck that weighed 7400 lbs. We would follow each other on trips. When we would stop to fill up, both vehicles would take the same amount of fuel. He would flat out run away from me on the highway and in the mountains. That’s what sold me on a 6.2. I used to have the same impression before about 6.2’s being fuel-guzzling dogs.

    Something to consider is that Chevy gas engine bell housing usually won’t accommodate the 6.2’s starter nose. Diesel bell housings are usually made for internal slave clutch cyl’s and large bolt pattern NV 4500’s and don’t mate up Advance Adapter stuff. Most 6.2 ‘s sold had auto trannys behind them . 6.2 flywheels can be hard to get. The cost of the conversion can add up $$. Expect steering column interference.
     
  19. Gumby

    Gumby Supamod Staff Member s-Moderator

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    That starter is what sealed the deal for me. 1 year old and it was needing it's second $300 starter. It broke starter bolts left and right.

    It didn't get enough mileage to deal with the PIA of getting diesel fuel, the smell, the smoke, the noise and the powerband that just didn't work well in the 60 with stock gears. Not to mention the .20 over the cost of premium gas in my area. Once it settled out, it was around 14 mpg.

    I dropped in a 307 and get nearly the same mileage and am back to all the ease of use of a petrol motor. And much more useable performance.

    I will be happy to sell the truck as it sits now (307/700R4) with a bonus 6.2L and matching TH400 cheap.

    I reject the idea that Banks or Bully Dog can get the 6.2L to make good power. They have head bolt and lower end issues that make it a bad idea to push them too hard.
     
  20. patpend2000

    patpend2000

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    How about converting your 350 to fuel injection to improve the gas mileage which would also improve driveability as well as off-road ability.
     
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