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I got an idea in my head

Discussion in '1982-Present GM Diesel' started by hunterguy86, Jan 13, 2006.

  1. hunterguy86

    hunterguy86 1/2 ton status

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    I'm thinkin of doin a 6.2 swap in my 86 k5. The plan is to try and find a complete truck and just swap everything over. From my research here it seems I would want one w/ a serp. belt setup with a J engine code. I guess that means no emissions. I'm not looking for a monster, I just want something w/ better fuel economy and power than my stock 305. This truck is my DD as well as weekend wheeler. I do everything from mud to sand to trails and mild rocks.
    I've got a few questions:

    Should I even attempt this? I've never done a motor swap before but I feel that with plenty of good info I can do it.

    I gather that the 6.2 should drop right in to the motor mounts. Is this correct?

    Will it bolt up to my 700R4/np208?

    Will this tranny even hold it?

    Do i need to move the tranny at all?

    How do yall like runin the 6.2 NA? Does it build enough tourqe for you?

    What are some real world numbers for this engine as far as hp/tq/mpg?

    I found this over at fourwheeler.com. http://fourwheeler.com/projectbuild/p52095_image_large.jpg
    They did a banks turbo on a 6.2 in a k5.
    Here is the write up: http://www.fourwheeler.com/projectbuild/7914/

    Sorry for the long post.
     
  2. skark_burmer

    skark_burmer 1/2 ton status

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    i've got an 83 blazer with a 6.2 and i like it. Stock i think this year makes around 130 hp, dunno about the torque. Mine has a 700r4 with the 208 tcase.
    I regularly see 20 to 22 mpg of daily commuting (1 hour of downtown San Jose traffic = 18 miles door to door) with some weekend highway thrown in. It has a 31 gal tank but i normally fill up with 20 to 25 gallons and mileage is around 400 to 500 per tank. No lift and stock tire size and i drive it like an a-hole. (lots of full throttle)

    Mine is the super emissions engine and it is ok. Certainly im not winning any drag races but its not a race car so i dont mind.

    I dont know about the motor swap but i do know the Diesel uses a larger radiator with more surface area. Un certain about mounting locations or any other specs if this radiator will fit easily.
     
  3. maynardogle

    maynardogle 1/2 ton status

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    I assume you love your 86 K/5 so much that you wouldn't dream of parting with it, i.e selling it an buying a diesel version. Making the coversion is a lot of work. I had an 85 gas suburban with that wierd computer controlled carb and I didn't like that i couldn't mess with it. My 84 K/5 diesel is nice because it is a 48 state version and didn't have a computer. As a fellow Californian, you know what a pain smog checks can be. I dumped my 85 gas suburban long ago but I must say I don't miss it at all.

    As far as the 700R4, I think my tranny guy said the biggest difference gas vs. diesel is the torque converter.

    Before you commit I suggest you should find somebody with a K/5 diesel and test drive it. I think you would find the performance about the same as your 305. I only get 19 mpg with mine, which is probably related to nuances in the IP or something. My drive train is stock and I run 31 inch tires on stock wheels.
     
  4. imiceman44

    imiceman44 1 ton status

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    If you really have something special about the K5 you have then you might consider it.
    It's not easy but it can be done.
    If you want a diesel K5 just sell yours and buy one.
    The 700R4 is the same except for the torque converter and the governor.
    The engine will mount in the same location, and the radiator will fit in all 81 and up blazers.
    The knowledge is not the issue anymore lots of people have done it and the info is shared.
    It's a lot of work, ask Rene TRustyK5.
    I am doing the conversion because I have a truck I like and couldn't find a decent diesel version that I could afford but was able to aquire the diesel engine and accessories for cheap and I like to work on vehicles just for fun.
    :D
    As for power, it has a little more than your 305 but way more torque.
    It will cost you less in gas.
    And for offroad, it's fuel injected.
    The 700R4 will do fine if you don't go with big tires, if you do then change the gears to match, and never pull hard in OD, drop it to D.
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I felt it was a bit of an intimidating swap when I did it three years ago. Mostly because I had pretty limited diesel knowledge...

    I can hotwire a gas engine in my sleep, but at the time I wasn't sure if I could get it running and was worried about the wiring stuff. I never would have attempted the swap without CK5 to lean on as a resource.

    As you already mentioned a complete truck as a donor is the easiest. I stripped my truck down to bare frame rails from the firewall forward and went from there. The engine bay wiring harness just plugs in at the firewall junction block (saves having to hack and splice) I swapped the underdash harness at the same time as well as the diesel specific dash/cluster. The good thing is that it's pretty much plug and play once you get into it.

    The motor drops into the sbc mounts without any trouble. I did have to massage my firewall just a scoach, but my truck has been hit hard a few times so it's probably the exception rather than the rule.

    Your current rad support will work, but you will need the diesel rad mounts from the donor.

    The diesel 700R-4 is pretty much the same tranny from what i've heard, except for the torque convertor. The diesel convertor has a lower stall speed, so you'll need that.

    20-22 mpg in a stockish K5 is common with the 6.2. I get about 16.5 with mine, but I have no overdrive and run 39.5's. Working on an NV4500 for it right now and expect to see 20mpg or near enough to it.

    Power levels...about the same as a dead stock 305, maybe a little better depending on your gearing. The 6.2 doesn't mind the higher rpms being a V-8 and really responds well to deeper gearing. If you have overdrive don't be afraid to gear it somewhat aggressively. Aim for ~1900-2000 cruise rpm in overdrive and you'll be quite happy with it IMO.

    Rene
     
  6. hunterguy86

    hunterguy86 1/2 ton status

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    My plan is to run 33 or 35 inch tires. I know with a gasser I would want to drop to 4.10 or 4.56 gears. Is this the same w/ the diesel or would my 3.73s be ok? Seems like the gov on the tranny and the TC would be cake to replace. Its nothing to drop the tranny. I can do that pretty easy. Same with the brakes and stuff. That seems pretty easy.

    My K5 has been in the family since it was bought brand new from my great uncles dealership in 1986, so it has to much sentemental value to part with it.

    Thanks for the input yall. This is going to be a summer project so I have a long time to do my research.
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Go with 4.56's and 35's...that'll give you a ton of grunt around town and get your cruise rpm at ~2000 rpm at 65 mph. That should have the mileage at or better than 20 mpg too.

    Without a turbo the 6.2 really benefits from deep gears same as a small block does.

    Rene
     
  8. snoman87

    snoman87 Registered Member

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    Getting the donor truck idea is best. Then you can swap everything over, I just finished doing mine and am really looking forward to getting it on the road. If your not that lucky at least get a diesel rad/shroud, hydoboost, glow plug harness from inside, complete engine. Then you will need your tranny stuff. The flexplate and TC are different, 1800 RPM TC ... if you happen to go manual only the flywheel is different.

    I signed up at thedieselpage.com and learn't a whole lot there ... check out my website for some details and images that might help you http://www3.telus.net/gmc62td/home.htm
     
  9. Eastcoast 4WD

    Eastcoast 4WD Registered Member

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    For my dime its not worth the time to do a 6.2 swap. I would go for a 6.5 Turbo. Its way more powerful than a na 6.2. As far as I know the 6.2 never came with a serp. belt, only the 6.5's did. If you are not in a hurry I would look for a 1993 6.5TD these were still non-electronically controlled. Just as easy to make work as a 6.2. I have an '82 with a 6.2NA and 3.73 gears and 35's. I am in the middle of putting a turbo on it. IT should hold overdrive at 65 while towing my trailer. As far as the MPG I get about 16-18mpg empty or towing.
     

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