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6.5L TD swap ??

Discussion in '1982-Present GM Diesel' started by jarheadk5, Dec 6, 2003.

  1. jarheadk5

    jarheadk5 1/2 ton status

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    Been kicking around the idea of swapping a 6.5L TD into my '87 K5 to replace the 305. Is this do-able? What's involved with this swap? Will a 700R4 bolt up? How much more does the 6.5 weigh over a SBC? Is it worth the efforts involved?
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Most 6.2 Blazers came with 700R-4's so I know they bolt up. I'm thinking there is probably a diesel specific convertor though...and maybe a diesel specific TV cable. Hopefully someone that is more familiar with the diesel version 700R-4 will chime in as well.

    The 6.5 TD wieghs a little more than a big block, and probably 200 lbs more than a 305. Don't forget the extra battery weight...

    If you stuck with the mechanically injected 6.5 TD it'd be a very nice swap. I think 93 was the last year for the mechanical pump...

    Are the efforts worth it? That's a fair question and the answer is "It depends". How do you envision using your truck and what is important to you? The 6.5 makes more horsepower and way more torque than the 305. It'll also get nearly double the mileage.

    Rene
     
  3. Steve_87K5

    Steve_87K5 1/2 ton status

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    I am building a 6.5 for my '87. The radiator needs to be replaced with a diesel version. The sock (filter) inside the fuel tank is different. The fuel (lift) pump needs to be low pressure 5psi. So the gas FI pump has to be taken out. I'm going to try a single Optima battery. If that's too weak, I'll add another one. The newer geared starter uses less amps I think. Stock gas tach won't hook up directly AFAIK. You'll need the diesel fuel filter and glow timer. I bought a junked diesel pickup for all the small parts. Torque converter in both 400 and 700 is diesel specific. The '93 pump is a DB2-4911. Earlier 6.2 pumps are cheaper and will work OK if matched to the injectors.
     
  4. bigblock454

    bigblock454 Clack Clack Clack Premium Member

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    If your K5 has AC then the stock turbo location on the 6.5TD will hit the AC box. I I have heard this can be trimmed to proper clearance.
     
  5. jarheadk5

    jarheadk5 1/2 ton status

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    I REALLY like the idea of gobs of TQ with way better fuel mileage. Not too crazy about all the extra weight up front; I knew the oil burner would be a little heavier than a SBC but ~200lbs is more than I thought.

    So what year should I start looking for? What's the difference between the mechanically-injected and (assuming) electronically-injected motors? Would the wiring be too much of a PITA to be worthwhile?

    What years should I be looking for in a donor vehicle? Was there a difference in these motors between 1/2 - 3/4 - 1ton applications?


    This is starting to sound like a good deal... Time to start prowling the yards and compare the costs of the 6.5TD swap vs. the hi-po 350 swap!
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I think if you stay with mechanical injected it'll be a lot more reliable. There were a lot of problems with the electronic ones...many injection pumps got replaced under warranty.

    I think that narrows the search down to 92 and 93. Best bet would probably be the 3/4 and one ton pick-ups and 3/4 ton burbs. I'm not sure if the 6.5TD was available in the 1/2 tons (prolly too much torque for the 10 bolt rears...)

    To be honest I hardly noticed the extra weight up front, in fact all it does is ride nicer now /forums/images/graemlins/smile.gif. Of course I have some fairly stiff Rancho front springs...

    If you stick with the mechanical pump the wiring is dead simple, a lot simpler than any gas engine's wiring.

    Rene
     
  7. azblazor

    azblazor 1/2 ton status Premium Member

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    I agree. Although there were no diesel suburbans made in 92 or 93. Last 6.2 Sub was 91 (82-91), first 6.5 Sub was 94 (94-99)(electronic injection pump).
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Thanks, I wasn't aware there weren't any diesel Sub's in 92 0r 93.

    Rene
     
  9. azblazor

    azblazor 1/2 ton status Premium Member

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    It's pretty well engraved on my mind because to get the elusive non-electronic diesel 4L80E computer/harness you need to look for 91 sub 3/4 or PU 3/4 or 1t OR 92-93 pickup 3/4 or 1t:-)
     
  10. jarheadk5

    jarheadk5 1/2 ton status

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    OK, cool. Trans & T-case will likely be a 700/241 combo; she'll see some daily driving and mostly general wheeling (sand, dirt, mud, trails, snow, maybe a few mild rocks). I was originally planning to use 4.11's with the 35" MT/R's I want... Is this still a good gear? I don't know the recommended RPM range of the 6.5, but I'm pretty sure the redline will be quite a bit lower.

    The more I think abut this, the more I want to do it... /forums/images/graemlins/thinking.gif /forums/images/graemlins/thinking.gif /forums/images/graemlins/thinking.gif
     
  11. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Your gearing choice would be ideal for mileage. Cruise rpm at 65 in OD is just under 1800 which is where the 6.2's and 6.5's run most efficiently. For comparison my cruise RPM at the same speed is just under 2600 rpm and I still get 16+ mpg. With your proposed gearing 20 mpg should be dead easy.

    You could run 4.56's easily enough for a bit more oomph.

    The redline is lower than a gas engine, but it's not often you'll feel limited by it. The redline is a pretty generous 3600 rpm and is governed.

    Rene
     

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