6.5 swap questions

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Wademacsr

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I'm new to the thread guys, and I hope you don't mind that I chime in on this swap. I have 2000 K3500 cclb dually that I just placed a 12v 5.9 into. I took a 123,000 6.5 turbo diesel out that just about killed me. The fuel injection pump went out and would shut off any time it wanted, keep in mind, no stopping or steering when that happens. either. The engine ran good when it was running good, wasn't strong at all and averaged about 16 empty - 12 pulling. Personally, I would steer away and look towards a 4bt - 6bt swap. You don't want your wife pulling her horses with a vehicle that may not stop. Take your time, purchase what you need over time, search your surrounding states for parts, and do your research - as you are.
 

deejaaa

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I'm new to the thread guys, and I hope you don't mind that I chime in on this swap. I have 2000 K3500 cclb dually that I just placed a 12v 5.9 into. I took a 123,000 6.5 turbo diesel out that just about killed me. The fuel injection pump went out and would shut off any time it wanted, keep in mind, no stopping or steering when that happens. either. The engine ran good when it was running good, wasn't strong at all and averaged about 16 empty - 12 pulling. Personally, I would steer away and look towards a 4bt - 6bt swap. You don't want your wife pulling her horses with a vehicle that may not stop. Take your time, purchase what you need over time, search your surrounding states for parts, and do your research - as you are.
all that and it was probably just the PMD. research is key!
 

someotherguy

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all that and it was probably just the PMD. research is key!
Probably was, but plenty replace them multiple times throughout the life of the truck, and never gain any reasonable degree of reliability - even with the PMD relocate.

Richard
 

GM Guy

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another happy 6.5 owner here, and there is a Duramax and a few 350s here on the farm.

mine all get worked pretty well and get awesome mpgs.

For outright cheap to run and good towing torque, give me the 6.5L.

I needed to take a trailer up to get a cornheader up in Nebraska, 600 mile loop. Did I take Dad's 350 or my 06 Duramax? Nope, the 438,000 mile 95 GMC K2500HD 6.5L 5spd was the one I picked.

up and down the rolling hills, held 5th most of the time.

So basically if you just want one to tow some moderate loads with or get good mpgs, get one, they are awesome in that regard. Performance and charging up the hill 50-60 mph with the a/c on full blast, not so much.

IMO they are 4.3L fuel economy with stock 454 power.

So to the OP, with the 350 auto, you could go crazy and swap the 6.5L as-is, and then back it up with an Allison 1000 from behind a Duramax. 6 spd double OD would work great if it had 4.10s. Put an A-team turbo on, and good to go.

Regardless, if you do want to go through with the 6.5L swap, you need to talk to Leroydiesel.com he can get your 4L80E shifting and he sells performance exhaust and a big turbo along with many other things.
 

Wademacsr

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No sir, after the 3rd PMD and extensive testing, I took it to a local fuel injection repair shop where a friend works and they confirmed it.
 

GM Guy

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Probably was, but plenty replace them multiple times throughout the life of the truck, and never gain any reasonable degree of reliability - even with the PMD relocate.

Richard

I respectfully disagree, the only PMDs I have ever changed have been ones that the previous owner relocated to the intake or somewhere in the engine bay, a known failure point encouraged by a few less than reputable relocation kit sellers. The stock location ones and my relocated to bumper ones have yet to fail me.

IMO PMD failure in the stock location is the effect from something else. Stock location failure is almost allways lack of fuel flow causing it to overheat. cause of fuel flow loss is a non functioning lift pump, and the pump can be good but not running due to a bad OPS on a 95 and older.

I will say they are a finicky engine to diagnose, and there is a couple chain reaction failures on them that can occur, so for some folks, they can be very frustrating.

What was your 6.5L Richard? IIRC it was kind of a project to start with, right? If a guy can start off with a healthy 6.5L it ignites an inner fire that cannot be put out. :) Buy a basket case 6.5L and not subdue and conquer it in short order, it will ignite an inner rage... :)
 

michael hurd

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Relocation to the bumper can work, provided you are moving. A better location IMO would be a heatsink in the air cleaner housing, there is plenty of air flow to cool it there when the engine is running.

Having driven different 6.5's over the years, most of my family has had rather good luck with them.

That being said, they have their issues. Vacuum pumps, solenoids for boost control on the later ones, PMD's deciding to fail in the least opportune moment.

I would never own one myself: dual batteries are required, addiction to an extension cord when the temperature gets close to freezing, large rad that is $$ compared to a gas engine. Engine block casting issues. ( cracks ) Heavy.. did I mention HEAVY?

Changing glow plugs is not a fun job, even if you drill holes for access in the inner fenders.

The low sulfur diesel fuels of today aren't what was available when the injection pumps were designed, the lubricity just isn't there, so you must use a lubricant additive.

454 power? Not likely, at least in stock condition.

4.3 mileage? No way. 2005 C1500 4.3L gets almost double the mileage of a 1996 K3500 6.5L, doing the same trip.

Having looked at the engine load reported on a scanner, a bit over 2/3rd's throttle on the 6.5 is reported as 99% load. This programming makes the 6.5 'feel' lively, when in fact, it is not that great.
 

GM Guy

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the beauty of the bumper relocation is that you do not need to be moving, provided you get the right kit with a adequate heatsink. I dont do it, but according to someone who does, the bumper kit will run about 5 degrees over ambient in the middle of summer idling for hours with the a/c on.

IMO the last thing I want to do on a non-intercooled diesel is add heat to the intake air.


As far as the extension cord addiction, it is nice to have it plugged in to be easier on the engine, but its not required on a healthy one, they should fire down to zero, and if a guy is really on top of maintenance, supposedly the best is about a 25 below zero dead cold start.

I agree on glow plugs. :) everything on the RH side sucks. :)

As far as the fuel, I run a lube boosting fuel additive on every single tank and have yet to have issues. Stanadyne does have some re-designed parts to make it ULSD compatable that any good pump shop should know about, and if a guy gets a pump rebuilt, it should have the parts.

As far as mpgs, trying to keep it as apples to apples as possible, my 95 C2500HD and 91 C1500 are both 5spd 2wd RCLBs, the C2500HD a 6.5L with 4.10s, the C1500 a 4.3L with 3.42s. both will average 21 mpg empty.

I can never get great mpg out of a K series 6.5L, especially with an auto. Dad's K2500HD will routinely get 14 mpg, which IMO kinda sucks. What is weird is my 2 K2500HDs, both 5 speeds, will get roughly the same mpg towing as my 2wds, but take the trailers off and the 2wds will get much better. Do you think if your 96 had been a C series with a 5 speed the gap would have been much?

As far as power, I should have said low RPM Torque instead, as the 454 does have more horsepower across the board. Stoplight to stoplight and no holes barred charges up a hill with a trailer at WOT, the 454 will be king, but with a 5 speed lugging along in OD, I still prefer the low end of the 6.5L.
 
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tanman_2006

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My 6.5's start unplugged down to -35. Glow plugs aren't much harder than spark plugs. Injectors a bit harder but can easily be done in a day.

My wife hauls with a 6.5 anyways. What will another hurt?

Before I relocated to the bumper with a good harness I had a PMD fail and light the rear tires at a stop light. Should have seen the looks the old truck got! Haha

2 batteries are handy for jumping tractors, hooking up all my accessories, and you can run a bigger stereo straight from the factory.

I won't say a 6.5 is for everyone but they can be good engine if someone wants to spend the time to take care of it.
 

skylark

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I won't say a 6.5 is for everyone but they CAN be good engine if someone wants to spend the time to take care of it.
They can also be a giant pain in the ass even spending the time, money and dedication that they REQUIRE to have a chance at reliability. I'd rather slam my manhood in a door than replace the 104K 6.5 in my dually but unfortunately it looks like my boys are going to be hurting for a long time.
 
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