Engine Swap

[Gator boy]

Hello everyone!
This is my first post on CK5. And I am also a novice when it comes to the K5 Blazer. So, getting to the point - just got a 1988 K5 Blazer 4WD 5.7L and want to swap the gas engine for a diesel. I don't have the expertise or tools. Any suggestions on the engine and garages in my area (Cumberland County, NC) ?

 

[fourwheelerjeff]

why? what is your end goal? mileage? novelty? GM did make diesel blazers during this era; do you have a specific motor you have in mind? and be prepared; it will be rather expensive

 

[Gator boy]

As I am heading towards retirement I'd like this to be my first vehicle restoration. Just going to use it for weekend rides with the wife and fishing trips., maybe picking up a few things for the house that my car is not suited for.

 

[Gator boy]

Diesel engines seem to be more expensive but I would like an engine that has better mileage than the typical gas engine. I've seen a few online and locally. Just trying to save a few hundred dollars but still get something reliable.

 

[Wes Harden]

Welcome to CK5 @Gator boy.
Question does the 350 run now?
Swapping to diesel power pant will be spendy. Neither of the 2 diesel engines commonly used in a square are well supported any more and they both have flaws that need to looked for.
You can buy a boat load of gasoline for what Cummins swap will cost.
Duramax ? I'm sure it has been done.
If you had a running diesel Donner cheap enough and the space, time and money anything is doable.
For a retirement project try and do some maintenance, get out and enjoy your truck figure out what changes you wish to make. Lord knows many of have changed ours in many ways.
Look for our K5 buyers guide sticky, give your truck a once over with those points in mind.

 

[500$k5]

Mileage on a weekend rig, is never a reason for putting in a diesel. (IMO). Here's why. A good TBI 5.7 Blazer will get about 15 mpg average. Regular gas average right now is $3.82 per gallon. If you drive 10,000 miles a year you will use about $2546 dollars a year in gas. A diesel swap, that will get 20 mpg average will use $2180 of more expensive diesel fuel. ($4.36) This will be a savings of $360 per year. If you pay someone to put a diesel engine in, this could cost upwards of $10,000. In fuel savings, it would take you 27 years to get a return on your money. This doesn't account for the extra cost in maintenance. Oil change cost, etc. I would say spend the $10,000 on wheels, tires, suspension, new TBI engine, transmission rebuild, rear locker, new shocks, etc, and still have money left over for some good old 85 octane regular.

 

[dyeager535]

For my purposes a 6.2 or 6.5 diesel would be great. I would love the additional range it would give me for when I'm off-highway.

I'm a huge proponent of fuel economy, and I like diesels, but as broken down above, economically, you will essentially never get your money back from the swap, so economy shouldn't/can't be a primary factor to convert.

The '87-91 trucks were the pinnacle of what GM did with these rigs. The fuel injection works well and gets reasonable mileage. Freshened up, they give excellent service. No, they don't easily facilitate modifications due to the archaic fuel injection either, but as-is, reasonably powerful and reliable.

FWIW, I've run K5s with a carbed 305 with overdrive, a carbed 350 with manual trans, and a TPI Vortec 350 with manual, and *all* of them peaked out at 18MPG under best conditions. The highest economy I've heard in a stock combination in these rigs is 22, with a 6.2 diesel and manual trans.