Rebuilding a GM 4.3 Liter V6 Part 1


2017-09-20

The beginning of the 4.3 V6 engine extraction

As I talked about in my previous post, The The New Project: 1991 C1500, I need to rebuild the engine in the truck I recently bought. It's a 4.3 liter V6 with TBI. I've been interested in learning to rebuild an engine since I bought my 1990 K2500, but I did a little research first to make sure I wanted to take on the task.

Should I rebuild?

There are few options when it comes to reviving a vehicle with a worn out or destroyed engine. I considered each of them before I made my decision.

Option 1: Get a Salvage Yard Engine

A lot of people say to just buy an engine from a salvaged vehicle. This would have been pretty nice. You buy the engine from a salvage yard and just swap it in. Very little down time and it gets you on the road faster. However, two of three of my local salvage yards said the truck was "too old" and they didn't have any engines available. The third place said they could get me one shipped in from another yard, but it would be high mileage engine and would cost at least $800. I wasn't ready to pay that for another engine that might be just as worn out as my current one.

So unless your vehicle is a bit newer, this option doesn't really work.

Option 2: Get a Crate Engine

A lot of places sell crate engines, either long blocks (engine block and heads) or short blocks (just the engine block and rotating assembly), that will fit in almost any vehicle. I searched a while for a 4.3 liter V6 and found I would essentially have to pay $1,800 and a core charge of $300 for a long block. That's a lot of money compared to rebuilding my current engine. There were also fewer options than I expected. I think this is because the V6 in these trucks is both not as common and not as desirable as the 5.7 liter V8. Also, many people swap in a newer engine like a GM LS. However, I am not interested in the wiring work that comes with that. LS engines are also very popular and expensive right now.

Option 3: Have a Local Mechanic Rebuild the Engine

I was tempted to have a local mechanic rebuild the engine for me. I'm too excited about driving this truck and I started getting impatient. I called a mechanic nearby and they told be "we don't tear anything down past the heads". This wouldn't work because my problem is likely connecting rod bearings ("below" the heads) and I want the engine completely rebuilt or new. I also got this truck as a hobby and to learn more about mechanic work, so farming out all the work defeats the purpose.

Option 4: Rebuild the Engine Myself

After doing the research, I decided I want to rebuild this engine myself. It's going to be a lot of work, but it's my cheapest option and allows me to learn even more about engine maintenance and repair. I'm estimating it will be around $1,000 after I buy the rebuild kit and get the block honed or bored at a machine shop. But after I'm done, I will know everything there is to know about this truck and its engine. I'll be using my Haynes Repair Manual to guide me, as usual. Wish me luck!

Here's a gallery of pictures I took throughout the process:

Rebuilding a 4.3 V6