6.2 head and injector differences and other random questions.

[Robert79K5]

I have a 82 6.2 in my Blazer and even though it runs great Im thinking ahead for a rebuild.

*warning... Lots O Questions*

I have the origional coarse thread injector heads in but I am planning to buy fine thread heads to swap on.

I read that the turbo injectors will net you more power but will I be getting a lot of black smoke with the added fuel since I wont have a turbo on there? What would installing turbo precombustion chambers do for me being normally aspirated?

Is there any difference between the turbo injectors that would keep me from being able to reuse my injector lines. I know that somewhere along the way they changed the angle of the injector s in the head casting but other than the van injectors that are shorter they are all the same dimensions in the outside right?

Other that having coarse thread injectors are there any other differences between the 1982 and the later 6.2 heads?

I hope this all makes sense. Any help at all is if course greatly appreciated

 

[arveetek]

Swapping heads will be a good idea...you're limited in what you can do with coarse-thread injectors.

Turbo injectors will not increase the black smoke if you use the same injection pump. Turbo injectors have a higher pop pressure, so the fuel atomizes better, but they don't really flow any more fuel. Your injection pump determines how much fuel flows through the injectors. When upgrading/replacing injectors, you might as well go ahead and install the 6.5L turbo injectors....they'll add a few ponies. Add a 4911 6.5L mechanical pump, and you'll be doing well. I wouldn't use a 4911 pump without a turbo, though...it's a waste of fuel.

If you plan on installing a turbo later, it would be wise to install turbo precups, and it shouldn't affect n/a running or mileage.

The 6.5L turbo injectors are short body injectors, just like the 6.2L van injectors. In fact, you can use 6.2L van injectors as 6.5L turbo injector cores. You can reuse your current injection lines and bend them slightly to make them fit, or use 6.5L turbo lines or 6.2L van lines.

The '82 heads had larger exhaust valves. After that, they're pretty much all the same except for various pre-combustion chamber sizes. However, somewhere in '88 or so, they elminated a cooling port that isn't used, to help prevent coolant leaks on newly assembled engines. If you have older heads with the extra cooling passage, it's best to use 6.2L head gaskets. My '86 6.2L heads that I used on my '82 block have the extra passages, so I used the 6.2L head gaskets. The 6.5L fel-pro gaskets are better, but are prone to leak when using the earlier heads.

If you can get crack-free heads, use any years, except '82 to avoid the coarse-thread injectors. When having the heads rebuilt, make sure to install sleeves between all the exhaust and intake valve seats, to prevent cooling leaks when the heads crack...and they will crack. Always use heads with matching casting numbers to avoid any small differences between the pair.

Casey

 

[Robert79K5]

Thanks so much for taking the time to type out all of that good info. I am ready to start moving forward on this project now.

I don't plan to turbocharge this particular engine so I guess I will go with post 1982 heads with 6.5 turbo injectors, standard cups and just have my stock IP rebuilt.

Thanks again im really looking forward to this.