another newb begging expert knowledge

[Isolde]

Hey all,
Need advice on doing valve seals on an '83 6.2. Also have a few questions. First, can I find anything to screw in to the heads to use compressed air to hold the valves closed? Does it screw in in place of the injectors or the glow plugs? Who sells it? Is this engine really heavier than an all-iron 454? If the heads must come off for valve seals, can I mill them for more compression? And if they come off, are there any dangers to some mild porting? TIA. BTW, I live at 4500' elevation, my truck is an '83 C-10 standard cab 8-foot bed 2 wheel drive, with a 700R-4, 3.42:1 8.5" 10-bolt, and 235/75R15 tires. It drove fine 2 years ago, It got 24 mpg with OD not working. Then it had no airdam, but now I bought one from the salvage yard off an '84 C-10. I put a new ****** dual exhaust on it, 2.25" mandrel-bent, and an Air Inlet Systems dual-snorkel air cleaner. Too bad I used cheap Summit Racing turbo mufflers. So I moved from Ogden to Logan with it, Climbing through a canyon that hits 5000 feet elev. It made a little black smoke, I assumed a mix of high elevation air being low in oxygen, and cheap summit mufflers reducing exhaust flow. Then I towed a 16-foot camper to Bear Lake, through Logan Canyon. This truck feels torquey and quick and responsive when empty, but is a lazy dog when loaded like that. When empty, I think it might like a 3.23:1 axle for steady cruising at 55 mph.

 

[Isolde]

BTW, I also replaced the failed 700R-4, before any hauling, and my thoughts about gearing are with a good 700 that has working OD.

 

[towcat]

welcome to the site
to answer your questions on holding the valves closed, you can access the air either way. i've seen the glowplug style system which is more common and also if you get really fancy, there is a option where you can remove the injector and put in an adaptor. The injectors are Bosch design, so if a diesel mercedes tech lives near you and owns the tool, that would be an option.
word of advice, do not mess with milling the heads. they crack too easy for one, and second, they are flat to begin with. where we suffer is in the precumbustion chamber where the injector and glowplug resides.
I'm not really big on doing porting on diesel heads for street. There are some who do it, I'm not one. Want better bang for the buck? throw a turbo on it and it will come alive

 

[Isolde]

Thanks for the great reply! Anyone know where I can get an air hold adapter/hose assembly? Or a brand name?

 

[towcat]

check out OTC/SPX tools.
i got mime from the Snap-on dealer
here's a hint....
the gm 6.2/6.5 uses the same glow plug sizing as the IH 6.9/7.3 therefore the adapter is interchangable.

 

[ameristar1]

Give Heath Diesel or Kennedy Diesel a call about modding the 6.2/6.5, and as far as doing real fancy machine work to the heads, there's no need.

When you get on Heath Diesel's site, you'll see a Bonneville truck go really fast with a ton of stock parts and twins. Talk to Todd, he built a 6.5 for his tow vehicle that has 24.5 to 1 compression and a turbo. Got 20 mpg with 4.10s and big rubber. Just wanted to see if he could do it.

As Towcat said, put a turbo on that thing and get ready to smile. Add the 3.23s and the mileage will be really good.

If you ever feel like a swap, find a later model J code (87 and up) 6.2, do the mods that Heath did for their Bonneville truck, and you'll have a powerful, 30 plus mpg ride.

 

[4320diesel]

a 1/8 pipe thread fits in the glowplug hole.