6.2L timeline/parts interchange? (engine knock)

[Corpse]

Hello all, i'm a new guy here and to diesels in general (just bought an 83 K5 for cheap up here in Toronto Canada)

on with the questions...

Not sure what to search for, but the information i'm seeking is from what years did GM make changes to the 6.2L...

i heard about injector threads being changed in 85?(from a course thread to a fine thread)

these types of details are what i'm after, reason being my 83 6.2 looks all original (all covered in rust as if nothing has ever been replaced... also seems to have a terrible knock while running {awaiting on getting a deisel compression tester to check it}).

If after i diagnose this knocking problem (im guessing a bad injector if not a pooched cylinder) it ends up being that it is on its last legs. I would like to know if i end up replacing parts for maintenaince could they be saved for use in a newer rebuilt motor so i dont have to buy parts twice.

FYI, mileage of this motor is unknown and the previous owner did nothing to it since 91(other than oils and filters).

[DieselDavy]

Welcome Corpse,
There is a wealth of info here. Try to refine your searches and I'm sure something will pop up.
I hope someone else will chime in here, but from the cobwebs in my head, I'm pretty sure that injectors styles changed after the '83 MY. (might be '82 MY though)
Someone in the know will jump in here....
Dave

[john8662]

82 - Painted Red, only year for coarse thread injectors. Two fuel filters, one on firewall, one on back of intake.

83 - Painted Black from here on out. Fine thread long-body injectors. Two fuel filterse, like the 82.

84 - 87 Same as 83 engine wise, but with FM 80 fuel filter mounted on the firewall.

88-89 GMT 400, sepentine belt system, new body style truck, filter on back of intake. CDR Breather on valve cover. Electric Fuel Lift Pump.

90-93 GMT 400, sepentine belt system, new cylinder head design "567" heads, short-body injectors. CDR Breather on valve cover. Electric Fuel Lift Pump.

88-89 Suburban & Blazer same as 84-87 6.2L Trucks CDR Breather on valve cover.

90-91 Suburban & Blazer same as 84-87 6.2 Trucks but with "567" heads and short body injectors. CDR Breather on valve cover.

Class dismissed.

[Corpse]

thank you very much! that info should be in a stiky!

[Yukon6.2]

82 - Painted Red, only year for coarse thread injectors. Two fuel filters, one on firewall, one on back of intake.

83 - Painted Black from here on out. Fine thread long-body injectors. Two fuel filterse, like the 82.

84 - 87 Same as 83 engine wise, but with FM 80 fuel filter mounted on the firewall.

88-89 GMT 400, sepentine belt system, new body style truck, filter on back of intake. CDR Breather on valve cover. Electric Fuel Lift Pump.

90-93 GMT 400, sepentine belt system, new cylinder head design "567" heads, short-body injectors. CDR Breather on valve cover. Electric Fuel Lift Pump.

88-89 Suburban & Blazer same as 84-87 6.2L Trucks CDR Breather on valve cover.

90-91 Suburban & Blazer same as 84-87 6.2 Trucks but with "567" heads and short body injectors. CDR Breather on valve cover.

Class dismissed.Add the Crewcabs in with the 88-89 subs and blazers,likewise 90-91

[Corpse]

im gathering as much misc useful knowledge i can on the 6.2L so the next newbie has an easier time finding it. i'll post it in here once i have a good amount

[Robyn]

The late 91 6.2 and later engines had the same crank as the 6.5 with the one piece rear main seal.

The serp drive system can be swapped onto any of the 6.2 engines.

There was also running changes in the little knick knack crap like wiring and such.
The early trucks had a two piece glow control system with a controller in the block and the relay over on the LH fender.

Later trucks (85 and later) have the one piece unit thats fastened to the LH rear of the LH head

Some modles in the mid 80's also had a "Glow inhibit switch" in the rear top of the RH head. This was to shut off the glow system when the engine was warm. It was a boondoggle and just a source of agravation when it would quit and leave you without a working glow system.

Injection pumps saw a wide array of changes in calibration depending on whee the rig was to be sold.
Early engines had cast iron rocker arms that were discontinued in favor of the stamped steel rockers that are the most common.

A tid bit here that can save you a BUTTLOAD of grief.

Push rods in these engines can only be installed one way (and live)
The end that goes to the rocker arm has a copper colored ball end and is hardened.

The copper color can be hard to see after the engine has been run many many years.

Just be sure to keep the push rods in the same position (colored ball up)

If you have some that you can't identify with certainty, toss them and buy a fresh set from NAPA or ???

Installing in the wrong direction will result in a failed rocker and pushrod.

Best way, is to place a little colored zip tie around the rocker arm end when you pull apart a running enigne.

You can then worry about it later when you wash them.

Remove the zip tie as you reinstall them.

Late 6.2 and 6.5 cranks will not fit the early blocks due to the one piece rear main.

The pan on the 6.2 with the two piece rear main is slightly different in the rear arch than the late 6.2/6.5 pans They will not swap.

Installing a 6.5 into a early style straight axle truck is easy.

Installing an early 6.2 into a later truck require the oil pan with the angle sump to clear the 4x4 IFS axle (if its a 4x4)

The 88-90 trucks used a pan that will work with the 2 piece rear main

87-90 Burbs, Blazers and crew cabs also used this pan too. (it became the standard part)

The Burbs, K5 Blazer and crew cabs retained the V belt drive, but can be easily converted to use the serp drive.

The one thing to remember when converting to a serp drive, THE WATER PUMP must be used from the serp drive engine (6.5) as the early V belt driven pumps turn the opposite direction and will not work with a Serp drive.

When the heads were redesigned, the high pressure steel injector lines were changed too. The short body injectors took a slightly longer line.
When the injector angle was changed to accomodate the turbo on the 6.5 the fuel lines were again changed slightly.

There was also some oddities on the 6.2/6.5 when the engine was used in a G van chassis.

Not sure on these as I have only seen a few of them.

Hope this helps

Missy