horse power and torque ratings

[allformike]

i was wondering if you guys know what the specs are for the 6.2 on my air breather it says something like 155 hp, but says nothing about torque. i know it should be lower than stock since mine has about 268000 miles. but i would just like to be more knowledgeable about the 6.2

[More Power]

Depending on model year and application, the 6.2L diesel was rated at between 130 and 155 hp and 240-260 lb-ft of torque. The NA 6.5L diesel was rated at 160 hp and 290 lb-ft. The hp figures weren't far behind the 6.5TD, but most NA 6.2/6.5's were governed at ~3600-rpm vs 3400 for the EFI 6.5TD... and the turbo is what gives the 6.5TD its torque advantage. :)

Jim

[allformike]

Depending on model year and application, the 6.2L diesel was rated at between 130 and 155 hp and 240-260 lb-ft of torque. The NA 6.5L diesel was rated at 160 hp and 290 lb-ft. The hp figures weren't far behind the 6.5TD, but most NA 6.2/6.5's were governed at ~3600-rpm vs 3400 for the EFI 6.5TD... and the turbo is what gives the 6.5TD its torque advantage. :)

Jim

i have a 89 k2500 4x4 6.2

[More Power]

Since you have a later model 6.2, it is likely what the sticker says... 155 hp. :) GM made minor changes through the years, since its original introduction in 1982. This was made possible through minor changes in valve diameters, intake manifold changes (eventually resulting in a single-plane design), an evolution in intake/air cleaner design and of course - fuel calibration.

Jim

[allformike]

what would be a good way to increase those numbers? would going from a single 3'' exhaust to a 4'' help, or to a dual 3''? thanks again

[More Power]

The difference in horsepower between an untouched factory original 100K mile 6.2 and a 100K 6.2 with a fresh timing set, fresh injection system, and with the injection timing set to 4 degrees BTDC could be 10-20%.

The last 6.2 I disassembled had 135,000 miles on it (4.10 geared truck with a TH400 non-OD trans). The timing chain had worn beyond specs, which produced hard starts and down on power - even with a fresh fuel injection pump. It was very hard to time, and moving the pump CCW 1/8" then CW 1/8" didn't produce much change. The chain was just too sloppy. A new chain woke it right up... :)

Jim

[allformike]

mine timing chain may need replacing, since i don't know when it was changed, if ever. it will still spin the tires if i get on it and it does have a new injection pump that my friend(previous owner had put on, though i don't what one) so do you think mine could use a chain? also how do i turn up the pump? i also heard from a few people that if the pump is too high it could burn the top of the pistons, is this true? would turning the pump up decrease my mpg a noticeable amount? thanks again

[More Power]

The condition of a timing chain is hard to diagnose without checking it. I know of one 6.5 timing set that went for more than 250,000 miles, and the chain was still in spec. When a number of symptoms exist, like hard starting, excessive white smoke, low power, low fuel economy, rough idle, etc., the chain should be on the list of items to check. The 135K 6.2 mentioned above had all of these symptoms. GM's upper wear limit on the timing chain is 0.8" of timing chain slack. The slack in the timing chain can be measured without removing the water pump and timing cover. It's really easy!

Measuring timing chain slack: Remove the oil filler pipe from the front of the engine, rotate the scribe line on the harmonic damper into the center of the timing index plate using a 15/16" socket and flexhandle on the damper bolt, then rock the crankshaft back and forth while looking through the hole in the timing cover (where the oil filler pipe was) to see how many crankshaft degrees you can move the crank before the pump gear moves.

I performed a series of tests some years ago for an article I did for The Diesel Page using a selection of chains - a new one (it produced 0.25" timing chain slack), one well-used but in spec (0.5" timing chain slack) and one that was worn out (0.8" timing chain slack). I learned that 4 degrees of crank rotation or more indicates an out of spec timing chain that should be replaced. 3 degrees means it's nearing the upper wear limit, and one that would improve engine performance if it was replaced. A new chain will produce about 2 degrees or a little less.

The DSG gear drive timing sets I've installed all produced about 2 degrees or a little less - same as a new chain. However, with a gear drive, the cam and injection timing won't measurably change for the life of the engine (and it's reusable on your next engine). The decision of whether to install either a new timing chain set or DSG gear drive is really a question of how long you intend to own the truck and how much you want to spend. A chain/sprocket set costs $70-140 depending on whether you buy a parts store aftermarket or OEM. The DSG 6.2 gear set cost about $250 the last time I checked.

Jim Bigley