6.2 engine swap/fix general questions- 1991 K2500

[mike73]

I bought a 1991 K2500 that was smoking from exhuast, oil cap, etc, sucking in upper rad hose, but running. I made a bad call to drive it home and it's now locked up. 6.2 diesel NA, automatic trans that I assume is 4L80E. I'm working on pulling components to either do a swap or out-of-frame service (or part-out in worst case) depending on the severity of internal damage. This is my first engine swap, so I have a few questions about this specific engine configuration (maybe more to come later):

1. Is there one plug to disconnect the entire engine harness so I can leave it on the engine, or do I need to disconnect each component on the motor?

2. With the engine being locked up, I don't think I can unbolt the torque converter from the flexplate- I can get to 4 bolts, but it appears there are at least 5. What precautions do I need to take when I'm pulling the engine with the converter on in order to avoid bent input shaft or other damage?

Also, just anything else unique about 6.2 engine swaps that you think I might need to know. Thanks

 

[skylark]

I bought a 1991 K2500 that was smoking from exhuast, oil cap, etc, sucking in upper rad hose, but running. I made a bad call to drive it home and it's now locked up. 6.2 diesel NA, automatic trans that I assume is 4L80E. I'm working on pulling components to either do a swap or out-of-frame service (or part-out in worst case) depending on the severity of internal damage. This is my first engine swap, so I have a few questions about this specific engine configuration (maybe more to come later):

1. Is there one plug to disconnect the entire engine harness so I can leave it on the engine, or do I need to disconnect each component on the motor?

2. With the engine being locked up, I don't think I can unbolt the torque converter from the flexplate- I can get to 4 bolts, but it appears there are at least 5. What precautions do I need to take when I'm pulling the engine with the converter on in order to avoid bent input shaft or other damage?

Also, just anything else unique about 6.2 engine swaps that you think I might need to know. Thanks

Your tranny is most likely a th400. You have to unplug everything individually. There should be 6 torque converter bolts. If you can't get to them as long as you pull straight forward on the engine from the transmission the torque converter will separate from the transmission and not cause damage. Remove the torque converter from the flex plate after you pull the engine. There is nothing special about a 6.2 over anything else it is pretty straightforward.

 

[mike73]

Thanks for the advice. I'm confident that the tranny is 4L80E though- the shift selector shows P R N OD D 2 1 and it looks beefier than the 4L60/700r4. Novak adapters confirms 1991 was the first year for 4L80E, interesting article

 

[GM Guy]

a guy over on dieselplace can pull an entire powertrain out of a GMT400 as long as its an automatic, so I guess its possible to pull engine and tranny at the same time.

Use car-part.com and searchtempest.com and find another 6.2L. They are pretty low on power, but big on personality and MPGs.

 

[mike73]

UPDATE, NEW QUESTION ABOUT SWAP

I got the old one out with the TC on it. was tricky, needed fan off and had to tilt it to get TC past upper firewall, but it worked. Engine was FUBAR, not quite sure what happened completely but #8 piston appears to have FOD and melting and a hole burnt though it at prechamber area. HG is burned out cleanly around prechamber, bent just slightly near one water jacket area. Rod is bent, wrist pin still in it pulled off the piston. Cracked head between valves on same cylinder, bent exhaust pushrod, broken rocker rail at end where the intake rocker is. Hole in block on upper side of cylinder (only visible inside with head off). Before it quit running, there was oil smoke in exhaust, sucked in upper rad hose, and smoke coming out oil cap if you removed it. The other cylinders were all fine as far as I can tell. Not sure that either hydrolock from blown HG or damage from stuck injector fully explain the problem on their own, or which would have come first

MY NEW QUESTION- CONVERTING V-BELT ENGINE TO SERPENTINE

I got a junkyard engine for $642 (including tax and $100 core), but it's from a (supposedly) '87 blazer and the truck is a '91, so I need to convert the engine hardware- I know I need to swap intake, some sensors, coolant crossover, valve covers (for CDR and some damage during pulling). The big question though is about the accessories- do I need to change the whole water pump, or just the pulley? Someone said that v-belt water pumps turn in the opposite direction of serpentine , but I'm not an expert.

 

[dave_erald]

V belts do run backwards you are correct. Coolant crossover should be the same. Everything else is near identical I believe

 

[mike73]

The coolant crossover is similar, but the '91 has the thermostat facing up with an elbow directing it forward, and the replacement blazer engine has the thermostat facing forward with a straight output. It may be close enough to work, but they are not 100% identical.

It's the same engine, but almost all accessories and other bolt-on components are different. Replacement came from squarebody era, project truck is GMT400