Removed Intake Manifold - ? ? ? ?

[Andy Chesek]

My truck has a leak, and as of late the transmission bellhousing and exhaust crossover have been mucked up. I noticed the valley of the engine was wet under the fuel filter, so today I pulled the intake manifold to investigate.

After the intake manifold was removed, I recovered a threaded bolt, nut and washer from the valley. Then, I spotted a threaded boss in the rear of the valley. I was wondering what its purpose is, and if it should be open. The bolt I recovered fits in the boss, and the washer onto the bolt.

Mystery Boss (http://home.ptd.net/~chesek/)

Just to clarify the rough pic, the OPS is "below" the green rectangle. So, the boss is on the driver's side.

[ees]

I saw that when working on my truck (mine was not missing however). I had read several places that the 6.2/6.5 was designed from the begining as a Diesel engine. When I saw that I said bull s**t. I think it is for a distributor, but I could be wrong.

[arveetek]

Originally posted by ees:
I saw that when working on my truck (mine was not missing however). I had read several places that the 6.2/6.5 was designed from the begining as a Diesel engine. When I saw that I said bull s**t. I think it is for a distributor, but I could be wrong. In fact, Detroit Diesel did design the 6.2L from the ground up. They chose to incorporate similar gasser designs, however, by using the camshaft to drive the oil pump. On the early model trucks (82-87), they also used a camshaft-driven vacuum pump, that fits in the same place as a distributor would in a Chevy gas engine.

When GM went to a serpentine belt system in '88, they ditched the cam-driven vacuum pump, and mounted it up front to be driven by the belt. They then installed a cap with a shaft to drive the oil pump.

The 6.5L is just a bored-out 6.2L (some may not agree, but that is my opinion), so the blocks are very similar.

The 6.2L block was never the basis for any gas engine, but similarities such as this do make you wonder. It doesn't help prove to people that it's not a converted gasser. Looking at the rest of the block reveals that it's like no other GM block, that's for sure.

93,

Sorry, can't tell much from your pic. :confused:

Casey

[Andy Chesek]

Spent some more time on the truck today. Of the three bolts that hold the injection pump to the timing area, two were missing nuts and the third's nut walked half off.

And on a seperate note, finally said what the heck and removed the vacuum pump. Already had a TurboMaster, just needed the shorter belt. Used a Goodyear Gatorback 4061000.

If anyone is interested in the vacuum pump, it's yours for the price of shipping. The truck has 103k miles on it, and I am assuming it's the original pump.

[Dvldog 8793]

Howdy
If it were mine I would pull the pump and check the gears for wear as the pump being that loose might have caused the teeth on the drive gear to load up at a bad angle. I could be wrong, it's happened before, just ask my kids! :D
Good luck!
L8r
Conley