New engine for the family truckster!

[daverd]

Did you move the injector power control unit form indeed the intake manifold?
With a new cool plate?

[njsteve]

The PMD (Pump Mounted Driver) is the little computer box that was originally mounted to the side of the injection pump under the intake. The designers thought it would be a great idea to have the super-hot running circuitry inside it get cooled by the diesel fuel running through the pump when the engine was running...only they didn't think about what happens when you shut the engine off and the heatsink effect fries the PMD.

I relocated it to behind the front bumper about ten years ago and never had a problem since. The truck went through three injection pumps when new. I bought it new in Florida and the first PMD fried five miles from the dealership the day I bought the truck! Back then GM refused to acknowledge the design defect and would replace the entire thousand dollar injection pump (with PMD attached) instead of just swapping out the PMD. GM eventually admitted the problem and extended the warranty on the pumps to 10 years or 100,000 miles. But they still would replace the entire pump instead of the PMD.

Here's a photo of the original PMD still on my injection pump. I bypassed it with an aftermarket four-foot long harness extension that reaches to the back of the front bumper behind the license plate brackets. It is mounted on a large heat sink in the protected airflow of the oil cooler duct holes in the bumper. I finally removed this old PMD from the pump last week and am keeping it as a spare - you always carry a couple spares in the tool box when you have a 6.5 diesel.

Kind of like the Mopar guys always carry a couple extra ballast resistors in the glove box for the old Mopar ignition systems.

[Xplantdad]

Steve, One of my jobs while working at Hardin Olds/Honda/DeLorean was to drive the numerous diesel injection pumps to the rebuilder on a daily basis from Anaheim to Ports of Call, Long Beach area...I put over 100,000 miles on a new Delta 88 in one year...taking them back and forth. I think this was 1979, maybe 1980.


That's what they get for converting a gas 350 to diesel...and not putting a water separator under the hood


Great job!

[njsteve]

Here are the necropsy photos. We'll start with the rod bearings. Looks like the oil analysis was spot on based on the flaking of the outer bearing material and the wear in the second layer.

[njsteve]

and next, the mains:

[njsteve]

The oil pan was pristine. nothing whatsoever in the sump area. You are looking at an empty pan - not one full of oil - it's that clean!

[njsteve]

And now for the bad news...these block were notorious for developing cracks in the main web area emanating from the main bearing cap bolt holes and the sharp transition where it was machined for the mating surface with the main cap. A lot of guys consider this normal and rebuild the blocks using some type of main web girdle.

So it looks like my gamble paid off of buying a new AM/GEP engine off the assembly line instead of waiting to see if my engine was rebuildable. You can't buy the AM/GEP block outright (despite the many chinese knockoffs being advertised on ebay and elsewhere as "AM/GEP updated blocks"). The only way to get it is to buy a brand new engine off the assembly line or buy a used HUMVEE takeout from a military salvager - which you would then have to take apart anyway to verify its condition..

The easy way to find the cracks is to spray the area with brake clean and then have a camera ready as you observe it evaporate. The crack will weep oil out at the last phase of evaporation and be visible for several seconds.