hd7gb stalling randomly

Sorry I stated it poorly. Yes if a line is sucking air it can't be from the pressure side. Your correction is appreciated.

On Roosa Master or Stanadyne pumps, atop the rectangular top cover there will be a steel fitting where the return fuel from the pump to tank is, it can either be a direct low pressure steel tube or a rubber hose to steel tube connection. Inside the fitting itself is the check ball. If it is hard sucking air it could be the umbrella seals on the pump drive shaft, one faces forward to stop oil migration to injection and one rearward to stop fuel to engine oil. In either case he pump should come off either with debris in the check ball or sucking air the seals are shot.

The stanadyne type pump is typical to have the injection tubes arranged in a circular pattern on the outside ring of the injector head, this type pump has but one injection plunger and works much as a distributor on a gas engine.

Tiger Joe wrote: Took a quick glance at the injection pump today. It's got all the injector lines arranged around it in a circle so it's a stanadyne I guessing

 give me the numbers on the pump tag. I'm thinking this is new enough to have a DM pump on it, which does not have a flex ring.

Ok guys bumping this up. Worked on the machine today.

New turbo is on. We checked all 6 injectors. Engine idling crack each injector line individually and the rpms dropped.

Couldn't get both return lines out of the injection pump but took the top one off (injector return) and looked down in. Clean diesel.

Started the machine and drove down the hill. Ran fine some blue smoke out of the stack. Start back up the hill and the machine starts blowing tons of blue smoke out the breather. Can idle down machine it would stop. Drive 10 feet up the hill it starts blowing out the breather. Blue smoke and looks like maybe some oil

Does this mean we have an internal problem?

With oil smoke after changing the turbo. I think your new turbo is bad. The return line from the turbo has to be unrestricted and about 3/4 inch diameter or the turbo will pass large quantities of oil into the intake manifold. If the return line is unrestricted try swaping the old turbo back. Once I replaced the turbo oil return line with a smaller metal line because I thought the hose looked ugly. I found a small reduction in diameter causes oil consumption.

Well pulled the cylinder head off today. 1 piston melted pretty bad, hole in it. That explains our excessive smoke. Two other pistons have minimal damage on top. Prolly change 3

Can I buy just 3 pistons and sleeves or do I have to buy a whole set?

Your best purchase is an in frame overhaul kit. Individual sleeve, piston and ring kits are available for $213. There are deep and shallow dish piston designs and there are two main and rod bearing designs. When I was trying to locate main bearings for my motor I found that the main bearing set has been discontinued. I purchased a dealers remaining inventory. I have main bearings and rod bearings for sale. When you purchase the in frame overhaul kit and if the seller can not supply the bearings send me a PM I have the bearings in most sizes.

welp we pulled the 3 pistons and noticed the rod bearings had excessive wear, so we decided to do the whole motor in frame.  knocked out all 6 sleeves yesterday and appears the previous rebuild only changed 2, 4 are still original.