well as some of you know i did a head gasket on the ole 1990 d250 5 speed
due to a blown head gasket and all the oil leaks and trany issues i pulled the motor out ....

so what i did...

bought a head kit from cummins with a 20 over head gasket
upgraded to a 2nd gen head due to cracks in mine
stock I/C injectors
stock valve train from that 2nd gen head
(question dose the 2nd gen head come with big honeycomb exaust springs?)
if not i got those as well
rolled out the main and rod bearings looked great for 500,000
they mic-ed out so i put them back in
had trany rebuilt
clutch was good stuffed it back in
killed KDP
had pump shop look at pump and turn it up to 135cc (stock is 60cc)
installed fule psi gauge (electric)
installed Cyl head tmp gauge (it was free)
replaced main seals
arp studs
and last but not least polished the valve covers


now after all this when i turn the key to start it wont turn over is there something typical that goes wrong here? i did gut out the grid heater stuff in the fender

and at the exaust pipe i get a Jake break noise (pop pop pop) and it gets faster with rpm but its smooth i adj the valves to 10 and 20 ran it got it up to temp with valve covers off re-torqued the head and re did the valves to 10 and 20 is this due to that the freshly ground valves haven't fully seated and iam getting blow by? running it with the covers off nothing looks bent or out of place it all looks to move equally some of the lifters rotate faster than others but that's about it whats wrong?

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well found out that i may have a valve not seating so off to jerk injectors out and fill it with air oh boy

 

ya sounds like something with the valves or lifters

 

The push rods will sit on the edge of the lifters sometimes, They look like they are down all the way but they are not. The best way to tell is after you seat teh rod in teh lifter pull up on it, it should have a sucking feel to it if its seated in the lifter right. I would pull them all out and make sure you didn't bend one.

 

well i pulled the rockers/push rods and shot 150psi of comp air in each cyl no air past the valves and very little around the rings now if the rods are not bent what else could it be?

 

The cam maybe?

 

u might have blown the rings out with the new head bumpin up the pressure

 

not the cam it ran fine when i took it apart 3 weeks ago

what pressure? this thing has only idled and a few free revs in the driveway maby 5min total run time since i put it together

 

If teh rods were not seated right it might not let the valve close.

Have you doen a compression check? How about a cyl leak down test?

 

bolth today good as new

 

is this the head that your machine shop put those "high performance valves" in it? if they grind the valves they have to grind the seats to match. if they didnt do this then it'd sound like a pop... although a leak down test should let you know right away. another thing is a sticking valve? lash way out of adjustment can cause the same sound... rebuilt an old john deer once; there was like a lash cap onto pf the valve. it wound up shattering and causing a "popping" noise on the intake side. i know the cummins doesnt use this but i'm just trying to relate lash problems. although the rod hung up on one of the lifters sounds pretty plausible too bud; a bend rod more likely. take em' out and roll them across a flat surface usually if one bends it's enough to notice