Fishing for some ideas as to what could be wrong...

C

Cord

New member
Joined
Oct 4, 2006
Messages
102
I have a freshly rebuilt motor. 5k governor springs that were installed on the bench (sorry don't know the brand), new marine flycut pistons, balanced rotating assembly, aftermarket cam (sorry, again, don't know the specs), pump was benched and the "barrels were turned", head was ported, decked a second time (.040 cut?) and was cut for fire rings. Obviously I need to get some more specs on exactly what was done to the engine. I had my existing 370 injectors rebuilt and the builder installed them. He also installed the pump and timed it to 20d. When I (finally!) got the engine started it was producing huge clouds of white smoke. Got bad enough that our vision was clouded and we got chased out of the shop. This was with an exhaust fan running. The truck starts really easily, just a quick tap of the starter and it's running. The idle was around 1200 so I adjusted the idle screw to bring it down to 750. Although the truck doesn't have a lope, the engine is very rough. Shakes the whole truck. Almost like a balance issue. As you bring the rpms up, around 1700 or so, the engine starts to break up and pop out of the exhaust. At this time the smoke turns coal black. This is before the turbo can spool. At first we thought maybe the timing had slipped, but it's still at 20d. With the truck idling, I cracked the injector nuts and each cylinder lays down and the idle gets rough. Couldn't really perceive one cylinder being worse than another. Tighten the nut and the idle smooths out, but the shake is still there. Wondering if you guys had any ideas as to what could be wrong?
 
We checked it yesterday and it came in at 19.5 degrees (6 turns on the small dial + 1.75 on the large dial). The builder was targeting 20.
 
not sure what you're talking about w/ large and small dials, but it's displaying symptoms of low timing... you could try a different set of injectors to rule them out, but I'd set the timing w/ plunger lift or spill port method (after finding TRUE TDC)
 
Forrest Nearing said:
not sure what you're talking about w/ large and small dials, but it's displaying symptoms of low timing... you could try a different set of injectors to rule them out, but I'd set the timing w/ plunger lift or spill port method (after finding TRUE TDC)
Click to expand...


Trying to tell you what the dial indicator was reading in case we read it wrong.
 
oh, I don't count turns, I measure plunger lift :o

are you sure you had true TDC or did you just use the pin? did you re-check plunger lift after you locked down the pump nut?
 
I think he means that when you are reading the dial indicator, you have the little small dial that tells you how many full revolutions the big dial has made.

And he was checking plunger lift with the dial indicator.
 
I understand that, but my point is I don't know what dial indicator he was using, if it was standard or metric scale, etc. etc.

you either had the plunger lift measurement right or wrong
 
You must log in or register to reply here.
Back
Top