Stupid needs help-rebuild barely runs!
 

The rebuilt engine in my 82SD barely runs! I'm fairly certain its related to the fuel not igniting and/or not delivering properly. Maybe the fuel is so bad even though it looks and smells normal, maybe I have air coming in that I can't see (all filters are new) or maybe there is something major wrong with the IP. Valve and IP timing are where they should be, unless I have IP off by 360 degrees. Like I said, STUPID

Pete,

How do you know the IP is timed correctly? Did you do a drip test?

P E H

yes, I did do a drip test, following the procedure proscribed in the 617 FSM, using an overflow tube I fashioned from a spare injection line. The transition from a small stream to a 1 Hz drip is very distinct. This is at 24 degreees BTDC

I read here of an injector test. Remove all injectors, reinstall the injector lines, so that the injectors face away from the engine and tighten them up.
Have someone crank the engine while you check the injector spray pattern. (cover up all paintwork and don't smoke while doing this)
If they spray a fine mist then they should be OK.
Have you checked Valve timing?

Injectors were tested by a good local Bosch trained shop before I installed them, all good patterns and opening between 132.7 and 136 bar. Valve timing is 10 degrees as measured by 2mm valve lift off #1 intake

[QUOTE]Originally posted by TonyFromWestOz
I read here of an injector test. Remove all injectors, reinstall the injector lines, so that the injectors face away from the engine and tighten them up.
Have someone crank the engine while you check the injector spray pattern. (cover up all paintwork and don't smoke while doing this)

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And if you do this test, stay away from the business end of the inj. as this harmless looking spray can inject fuel deep into ones skin. I think I remember the cure being amputation of the affected body part ! :eek:

Pete,

If you take the injectors out, do a compression check just to make sure the engine is timed right.

I don't think its the Diesel fuel. I have used fuel oil that was more than 10 years old and it ran just as good as new fuel.

Did you check the fuel strainer in the fuel tank to make sure its not plugged?

P E H

" I have used fuel oil that was more than 10 years old ....." --PEH

Now why does this not surprise me ?

Leather,

What would you have done with the 10 year old fuel?

P E H

easier way to see if fuel is being delivered is take out the glow plugs. crank the engine. you should see a good puff of atomized fuel out of each glow plug hole. if you get good puffs, its not delivery...

Pete, I'll just take a stab at this one because I'm not sure how it runs or if it just idles.

I would not think that it could run at all under this condition, BUT:

Is is possible that the pump is delivering on the exhaust stroke at 24 degrees BTDC? I would think that this would be almost impossible because it probably would not start, but, like I said, just a stab...........

We need to get this machine running by Sunday:D

I don't see how the engine could possibly fire on the exhaust stroke. You need compression to create heat to ignite the fuel. With the exhaust valve open there is no compression, thus no heat. And on the next storke, the intake valve is open, so again, no compression.

P E H

"This is at 24 degreees BTDC"
OK,,,, you are sure this is Before Top Dead Center on the Number one cylinder Compression stroke ?

You must go to Ground Basics since you are dealing with a newly rebuilt engine.... you can not assume anything given it is not working as you expected it to... Try to get to NO ASSUMPTIONS as to the rebuild and check everything... and do it fast if it has to be ready by Sunday..... :D

PEH, I would add small amounts to known new fuel and use it up... or use it to start bonfires of dead limbs.

Thanks everyone, I think I know what the problem is, hopefully I can confirm it tonight. It looks like the IP is 180 degrees out of phase with the cam. I tried to check the timing last night and it seems that fuel delivery begins shortly before the #1 intake opens, which is actually at the exhaust stroke like Brian said. This is NFG of course, it must start to inject before the stroke where both valves are closed. The reason I'm not exactly sure is the hand pump is so leaky that I can't seem to get any pressure to keep a stream going from the overflow tube while I move the crank. Also, for obvious reasons, I'm doubting my abilities right now. But, I'll try to get a replacement pump and fix that first, then check again. If it is what I think, I'll pull the IP out, rotate the crank exactly once, then put it back in. Wish me luck, wait, wish me a brain instead.:rolleyes:

This would be very interesting if the engine can run on the residual fuel left over in the cylinder after an exhaust stroke. But, dare I say, not impossible. The exhaust valve should be closing somewhere around the 24 degree BTDC point, so, the fuel would just remain in the cylinder throughout the next intake stroke and then fire on the next compression stroke. Granted, the fire is not going to be very hot but the engine could possibly run on it.