[SMorno75]

I am new to this forum, I have been reading it for a while and would like some feed back to see if I am going in the right direction. I have rebuilt a 6.9, didn't bore the block. I got the engine from a wreckers it looked liked it had recently been rebuilt. I put in new rings, rods, mains and had the heads checked, new valve seals put in and the guides were good. Smokie on start up and the smoke is slightly blueish at idle.
Quick throttle lots of white smoke thinking timing, new injectors, but I am using a 7.3 IP pump. I've been told you can't use a 7.3 pump on a 6.9
is that correct? I am trying to figure out how to clear up the smokie exhaust on idle. I've played with the timing a bit but that doesn't seem to help. Played with the timing arm on the side of the injector pump ie. pushed it in while it was running and it is definitively retarding the timing. Could it be burning oil? Or should I just have it timed? Truck sat for about a year before I got to rebuilding the motor. I put an octane buster in and fresh diesel. Am I forgetting something?

 

[Mr_Roboto]

7.3 pump is fine on a 6.9

White smoke can be caused by retarded timing. Mark your present position and start experimenting. Turn to passenger side to advance.

 

[LMJD]

[ QUOTE ]
I put in new rings,---slightly bluish at idle...

[/ QUOTE ]
Did you use a glaze-breaker (and get the proper cross-hatch pattern) when doing your ring job so they'd seat correctly?

 

[SMorno75]

Mr_Roboto I tried playing around with the timing, advancing it(also jumped cold advance solenoid) noticeable clacking noise increases at idle but still smokes.

LMJD Yes used my handy dandy ball hone got a good cross hatch pattern I think you might be on the right track I have not driven the truck at all, only idled it. was speaking with someone today and break in procedure may be needed.this is my first diesel rebuild and Im finding things are a little different than a gasser rebiuld Truck should be on the road next week will be taking long drives up some mountain passes. hopefully this makes the rings seat up I think. I'll see what happens next week Thank you both for your helpful information.

 

[LMJD]

Please don't take this as correct, I might be thinking of the wrong manual, wrong engine, but I seem to recall that in the 7.3/6.9 engine overhaul section of the Ford manual, they say DO NOT use a "dingleberry" type glaze buster, but use the straight stone type. If you have the Ford manual, you might take a look. With that said, I sure don't know why it would make a difference anyway.

Like you said, I'd sure put some miles on it and give the rings a chance to seat. I can't remember the reasoning behind the theory plus it may be just an old "mechanics' wives' tale", but through the years I've always heard your rings do most of the seating on deceleration like coming down long grades with your foot off the throttle.

 

[sle2115]

[ QUOTE ]
Like you said, I'd sure put some miles on it and give the rings a chance to seat. I can't remember the reasoning behind the theory plus it may be just an old "mechanics' wives' tale", but through the years I've always heard your rings do most of the seating on deceleration like coming down long grades with your foot off the throttle.

[/ QUOTE ]

Not a wives tail at all. Puts back pressure on the rings and less compression pressure. We have a long hill near where I used to work, we always took our new rebuilds around to the top and held them in low gear and down that hill a few times, did wonders for seating the rings.

If you used moly rings, you will most likely never get them seated just idling, they need heat and some pressure, not that I would go run the damnation out of it, but driving it will seat them. Don't lug it, but don't run the daylights out of it either. No synthetic oil for the first few thousand miles either (just in case you were considering it).

 

[Bill1013]

Was 20 yrs. as GF of maintenance on the Ford 460 CID block line. We were very strict on the bore hones especially the crosshatch pattern. If I remember correctly the stones were about 5" long 1/2" wide and 8 stones per hone, that was to keep the cyl. walls as straight and round as possible and with a good figure 8 crosshatch. Depending on how much you honed to break the glaze with that type of hone, and how fast it was turning, ie.(outward pressure) it would be possible to get the bores out of round (limit 0.0003) and/or cone shaped (limit 0.002). When glaze busting a lot of lubricant like mineral seal oil, honing oil or kerosene should be used to keep the stones flushed. You will prolly be OK but may take a long time to seat the rings. A 6.9L 420 CID standard bore is 3.9935 to 4.0015. /ubbthreads/images/graemlins/shrug.gif
You might want to read this: Main Index - TDS.com Archives - More Articles - Feature Articles - Breaking in a Diesel engine . Very interesting.

20 YRS. RETIRED this July but I think I'm right.


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