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Post by wayne83 on Nov 22, 2014 22:51:00 GMT -5
I just got my engine all back together and back in the truck. the cylinders were honed, new rings, main and rod bearings installed and new pin bushings installed. the valves have also all been re ground as well. new injectors and injector pump. the truck runs fantastic and is quite a bit more quiet than it used to be, but it has just as much blow by as before. now I only have drove it about 15 miles so I'm sure the rings are not seated yet, but why would I have so much blow by still? I'm hoping after driving it for a few hundred more miles it'll go away, but it has me a little annoyed currently.
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Post by DieselDangerRanger on Nov 23, 2014 17:21:46 GMT -5
Perhaps there is some out of round in the cylinder bores from unequal wear and it may improve in time as you say. also could valve and guide wear account for some?
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Post by wayne83 on Nov 23, 2014 20:45:26 GMT -5
the machine shop that honed the cylinders said they were perfectly round, but who knows i suppose. the valves themselves have all been re ground so there good to go, but i did not replace the guides, but once again the machine shop who ground the valves said they were still good. Ive drove it some more today about another 30 miles, but it has not got better yet. After i put about 200 or 300 miles on it ill let everyone know if it has got better or not. How would you guys break in a rebuilt engine? I just did as the hastings rings said to, but i ran it on a high idle for about 15 minutes instead of letting it idle for 30 as they wanted, because alot of other diesel forum sites said do not let it idle as the rings need higher combustion pressures for them to expand properly in the cylinder. I then drove it up to 30 mph between 1/2 and 3/4 pedal as it says to do. then i did 10+ times of speeding up from 30 to 50 mph and downshifting back down to 30 then going back up to 50. I have been repeating this basically everytime ive drove it so far, but from other forums they claim it will still take up a couple hundred miles for the rings to seat.
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Post by fatguppy on Nov 24, 2014 13:43:51 GMT -5
It's going to take awhile, if ever. It all depends on the hone and the ring gap. Since it sounds like you just installed new rings and honed the original walls, there is a rough sealing surface for the rings to wear away. This takes time, which is good. Dont try to rush it. The cylinders are very hard steel, which lend to long life because they don't wear. I have always done the initial ring seat, which you described, and then I just drove it around like normal. Change the oil and filter often (1000 miles max), cause you are wearing away metal from the cyl walls. Now, notice I said "if ever". If the original wear to the engine was towards the max limit, you will never get rid of the blow-by. What was the ring gap when you installed the new rings? Also, remember that the rings and the cyl walls will wear a little more on this break in, thus increasing the tolerances, increasing the likely hood of blow-by. More than likely you'll be fine, but like I said, don't rush.
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