Mcrafty1

I don't know that they did any flow testing, I'll have to check and see, thanks for the help....both you and Glenn, I hope to get to the bottom of this before anything happens to this engine. This should help me do that.

Last time I had mine gone over it was around $1600.00 The pump was worn pretty bad though and in need of an overhaul....This is on a 250 econodyne.

No scoring, just melted down over the edge of the piston to the point of breaking the ring and then the ring ledge......the pump was completely gone through when the engine was rebuilt two pistons ago.....and the timing was checked when the engine was rebuilt and possibly when the first piston was replaced....the second time the piston was replaced and the injector in the same hole was replaced but nothing else was done. The fuel is maxed out but as I said in my OP I am very careful of heat, My concern is the fact that its the same hole each time so the over fueling in that one hole is deafinatly a possibility I'd not considered......However I take your an anyone elses info and advise to heart and appreceate any and all input.

Hello all, As stated I'm the new kid on the block. I own a small earth work business in the great state of Maine and own an 1986 Mack RD685S that I use as my primary truck (its my only truck at the moment) and at my age(59yo) I hope to 'finish out" with it. Its a great piece of equipment which I've owned for a dozen years or so and built up to what I have now. Looking forward to reading about and hearing from thuroughbred Mack owners and all others about thier experiences over the years with these truck and will throw in my 2cts when I feel it will contribute to the mix.

Hello, I'm new to the forum.....I have an 1986 maxidyne 250 four valve engine and have (twice now) melted the rear most piston at the ring ledge Same hole both times? the second time I changed the injector although all tested out ok, this was the beginning of last construction season and thus far the problem has not risen its ugly head,,,,, I have a pyrometer and have always been very careful not to exceed the 1050* heat max. and would like some input into this...also like to know if anyone else has experienced this problem....oh, it was an econodyne engine and I did open the fuel up on it a while ago (before the first meltdown) which I don't believe is related...I've been wrong before.