Join Date: Jul 2009
Location: Siler City, NC
Thanked 574 Times in 451 Posts
I finally had time to pull the head off and found exactly as you guys suspected. Fire ring on 5 was blown out by one of the bolt holes, closest to 6. I need some help figuring out what caused this. I plan on bolting down the spacer plate around 5 and checking the liner protrusion again. I don't suspect this will be the problem as the new block was disassembled from a new motor and sent to machine shop for machining before I got it. Could a warped head or spacer plate be the cause? What else should I look for?
The block is eroded on top. Look around each hole, about 1/8" from the edge, you'll see a line in the block. The liner flange wears and drops in the block. Call Cat or a good reputable machine shop and have the counterbores cut. Don't let them cut just one or two, cut them all. They'll also want to set protrusion at .001-.004 but make them cut to result at .005-.006 protrusion. Argue with them and make them do it.
Have head surfaced, and new spacer plate.
While the pistons are out, have a good machine shop cut .080 off the tops. Trust me, you'll thank me later. That's drops the comp ratio from 18.1 to around 16.
2005 250 Super Duty Crew. White and Grey. ARP studs, EGR Delete, and SCT from Vivian. CCV re-route, and 4" Magnaflow turbo back.
Other trucks:1980 KW Ext hood, 1982 Kenworth Cabover Aerodyne (BJ and the Bear) 2000 and 2003 Kenworth W900's. 2003 Pete EXHD. All Caterpillar Power. My 2003 has an MBN I converted to 6NZ. Early 550 file, 211-3025 squirts. 800 cam. Acert twins via custom mount. ARP head bolts.
Transporter and Operator of a Bauer Built Championship Unlimited Tractor Pulling Sled for the United Pullers of the Carolinas, Region IV affiliate of the National Tractor Pullers Association (NTPA), and damn proud of it!!!!