jsh40

lol. actually the old Macks were always my favorite.

I suspect the cause of this problem was neglect on the part of the last tech to work on top end of this engine. I found the injector caps on cyl#5 & #6 not torqued to 45-50ftlbs. #6 had maybe 15-20ftlbs & I suspect that this it what caused the nozzle seal to be blown out. It cooked the orings on #5 also as it was not torqued correctly either. I am very happy not to have to do cam job as $$$$ are tight but I remain causously optomistic about the condition of the cyl. head & particularily #5 #6 injector cups. Still have problem of coolant res. leaking out of overflow cap but engine runs & pulls great with lots o power & no smoke. I have not pulled the y coolant hose off & checked the screen on oil cooler but I suspect this may be problem.

UPDATE: Turns out my chirping sound was #6 injector fire ring blown out(found three little pieces left of it). I replaced all the injectors & engine now purrs & the chirping is now gone. Under load this cylinder was losing compression into the injector cup (made for a real fun time getting #6 out of its hole,took me 2hrs on #6 & the rest I had changed in an hour & half. I am a Peterbilt/KW Tech. currently but I have much experience with all other makes & I very much appreciate the help you guys gave me. If there is anything I can help anyone with please don't hesitate to ask me.I specilize in diagnostics & troubleshooting & am not always right but I offer my opinion to any & all who have questions. Once again thanks for the help & hope I can return the favor. Sincerely, Jim

what is the fix for the chirp. I do believe the cause is one of the lifters rotating in its bore due to sheared locating pin. What is the torque on the injector hold downs,jake hsng & box. Unit also has intermittent loss of power & blueish white smoke pours out. I suspect bad o-rings on injector can cause this, yes?

This engine has JAKEBRAKE housing with JACOBS tags on the housing. This is fuel leaking out of nut not engine oil. Do I not have to remove the Jake housings or rocker shafts to get at these injectors?

Can any one help with some procedure & specs. for injector replace & tune up on 2004 ai 400 engine?

Hello all, I am new to this site & in desperate need of some tech. info for a 2004 ai 400 engine. this unit has a chirping sound that comes & goes & #5 injector line is leaking through the fitting in the head.We replaced the line but now leak has returnned so we replaced line again & still leaks. Next step is replace injector #5 but only makes sense to do all injectors to eliminate any chance of cyl. imbalance issues.Unit is RD tri-axle dump with 300+miles on it. From reading this forum I found out that these AI engines were prone to shearing locating pin off of lifter & letting lifter turn in bore causing cam failure. Also I see there is a servcie bullitain for mounting hardware in valve train. I am a licenced mechanic & also I am ASE certified master truck technician but the problem is I have not worked on Mack since 2001. If anyone can & wishes to shed some light , has an opinion or can help me with some tune up specs.(timming mark location,valve lash settings,JAKEBRAKE lash,torque specs for rack,housing & cover). I am fixing this truck for a friend of mine & it is currently losing $100 an hour sitting & waitning for parts. With any luck I will be able to get it back together Saturday. I will gladly offer my experience & or opinion to any & all who can help out here.