Hi Y'all! I finally got around to replacing ( well, at LEAST starting to! ) the valve cover gaskets on my '87 F250 420 cu." diesel (sans turbo) heretofore known as "teacher" (derived from my handle- "Learner").
Background:
I knew from a compression test that my "teacher" had a geriatric heart, compression #'s being low @285-315psi on cyls. 2-7, with #1 reading a complete ZERO!
Forewarned is forearmed.
Todays data:
Starts fairly easily on the first try- settles to 850rpm
Exhaust is clean enough on cold start-up (24deg. F. this morning) UNTIL the glow plugs stop cycling, then gets a bit thicker while idling 'till it steps down from high idle, when it gets even worse, running a teensy bit worse still, blueish cloud drifting slowly away in the air. An obvious but livable "chuffing" (not sharp enough to call it a "popping" ) sound in the tailpipe also follows this pattern.
Sorry for the digression, but I'm SURE all of this info is helpful for any who wish to help.... BACK to the valve cover!!--
Since #1 cyl. is my WORST case, I peel the curbside cover first. BTW- WHAT A PIECE OF CAKE this ol' truck is to work on!-- and start to check the valve train for problems. AKA "LESSONS" for LEARNER. # 1's intake rocker was floppin' around, and the pushrod with it seemed to have fallen past the lifter.. I checked the pivot bolts tightness finding the EXHAUST
nice an' tite, and the INTAKE seemed to be until I tested it in a CCW direction, when it let loose sharply but a bit too easily for my liking. Sleuthing on I go ahead an' remove both rockers AND pushrods so as to F.I.T. things slowly by hand. ( I'm a VERY sensory-oriented learner, hands-on and more situation-aware than most. Scents and sounds and physical vibrations are equal in MY toolbox.) The intake pushrod was visibly deeper in the block than the exhaust, so I CAREFULLY did a thorough see-how-this-might've-happened bunch of experiments, first fitting the int. rod into it's lifter pocket, something's not normal, I can CLEARLY feel the lifter spring rebounding roughly, as if it was devoid of oil ( see the ?'s forming in my head yet? No comparison to the exh. rod, which started out where it should'a been, dropping smoothly into the lifter, where it stops solid, telling me ITS full of oil. I can also pull the ex. lifter up ( smoothly ) by the rod-and-oil vacuum bit- not so the int. lifter. Inspecting both rods reveal they're both un-straight, exh. wear is visibly age-appropriate on the ball ends, but INTAKE rod is 2-3 times more un-straight, and also has copper sub-plating showing on the LIFTER end, and looking like it's been bouncing around loose for quite a while, with severe impact dents and ring-shaped grooves in many places along it's length. Next trick I performed?- I took my smallest rubber-tipped air nozzle, fitted my 24" extension wand, and proceeded to blow out all the engine oil in the head, pushrod holes, and lifter crowns well enough to look down in there for more visual clues. Exh. lifter appears normal, Int. lifter looks odd- so I grab a VERY stiff hunk of hardened rod- 3/32" or so, rounded the end, and GENTLY guided it down into the Int. lifter crown, feeling it landing slightly softer, then suddenly dropping past some shoulder deeper into the lifter body, (WTHWT? What The **** Was THAT? ) ending up on the spring-loaded guts, where the same amount of spring-return is waiting to tease my diagnoser. I SUPER-CLEANED that hole/lifter with a clawgrabbing tool ( ALSO an excellent teeny-solvent-laden-sponge holder) and saw that the lifter crown pocket was completely NON- semi-spherical in shape, -the case hardening GONE- to reveal a deep and oddly
yellowish "cavity". Probing with the rod-tool verified what my eyes were doubting, I can't recall EVER seeing lifter wear like this, certainly never on the TOP of the lifter where everything is spherically fitted together. I've been ALL THE WAY through a BROAD variety of engines in my 58 years, and can only recall cam-to-lifter wear situations where a WHOLE was created in the lifter BASE by shear friction, and the usual collapsed lifter collection. Learners Learn.....
And to that end- on to my TRUE request-I'm hoping for a true class-in-session lecture to explain what I've found, and even more critical to ME- how to fix it BEST.
After dinner/ posting/ referring to my $180 ( FRIKKEN OUCH! ) Navistar ENGINE ONLY manual ( IHC part# : CGES-340-3 ) for a few hints as to what observations may prove more result-gathering, I'll TRY to upload photos to match.
P.S. & FYI:
I'm actually VERY glad I bought that manual- The IHC parts guy (Charlie in Sparks, NV. shop ) was MORE than correct about the engine serial #'s being -CRITICAL HERE- GROUPED and/or SEPARATED in MANY different ways because of all the production/application, mid and 2/3 year and ECO's (and I'm guessing here--atmospheric, political, religious or whatever-you-feel-like-calling-it) changes that happened to the '87 6.9L ALONE, and ALL are all listed, and even include light/heavy/industrial AND MARINE categories throughout the pages. Only a true 6.9L FREAK of a FAN ( I'm not there YET, but I AM walking that direction!!
( IDIot- watch y'er 6!)) or the poor ******** in the BIG shops would truly appreciate the depth, detail, and completeness of this book.
I hereby offer to share any details therein with anyone in the group. Us '87 owners are unknowingly parked in a VERY tight space in our own little cloud of changes.... I aim to help us all stay out of trouble when it comes to the nitty-gritty we stepped in when we bought our trucks.
Background:
I knew from a compression test that my "teacher" had a geriatric heart, compression #'s being low @285-315psi on cyls. 2-7, with #1 reading a complete ZERO!
Forewarned is forearmed.
Todays data:
Starts fairly easily on the first try- settles to 850rpm
Exhaust is clean enough on cold start-up (24deg. F. this morning) UNTIL the glow plugs stop cycling, then gets a bit thicker while idling 'till it steps down from high idle, when it gets even worse, running a teensy bit worse still, blueish cloud drifting slowly away in the air. An obvious but livable "chuffing" (not sharp enough to call it a "popping" ) sound in the tailpipe also follows this pattern.
Sorry for the digression, but I'm SURE all of this info is helpful for any who wish to help.... BACK to the valve cover!!--
Since #1 cyl. is my WORST case, I peel the curbside cover first. BTW- WHAT A PIECE OF CAKE this ol' truck is to work on!-- and start to check the valve train for problems. AKA "LESSONS" for LEARNER. # 1's intake rocker was floppin' around, and the pushrod with it seemed to have fallen past the lifter.. I checked the pivot bolts tightness finding the EXHAUST
nice an' tite, and the INTAKE seemed to be until I tested it in a CCW direction, when it let loose sharply but a bit too easily for my liking. Sleuthing on I go ahead an' remove both rockers AND pushrods so as to F.I.T. things slowly by hand. ( I'm a VERY sensory-oriented learner, hands-on and more situation-aware than most. Scents and sounds and physical vibrations are equal in MY toolbox.) The intake pushrod was visibly deeper in the block than the exhaust, so I CAREFULLY did a thorough see-how-this-might've-happened bunch of experiments, first fitting the int. rod into it's lifter pocket, something's not normal, I can CLEARLY feel the lifter spring rebounding roughly, as if it was devoid of oil ( see the ?'s forming in my head yet? No comparison to the exh. rod, which started out where it should'a been, dropping smoothly into the lifter, where it stops solid, telling me ITS full of oil. I can also pull the ex. lifter up ( smoothly ) by the rod-and-oil vacuum bit- not so the int. lifter. Inspecting both rods reveal they're both un-straight, exh. wear is visibly age-appropriate on the ball ends, but INTAKE rod is 2-3 times more un-straight, and also has copper sub-plating showing on the LIFTER end, and looking like it's been bouncing around loose for quite a while, with severe impact dents and ring-shaped grooves in many places along it's length. Next trick I performed?- I took my smallest rubber-tipped air nozzle, fitted my 24" extension wand, and proceeded to blow out all the engine oil in the head, pushrod holes, and lifter crowns well enough to look down in there for more visual clues. Exh. lifter appears normal, Int. lifter looks odd- so I grab a VERY stiff hunk of hardened rod- 3/32" or so, rounded the end, and GENTLY guided it down into the Int. lifter crown, feeling it landing slightly softer, then suddenly dropping past some shoulder deeper into the lifter body, (WTHWT? What The **** Was THAT? ) ending up on the spring-loaded guts, where the same amount of spring-return is waiting to tease my diagnoser. I SUPER-CLEANED that hole/lifter with a clawgrabbing tool ( ALSO an excellent teeny-solvent-laden-sponge holder) and saw that the lifter crown pocket was completely NON- semi-spherical in shape, -the case hardening GONE- to reveal a deep and oddly
yellowish "cavity". Probing with the rod-tool verified what my eyes were doubting, I can't recall EVER seeing lifter wear like this, certainly never on the TOP of the lifter where everything is spherically fitted together. I've been ALL THE WAY through a BROAD variety of engines in my 58 years, and can only recall cam-to-lifter wear situations where a WHOLE was created in the lifter BASE by shear friction, and the usual collapsed lifter collection. Learners Learn.....
And to that end- on to my TRUE request-I'm hoping for a true class-in-session lecture to explain what I've found, and even more critical to ME- how to fix it BEST.
After dinner/ posting/ referring to my $180 ( FRIKKEN OUCH! ) Navistar ENGINE ONLY manual ( IHC part# : CGES-340-3 ) for a few hints as to what observations may prove more result-gathering, I'll TRY to upload photos to match.
P.S. & FYI:
I'm actually VERY glad I bought that manual- The IHC parts guy (Charlie in Sparks, NV. shop ) was MORE than correct about the engine serial #'s being -CRITICAL HERE- GROUPED and/or SEPARATED in MANY different ways because of all the production/application, mid and 2/3 year and ECO's (and I'm guessing here--atmospheric, political, religious or whatever-you-feel-like-calling-it) changes that happened to the '87 6.9L ALONE, and ALL are all listed, and even include light/heavy/industrial AND MARINE categories throughout the pages. Only a true 6.9L FREAK of a FAN ( I'm not there YET, but I AM walking that direction!!
( IDIot- watch y'er 6!)) or the poor ******** in the BIG shops would truly appreciate the depth, detail, and completeness of this book.I hereby offer to share any details therein with anyone in the group. Us '87 owners are unknowingly parked in a VERY tight space in our own little cloud of changes.... I aim to help us all stay out of trouble when it comes to the nitty-gritty we stepped in when we bought our trucks.
